JP2772636B2 - Lock-up clutch hydraulic control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lock-up hydraulic control device for a construction machine or a traveling machine. [Prior Art] A conventional lock-up clutch has a configuration in which hydraulic pressure is controlled by a mechanical modulation valve, and the hydraulic pressure cannot be arbitrarily changed. For this reason, the characteristic of gradually increasing the hydraulic pressure of the lock-up clutch at the time of starting or shifting is always uniform, and there is a problem that a large lock-up shock occurs due to various factors. For example, when the same hydraulic pressure is gradually increased, the lock-up shock is larger in the unloading speed than in the loading speed. [Problems to be solved by the invention] The present invention has been made in view of such circumstances,
An object of the present invention is to provide a lock-up clutch hydraulic pressure control device capable of suitably reducing a lock-up shock. [Means for Solving the Problems] In the first invention, an input shaft and an output shaft of a torque converter disposed between an engine and a transmission are directly connected, and the torque converter A lock-up clutch that is engaged and released in accordance with the differential pressure obtained by subtracting the internal pressure of the clutch, a pressure control valve that varies the clutch oil pressure supplied to the lock-up clutch in accordance with an electric command applied to a proportional solenoid, A lock-up clutch control device comprising: a control unit that inputs an electric command of the proportional solenoid of a pressure control valve and controls opening and closing of the pressure control valve and control of a clutch oil pressure of the lock-up clutch by the electric command. A first detecting means for detecting a throttle amount and a second detecting means for detecting a vehicle weight. Means, third detecting means for detecting a gear ratio of the transmission determined by the speed stage, internal pressure calculating means for calculating the internal pressure of the torque converter, and shift end detecting means for detecting the end of the shift. At the same time, when a shift start command is input, the control means lowers the lock-up clutch oil pressure to a substantially calculated value of the internal pressure calculating means at this time, and outputs a predetermined pressure corresponding to the calculated value from the shift end detecting means. A first control unit for inputting a first electric command to the pressure control valve to be maintained until a shift end detection signal is output, and a detection output of the first, second, and third detection units. A gradually increasing speed of the lock-up clutch oil pressure is calculated. Second inputting the second electrical command to recruit up clutch hydraulic pressure to the pressure control valve
Control means. According to the second invention, the input shaft and the output shaft of the torque converter disposed between the engine and the transmission are directly connected, and according to the differential pressure obtained by subtracting the internal pressure of the torque converter from the clutch oil pressure in the lock-up clutch chamber. A lock-up clutch that is engaged and released, a pressure control valve that varies a clutch oil pressure supplied to the lock-up clutch according to an electric command applied to the proportional solenoid, and an electric command to the proportional solenoid of the pressure control valve. And a control means for controlling the opening and closing of the pressure control valve and the control of the clutch oil pressure of the lock-up clutch in accordance with the electric command. Detection means, second detection means for detecting the vehicle weight, and Detecting means for detecting the gear ratio of the transmission, internal pressure calculating means for calculating the internal pressure of the torque converter, and filling completion detecting means for detecting filling completion of the lock-up clutch. When the start command is input, the lock-up clutch oil pressure is set to a high pressure state for a predetermined time, and thereafter, the lock-up clutch oil pressure is reduced to a substantially calculated value of the internal pressure calculating means, and a predetermined value corresponding to the calculated value is determined. First control means for inputting a first electric command to the pressure control valve for maintaining a pressure until a filling signal is output from the filling end detection means, and the first, second and third detection means Means for calculating a gradual increase speed of the lock-up clutch oil pressure based on the detection output of the means. Then, a second control means for inputting, to the pressure control valve, a second electric command for gradually increasing the lock-up clutch oil pressure at the calculated gradually increasing speed from the time of this detection. An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a transmission system to which the present invention is applied. The output of an engine 20 is applied to a gear-type transmission 30 via a torque converter (torque converter) 25, and the output of the transmission 30 is The power is transmitted to the drive wheels 41 via the final reduction gear 40. A lock-up clutch 50 for directly connecting the input and output shafts of the torque converter 25 is interposed. The engine 20 has an engine rotation sensor 21 that outputs a signal corresponding to the number of rotations n ₁ , and the transmission 30 has a number of rotations n ₂ and n ₃ corresponding to the number of rotations of the input shaft 2 and the output shaft 3. Rotation sensors 22 and 23 for outputting signals are provided, and the outputs of these sensors are applied to the controller 10. The throttle amount sensor 70 detects the amount of depression of the throttle pedal and inputs a signal S indicating the amount of depression to the controller 10. Vehicle weight sensor 75 is vehicle weight I (body weight + load weight)
Is detected and the detected value is input to the controller 10. The shift selector 80 outputs a signal indicating the shift position (R, N, D, 1...) Selected by the shift lever 81 to the controller 1.
