JPS61112859A - Lock-up control device of power transmission device with non-stage speed change gear - Google Patents

Abstract

PURPOSE:To save memory capacity of data by controlling rotating speed of a rotating member between a non-stage speed change gear and a fluid transmission device and engaging and disengaging of a lock-up clutch based on an engine load. CONSTITUTION:An input side rotating angle sensor 64 detects rotating speed Nin of an input side sheave 2a, that is turbine rotating speed of a fluid joint 12, and a throttle opening sensor 36 detects suction throttle opening theta as an engine load. A switching rotating speed calculating means 368 calculates rotating speed of the input side sheave Nla at the time when a lock-up clutch 22 is switched from OFF to ON and rotating speed of the input side sheave Nlr at the time when the lock-up clutch 22 is switched from ON to OFF based on the suction throttle opening theta. Then, a solenoid valve 100 is switched by a lock-up clutch switching means 370.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a continuously variable transmission (hereinafter referred to as "C") in an engine power transmission path.
vT”. ), a fluid transmission device such as a fluid torque converter or a fluid coupling is provided upstream thereof, and a lockup clutch is provided in parallel with the fluid transmission device.

BACKGROUND ART A lock-up clutch of a power transmission device with a CVT transmits engine power without going through a fluid transmission device.
It has the role of avoiding transmission loss in fluid transmission devices,
Further, the lock-up clutch is engaged in a driving range where drivability problems such as vehicle surges and jerks can be avoided. Such an operating range is defined by, for example, the intake throttle opening and the rotation speed of the output member of the fluid transmission device, but in conventional lock-up control devices, for example, the turbine rotation speed is defined as the rotation speed of the output member of the fluid transmission device. Vehicle speed V and CVT gear ratio 1” (
r = Ntn, /N.

ut: However, Nin1NOut is calculated from the input and output side rotational speeds of the CVT).In other words, the vehicle speed is determined as a function of the turbine rotational speed that allows engagement of the lock-up clutch and the CVT gear ratio r. When V reaches, the lock-up clutch is engaged,
It is necessary to detect the gear ratio r of the CvT, which complicates lock-up control.

JP-A No. 50-40957 as a prior art discloses engaging and disengaging a lock-up clutch based on the output shaft rotational speed of a fluid torque converter in lock-up control of a stepped transmission. C instead of
There is no disclosure regarding lock-up control when VT is used.

Problems to be Solved by the Invention An object of the present invention is to provide a lock-up control device for a power transmission device with a CVT that can simplify lock-up control by omitting detection of the CVT gear ratio.

Means for Solving the Problems In order to achieve this object, according to the present invention, a fluid transmission device is provided upstream of the CVT in the engine power transmission path, and a lock-up clutch is provided in parallel with the fluid transmission device. A lock-up control device for a power transmission device with a CVT, which has been described above, detects the rotational speed of a rotating member in an engine power transmission path between a CVT and a fluid transmission device,
Engagement and release of the lock-up clutch are controlled based on this rotational speed and engine load.

Effects of the invention In this way, CV is used instead of vehicle speed for lock-up control.
Since the rotational speed of the rotating member in the engine power transmission path between the T and the fluid transmission device is directly detected, the CVT control can be simplified by omitting the detection of the CVT gear ratio r.

Preferably, the rotating member is an input sheave of a CVT. C
Since a sensor that detects the rotational speed of the input sheave is already used to control the gear ratio of the VT, by using this sensor, the lock-up control of the present invention can be performed without adding a new sensor. I can do it.

Preferably, the rotational speed of the input sheave when the lock-up clutch is engaged and released is a function of the intake throttle opening, and the rotational speed of the input sheave at this time is ifi!
Calculated by interpolation method from the detected value of the load. As a result, data storage capacity can be saved.

Preferably, the rotation speed of the input sheave when the lock-up clutch is engaged is set to a higher value than the rotation speed of the input sheave when the lock-up clutch is released, and hunting is prevented by creating such hysteresis. be able to.

Example The present invention will be explained with reference to the embodiments shown in the drawings.

