JPS6252260A - Oil pressure control device for continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent the slipping of a belt and to enable the minimum speed running by controlling clutch torque so as to be less than that capable of being transmitted at the minimum line pressure which is determined only by the spring force of a line pressure control valve when the line pressure control is abnormal. CONSTITUTION:On the oil passage 33 under a reducing pressure at the output side of a reducing valve 60, an oil pressure switch 90 is provided, and when the pressure in this oil passage 33 falls below a given value, abnormal decreases in the line pressure are judged, and when it is abnormal, clutch torque is restricted so as to be less than that capable of being transmitted at the minimum line pressure which is determined only by the force of the spring 43 in a line pressure control valve 40. Thus, since the transmission of engine output is reduced by the slipping of the clutch, the slipping of a belt is prevented, enabling the minimum speed running of a vehicle.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a hydraulic control device for a belt-type continuously variable transmission for use in a vehicle. In a hydraulic control system that operates valves and controls them electronically, it relates to a valve failure in response to an abnormal drop in line pressure, etc. Regarding this type of URA H [speed change control], for example, it is disclosed in Japanese Patent Application Laid-Open No. 55-65755. One basic hydraulic control I
There is a system. The gear ratio control valve is operated to balance the gear ratio control valve based on the factors of accelerator depression nt and engine speed, and the gear ratio is determined based on the relationship between the two, and the gear ratio is controlled. In addition, since pushing the pulley necessary for torque transmission requires 1q of force, the pressure regulating valve is operated depending on the I creel depression amount and the gear ratio, and the line fluid 1. ! I
III. By the way, according to 1-2, in the case of shift 1ii control, the speed of change in the gear ratio (hereinafter referred to as the shift speed) is uniquely determined, so for example, the change in the gear ratio In a transient state with a large value, shortcomings in response, hunting, and A-bashoot occur.Also, regarding line pressure control, the characteristic ↑4 is uniquely determined, making it difficult to take various conditions e1 into consideration. Therefore, in recent years, when speed control or line n: control is required, electronic control is performed taking into account J3 and C1 various conditions and elements to perform optimal continuously variable speed control.

[There is a tendency to try. [Conventional technology]

Conventionally, in the electronic control of the above-mentioned continuously variable transmission, -C regarding line pressure control is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-161347.
There is a prior art in Japanese Patent Publication No. 2003-11002, which shows that the line pressure can be controlled in relation to engine torque, etc.

[Problems that can be solved by the invention]

By the way, the above prior art in 11- above is applied when the line pressure control is performed normally, and cannot be used when the line pressure control becomes abnormal, especially when the line pressure becomes abnormal. An abnormality occurred in the control and the line pressure IK
If normal dynamic transmission is carried out in such a low state, serious damage such as belt slip may occur.Therefore, the C line pressure control system must be It is necessary to have a fail t?-7 means for the case, and it is also desirable to make the vehicle runnable at the minimum.The present invention has been made in view of the following points: - It is an object of the present invention to provide a hydraulic control device for a continuously variable transmission that is capable of preventing bell 1 to slip and keeping the vehicle in a state where it is possible to keep the vehicle running at a minimum level in the event of a control abnormality.

[It's here. Means for Solving Problem 1] 1-In order to achieve the object 1, the present invention provides a system in which a solenoid valve always generates a constant pressure on the base 1F of the redecorsing fi table by an electric signal. , in a hydraulic control system that controls line pressure by applying the decouture pressure to a line pressure control valve, 1- EQ it a hydraulic clutch in the oil passage of reducing 1f to detect an abnormality in line pressure control;
In the event of an abnormality, the clutch torque is limited to several dozen IK torques that can be transmitted at the lowest line FF determined only by the line pressure control valve's sling force. [Function] According to L4 in the configuration 1, an abnormal drop in the line pressure that changes depending on the gear ratio can be detected by using the hydraulic clutch to detect the drop in the constant reducing pressure generated using the line pressure. It will be easy to judge. When this abnormality occurs, the clutch torque can be transmitted at the lowest line pressure.