Enter 0. The transmission 30 has, for example, four shift clutches 31, 32, 33 and 34, as shown in FIG. Are selectively engaged. As shown in FIG. 2, the clutch hydraulic pressure supply device 60 includes separate electronically controlled pressure control valves 61, 62, 63, 64 and a pump 65 for applying hydraulic pressure to the four shift clutches 31 to 34. , A relief valve 66 and the like. As shown in FIG. 2, the lock-up clutch hydraulic pressure supply device 51 for applying a hydraulic pressure to the lock-up clutch 50 includes an electronically-controlled pressure control valve 55 as described above. FIG. 3 shows a configuration example of the pressure control valves 61 to 64 and 55. This pressure control valve has a spool 904 provided with a first piston portion 901, a second piston portion 902, and a third piston portion 903. The left end of the spool 904 is connected to a plunger 906 of a proportional solenoid 905 and the right end of the spool. Is a spring
Each retainer 907 is in contact with a retainer 908 urged leftward at 907. The first piston portion 901 and the second piston portion 902 have an oil quality 90.
9, the second piston portion 902 and the third piston portion 903 define an oil chamber 910. And oil chamber 909 and oil chamber 910
Has an input port 911 and a tank port 912, respectively. The oil chamber 913 in which the spring 907 and the retainer 908 are disposed
It is connected to an output port 915 via a passage 914. The proportional solenoid 905 is provided as an actuator for moving the spool 904, and its plunger 906 is in contact with the left end surface of the spool 904. As is well known, this proportional solenoid has a characteristic that the thrust F of the plunger 906 is proportional to the input current i. Now, when the proportional solenoid 905 is operated and the spool 904 goes to the right, the oil supplied to the input port 911 flows into the output port 915, and at this time, a part of the oil passing through the output port 915 passes through the passage 914. Flow into the oil chamber 913. Here, when the pressure receiving area of the third piston portion 903 is A and the oil pressure at the output port 915, that is, the oil pressure in the oil chamber 913 is Pd, a force of A · Pd acts in a direction to move the spool 904 to the left. Thus, the spool 904 operates so that the thrust F of the plunger and the above-mentioned force A · Pd are balanced, that is, the balancing relationship shown in the following equation is satisfied. F = A · Pd (1) The spring 907 acts to bias the spool 904 to the left. However, since a spring having a small spring constant is used as the spring 907, in the above description, this spring 907 is used. Ignore the effects of As described above, between the thrust F of the plunger 906 and the drive current i of the solenoid, F = K · i (2) where K is a proportional constant, and therefore, equations (1) and (2) are used. From the following equation, the following relationship is obtained: Ki · A = A · Pd (3).
