Linear solenoid valve control device

Abstract

To suppress a large variation of the output hydraulic pressure of a linear solenoid valve.SOLUTION: A hydraulic pressure command value of a linear solenoid valve is set. Subsequently, a current command value of a solenoid portion is set in such a manner that the current command value becomes large as the hydraulic pressure command value becomes large. Then, when a first condition that a current command value increase rate being an increase amount of the current command value per unit time is equal to or higher than a first threshold is not established, a dither command value of a first amplitude is set, and when the first condition is established, a dither command value of a second amplitude which is equal to or larger than zero, and smaller than the first amplitude is set. Furthermore, a current based on the current command value and the dither command values is supplied to the solenoid portion.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a linear solenoid valve. [Background technology]

[0002] A conventional technique of this type is a linear solenoid valve drive device that converts a drive command value for a linear solenoid valve into a current command value for the linear solenoid valve, sets a dither command value including an amplitude command for the dither current, and generates a PWM signal based on the current flowing through the linear solenoid valve, the current command value, and the dither command value, and supplies this to the linear solenoid valve (see, for example, Patent Document 1). In this device, the current flowing through the linear solenoid valve is compared with the current command value, and the dither command value is set based on the comparison result. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-230463 Summary of the Invention [Problem to be solved by the invention]

[0004] In a linear solenoid valve having a sleeve with an input port and an output port, a spool slidably disposed within the sleeve, and a solenoid unit that moves the spool within the sleeve based on a supplied current, when the amount of communication between the input port and the output port changes greatly per unit movement of the spool, if the amplitude of the dither command value is large, this amount of communication will fluctuate greatly, and the output oil pressure of the linear solenoid valve may fluctuate greatly.

[0005] The main object of the linear solenoid valve control device of the present disclosure is to suppress large fluctuations in the output hydraulic pressure of the linear solenoid valve. [Means for solving the problem]

[0006] The linear solenoid valve control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] A first linear solenoid valve control device of the present disclosure includes a sleeve having an input port and an output port, a spool slidably disposed within the sleeve, and a solenoid unit that moves the spool within the sleeve to a side where the amount of communication between the input port and the output port increases as the current supplied thereto increases, and when the amount of communication is greater than a predetermined amount, the amount of change in the amount of communication per unit movement of the spool increases compared to when the amount of communication is equal to or less than the predetermined amount. The linear solenoid valve control device also includes a step of setting a hydraulic pressure command value for the linear solenoid valve. a current command value setting unit that sets a current command value for the solenoid unit so that the current command value increases as the hydraulic pressure command value increases; a dither command value setting unit that sets a dither command value of a first amplitude when a first condition is not met, that is, a current command value increase rate, which is an increase amount of the current command value per unit time, is equal to or greater than a first threshold value, and that sets the dither command value of a second amplitude, which is equal to or greater than 0 and smaller than the first amplitude, when the first condition is met; and a current supply unit that supplies a current based on the current command value and the dither command value to the solenoid unit.

[0008] In a first linear solenoid valve control device according to the present disclosure, a hydraulic pressure command value for the linear solenoid valve is set. Subsequently, a current command value for the solenoid unit is set so that the current command value increases as the hydraulic pressure command value increases. When a first condition, in which a current command value increase rate, which is the amount of increase per unit time of the current command value, is equal to or greater than a first threshold, is not met, a dither command value with a first amplitude is set. When the first condition is met, a dither command value with a second amplitude, which is equal to or greater than 0 and smaller than the first amplitude, is set. Furthermore, a current based on the current command value and the dither command value is supplied to the solenoid unit. When the first condition is met, the amount of communication between the input port and the output port may be greater than or already greater than a predetermined amount. Therefore, when the first condition is met, the current supplied to the solenoid unit is controlled using a dither command value with a relatively small second amplitude, thereby suppressing large fluctuations in the amount of communication between the input port and the output port and suppressing large fluctuations in the output hydraulic pressure of the linear solenoid valve. Of course, when the first condition is not satisfied, the sliding resistance between the spool and sleeve of the linear solenoid valve can be sufficiently reduced by controlling the current supplied to the solenoid unit using a dither command value with a relatively large first amplitude.

[0009] A second linear solenoid valve control device of the present disclosure includes a sleeve having an input port and an output port, a spool slidably disposed within the sleeve, and a solenoid unit that moves the spool within the sleeve to a side where the amount of communication between the input port and the output port decreases as the current supplied thereto increases, and when the amount of communication is greater than a predetermined amount, the amount of change in the amount of communication per unit movement of the spool increases compared to when the amount of communication is equal to or less than the predetermined amount, and the linear solenoid valve control device further includes a step of setting a hydraulic pressure command value for the linear solenoid valve. a current command value setting unit that sets a current command value for the solenoid unit so that the current command value decreases as the hydraulic pressure command value increases; a dither command value setting unit that sets a dither command value of a first amplitude when a first condition is not met, that is, a current command value decrease rate, which is an amount of decrease in the current command value per unit time, is equal to or greater than a first threshold value, and that sets the dither command value of a second amplitude, which is equal to or greater than 0 and smaller than the first amplitude, when the first condition is met; and a current supply unit that supplies a current based on the current command value and the dither command value to the solenoid unit.

