JP2819521B2 - Vehicle transmission clutch control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a clutch connection capacity at the time of starting or the like in a vehicle transmission. 2. Description of the Related Art A clutch in a vehicular transmission is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-95722. In this publication, a hydraulic pump and a hydraulic motor are used as a transmission. Is shown. In this device, a short-circuit path is formed between two oil paths that form a closed circuit by connecting a hydraulic pump and a hydraulic motor, and a clutch valve that can adjust the degree of opening is disposed in the short-circuit path. . The clutch engagement capacity is determined by the degree of opening of the clutch valve. For example, when the clutch valve is fully opened, the clutch engagement capacity becomes zero and the clutch is released, and when fully closed, the clutch engagement capacity becomes maximum (100
%) And this clutch is connected. In the apparatus disclosed in the above publication, the control device for controlling the operation of the clutch valve comprises a hydraulic servo cylinder for operating the clutch valve and a control valve for controlling the supply of the operating hydraulic pressure to the hydraulic servo cylinder. Is done. First control means for detecting the engine speed and second detection means for detecting the throttle opening are connected to the control valve. The hydraulic servo cylinder controlled by the control valve controls the clutch valve. It is configured to exert a control force proportional to the engine speed for driving in the closing direction and a control force proportional to the throttle opening for driving the clutch valve in the opening direction. In the above-mentioned conventional clutch device, the opening degree of the short circuit is almost proportional to the operation amount of the clutch valve. By the way, in order to prevent an unnecessary increase in the engine speed due to an increase in the output of the engine when the vehicle starts, that is, in order to prevent the engine from blowing up, the initial load of the engine is appropriate during idling rotation of the engine. It is necessary to appropriately select and control the opening of the short circuit path, that is, the opening of the clutch valve. However, when the accelerator pedal is suddenly depressed to start the vehicle, a signal for increasing the throttle opening in accordance with the amount of depression of the accelerator pedal is promptly input to the control device. Since the increase in the number is slightly delayed, the increase signal of the engine speed is input to the control device with a slight delay. Therefore, momentarily, there occurs a state where the engine speed has not yet risen even though the throttle opening is large, and accordingly, the opening of the short-circuit path is increased and the clutch opening becomes in the opening direction. Is controlled as follows. As a result, the load on the engine becomes too small, and the engine speed increases more than necessary. Moreover, when the increased engine speed is input to the control device, the clutch valve is suddenly operated in the closing direction, so that an appropriate half-clutch state cannot be obtained, and the vehicle starts smoothly. Is hindered. [0006] In order to solve this problem, a method is set in advance in which a target clutch opening is set so that a smooth start can be made from the relationship between the vehicle speed and the throttle opening, and control is performed based on the target clutch opening. In this case, however, in this case, there is a variation in the characteristics of each clutch device, and furthermore, even with the same device, variations in the characteristics occur due to aging or deterioration.Therefore, the target clutch opening must be set in accordance with this variation. For example, there is a problem that start control or the like with a good feeling cannot be performed. In view of the above, the present applicant sets a target clutch opening in accordance with the vehicle speed and the throttle opening,
The opening control speed of the clutch valve is set according to the difference between the target clutch opening and the actual clutch opening, and the opening of the clutch valve is set to the target clutch opening based on the opening control speed. Figured out how to control. The operation control of the clutch valve according to this method needs to be performed independently of the engine rotation and the throttle opening. This cannot be done with the device. For this reason, it is necessary to control the supply of the operating oil pressure to the hydraulic servo cylinder independently by using, for example, a duty control solenoid valve. However, when the supply of the operating oil pressure is controlled using the solenoid valve as described above, the duty ratio is set to 0 in the state where the opening of the solenoid valve is fully closed or almost fully opened, for example, in the case of the duty control solenoid valve. % Or close to 100%, the linearity of the change in the amount of oil flowing through the solenoid valve tends to deteriorate with respect to the change in the opening of the solenoid valve.