Is expressed as Pd = K ・ (i / A) (4). As is apparent from the equation (4), the hydraulic pressure Pd of the output port is proportional to the drive current i of the solenoid. Therefore, the command signal i output from the controller 10
Is appropriately changed, it is possible to apply an arbitrary clutch pressure to the transmission clutches 31 to 34 and the lock-up clutch 50. In such a configuration, the controller 10 performs the following lockup control. This will be described with reference to the flowchart of FIG. This description consists of three processes. (I) Lock-up engagement control other than during shifting. The first control is a hydraulic modulation control when the engine speed exceeds the lock-up minimum speed after the vehicle is started by a command from the shift lever 81. Fifth
FIG. 5 shows an example of a temporal characteristic such as a lock-up hydraulic pressure command by this control. The controller 10 after the start, and measure the engine speed n ₁ from the output of the engine speed sensor 21, exceeds the minimum rotational speed nr of the engine speed n ₁ is lockup (FIG. 5 (b)) At this point (step 100), by inputting a high-pressure trigger command to the solenoid of the pressure control valve 55 of the lock-up clutch 50 for a certain period of time, high-pressure oil is supplied to the lock-up clutch 50 to speed up the filling (step 110). . Thereafter, in order to complete the filling completely, the oil pressure command is set to an oil pressure (Pt +
The value falls to a value corresponding to β), and this value is held for a certain period of time (steps 120 and 130). The hydraulic pressure equal to or higher than the torque converter internal pressure is applied because the torque converter internal pressure acts on the piston back pressure portion of the lock-up clutch 50 in this case. . Since the torque converter internal pressure is substantially proportional to the engine speed, it can be calculated based on the output of the engine speed sensor 21 and the like. When the change in the engine speed is small, a constant hydraulic pressure (upper limit of the fluctuation) may be applied to the lock-up clutch. Further, in this case, the filling is completed by managing the time, but an appropriate filling detection sensor may be provided, and the filling completion may be detected from the output of this sensor. Next, upon confirming the end of the filling, the controller 10 gradually increases the hydraulic pressure command to be applied to the pressure control valve 55 to engage the lock-up clutch 50, and gradually increases the lock-up clutch hydraulic pressure. Inclination at this time (build-up rate)
Is changed according to the throttle opening and the vehicle body weight. Normally, lock-up engagement at the time of starting is performed at the lowest speed stage, but when performing other speed stages, a reduction ratio is added to the above parameters, and the three parameters (vehicle weight, throttle opening, gear ratio) are used. To properly change the build-up rate (step 140). Shift shock of a gear transmission is evaluated by a jerk value J defined by the following equation. J: jerk value α: body acceleration K: conversion coefficient G: reduction ratio constant I: vehicle weight (body weight + load weight) μ: clutch disc friction coefficient P: clutch oil pressure The above reduction ratio constant G is calculated from the speed stage. It is determined, but also includes a coefficient indicating the number and area of the clutch plates at each speed stage. Therefore, the value of this constant G differs slightly depending on the speed stage. Of course, when the number of stacked clutch plates and the area are the same for each speed stage, G is the reduction ratio itself. The second term P du / dt in parentheses in the above equation (5) is a term related to the case where the difference between static friction and dynamic friction is large, and has an effect when clutch engagement ends, but there is no difference between the two. Can be ignored. Hereinafter, the description will be made ignoring the second term. Therefore, the jerk value of the above equation (5) is Becomes The solution dp / dt that we want to find from equation (6) is Becomes In the above equation (7), since K and μ are known, I, J