Fig. 2 discloses a power transmission device in which a stepped sub-transmission is further provided downstream of the CVT in order to increase the control width of the gear ratio of the entire engine power transmission path. A fluid coupling is used instead of a converter.

In Fig. 2, CVT l is a pair of input side sheaves 2a.
+2b-, a pair of output sheaves 4. a, 4b, and a belt 6 that is hung over the sheaves on the input side and the output side to transmit engine power. One input side sheave 2a is provided on the input shaft 8 so as to be movable in the axial direction but fixed in the rotational direction, and the other input side sheave 2b is fixed to the input shaft 8.

Further, one output side sheave 4a is fixed to the output shaft IO,
The other output side sheave 4b is provided on the output shaft 10 so as to be movable in the axial direction but fixed in the rotational direction. Opposite surfaces of input sheave 2a + 2b and output sheave 4a
The opposite surfaces of +4b are formed in a tapered shape such that the distance between them increases toward the outside in the radial direction, and the cross section of the belt 6 is formed in the shape of an isosceles trapezoid. The pressing force of the output side sheaves 4a+4b is controlled to the minimum value that can avoid slippage of the belt 6 and ensure power transmission, and the pressing force of the input side sheaves 2a+2b is controlled by the gear ratio r of the CVT 1 (=rotation of the input shaft 8). Speed N
in/rotational speed Nout of the output shaft 10) is determined. The fluid coupling 12 includes a pump 16 connected to the crankshaft 14 of the engine, and a turbine 18 rotated by oil from the pump 16 and fixed to the input shaft 8. The lock-up clutch 22 controls the connection between the crankshaft 14 and the input shaft 8, and the damper 24 absorbs shock and engine torque fluctuations when the lock-up clutch is switched from a released state to an engaged state. When the vehicle speed or engine rotational speed exceeds a predetermined value, the lock-up clutch 22 is held in the engaged state, and the fluid coupling 12
Avoid power transmission loss due to oil in The oil pump 26 rotates integrally with the pump 16 and sends oil to the CVT l , the fluid coupling 12, etc. via a hydraulic control device. The counter shaft 28 is provided parallel to the output shaft 10 of the CVT l, and has two gears 30 and 32. The engine power of the output shaft 10 is transmitted from a gear 34 coaxial with the output shaft IO to a differential gear 36 via a gear 30.32 on the counter shaft 28, and further from the differential gear 36 to the left and right axle shafts 38.40. is sent to the left and right drive wheels via the The stepped E'LU transmission 42 is the output shaft 1 of the CVT 1.
It is provided coaxially with respect to 0. The sub-transmission 42 includes a Ravigneau type compound planetary gear set 43, which includes first and second sun gears 44, 46, a first planetary gear 48 meshing with the first sun gear 44, and a first planetary gear 48 meshing with the first sun gear 44. A second planetary gear 50 that meshes with the planetary gear 48 and the second sun gear 46, a ring gear 52 that meshes with the first planetary gear 48, and a carrier 54 that rotatably supports the first and second planetary gears 48 and 50. There is. The second sun gear 46 is connected to an integral shaft 64-\ of the output shaft 1o of the CVT 1 as an input part of the sub-transmission 42, and the carrier 54 is connected to the gear 34.
connected to. The high-speed gear clutch 56 controls the connection between the shaft 64 and the first sun gear 44, the low-speed gear brake 58 controls the rotation of the first sun gear 44, and the reverse brake 6o fixes the ring gear 52. Control.

Note that 64 and 66 are an input-side rotational speed sensor and an output-side rotational speed sensor, which detect the rotational speeds of the input-side sheave 2a and the output-side sheave 4b, respectively.