There is a problem that the influence of individual differences is large. In particular,
When the duty ratio is close to 0% and the solenoid valve is almost fully open, the flow rate through the solenoid valve is greatly affected by not only the opening area of the solenoid valve but also the line resistance before and after the solenoid valve. The flow rate change is not proportional to the change. Further, the pipeline resistance often differs from device to device, and as a result, the flow rate itself often varies greatly from device to device. For this reason, when the operation control of the hydraulic servo cylinder is performed using the solenoid valve, the state of the opening of the solenoid valve is fully closed or almost fully opened, that is, the state where the duty ratio is close to 0% or 100%. In this case, there is a problem that the operating speed of the hydraulic servo cylinder in this state varies greatly, and accurate clutch control cannot be performed. In the above, the clutch valve provided in the hydraulic continuously variable transmission has been described as an example. However, a similar problem occurs when a friction clutch is used instead of the clutch valve. In the case of a friction clutch, the engagement capacity of the clutch is to be controlled, and this engagement capacity can be determined by detecting the position of the clutch release bearing, for example. For this reason, in the following, both of these, including the opening of the clutch valve and the engagement capacity of the friction clutch, will be referred to as clutch capacity. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in a clutch control device in which the supply of hydraulic oil to a hydraulic servo cylinder for operating a clutch is controlled by a solenoid valve, the operation control is accurately performed. It is an object of the present invention to provide a clutch control method capable of causing the clutch control. [0013] In order to achieve the above object, a clutch control method according to the present invention is arranged such that the supply of control oil pressure to a hydraulic servo cylinder for operating a clutch is controlled by a solenoid valve. The actual throttle opening of the engine, the actual clutch engagement capacity of the clutch, and the actual vehicle speed of the vehicle,
The target clutch engagement capacity corresponding to the actual throttle opening and the actual vehicle speed is set from a table in which the relationship between the throttle opening, the vehicle speed and the target clutch engagement capacity is set. The operation speed of the solenoid valve is set in accordance with the clutch engagement capacity difference of the solenoid valve so that the actual clutch engagement capacity of the clutch approaches the target clutch engagement capacity based on the engagement operation control speed. Is controlled. At this time, when the clutch engagement capacity difference is within a predetermined range, a speed that increases in proportion to the absolute value of the clutch engagement capacity difference is set as the engagement operation control speed, and the clutch engagement capacity difference is set to a predetermined value. When the value exceeds the range, the maximum engagement operation control speed set when the clutch engagement capacity difference is a value within the predetermined range is set as the engagement operation control speed of the clutch. When the operation of the clutch is controlled using the above-described clutch control method, for example, when the throttle valve is rapidly opened when the vehicle starts moving, the target clutch is controlled in accordance with the vehicle speed and the throttle opening at this time. An engagement capacity is set, and according to a clutch engagement capacity difference between the target clutch engagement capacity and the actual clutch engagement capacity, control is performed to release the actual clutch engagement capacity at that time toward the target clutch engagement capacity. Speed is set. For this reason, even when the throttle valve is suddenly opened at the time of starting, the clutch engagement capacity is controlled to be the target clutch engagement capacity, and
At this time, the operation of the clutch is controlled so as to have a speed corresponding to the difference between the actual clutch engagement capacity and the target clutch engagement capacity, so that a half-clutch state suitable for starting is realized, and the engine speed increases. There is no smooth clutch connection. The clutch control is performed by controlling the supply of the operating oil pressure to the hydraulic servo cylinder by the solenoid valve. The engagement operation control speed set by the solenoid valve is different from the clutch engagement capacity difference. When the value is within the predetermined range, a speed that increases in proportion to the absolute value of the clutch engagement capacity difference is set, and when the clutch engagement capacity difference is a value exceeding the predetermined range, the speed is set within the predetermined range. The set maximum value (constant value) is set. That is, when the clutch engagement capacity difference is within a predetermined value range, the engagement operation control speed increases in accordance with the absolute value of the engagement capacity difference, but when the difference exceeds the predetermined range, the control speed is constant. Value and will not increase further. For this reason, in the opening control of the solenoid valve (that is, the duty ratio control), the duty ratio region (opening region close to 0% or 100% duty ratio) in which the opening degree is in the fully opened and fully closed state is not used. The control speed can be set using only the middle opening region (that is, the opening region centered on the 50% duty ratio), and the control speed can be set accurately. Preferred embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show the hydraulic circuit of a continuously variable transmission having a clutch valve controlled by the method according to the invention. The continuously variable transmission T has a constant displacement hydraulic pump P driven by the engine E via an input shaft 1 and a variable displacement hydraulic motor M having an output shaft 2 for driving wheels W. . The hydraulic pump P and the hydraulic motor M are connected to a first oil passage La that communicates a discharge port of the pump P and a suction port of the motor M, and a second oil passage Lb that communicates a suction port of the pump P and a discharge port of the motor M. The two oil passages are connected to form a hydraulic closed circuit. The discharge port of the charge pump 10 driven by the engine E is connected to a closed circuit via a charge oil passage Lh having a check valve 11 and a third oil passage Lc having a pair of check valves 3 and 3. The operating oil pumped up from the oil sump 15 by the charge pump 10 and regulated by the charge pressure relief valve 12 is supplied to the low-pressure side oil of the two oil passages La and Lb by the action of the check valves 3 and 3. Supplied to the road. Further, a fourth oil passage Ld having a shuttle valve 4 having high and low pressure relief valves 6 and 7 connected to an oil sump 15 and connected to fifth and sixth oil passages Le and Lf is connected to the closed circuit. It is connected to the. The shuttle valve 4 is a two-port three-position switching valve.