By limiting the engine power to less than 100 lbs., the transmission of engine output is reduced due to clutch slippage, preventing belt slippage and making it possible for the vehicle to run at a minimum. [Example 1] Hereinafter, an example of the present invention will be described based on the drawings. Referring to FIG. 1, the outline of the control system according to the present invention will be explained. First, as a transmission system, an engine 1 is connected to a main shaft 5 of a continuously variable transmission 4 via, for example, an electromagnetic clutch 21 and a forward/reverse switching device 3 capable of controlling clutch torque. The continuously variable transmission 4 has a subshaft 6 arranged parallel to a main shaft 5, and a
A primary pulley 7 is provided on the shaft 5, a secondary pulley 8 is provided on the acid 1 shaft 6, and a drive belt 1 is provided on both pulleys 7.8.
1 is wrapped around it. Each pulley 7.8 has one fixed side and the other 7J moves in the axial direction to make the pulley interval variable, and has oil IF cylinders 9, 10 on the movable side. Here, the primary cylinder 9 has a larger receiving 11 area than the secondary printer 10, and the primary pressure is used to change the diameter ratio of the winding f and opening of the drive belt 11 to the pulley 7.8. Continuously variable speed 1j
I'm here. Further, the subshaft 6 is connected to the output shaft 14 via a set of transmission gears V/12.13, and the drive gear t of the output shaft 14 is
715 is Final Gil'16. Differential gear 11. Power is transmitted to drive wheels 19 via an axle 18. The continuously variable transmission vs4 has a hydraulic circuit 20. It has a control lI unit 70 and controls the line pressure from the unit 10. The hydraulic circuit 20 is activated by the y′]-D signal for gear change speed control.
The structure is such that the hydraulic pressure of each cylinder 9.10 of the psi 7 and the cylinder 9.10 is controlled by &IJ m. In FIG. 2, the hydraulic control system including the hydraulic circuit 20 is explained. It has an oil pump 21 driven by the engine 1, and the line n oil passage 22 on the 01 output side of this A oil pump 21 is connected to the secondary cylinder 1. (), and the line I control valve 40 is passed through u1 to the transmission control valve 5.
01. This variable) * speed [α control valve 50 communicates with the oil path 2;
Route 24 is! Rai 7 Rishi ring 9, 4 r is completely 1
1. Prevent air from entering. The 1172 oil passage 271J from the control valve 40 connects the 1-precision valve 213 to the
A loaf is produced, oil path 27 glue 1-brino l, ishi:]
The -1-stream side of the engine valve 28 communicates with the oil passage 2 to the primary cylinder 9 via the lubricating nozzle 29.43 of the drive belt 11 and the Brinor ring valve 30. The in-pressure control valve 40 has a valve body 41, a spool 42, a spring 43 which is biased by fNl on one side of the spool 42, and the spool 42 transfers the bow 1-41a of the oil passage 22 to the bow 1 of the drain oil passage 27. ) 1 letter
c': I'm so excited. The opposite side of the spool 42 of the ring 43 is the adjustment screw 44 tC1' rl
/11 It is received by the screw 45, and the set load of the spring 43 is adjusted to account for the variations in each part.
The relationship between L and line pressure is adjusted according to the adjustment function. In addition, the line fr is opposed to the boat 41C+, 11 on the opposite side of the spring 43 of the spool 42, and the oil passage 36 branching from the oil passage 22 is connected to the boat 41 on the side of the sl ring 43. (1 has oil passage 37 [, 2 e] line 11
The control river f'-L-lie 1 [is higher than line 11 - 46
It acts in the direction of L/T. This gives -fin cat [)
, its effective area SL, lj': L-T If, P(1
, effective area Sd, sl ring?・11・1jIS
Between Ban, East, the following relationship is established\'t-=j. F s + P d ・Stl = PL −SLP
L (P d ・Sd LL' S ) /
S L- From this, the line R1)L is the data l-
Di1f[) (1 to λij l) proportional relationship)
controlled by The speed change control valve So has a valve body 51. 1m of spool 52
The oil supply 4 connects the boat 51a of the oil passage 22 to the boat t-51b of the oil passage 23 by moving the 11 stones of the slew 52.