[0010] In a second linear solenoid valve control device according to the present disclosure, a hydraulic pressure command value for the linear solenoid valve is set. Subsequently, a current command value for the solenoid unit is set so that it decreases as the hydraulic pressure command value increases. When a first condition, in which a current command value decrease rate, which is the amount of decrease in the current command value per unit time, is equal to or greater than a first threshold, is not met, a dither command value with a first amplitude is set. When the first condition is met, a dither command value with a second amplitude, which is equal to or greater than 0 and smaller than the first amplitude, is set. Furthermore, a current based on the current command value and the dither command value is supplied to the solenoid unit. When the first condition is met, the amount of communication between the input port and the output port may be greater than or already greater than a predetermined amount. Therefore, when the first condition is met, the current supplied to the solenoid unit is controlled using a dither command value with a relatively small second amplitude, thereby suppressing large fluctuations in the amount of communication between the input port and the output port and suppressing large fluctuations in the output hydraulic pressure of the linear solenoid valve. Of course, when the first condition is not satisfied, the sliding resistance between the spool and sleeve of the linear solenoid valve can be sufficiently reduced by controlling the current supplied to the solenoid unit using a dither command value with a relatively large first amplitude. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram showing an ECU and a linear solenoid valve according to the present disclosure. [Figure 2] 1 is a schematic configuration diagram showing an ECU and a linear solenoid valve according to the present disclosure. [Figure 3] 5A, 5B, and 5C are cross-sectional views illustrating the operation of the linear solenoid valve of the present disclosure. [Figure 4] 10 is a flowchart illustrating an example of a dither amplitude setting process repeatedly executed by a dither command value setting unit. [Figure 5] 5A and 5B are explanatory diagrams showing an example of a state when a hydraulic engagement element is engaged in the present embodiment. [Figure 6]10 is an explanatory diagram showing an example of a state when a hydraulic engagement element is engaged in a comparative example. FIG. [Figure 7] 10 is a flowchart illustrating an example of a dither amplitude setting process repeatedly executed by a dither command value setting unit. [Figure 8] 10 is an explanatory diagram showing an example of a state in which a hydraulic engagement element is engaged when the linear solenoid valve is a normally open linear solenoid valve; FIG. [Figure 9] FIG. 2 is a schematic diagram illustrating an ECU and a linear solenoid valve. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0013] 1 and 2 are schematic diagrams showing an electronic control unit (hereinafter referred to as "ECU") 6, which is a control device of the present disclosure, and linear solenoid valves SL controlled by the ECU 6. Each linear solenoid valve SL as shown in the figures is incorporated into the valve body of a hydraulic control device that performs hydraulic control of hydraulic engagement elements such as clutches and brakes of a transmission mounted on a vehicle, together with a primary regulator valve, a pressure regulating valve, a switching valve, a manual valve, etc.

[0014] In this embodiment, the linear solenoid valve SL is a so-called direct linear solenoid valve that supplies pressure-regulated hydraulic oil directly to an engagement oil chamber of a hydraulic engagement element. As shown in Figures 1 and 2, the linear solenoid valve SL includes a solenoid unit 2 and a valve unit 3 that is driven by the solenoid unit 2 and regulates the pressure of the hydraulic oil. The linear solenoid valve SL in this embodiment is a normally closed linear solenoid valve that outputs hydraulic pressure when power is supplied to the solenoid unit 2.

[0015] The solenoid unit 2 includes first and second cylindrical cores arranged side by side in the axial direction, a cylindrical coil surrounding the first and second cores, a plunger arranged within the second core so as to be freely movable in the axial direction, a rod 20 that can move axially within the first core in conjunction with the plunger, and a yoke (case) that houses these components (only the rod 20 is shown in FIG. 1). When current flows through the coil of the solenoid unit 2, a magnetic flux circuit is formed in which the current flows through the yoke, second core, plunger, and first core in this order. This attracts the plunger toward the first core, and the rod 20 moves in conjunction with the plunger in a direction that protrudes from the first core (to the left in FIG. 1). In this embodiment, the current supplied to the solenoid unit 2 is controlled by a PWM signal generated based on a hydraulic pressure command value.

[0016] As shown in Fig. 1, the valve section 3 has a substantially cylindrical sleeve 4 that is incorporated into the valve body, and a spool 5 that is axially slidable (movable) within the sleeve 4. One end of the sleeve 4 (the right end in the figure) is fixed to the solenoid section 2 (yoke), and a cap CP that closes the end is fixed (screwed) to the end of the sleeve 4 opposite the solenoid section 2 (the left end in the figure). A spring (elastic member) SP is also disposed within the sleeve 4, positioned between the spool 5 and the cap CP. In this embodiment, the spring SP is a coil spring that biases the spool 5 toward the solenoid section 2 (the right side in Fig. 1).