FIG. 3 shows the operating state of each frictional engagement element of the sub-transmission 42 and the reduction ratio in each range. ◯ means an engaged state, × means a released state, and ρ1 and ρ2 are defined from the following equation.

pl=Zsl/Zr p 2 == Zs2/ Zr where Zsl is the number of teeth of the first sun gear 44, Zs2 is the number of teeth of the second sun gear 46, and Zr is the number of teeth of the ring gear 52. That is, in the low gear of the D range, the first sun gear 44 is fixed by the low gear brake 58, so the engine power is transmitted at a reduction ratio of 1+ρl→2, and in the high gear of the L and D ranges, the first sun gear 44 is fixed by the low gear brake 58. are in a locked state, and the planetary gear unit 43 rotates as one, and this
The engine excitation gradient is transmitted at the reduction ratio l, and in the R range, the ring gear 52 is fixed by the reverse brake 6o, so the engine power is transmitted at the reverse rotation with the reduction ratio 1-1/p2.

4 to 6 are detailed views of the hydraulic control device. The oil pump 26 pressurizes the oil sucked through the strainer 72 and supplies it to the line pressure bend v574. The throttle valve 76 generates a throttle pressure Pth related to the intake/throttle opening θ to the output port door 8. The spool 77 of the throttle valve 76 is connected to the throttle cam 7.
9 and receives the acting force that increases as the throttle opening θ increases and the throttle pressure pth as feedback pressure from the control port 81, thereby controlling the connection between the line pressure oil passage 74 and the output port door 8. . Manual valve 8o is shift lever (low), 0 (drive),
The axial position is controlled in relation to the N (neutral), R (reverse), and P (parking) ranges, and the first line pressure PJ? 1 is led to port 83 when in the R range, to port 85 when in the L range, and to port)-85 and 87 when in the 0 range, respectively.

The relief valve 89 has jJltl as a safety valve that releases oil in the line pressure oil passage 74 when the first line pressure pH of the line pressure oil passage 74 exceeds a predetermined value.

The secondary hydraulic oil passage 82 has an orifice 84 and a port 8 where excess oil from the primary regulator valve 198 is discharged.
5, and the secondary pressure regulator valve 86 is connected to the line pressure oil passage 74 via the orifice 88.
A control chamber 90 connected to the secondary hydraulic fluid line 82 via
It controls the connection between the secondary hydraulic oil passage 82 and the port 94 in relation to the oil pressure in the control chamber 90 and the load on the spring 92, and controls the secondary oil pressure Pz of the secondary hydraulic oil passage 82 to a predetermined value. maintain it. The lubricating oil passage 95 is connected to the secondary hydraulic oil passage 82 via a port 94 or an orifice 97. The lock-up control valve 96 selectively connects the secondary hydraulic oil passage 82 to the engagement side and the disengagement side of the lock-up clutch 22 parallel to the hydraulic clutch 12 . 1a solenoid valve 100 controls the connection between the control chamber 102 of the lock-up control valve 96 and the drain 104, and when the solenoid valve 100 is off (non-energized), the secondary hydraulic oil passage 82 is connected to the release side of the lock-up clutch 98. The secondary hydraulic pressure Pz is transmitted and engine power is transferred to the fluid clutch 12.
When the solenoid valve 100 is on (, magnetized), the secondary hydraulic pressure Pz is transmitted from the secondary hydraulic oil passage 82 to the engagement side of the lock-up clutch 98 and the oil cooler 1.6.
is supplied, and the already engaged force is transmitted via the lock-up clutch 98. Cooler bypass valve 107 controls cooler pressure.