The operation is between the CI position and the JJI Hb position where 511+ to the boat 1 is connected to the boat 51c of the drain f+I+ path 24 so that the operation C is <T. Boat 51 (1) at the end of the oil supply side of the spool 52 (: J to L1 oil v853, a constant reso l-lung F1- acts on
1c, the oil passage 54 is operated by a day 1 filter for good control of the speed change, and the valves 1 to 51e are operated by a spring 5 for initial setting in the oil passage 52.・1
It is strong. Here, the duty sweat is the same r as the reducing pressure PR.
+ varies between force and zero (there is a τ of 0 that changes l-, this on/
'By changing the A ratio (decoration ratio), refueling and
The inflow and outflow flow rates of the oil change over time, making it possible to control the speed change. That is, the shift speed di/dt4, the primary cylinder 9
(7) Flow It Q (f> fill number r a n
, flow rate Q lit :j'' :t-7-iIf: l
”). Since the line LL [)L is a function of the brine pressure [)1), the following equation is formed)”I. di, /+lt= f(Q) = f(r), PL
, Pp) where the line I[1)l- is the gear ratio i,
-Controlled by engine torque, primary pressure P
Since p is determined by the line LEPL and the gear ratio i, di,
/dt= f (D, i) roar. On the other hand, strange) *
Since the speed change/dt is determined based on the deviation of the target -〇- speed change ratio IS in steady state 'r' M IP i , the following equation holds true. (I l / (mouth=l<(is-i)) From this, at the actual speed ratio 1, L: standard speed ratio is is determined and C
If the shift speed di/dt is determined and C is done, then the shift speed di
The f coati ratio can be found from the relationship between /dl and the gear ratio i. Therefore, with this duty It, n, the speed change old control well 50
If you operate it, the entire gear shift range will change to 3I! Speed 1 (controls 1
I know that I will do this. Next, the circuit for generating the duty cycle for controlling each of the ten valves 40 and 50 will be explained. First, an oil passage 31 branches from the line pressure oil passage 22 as a circuit for obtaining a constant base J.
2 to communicate with the reducing valve 60. Reno 4I-Singmei fi OLL N valve body 61.
The spring 63, which is applied to one side of the spool 62° spool 02, is connected to the oil passage 31.Pass 1-1 Boat 61a, Exit boat 61F+, Drenbo)-61
The reducing pressure oil passage 33 from the outlet (boat 61) communicates with the boat 61d on the opposite side from the spring 63 of the spool 62. Also, the block 64 that receives one of the springs 63 is adjusted. The spring load can be changed by moving the screw, and the reducing pressure can be adjusted. In this way, the line pressure is supplied to the boat 61a while being limited by the A refit 32, and the one-node coursing pressure of the reducing single oil passage 33 is applied to the lower hand 16 and the spring 631. ':J, Lisbourg 62 communicates bows 1-61a and 61b and introduces line pressure. When J, the spool 62 is returned by the hydraulic pressure of the boat 61d to connect the boats 61b and 61c and reduce the reducing pressure.By repeating this operation, the reducing pressure is reduced by 1ζ. While replenishing the no line Jf, a constant reducing pressure i+F is applied that matches the setting of the spring 63. The reducing pressure oil passage 33 is a line ``-''.
The oil passage 37 is in communication with the control solenoid valve 65 and the Aki 1 Muletaro 6, and branches from the downstream side of the orifice 34 in the middle of the reducing pressure oil passage 33. In this way, on the downstream side of the A refit 34, the solenoid valve 6 is
5 intermittently presses a constant reso 1-single to generate a pulsed oil 11 (), which is smoothed by the fluctuator 6 to produce a predetermined level of data 2-te (Jl).