And G may be obtained. I can be obtained from the output of the vehicle weight sensor 75, and G can be obtained from the reduction ratio. J is a target shock and is a value determined by the degree of load (a light load is smaller, and a heavy load is larger). Here, the load applied to the vehicle body cannot be measured, but since the load is proportional to the engine power, the target jerk value J can be determined by the throttle opening. That is, the jerk value J can be determined from the output of the throttle amount sensor 70, and the jerk value is changed in proportion to the sensor output. As described above, the controller 10 measures the throttle opening, the vehicle weight, and the gear ratio, calculates the optimum build-up rate dp / dt based on the measured values, and gradually increases the hydraulic pressure at the calculated dp / dt. At this time, dp / dt with the throttle opening, vehicle weight and gear ratio as variables are stored in a memory in the controller 10 in advance in a map format, and dp / dt corresponding to the detected values of the three variables is stored. dt may be read from the memory. As the storage data, a value calculated by the above equation (7) may be used, or data measured by an actual vehicle may be used. After gradually increasing the oil pressure, the controller 10
The torque converter E value (= n ₂ / n ₁ , n ₁ ; torque converter input shaft rotation speed, n ₂ ; torque converter output shaft rotation speed) is measured based on the outputs of the transmission shaft input sensor 21 and the transmission input shaft rotation sensor 22 (step 160). The E value is “1” or a predetermined value “E”
_{When it reaches} " ₀ " (FIG. 5 (c)), the gradual increase of the hydraulic pressure is stopped (step 190). During this gradual increase, if the clutch pressure exceeds the upper limit set pressure Pa (fifth (a)) before the E value reaches “1” or the set value E ₀ , the controller
10 so as to hold the clutch pressure until E value reaches E ₀ to the upper limit set pressure Pa (step 170, 180). When calculating the E value, the output speed of the torque converter output shaft may be determined using the output of the transmission output shaft rotation sensor 23 and the gear ratio. (II) Lock-up clutch hydraulic control during normal running. This second control is performed at the time of normal running after shifting or starting. When the above-described hydraulic pressure increasing control is completed, the controller 10 lowers the lock-up clutch hydraulic pressure to a value corresponding to the engine output torque or a value Pb slightly larger than this value (FIG. 5 (a)). Specifically, the controller 10 determines whether or not the shift is performed in step 200.If the shift is not performed, the controller 10 first controls the throttle amount sensor 70 and the engine rotation sensor 21 unless the engine speed becomes smaller than the lock-up minimum speed nr. Calculate the engine torque T from each output S, n ₁ (step
230). As shown in FIG. 6, the torque T output from the engine has a density relationship between the engine speed and the throttle opening, and a torque value T corresponding to each of these parameters is stored in a memory in the controller 10. Various pre-remembers. Then, an engine torque T is obtained by reading a torque value corresponding to the detection output of the engine rotation sensor 21 and the throttle amount sensor 70 from this memory. In practice, a value that completely matches the pre-stored parameter value is not always input from each sensor, so an intermediate appropriate value is obtained using interpolation processing or the like. And the controller
10 is set so that the transmission torque of the lock-up clutch 50 matches the engine output torque T determined by the engine speed and the throttle opening, or the transmission torque of the lock-up clutch is slightly larger than the engine output torque T. Control the clutch oil pressure to achieve. Here, the transmission torque T 'of the clutch is expressed by the following equation. Can be represented by Therefore, the engine output torque T can be converted into the clutch pressure P by obtaining the clutch pressure P that satisfies T '= T based on the above equation (8). That is, the controller 10 obtains the engine torque T from the outputs of the throttle amount sensor 70 and the engine rotation sensor 21.