The rapid speed ratio control device 108 is a first and a second Subu JL.
/ valves 110, 112, first and second 'taM valves 114, 116. During the period when the first solenoid valve 114 is off, the spool of the first spool valve 110 is pressed toward the spring 118 by the 2'/XMJI pressure Pz of the chamber 117, and the first line pressure PI of the port 119 !
I is sent through port 120 of first spool valve 110 to port 122 of second spool valve 112, and the connection between port 124 and drain 126 is broken. The period during which the first solenoid valve +14 is on is chamber]! 7 hydraulic pressure is the first
28 of the solenoid valve 114, the spool of the first spool valve +10 is pushed towards the chamber 117 by the spring 118, and the line pressure PI is supplied to the port 120.
! does not occur and port +24 is connected to drain 126. In addition, during the period when the second solenoid valve 116 is off, the spool of the second spool valve 112 maintains the secondary hydraulic pressure P2 of the chamber 128.
The connection between the ports 122 and 132 is broken, and the port 114 is pressed toward the spring 130 by the spring 130.
6.\Connected. The ports h' 132 and 134 are connected to the long side hydraulic cylinder of the CVT 1 via an oil passage 138. During the period when the second solenoid valve 116 is on, the hydraulic pressure in the chamber 128 is discharged from the drain 139 of the second S solenoid valve 116, and the spool of the second spool valve 112 is
30 toward the chamber 128, the port 122 is connected to the port 132, and the readout between the port 134 and the port 136 is cut off.The port 136 is connected to the port ! 24・″＼Slave connected. Orifice 140
is the second solenoid valve +167) When off, the insect oil is guided from the port 122 to the port h132, so the first solenoid valve l! 4 is off and the second solenoid valve 116 is on, oil is quickly supplied to the input hydraulic cylinder of the GVT 1, and the gear ratio T decreases. First solenoid valve 1
14 is off and the second magnet valve 116 is off, oil is supplied to the input hydraulic cylinder of the CVT 1 via the orifice 140, and the gear ratio of the CVT 1 is moderate. If the first solenoid valve +14 is on and the second solenoid valve 116 is on, the CVT
Oil is not supplied to or discharged from the input hydraulic cylinder of CVT 1, and the gear ratio r of CVT 1 is kept constant.

During the period when the first solenoid valve 114 is on and the second solenoid valve 116 is off, the oil in the input hydraulic cylinder 46 is discharged from the drain 126, so the gear ratio r of the CVT I is
rises rapidly.

The gear ratio detection valve 146 is shown in detail in FIG. Sleeves 148, 150 are coaxially disposed within valve bore 152 and are axially secured by snap rings 154. Rod +56 passes through the end of sleeve 148 and has spring seat 158 secured thereto.

Another rod 160 is coupled at both ends to the input movable pulley 2a and the rod 156, respectively, and moves the rod 156 in the axial direction by a displacement equal to the axial displacement of the input movable pulley 2a. The spool 162 has a land 164,
166, and is fitted within the sleeve 150 so as to be movable in the axial direction.

The land 164 is the space 16 between the lands 164 and 166.
8 to the oil chamber 170, and the land 166 has a port 174 of the sleeve 150 to the space 168.
control the aperture area. Port 174 is connected to sleeve 148
It is connected to a drain 176 through a space around the outer periphery of the drain 176.

The oil chamber 170 has an output port 178 that generates a control pressure Pc, and the output port 178 is connected to the line pressure oil passage 74 via an orifice 180. The spring 182 is provided between the spring receiver 158 and the sleeve 150 and is attached to the rod 156.
The spring 184
The spring is provided between the spring receiver 158 and the flange 186 of the spool 162 to bias the spool 162 toward the oil chamber 170. As the amount of displacement of the input movable pulley 2a of the CVT 1 with respect to the input fixed pulley 32 increases, the speed ratio r increases. Since the rod +56 is pushed out of the sleeve 148 due to an increase in the amount of displacement of the input movable pulley 2a, the biasing force of the spring 184 toward the oil chamber 170 on the spool +62 decreases.

As a result, the spool 162 moves toward the rod 156, and the land 166 increases the opening area of the port 174 to increase the oil discharge flow rate, so that the transmission specific pressure of the output port 178 decreases. Since the gear ratio specific pressure is generated by controlling the amount of hydraulic medium discharged from the output port 178, the upper limit is set to the line pressure Pi! stipulated in The broken lines in FIGS. 8 and 9 illustrate two relationships between the gear ratio pressure range and the gear ratio r. As will be described later, the first line pressure P7!
1 decreases as the gear ratio r decreases, but when the gear ratio 1 becomes equal to the line pressure PI (this gear ratio r1
is the throttle pressure pth.

Therefore, it is a function of the engine torque Te. ), in the gear ratio range below that Pr=PI! It becomes 1.