- and I', J2-1- are supplied to the line pressure control valve 40 by the theme pressure oil passage 37. The oil path 53 branches from the oil VfI 53
It branches off in the middle of j' +-17/A change 3 on the downstream side of oil passage 54 A refurbishment 35! ! The solenoid valve 67 for controlling smallpox is in communication. In this way, a constant reducing pressure is supplied to the speed change control valve 50 through the oil passage 53, and furthermore, the iL-T signal is transmitted on the downstream side of the A refit 350. The solenoid valve 61- is configured to drain oil in the case of A of the gen[-tee signal. The larger the duty ratio is, the smaller the duty ratio is. This results in a characteristic that changes linearly as a decreasing function for the duty iL. On the other hand, the solenoid 5P67 has a similar configuration, and )ru I
If the duty IL is large, it takes a long time to switch the speed change control valve 50 to the oil supply position (upshifts, and vice versa, the time to switch to the υ1 oil position increases and shifts down. >The larger the deviation, the larger the change in the duty IC, and the greater the shift speed for upshifting or downshifting.Furthermore, in Fig. 3, regarding the electric control system including the control unit 70, 8) , primary pulley rotation speed hinge 71. Zekanda pulley rotation speed sensor #f7
2. Throttle opening degree sensing13. Engine speed 1? These sensor signals are input to the IIIM unit 70. In the control unit 70, the speed change control system will be explained. Rotation signals @Np, Ns from both pulley rotation speed sense lift 1.72 are inputted to the actual speed change ratio calculation unit 75 and C, i
, N11/NS to calculate the actual gear ratio i. Also,
The signal NS from the secondary pulley four-rotation sensor 12 and the signal θ from the throttle opening sensor 13 are input to an 11-speed gear ratio search section 76 . Here, a table of N6-θ is set based on the shift=13-pattern, and iS is searched from the first shift of NS and θ of this daple. Then, the actual gear ratio i of the actual gear ratio calculation unit γ5, the target gear ratio is of the target gear ratio search unit 16, and the coefficient of the coefficient setting unit 77 are input to the gear speed identification unit 78, and the old /C Due to low k(is-i), the speed change speed (I i / (1(
, and determine shift 1-down or shift-up using the sign 8 on the right side. This speed change control system 78
The transmission speed di/dt and the actual transmission ratio i of the actual transmission ratio calculation section 75 are input to the duty ratio search section 79. Here, due to the relationship of duty ratio D = f (old/dt, I), the daple of duty ratio is di/dL-1
The duty ratio D is searched from this table, and this duty signal is input to the solenoid valve 61 via the drive unit 80. Next, to explain the line pressure control system I, the signal θ of the throttle opening sensor 73 and the engine speed sensor 1
The signal jt Ne of 4 is input to the engine torque calculation unit 81 and the engine torque is calculated from the table of −(“, Ne−〇. On the other hand, the actual speed IL from the actual gear ratio calculation unit 15 is
Parked at
~ Calculate the necessary mosquito line FF f] L L+ per torque, and calculate the torque line FF f〕L L+ per torque.
Ll) L ・ 1 (, 2, ", s 1 eye fbanon I'
E l) Leave the house. The output PL 1.15'' of the 1 mark line If output section 83 is 1.15''. This del −i−, (It: I) signal is
Drive I Jfft 8! 1 is input to the solenoid valve fMi at fF1. On the other hand, if there is a failure [de-) at the time of line pressure control abnormality,
An oil pressure switch f-1 is installed in the oil passage 33 of the 1-node coursing pressure on the output side of the reducing valve 60, and the output of this oil pressure switch f-1 is input to the line pressure abnormality/low/low determination section 91, and the output is inputted to the line pressure abnormality/low/low determination section 91. If the line pressure drops to the hand, judge whether the line pressure is abnormally low. Electromagnetic clutch 20 control system (1222 rotations 1
-Start detection section 9 using 6 signals VJNe and θ at 1 liter level
Second, the clutch direct connection portion 93 is activated by the signal Ns of the secondary brake rotation speed. And Konera is performance club 94
Determine the foot current, and this current is the driving current.