[0017] As shown in FIG. 1 , the sleeve 4 has an input port 4i, an output port 4o, a drain port (discharge port) 4d, and a feedback port 4f, each of which communicates with a corresponding oil passage formed in the valve body. The input port 4i receives hydraulic oil (line pressure) discharged from, for example, an oil pump and then adjusted by a regulator valve. The hydraulic oil, adjusted by the linear solenoid valve SL, flows from the output port 4o to a hydraulic supply oil passage in the valve body. The hydraulic supply oil passage communicates with the engagement oil chamber of the hydraulic engagement element. Furthermore, the drain port 4d communicates with a hydraulic oil reservoir via a drain oil passage in the valve body, and the feedback port 4f communicates with the output port 4o via an oil passage formed in the valve body. In this embodiment, the input port 4i, the output port 4o, the drain port 4d, and the feedback port 4f are formed in the sleeve 4 so as to be aligned axially at intervals in this order from the solenoid unit 2 side toward the spring SP (cap CP) side. That is, the input port 4i is formed closer to the solenoid section 2 than the output port 4o, the drain port 4d is formed closer to the spring SP than the output port 4o, and the feedback port 4f is formed closer to the spring SP than the drain port 4d.

[0018] An input chamber 40i communicating with the input port 4i, an output chamber 40o communicating with the output port 4o, a drain chamber 40d communicating with the drain port 4d, and a feedback chamber 40f communicating with the feedback port 4f are defined at intervals in the axial direction within the sleeve 4. Furthermore, a first communication chamber 41 opening at the input chamber 40i and the output chamber 40o, a second communication chamber 42 opening at the output chamber 40o and the drain chamber 40d, and a third communication chamber 43 opening at the drain chamber 40d and the feedback chamber 40f are defined within the sleeve 4. The input chamber 40i, the output chamber 40o, the drain chamber 40d, and the feedback chamber 40f are all circular space portions with the same inner diameter (cross-sectional area). The first to third communication chambers 41, 42, 43 are spaces with a circular cross section and have the same inner diameter (cross-sectional area) that is smaller than the inner diameter (cross-sectional area) of the input chamber 40i, etc. The input chamber 40i, the output chamber 40o, the drain chamber 40d, the feedback chamber 40f, and the first to third communication chambers 41, 42, 43 extend coaxially along the axis of the sleeve 4.

[0019] As shown in FIG. 1 , the spool 5 has four lands 51, 52, 53, and 54, a first shank 5a between the lands 51 and 52, a second shank 5b between the lands 52 and 53, and a third shank 5c between the lands 53 and 54. The lands 51, 52, and 53 are cylindrical and have the same outer diameter (cross-sectional area), while the land 54 is cylindrical and has a smaller outer diameter (cross-sectional area) than the lands 51-53. The outer diameters of the lands 52 and 53 are set to be slightly smaller than the inner diameters of the first to third communication chambers 41, 42, and 43 of the sleeve 4. Furthermore, in this embodiment, the land 52 of the spool 5 has an axial length longer than the axial length of the output chamber 40o of the sleeve 4. The first to third shanks 5a-5c are cylindrical and have smaller outer diameters (cross-sectional areas) than at least the outer diameters (cross-sectional areas) of the lands 52 and 53. The lands 51-54 and the first to third shaft portions 5a-5c extend coaxially with one another along the axis of the spool 5.

[0020] A land 51 of the spool 5 is slidably disposed within a hole (circular hole) formed in the sleeve 4 so as to communicate with the input chamber 40i on the solenoid unit 2 side. A contact portion 50 that contacts the rod 20 of the solenoid unit 2 and a stopper portion 5s are formed at the tip (right end in FIG. 1 ) of the land 51. A land 54 of the spool 5 is slidably disposed within a hole (circular hole) formed in the sleeve 4 so as to communicate with the feedback chamber 40f on the spring SP (cap CP) side, and the spring SP is disposed between the land 54 and the cap CP. The spool 5 is thus slidably disposed within the sleeve 4 and is biased toward the solenoid unit 2 by the spring SP. As the spool 5 moves, the state of communication between the input port 4i and the output port 4o of the sleeve 4 and the state of communication between the output port 4o and the drain port 4d are changed by the land 52 of the spool 5.

[0021] In the linear solenoid valve SL configured as described above, when power is not supplied to the coil of the solenoid unit 2, the spool 5 (and rod 20) is pressed against the plunger of the solenoid unit 2 by the biasing force of the spring SP, as shown in Figures 1 and 3(a). As a result, as shown in Figure 3(a), an end face 52i of the land 52 of the spool 5 facing the input chamber 40i is positioned within the first communication chamber 41, and an end face 52d of the land 52 facing the drain chamber 40d is positioned within the output chamber 40o. Because the end face 52i of the land 52 facing the input chamber 40i is positioned within the first communication chamber 41, the input port 4i and the output port 4o are communicated via a slight clearance between the outer peripheral surface of the land 52 and the inner peripheral surface of the sleeve 4 that defines the first communication chamber 41. Furthermore, since the end face 52d of the land 52 on the drain chamber 40d side is located within the output chamber 40o, the output chamber 40o and the drain chamber 40d communicate with each other with a sufficient amount of communication via the second communication chamber 42. Hereinafter, this state of the linear solenoid valve SL will be referred to as the "first state."