Note that in FIGS. 8 and 9, the two-dot chain line represents the ideal value of the first line pressure PA'l, and T1>T2.

The cut-off valve 190 is an oil path to the control S chamber 102 of the lock-up control valve 96! Chamber 19 communicating via 92
4, and a spool 196 that moves in relation to the oil pressure in the chamber 194 and the spring force of the spring 195, when the solenoid valve 100 is off, i.e., the lock-up clutch 22
is in the released state (when the auxiliary transmission 42 shifts gears, the lock-up clutch 22 is released in order to absorb collisions in the power transmission system), the lock-up clutch 22 is in the closed state and the gear ratio pressure is stabilized. is the primary regulator valve 198
Prevent transmission to.

The primary regulator valve 198 as a first line pressure generating means includes a port 200 supplied with throttle pressure pth, a port 202 supplied with gear ratio pressure, a port 204 connected to the line pressure oil passage 74, and a port 204 connected to the line pressure oil path 74. Port 206 connected to the suction side of pump 26 and port 21O1 supplied with first line pressure PJI through orifice 208; spool that moves in the axial direction to control the connection between port 204 and port 206; 2
12, a spool 214 that biases the spool 212 toward the port 2o2 in response to the throttle pressure pth, and a spring 216 that biases the spool 212 toward the port 202. The area of the two lands from the bottom of the spool 212 is A1. When A2 is defined as A3, the area of the land of the spool 214 that receives the throttle pressure Pth is defined as A3, and the acting force of the spring 216 is defined as Wl, the following equation holds true.

When the cut-off valve 190 is open and the speed change specific pressure town is present at the port 202, PJI = (A3・Pth1WI−AI・town)/(A2
PI! I = (A3・Pth+WI)/(A2−AI)
(2) The pH defined by formulas (1) and (2) is shown by a solid line and a dashed-dotted line in FIGS. 8 and 9, respectively.

The sub-primary regulator valve 220 as a second line pressure generating means generates the first line pressure pI! in the L and D ranges. Input port 222 leads t from port 85 of manual valve 80, Output port 224 generates second line pressure PA2, Port 2 leads to gear ratio pressure
26. Second line pressure PJ2 as feedback pressure
a port 230 that is guided through an orifice 228, a spool 232 that controls the connection between the input port 222 and the output port 224, a port 234 that receives the throttle pressure Pth, and a spool 232 that receives the throttle pressure Pth from the port 234. a spool 236 that biases the spool 232 toward the port 226, and a spring 238 that biases the spool 232 toward the port 226.

The area of the two lands from the bottom of the spool 232 is 81, B
2. If the area of the land of the spool 236 that receives the throttle pressure Pth is defined as 83, and the acting force of the spring 238 is defined as W2, the following equation holds true.

PJi! 2: (B3・Pth+W2−81・Town)/(B
2-Bl) (3) Figure 1O shows the relationship between the second line pressure PE2 generated by the sub-primary regulator valve 220 and its ideal value.

The shift valve 250 is connected to the second line pressure P12 when in the L range.
4,256, having an orifice 258 and a drain 260
The port 262 is connected to the discharge oil passage 261 ending in the first line pressure PI! from the port 87 of the manual valve 80 when in the D range. It has a control boat 264 supplied with I, other control ports 266, 268, a drain 270, a spool 272, and a spring 274 biasing spool 272 toward port 268.

The control port 1-266.268 receives secondary hydraulic pressure Pz through an orifice 276, and the hydraulic pressure of the control port 266.268 is controlled by a solenoid valve 278. Spool 272
The area of the bottom two lands is 51.52, and Sl
<52.

Further, whether the solenoid valve 278 is turned on or off is controlled in relation to the driving parameters of the vehicle, and when the solenoid valve 278 is turned on, oil is discharged from the drain 280.

When spool 272 is in the spring 274 position, input port 252 is connected to output port 254 and output port 256 is connected to port 262. Therefore, the second line pressure P12 from the output port 254 is applied to the piston 28.
1 to the accumulator 282 and the high speed clutch 56, and the auxiliary transmission 42 becomes the high speed speed.