The second oil passage La, Lb operates in response to a difference in oil pressure between the first and second oil passages La, Lb.
The oil passage Le is communicated with the oil passage Le, and the oil passage on the low pressure side is communicated with the sixth oil passage Lf. Thereby, the relief oil pressure of the high pressure side oil passage is adjusted by the high pressure relief valve 6, and the relief oil pressure of the low pressure side oil passage is adjusted by the low pressure relief valve 7. Further, a seventh oil passage Lg for short-circuiting both oil passages is provided between the first and second oil passages La and Lb, and the opening degree of the oil passage is provided in the seventh oil passage Lg. Is provided with a clutch valve 5 composed of a variable throttle valve for controlling the pressure. This clutch valve 5 is operated by a clutch servo cylinder 80 connected via a link 88. For this reason, the clutch servo cylinder 80 is operated, and the clutch valve 5
By controlling the throttle amount, clutch control for controlling transmission of driving force from the hydraulic pump P to the hydraulic motor M can be performed. Further, the displacement ratio of the continuously variable transmission T can be controlled by controlling the displacement of the hydraulic motor M. The hydraulic motor M is, for example, a swash plate axial piston motor. By controlling the swash plate angle, the displacement control can be performed by controlling the displacement thereof. The operation of the clutch servo cylinder 80 is controlled by a pair of solenoid valves 155 and 156 that are duty ratio controlled in response to a signal from the controller 100. The controller 100 includes a vehicle speed V, an engine speed Ne, a throttle opening θth, a swash plate inclination angle θtr of the hydraulic motor M, an accelerator pedal opening θacc operated by a driver, an atmospheric pressure Pat, an oil temperature To, Signals indicating the water temperature Tw and the clutch opening degree θcl are input, and based on these signals, a signal for controlling each of the above-described solenoid valves so as to perform desired clutch control is output. Here, the clutch servo cylinder 80 for controlling the operation of the clutch valve 5 will be described with reference to FIG. The cylinder 80 includes a cylinder member 81, a piston member 82 slidably inserted into the cylinder member 81 left and right in the drawing, and a cover member 85 attached to cover the cylinder chamber in which the piston member 82 is inserted. And a spring 87 for urging the piston member 82 leftward in the figure. The rod 82b of the piston member 82 is
1, the piston 82a projects outward from the left side, and the piston 82a divides the cylinder chamber into two to form a head-side cylinder chamber 83 in which the head surface of the piston 82a faces and a rod-side cylinder chamber 84 in which the rod 82b passes. Hydraulic lines 110 and 112 are connected to the two cylinder chambers 83 and 84 via ports 86a and 86b. The hydraulic pressure of the hydraulic pressure line 110 is such that hydraulic oil adjusted by the charge pressure relief valve 12 from the discharge oil of the charge pump 10 is led through the hydraulic pressure line 101, and the hydraulic pressure of the hydraulic pressure line 104 is Line 10
The hydraulic pressure is obtained by controlling the hydraulic pressure of the hydraulic line 111 having the orifice 111a branched from 1 by the first and second solenoid valves 155 and 156 whose duty ratio is controlled. The first solenoid valve 156 controls the flow of hydraulic oil from the hydraulic line 111 having the orifice 111 a to the hydraulic line 112 according to the duty ratio, and the second solenoid valve 155 controls the hydraulic pressure branched from the hydraulic line 112. Hydraulic line 1 communicating with the drain side via line 113 and orifice 114a
14 to allow the hydraulic oil to flow out from the hydraulic line 113 to the drain side according to a predetermined duty ratio. Therefore, the charge pressure relief valve 12 is connected to the rod side cylinder chamber 52 through the hydraulic line 110.