[0022] When current is supplied to the solenoid unit 2 and the rod 20 moves together with the plunger toward the spring SP, the spool 5 is pressed by the rod 20 and moves toward the spring SP (cap CP) against the biasing force of the spring SP. In the linear solenoid valve SL, as the spool 5 moves toward the spring SP, as shown in FIG. 3(b), an end face 52i of the land 52 on the input chamber 40i side is positioned within the first communication chamber 41, while an end face 52d of the land 52 on the drain chamber 40d side is positioned within the second communication chamber 42, beyond the boundary between the output chamber 40o and the second communication chamber 42. Because the end face 52i of the land 52 on the input chamber 40i side is positioned within the first communication chamber 41, the input port 4i and the output port 4o are communicated via a slight clearance between the outer peripheral surface of the land 52 and the inner peripheral surface of the sleeve 4 that defines the first communication chamber 41. Furthermore, because the end face 52d of the land 52 facing the drain chamber 40d is located within the second communication chamber 42, the output port 4o and the drain port 4d communicate with each other via a small clearance between the outer peripheral surface of the land 52 and the inner peripheral surface of the sleeve 4 that defines the second communication chamber 42. Hereinafter, this state of the linear solenoid valve SL will be referred to as the "second state."

[0023] As the current supplied to the solenoid unit 2 increases and the spool 5 is further pressed by the rod 20 to move toward the spring SP (cap CP), as shown in FIG. 3(c), the end face 52d of the land 52 facing the drain chamber 40d is positioned within the second communication chamber 42, while the end face 52i of the land 52 facing the input chamber 40i is positioned within the output chamber 40o, beyond the boundary between the first communication chamber 41 and the output chamber 40o. The end face 52i of the land 52 positioned within the output chamber 40o establishes sufficient communication between the input chamber 40i and the output chamber 40o via the first communication chamber 41. Furthermore, the end face 52d of the land 52 facing the drain chamber 40d is positioned within the second communication chamber 42, establishing communication between the output port 4o and the drain port 4d via a slight clearance between the outer circumferential surface of the land 52 and the inner circumferential surface of the sleeve 4 that defines the second communication chamber 42. Hereinafter, this state of the linear solenoid valve SL will be referred to as the "third state."

[0024] Hereinafter, the amount of movement of the spool 5 of the valve unit 3 of the linear solenoid valve SL from its initial position (position in the first state) will be referred to as the "stroke amount S1." Furthermore, the stroke amount S1 when the end face 52i of the land 52 of the spool 5 on the input chamber 40i (input port 4i) side is positioned at the boundary between the first communication chamber 41 and the output chamber 40o (output port 4o) will be referred to as the "predetermined stroke amount Sref1." The amount of communication between the input port 4i and the output port 4o of the sleeve 4 is a predetermined amount (a slight clearance between the outer peripheral surface of the land 52 and the inner peripheral surface of the sleeve 4 that defines the first communication chamber 41) when the stroke amount S1 is equal to or less than the predetermined stroke amount Sref1 (when in the first state or the second state). However, when the stroke amount S1 is greater than the predetermined stroke amount Sref1 (when in the third state), the amount of communication between the input port 4i and the output port 4o of the sleeve 4 gradually increases from the predetermined amount as the stroke amount S1 increases. Therefore, when the stroke amount S1 is greater than the predetermined stroke amount Sref1, the change in the communication amount between the input chamber 40i and the output chamber 40o of the sleeve 4 per unit movement of the spool 5 of the valve section 3, and therefore the change in the output oil pressure from the output port 4o of the linear solenoid valve SL, is greater than when the stroke amount S1 is less than the predetermined stroke amount Sref1.

[0025] 2, each linear solenoid valve SL is driven by power from an auxiliary battery 90 that serves as a power source mounted on the vehicle. The auxiliary battery 90 is, for example, a lead storage battery having a rated voltage of 12V.

[0026] The ECU 6 has a microcomputer including a CPU, ROM, RAM, input / output interface, etc., various logic ICs, etc. (all not shown). The ECU 6 receives inputs such as an accelerator opening Acc indicating the amount of depression of the vehicle's accelerator pedal, which is detected by an accelerator pedal position sensor (not shown), a vehicle speed V of the vehicle, which is detected by a vehicle speed sensor (not shown), a voltage Vbat of the auxiliary battery 90, which is detected by a voltage sensor (not shown), and a temperature (oil temperature) Toil of the hydraulic oil, which is detected by a temperature sensor (not shown). Note that the ECU 6 may also receive inputs such as a rotational speed (output rotational speed) Nout of the output shaft of the transmission, which is detected by a rotational speed sensor (not shown), instead of the vehicle speed V.

[0027] 2, in the ECU 6, a calculation processing unit 60 and a plurality of valve drive control units 70 connected to the corresponding linear solenoid valves SL are constructed as functional blocks (modules) using at least one of hardware such as a CPU, ROM, RAM, and various logic ICs, and software such as various programs installed in the ROM. For ease of explanation, only one valve drive control unit 70 is shown in FIG.

[0028] The calculation processing unit 60 has a hydraulic pressure command value setting unit 61 and a current command value setting unit 62. The hydraulic pressure command value setting unit 61 receives an accelerator opening Acc from an accelerator pedal position sensor and a vehicle speed V from a vehicle speed sensor, and sets a hydraulic pressure command value Ps*, which is a command value for the hydraulic pressure output from the output port 4o of each linear solenoid valve SL, based on the received accelerator opening Acc and vehicle speed V. The current command value setting unit 62 sets a current command value Is*, which is a command value for the current supplied to the solenoid unit 2 of each linear solenoid valve SL, based on the hydraulic pressure command value Ps* for each linear solenoid valve set by the hydraulic pressure command value setting unit 61. Specifically, the current command value Is* is set to increase as the hydraulic pressure command value Ps* increases. Here, the update cycle of the current command value Is* by the current command value setting unit 62 is set longer than the cycle (dither cycle Tdiz) of a dither command value Vdiz, which will be described later.