When the spool 272 is in the port 268 position, the input port 252 is connected to the output port 256 and the output port 254 is connected to the drain 270.

Therefore, the second line pressure PJ from output port 256
2 is supplied to the low speed accumulator 58, and the auxiliary transmission 42 becomes the low speed.

In the case of a microwave oven, the first line pressure Pl! is applied to the control port 264. is not guided, so when the solenoid valve 278 is turned off, the spool 272 is first activated by the secondary hydraulic pressure Pz acting on the land with an area S2, and then by the secondary hydraulic pressure Pz acting on the land with an area S1, the spring 274 is However, when the solenoid valve 278 is turned on, the control boat 266.2
As the oil pressure at 68 decreases, the spool 272
4 toward port 268. In other words, in the microwave oven, the auxiliary transmission 4
It is possible to switch between two high speed stages and a low speed stage.

In the D range, the first line pressure PJI is applied to the control port 264.
! 1 is guided, so the spool 272 is connected to the -tan spring 27
When the position is on the 4 side, control port 2 is placed on the land with area S2.
The first line pressure PJI from 64 acts, and regardless of whether the solenoid valve 278 is turned on or off thereafter, the spool 272 is held in the position on the spring 274 side, and therefore the sub-transmission 42 is held in the high speed gear.

The shift timing valve 290 is connected to the high speed clutch 5.
control port 292 communicating with 6, and control port 29
Spool 2 whose axial position is controlled by hydraulic pressure of 2
94, and the flow rate of oil supplied to the high speed clutch 56 and the flow rate of oil discharged from the low speed brake 58 during an upshift from a low speed to a high speed are wJ#.

The solenoid valves 100, 114, 116, 278 receive the secondary hydraulic pressure Pz from the secondary hydraulic oil passage 82, and control the discharge of the secondary hydraulic pressure Pz. In the hydraulic control device disclosed in Japanese Patent Application No. 59-12017, the solenoid valve is guided by the throttle pressure Pth. Therefore, in conventional devices, the spring force and solenoid suction force of the solenoid valve must be set to cope with the maximum throttle pressure, which has the disadvantage of increasing the size of the solenoid valve. There are problems in that the responsiveness of the spool of the spool valve deteriorates and the setting of the spring force acting on the spool becomes complicated. In this embodiment, by using the secondary hydraulic pressure Pz, these problems are solved and the degree of freedom in design is improved.

FIG. 11 is a control block diagram. Electronic control device 310
receives parameters such as the intake throttle opening θ, the input side rotational speed Nin of the vehicle speed v1CVT1, the engine cooling water temperature Tv, and the shift position as input signals,
Solenoid valve 100.114.116 of hydraulic control device 312,
278 is controlled via an amplification stage 314.

FIG. 12 shows NJa as the rotation speed Nin of the input sheave 2a when the lock-up clutch 22 is switched from off to on, and the rotation speed Ni of the input sheave 2a when the lock-up clutch 22 is switched from on to off.
Nlr as n is shown as a function of intake throttle opening θ.

The engagement and release of the lock-up clutch 22 will be referred to as on and off, respectively, in the following description. The input side rotation speed sensor 64 determines the rotation speed Ni of the input side sheave 2a.
Therefore, the turbine rotation speed of the fluid coupling 12 is detected, and when Nin becomes equal to or higher than N23, the lock-up clutch 22 is switched from off to on, and Nin t6 Nlr
When it becomes less than 1, the lock-up clutch 22 is switched from on to off. In order to prevent hunting in lock-up control, NJa>NJr. In addition, in order to save ROM data capacity -1, select multiple intake throttle openings 00 to on that are separated by an appropriate interval from 0 to 100%, and NJa, NI! at selected intake throttle opening degrees θ0 to θn. Only r is stored in the ROM, and NJa or Nlr corresponding to the detected intake throttle opening θ is stored.
is advantageously calculated from ROM data using an interpolation method.

FIG. 1 is a block diagram of the main parts of the present invention.