The torque value T or a value slightly larger than the torque value T is converted into a clutch pressure P according to the above equation (8) (step 240), and a hydraulic command corresponding to the converted clutch pressure is sent to the pressure control valve 55. (Step 25
0). During traveling, the engine output torque T fluctuates as shown in FIG. 7 (b). However, according to the above-described control, the lock-up clutch pressure is reduced to an oil pressure conversion value of engine output torque (broken line in FIG. 7A) or a hydraulic pressure slightly larger than the conversion value (solid line in FIG. 7A). Since the vehicle travels at a reduced speed, fluctuations in the transmission output shaft due to fluctuations in the engine output torque can be reduced, so that even if a large fluctuation occurs in the engine speed as shown in FIG. 7 (c). The fluctuation of the transmission output shaft can be controlled as shown in FIG. 7 (d). Therefore, the minimum rotation speed nr of lock-up can be set to a lower speed side than before, and fuel efficiency is also improved. Although so lowered to a value Pb immediately corresponding to the engine output torque of the clutch oil pressure when the torque converter E value in this example becomes the set value E _0, after hydraulic increasing measures time a predetermined time elapses After that, set the clutch oil pressure to the value Pb
You may make it lower to. (III) Lock-up engagement control during gear shifting This third control is performed during gear shifting. In conventional shifting, the lock-up clutch is fully disengaged and then engaged in order to reduce the load on the shifting clutch.In this proposal, however, the shift-up lock-up clutch is not completely disengaged during shifting, and is as low as possible above the torque converter internal pressure. After the oil pressure is maintained, a gradual increase operation is performed. Therefore,
In this control, there is no filling time required to fill the clutch pack. FIG. 8 shows the aging characteristics of the lock-up hydraulic pressure command at the time of this shift. When performing a gear shift, the controller 10 calculates the torque converter internal pressure Pt based on the output of the engine rotation sensor 21 (step 260 in FIG. 4 (b)).
As shown in FIG. 8, the calculated torque converter internal pressure value Pt falls to (Pt + β) obtained by adding a predetermined pressure β to the hydraulic pressure value Pt + β.
Is held for a while (step 270). In this state, the controller 10 determines a build-up start time point ts at which the gradual increase of the hydraulic pressure is started (Step 280). There are the following three methods for determining the timing of starting the build-up. (A) Interval time setting The optimum interval time TI (see FIG. 8) is obtained in advance by using parameters such as the speed and the engine power (throttle opening) as parameters by simulation, actual vehicle test, etc., and this is shown in FIG. As shown, it is stored in a memory in the controller 10 in a map manner. Then, at the time of gear shifting, the output of the throttle amount sensor 70 and the interval time TI according to the current gear position are read from this memory,
When the interval time TI has elapsed, the hydraulic pressure build-up is started. (B) Clutch relative rotational speed sensitive type The clutch relative rotational speed (= n ₃ G−n ₂ .G: gear ratio) is obtained from the outputs n ₂ and n ₃ of the input shaft rotation sensor 22 and the output shaft rotation sensor 23 of the transmission. And this calculated value is the 10th
When the value becomes zero or a value close to zero as shown in FIG. (C) Torque converter E value sensitive type A torque converter E value (= n ₂ / n ₁ ) is calculated from the output of the engine speed sensor 21 and the transmission input shaft sensor 22 (or the output shaft 23), and this E value is the eleventh. when you as there is a set value E ₁ or shown in the drawings will build up at the start. Of the above three methods, (a) is the simplest and most practical. (B) and (c) require a rotation sensor, but (b) is a method advantageous for improving acceleration, and (c) is a method advantageous for reducing shift shock. When the controller 10 determines the buildup start time ts by any of the above methods (step 290), the controller 10 measures the throttle opening S, the vehicle weight I, and the gear ratio as in the control at the time of starting, and determines the measured value and the aforementioned value. The optimum build-up rate dp / dt is calculated using equation (7) (step 300), and the hydraulic pressure is gradually increased with the calculated value dp / dt (step 310). This hydraulic pressure gradually increasing operation is performed when the torque converter E value is “1” as in the case of the start.