[0029] Each valve drive control unit 70 has a target voltage setting unit 71, a dither command value setting unit 72, a current supply unit 73, a current detection unit 77, and a filter processing unit 78. The current supply unit 73 has a voltage superimposing unit 74, a PWM signal generating unit 75, and a drive circuit 76.

[0030] The target voltage setting unit 71 has a feedback control unit, a feedforward control unit, and an adder, and outputs the sum of the feedback voltage obtained by feedback control and the feedforward voltage obtained by the feedforward control unit as a target voltage Vtag, which is a target value of the voltage to be applied to the solenoid unit 2 of the linear solenoid valve SL. The feedback control unit calculates and outputs the feedback voltage by feedback control (PI control or PID control) so as to cancel the difference between the current command value Is* set by the current command value setting unit 62 and the processed current Isf, which is obtained by filtering the current Is detected by the current detection unit 77 using a filter processing unit 78. For example, the feedback control unit calculates and outputs the sum of a proportional term and an integral term based on the difference between the processed current Isf and the current command value Is* as the feedback voltage. The feedforward control unit calculates and outputs the feedforward voltage by feedforward control based on the current command value Is* set by the current command value setting unit 62. For example, the feedforward control unit outputs, as the feedforward voltage, the product of the current command value Is* and the resistance value (estimated value) of the solenoid unit 2 calculated from the previous value of the target voltage Vtag and the current command value Is*, taking into account the oil temperature Toil. Note that the target voltage setting unit 71 may not have the feedforward control unit and the adder, i.e., it may output the feedback voltage as the target voltage Vtag.

[0031] The dither command value setting unit 72 sets a dither amplitude Adiz based on the current command value Is* set by the current command value setting unit 62, and generates a dither command value Vdiz for varying the voltage command value Vs* (described later) with a dither period Tdiz and a dither amplitude Adiz, for example, sinusoidally with respect to the target voltage Vtag. Here, the dither period Tdiz is set to be shorter than the update period of the current command value Is* by the current command value setting unit 62 and longer than the period (PWM period) of the PWM signal generated by the PWM signal generating unit 75. A method for setting the dither amplitude Adiz will be described later.

[0032] The voltage superimposing unit 74 generates a voltage command value Vs* by superimposing the dither command value Vdiz set by the dither command value setting unit 72 on the target voltage Vtag set by the target voltage setting unit 71. That is, the voltage superimposing unit 74 generates a voltage command value Vs* by varying the target voltage Vtag with the dither amplitude Adiz and the dither period Tdiz.

[0033] The PWM signal generating unit 75 generates a PWM signal whose pulse width is modulated based on the voltage command value Vs* generated by the voltage superimposing unit 74 and the voltage Vbat of the auxiliary battery 90 for each PWM period, and outputs the PWM signal to the drive circuit 76. In this embodiment, the PWM signal generating unit 75 reduces the duty ratio of the PWM signal as the voltage Vbat of the auxiliary battery 90 increases and as the hydraulic pressure Toil increases, i.e., as the resistance value of the solenoid unit 2 decreases. The period of the PWM signal is set shorter than the dither period Tdiz.

[0034] The drive circuit 76 includes first and second switching elements SW1 and SW2, each of which is a MOSFET. The drain of the first switching element SW1 is connected to the positive electrode of the auxiliary battery 90, the source of the first switching element SW1 and the drain of the second switching element SW2 are connected to each other, and the source of the second switching element SW2 is grounded via a shunt resistor (not shown) of the current detection unit 77. The source of the first switching element SW1 and the drain of the second switching element SW2, which are connected to each other, and the source of the second switching element SW2 are connected to the solenoid unit 2 of the linear solenoid valve SL. The gates of the first and second switching elements SW1 and SW2 are connected to the PWM signal generation unit 75. The first and second switching elements SW1 and SW2 may be bipolar transistors or IGBTs instead of MOSFETs.

[0035] In this drive circuit 76, when the first switching element SW1 is turned on and the second switching element SW2 is turned off by the PWM signal from the PWM signal generation unit 75, the voltage Vbat of the auxiliary battery 90 is applied to the solenoid unit 2 (coil) of the linear solenoid valve SL, causing an electromotive current to flow in the solenoid unit 2. In contrast, when the first switching element SW1 is turned off and the second switching element SW2 is turned on by the PWM signal from the PWM signal generation unit 75, the solenoid unit 2 (coil) of the linear solenoid valve SL is grounded, causing a counter-electromotive current to flow in the solenoid unit 2.

[0036] The current detection unit 77 includes a shunt resistor having one end connected to the source of the second switching element SW2 and the other end grounded, an operational amplifier that detects the voltage between the second switching element SW2 side and the ground side of the shunt resistor, and an A / D converter that converts the output of the operational amplifier (analog voltage signal) into an analog signal of the current value flowing through the linear solenoid valve SL and further converts it into a digital signal (current value Is) (all not shown).