The charge pressure adjusted by the pressure acts on the other hand, while the two solenoid valves 155, 1
By the operation of 56, a pressure lower than the charge pressure is supplied to the head-side cylinder chamber 83. Here, since the pressure receiving area of the rod side cylinder chamber 84 is smaller than the pressure receiving area of the head side cylinder chamber 83, the force received by the piston member 82 by the oil pressure in both cylinder chambers 83, 84 takes into consideration the urging force of the spring 87. However, the hydraulic pressure P1 in the rod side cylinder chamber 84
On the other hand, when the hydraulic pressure in the head side cylinder chamber 83 is lower than the predetermined value P2 (P1> P2), the pressure is balanced. Therefore, if the hydraulic pressure supplied from the hydraulic line 112 to the head side cylinder chamber 83 is controlled by the first and second solenoid valves 155 and 156 so as to be larger than the predetermined value P2, the piston member 82 is controlled. If the hydraulic pressure supplied to the head side cylinder chamber 83 is controlled to be smaller than P2, the piston member 82 can be moved to the left. Further, at this time, the larger the difference from the predetermined value P2, the faster the moving speed of the piston member 82. That is, the first and second solenoid valves 155 and 156 control the moving direction and the moving speed of the piston member 82. The left-right movement of the piston member 82 is transmitted to the clutch valve 5 via a link mechanism 88. The clutch valve 5 includes a fixed member 5a having a first valve hole 5b and a rotating member 5c having a second valve hole 5d rotatably disposed in the fixed member 5a, and is connected to the rotating member 5c. The arm 5e is connected to the link mechanism 88.
The rotation member 5c is rotated with the movement of the piston member 82. When the rotating member 5c is rotated, the communication opening degree of the first and second valve holes 5b and 5d changes from fully open to fully closed. As shown in the figure, when the piston member 82 has moved to the left
Is fully opened, and thereafter the communication opening gradually changes to fully closed as the piston member 82 is moved rightward. Here, the first valve hole 5b is provided in the continuously variable transmission T.
And the second valve hole 5d communicates with the second oil passage Lb, so that the communication opening degree of the first and second valve holes 5b and 5d is changed. By doing so, the degree of opening of the seventh oil passage Lg, which is a short circuit between the first and second oil passages La and Lb, can be changed, whereby clutch engagement capacity control is performed. That is, clutch engagement control is performed by controlling the duty ratio of the first and second solenoid valves 155 and 156 based on a signal from the controller 100. Note that the clutch engagement capacity at the time of performing this control is determined by the opening degree, and therefore, the clutch engagement capacity can be obtained by detecting the rotational position of the rotating member 5c. The clutch control by the operation control of each solenoid valve in the continuously variable transmission having the above-described configuration will be described. This control is performed as shown in the flowchart of FIG. In this control, the engine throttle opening θacc and the vehicle speed V are read, and the target clutch opening θcln is calculated from the vehicle speed V and the throttle opening θacc. This calculation is performed for each throttle opening θacc (1), θacc (2),... Θacc (n) as shown in FIG.
c (1): throttle fully closed, θacc (n): throttle fully open),
From a graph representing the target clutch opening θcln set corresponding to the vehicle speed V, a calculation is performed based on the read vehicle speed V and the throttle opening θacc. Note that θcln is 0
It has values from ° to 90 °. Thereafter, the difference Δθcl (= θclo−θcl) between the target clutch opening θclo and the actual clutch opening θcl is calculated, and the clutch opening control speed Scl is obtained from the graph of FIG. As can be clearly understood from FIG. 6, the control speed Scl is set in the connection direction (ON direction) in which the clutch valve 5 is closed when the difference Δθcl is positive, and the clutch valve 5 is opened when the difference Δθcl is negative. Cutting direction (OFF
Direction). Further, when the difference Δθcl is within the predetermined range, the speed Scl increases in proportion to the difference Δθcl, and when the difference Δθcl exceeds the predetermined range, the control speed Scl is set to be substantially constant. When the control speed Scl is calculated in this manner, the clutch valve 5 is calculated based on the control speed Scl.
Is activated from controller 100 to solenoid valves 155 and 156.
At this time, as shown in FIG. 6, the control speed Scl increases in proportion to the clutch opening difference Δcl up to a predetermined value, but is constant when the clutch opening difference Δcl is larger than the predetermined value. Therefore, the solenoid valves 155 and 156 can be used in a range in which the opening degree of the solenoid valves 155 and 156 is in an intermediate opening region (that is, an intermediate region where the duty ratio is about 50%), and the solenoid valves 155 and 155 for duty control can be used.