The input side rotation angle sensor 64 detects the rotation speed Nin of the input side sheave 2a, that is, the turbine rotation speed of the fluid coupling 12, and the throttle opening sensor 366 detects the intake throttle opening θ as the engine load. The switching rotational speed calculation means 368 calculates the input side sheave rotational speed N/a when the lockup clutch 22 is switched from off to on, and the input side sheave rotational speed Nlr when the lockup clutch 22 is switched from on to off. Calculation is performed based on the throttle opening degree e, for example, according to FIG. 12. The lock-up clutch switching means 370 switches the solenoid valve 100 from off to on, that is, switches the lock-up clutch 22 from off to on (from a released state to an engaged state) when Nin≧Nla from N1n<Nla, and when Nin≧ N
When Nin<NJr from lr, the solenoid valve 100 is switched from on to off, that is, the lock-up clutch 22 is switched from on to off (from the engaged state to the released state).

FIG. 13 is a flowchart of the lockup control routine. First, the intake throttle opening degree θ and the input side sheave rotation speed Nin are detected (step 376). Next, whether the lock-up clutch 22 is on or off (step 378), Nin and NA'a+NA! r (steps 380, 382). When the lock-up clutch 22 is off, when Nin<NAa, keep the lock-up control solenoid valve 100 off (step 384), and when N1n≧Nla, turn on the lock-up control solenoid valve +00 (step 386) . When the lock-up clutch 22 is on, Nin>N
When Jr, the lock-up control solenoid valve 100 is kept on (step 388), Nin<Nj! When r, the lock-up control solenoid valve 22 is turned off (step 3
90).

Although the present invention has been described with reference to embodiments, it will be obvious to those skilled in the art that the present invention is not limited thereto and can be implemented with various modifications and variations.

[Brief explanation of drawings]

A skeleton diagram of the entire power transmission system, Figure 3 is a chart showing the operating status of each friction engagement device in each range, Figures 4 to 6 are detailed diagrams of the hydraulic control system, and Figure 7 is a gear ratio detection valve. , FIG. 8 and FIG. 9 are graphs showing the characteristics of the first line pressure, FIG. 1O is a graph showing the characteristics of the second line pressure, FIG. 11 is a control block diagram, and FIG. FIG. 13 is a graph illustrating the input sheave rotational speed as a function of the intake throttle opening when the lock-up clutch is switched on and off, and is a flowchart of the lock-up control routine. I...CVT, 12...Fluid coupling, 22...Lock-up clutch, 64...Input side rotation angle sensor, 9
6... Lockup control valve, 100... Solenoid valve, 3
66...Throttle opening sensor, 368...Switching rotation speed calculation means, 370...Lock angle clutch switching means. -----Ideal value of pH □Pe1 when the cut-off valve is open -'-Pe1 when the force-off valve is closed---Pγ □Transmission ratio r Fig. 9--Ideal value of pH □Cut pH when off valve is open □Transmission ratio r

Claims (1)

[Scope of Claims] 1. A power transmission device with a continuously variable transmission, in which the fluid transmission device is provided upstream of the continuously variable transmission in the engine power transmission path, and a lock-up clutch is provided in parallel with the fluid transmission device. A lockup control device detects the rotational speed of a rotating member in an engine power transmission path between a continuously variable transmission and a fluid transmission device, and engages and controls a lockup clutch based on this rotational speed and engine load. A lock-up control device for a power transmission device with a continuously variable transmission, characterized by controlling release. 2. The lockup control device according to claim 1, wherein the rotating member is an input sheave of a continuously variable transmission. 3. The rotational speed of the input sheave when engaging and disengaging the lock-up clutch is a function of the intake throttle opening, and the rotational speed of the input sheave at this time is calculated by interpolation from the detected value of the engine load. A lock-up control device according to claim 2, characterized in that: 4. Claim 3, characterized in that the input side sheave rotational speed when the lockup clutch is engaged is set to a higher value than the input side sheave rotational speed when the lockup clutch is released. lock-up control device. 5. The lock-up control device according to claim 4, wherein the fluid transmission device is a fluid coupling or a fluid torque converter.