[0037] The filter processing unit 78 performs filtering on the current value Is detected by the current detection unit 77 to remove the frequency component of the dither cycle Tdiz, and outputs the processed current Isf to the target voltage setting unit 71. The filter processing unit 78 may be any filter that can remove the frequency component of the dither cycle Tdiz, and may use, for example, a band-stop filter (notch filter), a high-pass filter, or a band-pass filter.

[0038] By using these functional blocks of the ECU 6, the current supplied to the solenoid section 2 of each linear solenoid valve SL is varied at a dither period Tdiz to vibrate the plunger, rod 20, and spool 5 of each linear solenoid valve SL, thereby reducing the sliding resistance between the spool 5 and sleeve 4 and reducing the decrease in responsiveness and response variation of the linear solenoid valve SL.

[0039] Next, a description will be given of the process of setting the dither amplitude Adiz by the dither command value setting unit 72 of the ECU 6. Fig. 4 is a flowchart showing an example of the dither amplitude setting process that is repeatedly executed by the dither command value setting unit 72.

[0040] 4, the dither command value setting unit 72 first receives the current command value Is* set by the current command value setting unit 62 (step S100), and calculates a current command value increase rate Iup, which is the increase amount per unit time of the current command value Is*, based on the received current command value Is* (step S110). Here, the current command value increase rate Iup is calculated, for example, by subtracting the previous current command value (previous Is*) from the current current command value Is* and dividing the result by the input period Δts of the current command value Is*.

[0041] Next, it is determined whether the current command value increase rate Iup is equal to or greater than a threshold value Iupref1 (the first condition is met) (step S120), and if it is determined that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 (the first condition is met), it is determined whether the current command value increase rate Iup is equal to or greater than a threshold value Iupref2 that is greater than the threshold value Iupref1 (the second condition is met) (step S130).

[0042] Here, the threshold value Iupref1 is a threshold value used to determine whether there is a possibility (hereinafter referred to as a "first possibility") that the stroke amount S1 of the linear solenoid valve SL will change from a side smaller than the vicinity of the predetermined stroke amount Sref1 to a side larger than the predetermined stroke amount Sref1 or that it is already near the predetermined stroke amount Sref1 or larger, and is determined in advance through experiments and analyses. The threshold value Iupref2 is a threshold value used to determine whether there is a possibility (hereinafter referred to as a "second possibility") that the stroke amount S1 of the linear solenoid valve SL will change from a side smaller than the vicinity of the predetermined stroke amount Sref1 to a side larger than the predetermined stroke amount Sref1 in an extremely short time and that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 for only an extremely short time (the first condition will be satisfied for only an extremely short time), and is determined in advance through experiments and analyses. If the linear solenoid valve SL is a normally-open linear solenoid valve, the stroke amount S1 increases as the current supplied to the solenoid section 2 increases, and when the stroke amount S1 is greater than a predetermined stroke amount Sref1, the amount of change in the communication between the input chamber 40i and the output chamber 40o of the sleeve 4 per unit movement of the spool 5 of the valve section 3, and therefore the amount of change in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL, becomes greater than when the stroke amount S1 is equal to or less than the predetermined stroke amount Sref1. The processing of steps S120 and S130 is performed taking this into consideration.

[0043] If it is determined in step S120 that the current command value increase rate Iup is less than the threshold value Iupref1 (the first condition is not satisfied), it is determined that the first possibility does not exist, and normal amplitude processing is executed to set the dither amplitude Adiz to a relatively large first amplitude Adiz1 (step S240), and this processing ends. By executing the normal amplitude processing, the voltage command value Vs* generated by the voltage superposition unit 74 fluctuates with a relatively large amplitude, the current supplied to the solenoid unit 2 of the linear solenoid valve SL by the drive circuit 76 fluctuates with a relatively large amplitude, and the spool 5 of the valve unit 3 vibrates with a relatively large amplitude. As a result, the sliding resistance between the spool 5 and sleeve 4 of the valve unit 3 of the linear solenoid valve SL is sufficiently reduced, and deterioration in the responsiveness and response variation of the linear solenoid valve SL can be sufficiently suppressed.

[0044] If it is determined in step S120 that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 (the first condition is met), and it is determined in step S130 that the current command value increase rate Iup is less than the threshold value Iupref2 (the second condition is not met), it is determined that there is a first possibility but not a second possibility, and vibration reduction processing is executed to set the dither amplitude Adiz to a second amplitude Adiz2 that is equal to or greater than 0 and smaller than the first amplitude Adiz1, that is, the process shifts from normal vibration processing to vibration reduction processing (step S140). By executing the amplitude reduction processing, the amplitude of fluctuation of the voltage command value Vs* generated by the voltage superimposition unit 74 becomes smaller than when normal amplitude processing is executed, and the amplitude of fluctuation of the current supplied to the solenoid unit 2 of the linear solenoid valve SL by the drive circuit 76 becomes smaller, and the amplitude of vibration of the spool 5 of the valve unit 3 becomes smaller. As a result, when the stroke amount S1 fluctuates around the predetermined stroke amount Sref1 or on the larger side, the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve section 3 is prevented from fluctuating significantly, and the output oil pressure from the output port 4o of the linear solenoid valve SL is prevented from fluctuating significantly.