Or, it stops when it reaches the set value "E ₀ " which is close to 1 and
If the clutch pressure exceeds the upper limit set pressure Pa before the E value reaches “1” or the set pressure value E ₀ , the clutch pressure is adjusted to the upper limit set value Pa until the E value reaches the set value E _0. (Steps 320 to 350). Then, during subsequent traveling, the second control for controlling the lock-up hydraulic pressure to a value corresponding to the engine output torque T is performed. [Effects of the Invention] According to the first invention, at the time of shifting, first, the lock-up clutch oil pressure is reduced to substantially the internal pressure value of the torque converter calculated by the internal pressure calculating means, and the predetermined pressure is maintained until the hydraulic pressure is gradually increased. By doing so, the filling time generated for filling the oil in the clutch pack of the lock-up clutch is eliminated, so that the lock-up clutch can be immediately engaged when the shift end is detected. Gear shifting operation becomes possible. Further, in the first invention, an optimum gradient for the clutch oil pressure gradually increasing for engagement of the lock-up clutch at the time of shifting is determined based on the throttle amount, the vehicle weight, and the gear ratio of the transmission, and the determined gradient is determined. , The lock-up clutch is engaged by gradually increasing the hydraulic pressure, so that the lock-up shock due to the fluctuation of these parameters can be reduced. According to the second invention, when the start command is input, the lock-up clutch oil pressure is raised to a predetermined high pressure state larger than the internal pressure of the torque converter for a predetermined time, thereby filling time required for filling the clutch pack with oil. And then reduce the lock-up clutch oil pressure to a value near the internal pressure of the torque converter,
By maintaining this predetermined pressure, the oil filled in the clutch pack is prevented from leaking. In addition,
According to the present invention, the optimum gradient for the clutch oil pressure gradual increase for the lock-up clutch engagement at the time of starting is determined based on the throttle amount, the vehicle weight, and the transmission gear ratio. Since the lock-up clutch is engaged, the lock-up shock due to the fluctuation of these parameters can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an example of an overall configuration of a transmission system according to an embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram showing an example of an internal configuration of a clutch hydraulic pressure supply device, and FIG. FIG. 4 is a sectional view showing a detailed configuration of the pressure control valve, FIG. 4 is a flowchart showing an operation example of one embodiment of the present invention, FIG. 5 is a time chart for explaining the behavior of each part at the time of starting, FIG.
FIG. 7 is a graph showing the relationship between the engine speed and the throttle amount and the engine output torque. FIG. 7 is a time chart for explaining the behavior of each part during traveling. FIG. FIG. 9 is a chart for explaining one method for determining the build-up start timing, FIG. 10 and FIG.
The figures are time charts for explaining another method for determining the build-up start timing. 10 ... Controller, 20 ... Engine, 21 ... Engine rotation sensor, 22 ... Transmission input shaft sensor,
23: Transmission output shaft sensor, 25: Torque converter, 30: Transmission, 40: Final reducer, 41: Drive wheel, 50: Lock-up clutch, 55, 6
1 to 64: Pressure control valve, 51, 60 ... Clutch hydraulic pressure supply device, 70 ... Throttle amount sensor, 75 ... Vehicle weight sensor, 80
… Shift selector, 905 …… Solenoid.

Continuation of the front page (56) References JP-A-60-143268 (JP, A) JP-A-61-24621 (JP, A) JP-A-61-74948 (JP, A) JP-A-61-65946 (JP) , A) JP-B 60-2549 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 61/14

Claims (1)

(57) [Claims] An input shaft and an output shaft of a torque converter disposed between an engine and a transmission are directly connected, and are engaged and released according to a differential pressure obtained by subtracting an internal pressure of the torque converter from a clutch oil pressure in a lock-up clutch chamber. A lock-up clutch, a pressure control valve that varies the clutch oil pressure supplied to the lock-up clutch in accordance with an electric command applied to the proportional solenoid, and an electric command input to the proportional solenoid of the pressure control valve. Control means for controlling the opening and closing of the pressure control valve and controlling the clutch oil pressure of the lock-up clutch by an electric command; a first detection means for detecting a throttle amount; Second detecting means for detecting the vehicle weight, and a train determined by the speed gear. A third detecting means for detecting a gear ratio of a transmission; an internal pressure calculating means for calculating an internal pressure of the torque converter; and a shift end detecting means for detecting the end of a shift. When a start command is input, the lock-up clutch oil pressure is reduced to a substantially calculated value of the internal pressure calculating means at this time,
A first pressure for maintaining a predetermined pressure corresponding to the calculated value until a shift end detection signal is output from the shift end detecting means.