The flow control by 156 is performed accurately. For this reason, clutch operation speed control is also performed accurately. As described above, according to the present invention,
The target clutch engagement capacity is set according to the actual throttle opening and the actual vehicle speed, and the clutch engagement operation control speed is set according to the clutch engagement capacity difference between the target clutch engagement capacity and the actual clutch engagement capacity. The operation of the solenoid valve is controlled so that the actual clutch engagement capacity of the clutch is set closer to the target clutch engagement capacity based on the engagement operation control speed. Is rapidly opened, the target clutch engagement capacity is set according to the vehicle speed and the throttle opening at this time, and the target clutch engagement capacity is set according to the clutch engagement capacity difference between the target clutch engagement capacity and the actual clutch engagement capacity. The control speed at which the actual clutch engagement capacity at that time is released toward the target clutch engagement capacity is set. For this reason, even when the throttle valve is suddenly opened at the time of starting, the clutch engagement capacity is controlled to be the target clutch engagement capacity, and the operation of the clutch at this time is determined by the actual clutch engagement capacity. And a speed corresponding to the difference between the target clutch engagement capacity and the target clutch engagement capacity, so that a half-clutch state suitable for starting is realized, and smooth clutch connection without engine blow-up is performed. Further, in the control method of the present invention, when performing the above-described clutch control, if the clutch engagement capacity difference is within a predetermined range, the clutch engagement capacity difference is proportional to the absolute value of the clutch engagement capacity difference. Is set as the engagement operation control speed, and when the clutch engagement capacity difference exceeds the predetermined range, the maximum value (constant value) of the values set within the predetermined range is set as the engagement operation control speed. To be set. Since the clutch control in the present invention is performed by controlling the supply of the operating oil pressure to the hydraulic servo cylinder by the solenoid valve, the engagement operation control speed is controlled in such a manner that the clutch engagement capacity difference is within a predetermined value range. If the difference exceeds a predetermined range, the control speed becomes a constant value and if it is set so as not to increase further, the opening degree of the solenoid valve is increased. At the time of control, the duty ratio region (opening region close to 0% or 100% duty ratio) in which the opening state is in the fully opened and fully closed state is not used, and the intermediate opening region (that is, the center of the 50% duty ratio) is used. The control speed can be set only by using the range of the opening degree in which the control is performed, and the control speed can be set accurately.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission clutch controlled by the method of the present invention. FIG. 2 is a hydraulic circuit diagram of a continuously variable transmission clutch controlled by the method of the present invention. FIG. 3 is a sectional view of a clutch control servo cylinder of the continuously variable transmission. FIG. 4 is a flowchart illustrating clutch control according to the present invention. FIG. 5 is a graph showing a relationship between a target clutch opening, a throttle opening, and a vehicle speed. FIG. 6 is a graph showing a relationship between a clutch opening difference and a clutch opening control speed. [Description of Signs] 4 Shuttle valve 5 Clutch valve 80 Clutch servo cylinder 100 Controller 155, 156 Solenoid valve E Engine T Continuously variable transmission

Claims (1)

(57) [Claims] A transmission mechanism capable of variably controlling a transmission ratio, a clutch for controlling transmission of engine output transmitted to the drive side via the transmission mechanism, a hydraulic servo cylinder for operating the clutch, and control for the hydraulic servo cylinder A method for controlling the operation of the clutch in a vehicle transmission having a solenoid valve that controls the supply of hydraulic pressure to control the operation of the hydraulic servo cylinder, comprising: The actual clutch engagement capacity of the clutch and the actual vehicle speed of the vehicle are detected, and the relationship is set so that the clutch engagement capacity decreases as the throttle opening increases and the clutch engagement capacity increases as the vehicle speed increases. From the table of the target clutch engagement capacity with respect to the throttle opening and the vehicle speed, A corresponding target clutch engagement capacity is set, and a clutch engagement capacity difference between the target clutch engagement capacity and the actual clutch engagement capacity is determined. When the clutch engagement capacity difference is within a predetermined range, A speed that increases in proportion to the absolute value of the clutch engagement capacity difference is set as an engagement operation control speed of the clutch. When the clutch engagement capacity difference is a value exceeding the predetermined range, the clutch engagement capacity is increased. A maximum engagement operation control speed set when the capacity difference is a value within a predetermined range is set as an engagement operation control speed of the clutch, and an actual clutch engagement capacity of the clutch is set to the engagement operation control speed. And controlling the operation of the solenoid valve so as to approach the target clutch engagement capacity on the basis of the following.