[0045] Next, similarly to the processing of steps S100 and S110, the current command value Is* is input and the current command value increase rate Iup is calculated (steps S150 and S160). Then, it is determined whether the calculated current command value increase rate Iup is less than the above-mentioned threshold value Iupref1 (the first condition is no longer satisfied) (step S170). If it is determined that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 (the first condition is not no longer satisfied), the process returns to step S150. In this manner, the process waits until the current command value increase rate Iup becomes less than the threshold value Iupref1 (the first condition is no longer satisfied). Then, if it is determined in step S170 that the current command value increase rate Iup is less than the threshold value Iupref1 (the first condition is no longer satisfied), the dither amplitude Adiz is set to the first amplitude Adiz1, that is, the process shifts from the amplitude reduction processing to the amplitude normal processing (step S240), and this process ends.

[0046] If it is determined in step S120 that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 (the first condition is met), and if it is determined in step S130 that the current command value increase rate Iup is equal to or greater than the threshold value Iupref2 (the second condition is met), it is determined that the first possibility and the second possibility exist, and similarly to the processing of step S140, the dither amplitude Adiz is set to the second amplitude Adiz2, that is, the process shifts from normal amplitude processing to amplitude reduction processing (step S180), and measurement of the duration Td of the amplitude reduction processing begins (step S190). By performing the amplitude reduction processing, as described above, when the stroke amount S1 fluctuates around or greater than the predetermined stroke amount Sref1, large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve portion 3 can be suppressed, and large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL can be suppressed.

[0047] Next, similarly to the processing of steps S100 and S110, the current command value Is* is input and the current command value increase rate Iup is calculated (steps S200 and S210). Then, it is determined whether the calculated current command value increase rate Iup is less than the above-mentioned threshold value Iupref1 (the first condition is no longer satisfied) (step S220), and it is determined whether the duration Td of the amplitude reduction processing is equal to or longer than the predetermined time Tdref1 (step S230). If it is determined that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 (the first condition is not no longer satisfied) or if it is determined that the duration Td of the amplitude reduction processing is shorter than the predetermined time Tdref1, the process returns to step S200. In this way, it waits until the current command value increase rate Iup becomes less than the threshold value Iupref1 (the first condition is no longer satisfied) and the duration Td of the amplitude reduction processing becomes equal to or longer than the predetermined time Tdref1. Then, if it is determined in step S220 that the current command value increase rate Iup is less than the threshold value Iupref1 (the first condition is no longer satisfied) and if it is determined in step S230 that the duration Td of the amplitude reduction process is equal to or longer than the predetermined time Tdref1, the dither amplitude Adiz is set to the first amplitude Adiz1, i.e., the process transitions from the amplitude reduction process to normal amplitude process (step S240), and this process ends.

[0048] Here, the predetermined time Tdref1 is set in consideration of the controllability of the linear solenoid valve SL. When the current command value increase rate Iup is equal to or greater than the threshold value Iupref2, there is a possibility that the current command value increase rate Iup will be equal to or greater than the threshold value Iupref1 for only a very short time (the first condition will only be satisfied for a very short time). For this reason, if the current command value increase rate Iup becomes less than the threshold value Iupref1 (the first condition will no longer be satisfied), and the process immediately shifts from the amplitude reduction process to the normal amplitude process regardless of the duration Td of the amplitude reduction process, the process will switch to the normal amplitude process, the amplitude reduction process for a very short time, and then the normal amplitude process, and this may result in a deterioration in the controllability of the spool 5 of the valve unit 3 of the linear solenoid valve SL. In contrast, in this embodiment, when the current command value increase rate Iup reaches or exceeds the threshold value Iupref2 (both the first and second conditions are met) and the process shifts from normal amplitude processing to amplitude reduction processing, the amplitude reduction processing is continued until the current command value increase rate Iup falls below the threshold value Iupref1 (the first condition is no longer met) and the duration Td of the amplitude reduction processing reaches or exceeds the predetermined time Tdref1. This makes it possible to prevent deterioration in controllability of the spool 5 of the valve unit 3 of the linear solenoid valve SL.

[0049] Next, an operation when engaging a hydraulic engaging element corresponding to the linear solenoid valve SL will be described. Figures 5 and 6 are explanatory diagrams showing an example of the current command value Is*, current command value increase rate Iup, dither amplitude Adiz, stroke amount S1 and stroke amount average value S1av, hydraulic command value Ps*, output hydraulic pressure Ps, and output hydraulic pressure average value Psav when engaging a hydraulic engaging element in this embodiment and a comparative embodiment, respectively. The stroke amount average value S1av and output hydraulic pressure average value Psav are average values per unit time of the stroke amount S1 and the output hydraulic pressure Ps, respectively. In the comparative embodiment, the dither amplitude Adiz is set to the first amplitude Adiz1 regardless of the current command value increase rate Iup (normal amplitude processing is executed).