A first control means for inputting the electric command to the pressure control valve, and a gradually increasing speed of the lock-up clutch oil pressure based on a detection output of the first, second, and third detection means,
When the end of shift is detected by the shift end detecting means, a second electric command for gradually increasing the lock-up clutch oil pressure with the calculated incremental speed from the detection point is input to the pressure control valve. And a lock-up clutch hydraulic control device that is provided with: 2. The second control means has a memory for preliminarily storing a hydraulic pressure gradually increasing speed corresponding to a throttle amount, a vehicle weight, and a gear ratio, and a hydraulic pressure corresponding to a detection output of the first, second, and third detection means. 2. The lock-up clutch hydraulic control device according to claim 1, wherein an electric command to be input to said pressure control valve is formed by reading a gradually increasing speed value from said memory. 3. The shift end detecting means includes: a memory in which an optimum interval time is stored in advance corresponding to each value of a gear ratio and a throttle amount; and an interval time value corresponding to a detection output of the first and third detecting means. 2. The lock-up clutch hydraulic control according to claim 1, further comprising: means for reading out from the memory, and detecting a point in time at which the read-out interval time elapses from a point in time when a shift start command is input as a shift end time. apparatus. 4. 2. The lock-up clutch hydraulic control according to claim 1, wherein said shift end detecting means detects a point in time when the relative rotational speeds of the input shaft and the output shaft of the transmission become zero or a value near zero as the end of shift. apparatus. 5. The shift end detecting means detects, as a shift end time, a point in time at which a speed ratio between an input shaft and an output shaft of a torque converter (torque converter output shaft rotation speed / torque converter input shaft rotation speed) reaches a predetermined value. The lock-up clutch hydraulic pressure control device according to claim 1. 6. The input shaft and the output shaft of the torque converter disposed between the engine and the transmission are directly connected, and are engaged and released according to a differential pressure obtained by subtracting the internal pressure of the torque converter from the clutch oil pressure in the lock-up clutch chamber. A lock-up clutch, a pressure control valve that varies the clutch oil pressure supplied to the lock-up clutch in accordance with an electric command applied to the proportional solenoid, and an electric command input to the proportional solenoid of the pressure control valve. Control means for controlling the opening and closing of the pressure control valve and controlling the clutch oil pressure of the lock-up clutch by an electric command; a first detection means for detecting a throttle amount; Second detecting means for detecting the vehicle weight, and a train determined by the speed gear. A third detecting means for detecting a gear ratio of a transmission; an internal pressure calculating means for calculating an internal pressure of the torque converter; and a filling end detecting means for detecting filling end of the lock-up clutch. When the start command is input, the lock-up clutch oil pressure is set to a high pressure state for a predetermined time, and thereafter, the lock-up clutch oil pressure is reduced to substantially the calculated value of the internal pressure calculating means, and the predetermined pressure corresponding to the calculated value is reduced. Control means for inputting a first electric command to the pressure control valve, the first electric command being maintained until a detection signal is output from the filling completion detection means, and the first, second, and third detection means. Calculating the gradually increasing speed of the lock-up clutch oil pressure based on the detection output of
When the end of gear shifting is detected by the filling end detecting means, a second electric command for gradually increasing the lock-up clutch oil pressure at the calculated gradually increasing speed from the detection point is input to the pressure control valve. And a lock-up clutch hydraulic control device that is provided with: 7. The second control means has a memory for preliminarily storing a hydraulic pressure gradually increasing speed corresponding to a throttle amount, a vehicle weight, and a gear ratio, and a hydraulic pressure corresponding to a detection output of the first, second, and third detection means. 7. The lock-up clutch hydraulic control device according to claim 6, wherein an electric command to be input to said pressure control valve is formed by reading a gradually increasing speed value from said memory.