The j part 95 is supplied to the clap contact f = 1 2a, and the clap contact -1 Takekawa J is supplied. Now, a clutch torque limiting section 96 is added to the output side of the drawing section 94, and the output color V>7+/) of the abnormal line pressure drop determining section 91 is limited. (In other words, if there is an abnormality in line pressure control,
valve 6j) (, -5J, ru) I-b line I'F, f
J to still valve 40, the line pressure is spring 4
3 only, the Rk low lining pressure PN shown in Figure 4
In addition, the sound/speed ratio when the medium runs at a minimum (as it is the maximum, the transmission from Bell 1 to part)
tl~l talc low line month, ``maximum change'', unformed 03. Also, Yl-,), -1 clutch 1-luke is limited to less than this transmission i-luke t). A1, 6If of the spring 43 of the line pressure control valve 40
The width is set so as to obtain the minimum line pressure of 1/2 to enable running of medium thickness.Next, we will explain the operation of the hydraulic control device configured as shown in Fig.4. The A oil pump 21 is driven by the operation of , and the input Ff of the oil passage 22 is supplied only to the secondary cylinder 10, and the C1 speed IL is at the maximum I1 (speed I).At this time, the reducing cylinder to which line pressure is supplied j
'i' li I) (・-1■, resulting in a reducing 1[ of the lead Ii2, which causes each solenoid valve 6!i,
67, due to ',/' - (JT is not suitable for cattle handling. Therefore, when you step on the accelerator at the time of starting, control: I unit 70, C low gear shift IL changes the line pressure setting section. 82, the line pressure is set too high, and the engine torque output section 81 also outputs a large amount of engine torque, so that the target line n of the target line pressure calculation section 83 becomes large.At this point, the due-eye ratio is set. In the section 84, the solenoid valve 65 is operated at this data L-ter ratio, which corresponds to a small duty ratio.
), the amount of oil discharged is small and a high level of pressure is generated, which causes the boat 41d of the line control valve 40 to
By introducing this into the system, the line pressure can be set high. After that, when the shift is started and the actual gear ratio i becomes small, or the engine torque l- becomes small and the target line pressure &j is reduced, the solenoid valve changes. 65 IJI oil suspension is increased to lower the duty compound. Therefore, the line pressure in the line pressure control well 40 is set to higher values in sequence. Then, this line pressure enters the secondary cylinder 10 and acts on the pulley 8, which causes the block to be pressed (maintained) in accordance with the transmitted torque. or the line pressure relief valve 4() is closed to the line F due to an abnormal decrease in the duty ratio due to the reducing pressure.
1- in the direction of decreasing, this is detected by the oil pressure switch 90. Then, the clutch torque limiter 96 uses the output signal of the line pressure abnormality drop determination section 91 to
The torque of clutch 2 is transmitted at the lowest line pressure and the highest gear ratio! The torque is now limited to F less than the torque. Therefore, the engine output is reduced by the slippage of the clutch 2 and inputted to the primary pulley l, thereby preventing bell slip after an abnormality occurs. By transmitting power using the clutch 2 within a range smaller than the transmission torque J of the belt portion, it is possible to run the vehicle to the minimum possible level without causing any sagging to the belt. The above description has been made regarding one embodiment of the present invention, but the present invention is not limited thereto. [Reno Effects of the Invention] As we have seen for the past few years, according to the present invention, the clutch is activated when the line pressure is all + abnormal. - Since belt slip is prevented by limiting the torque, damage to the belt etc. can be avoided. Since the vehicle is in a minimally drivable state, it can be driven on its own and headed for repairs. Since a constant decrease in reducing pressure is detected, the structure of the oil pressure switch is only 0 (1).

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an embodiment of the hydraulic control all device of the present invention, Fig. 2 is a circuit diagram showing the hydraulic control system, and Fig. 3 is a dimensional diagram showing the electric control system. Figure 4 shows line pressure characteristics 1
) Figure 1. 2...Electromagnetic clutch, 4...Continuously variable transmission, 40.
...Line pressure control valve, 60...Reducing valve, 6
5... Solenoid valve, 70... Control: J leek [...
90... Oil pressure switch, 91... Line pressure abnormal drop determination unit, 96... Clutch 1 herk limiter. ,

Claims (1)

[Claims] Hydraulic control in which a solenoid valve generates a duty pressure that corrects the reducing pressure based on an electric signal using a constant reducing pressure as a base pressure, and controls the line pressure by applying the duty pressure to a line pressure control valve. In the system, a hydraulic clutch is installed in the oil path for the reducing pressure to detect an abnormality in the line pressure control, and in the event of an abnormality, the clutch will reduce the torque below that which can be transmitted at the minimum line pressure determined only by the spring force of the line pressure control valve. A hydraulic control device for a continuously variable transmission that limits torque.