[0050] As shown in FIGS. 5 and 6 , when engaging a hydraulic engagement element, the filling process (time t11 to t12), the standby process (time t12 to t13), the pressure increase process (time t13 to t14), and the holding process (from time t14) are executed in this order. In this embodiment, the threshold value Iupref1 described above when engaging a hydraulic engagement element is set so that the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 during the filling process and the pressure increase process, and is less than the threshold value Iupref1 during the standby process and the holding process. Furthermore, the threshold value Iupref2 when engaging a hydraulic engagement element is set so that the current command value increase rate Iup is equal to or greater than the threshold value Iupref2 during the filling process, and is less than the threshold value Iupref2 during the standby process, the pressure increase process, and the holding process. Furthermore, the predetermined time Tdref1 is set as the time for the filling process.

[0051] The filling process is a process of changing the hydraulic pressure command value Ps* so that hydraulic oil is rapidly filled into the engagement oil chamber of the hydraulic engagement element. Specifically, the hydraulic pressure command value Ps* is increased sharply from zero to a relatively high value and maintained there. At this time, the current command value Is*, like the hydraulic pressure command value Ps*, is increased sharply from zero to a relatively high value and maintained there. As the current command value Is* increases sharply, the current command value increase rate Iup increases from zero to a threshold value Iupref2 or greater for a very short time and then returns to approximately zero. As the current command value Is* is increased sharply from zero to a relatively high value and maintained there, the stroke amount average value S1av is increased sharply from zero to near the predetermined stroke amount Sref1 and maintained there. The output hydraulic pressure average value Psav is gradually increased from zero.

[0052] Here, the stroke amount S1 is based on the relationship between the thrust (leftward force in FIG. 3) generated by the current supplied to the solenoid unit 2 and the thrust (both rightward forces in FIG. 3) acting on the spool 5 due to the biasing force of the spring SP and the hydraulic pressure supplied to the feedback chamber 40f. During the filling process, the output hydraulic pressure average value Psav is low, and the hydraulic pressure at the feedback port 4f (feedback chamber 40f) communicating with the output port 4o via an oil passage formed in the valve body is also low. Therefore, when the current command value increase rate Iup becomes equal to or greater than the threshold value Iupref2 and then falls below the threshold value Iupref1 and the current command value Is* is maintained at a relatively high value, the stroke amount average value S1av is maintained near the predetermined stroke amount Sref1.

[0053] The standby process is a process in which the hydraulic pressure command value Ps* is abruptly reduced from the relatively high value of the filling process to a relatively low standby pressure and maintained there. Similarly to the hydraulic pressure command value Ps*, the current command value Is* is abruptly reduced from the relatively high value of the filling process to a relatively low value and maintained there. The current command value increase rate Iup, as the current command value Is* abruptly reduces, becomes relatively large in absolute value within a negative range from approximately zero for a very short time and then returns to approximately zero. As the current command value Is* is reduced from the relatively high value of the filling process to a relatively low value and maintained there, the stroke amount average value S1av is reduced from near the predetermined stroke amount Sref1 and maintained there. The output hydraulic pressure average value Psav gradually increases to approach the hydraulic pressure command value Ps*.

[0054] The pressure increase process is a process for gradually increasing the hydraulic pressure command value Ps* so that the hydraulic engagement element is engaged. Specifically, the hydraulic pressure command value Ps* is increased at a substantially constant rate of increase. At this time, the current command value Is* increases at a substantially constant rate, similar to the hydraulic pressure command value Ps*, and the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 and less than the threshold value Iupref2. As the current command value Is* gradually increases, the stroke amount average value S1av increases from a relatively small value during the standby process to near the predetermined stroke amount Sref1 and is maintained there, and the output hydraulic pressure average value Psav gradually increases from a relatively small value during the standby process. Note that as the output hydraulic pressure Ps from the output port 4o increases, the hydraulic pressure at the feedback port 4f (feedback chamber 40f) also increases.

[0055] The holding process is a process for holding the hydraulic pressure command value Ps*. At this time, the current command value Is* is held in the same manner as the hydraulic pressure command value Ps*, and the current command value increase rate Iup is set to approximately zero. In addition, because the current command value Is* is held and the hydraulic pressure in the feedback chamber 40f is increased, the stroke amount average value S1av is held at a value that is reduced to a certain extent from near the predetermined stroke amount Sref1.

[0056] 6, in the comparative example, the dither amplitude Adiz is set to the first amplitude Adiz1 regardless of the current command value increase rate Iup (normal amplitude processing is executed). Therefore, when the stroke amount S1 fluctuates near or greater than the predetermined stroke amount Sref1 during the filling processing or pressure increasing processing, the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve portion 3 fluctuates greatly, and the output hydraulic pressure from the output port 4o of the linear solenoid valve SL fluctuates greatly.

[0057] In contrast, in this embodiment, as shown in Fig. 5, when the current command value increase rate Iup reaches or exceeds the threshold value Iupref2 during the charging process at time t11 (when the first and second conditions are met), the amplitude reduction process is executed. This suppresses large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve section 3 when the stroke amount S1 fluctuates around the predetermined stroke amount Sref1 during the charging process, thereby suppressing large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL. Furthermore, when the current command value increase rate Iup reaches or exceeds the threshold value Iupref2 during the charging process (when the first and second conditions are met), the amplitude reduction process is continued (from time t11 to t12) until the current command value increase rate Iup falls below the threshold value Iupref1 (when the first condition is no longer met) and the duration Td of the amplitude reduction process reaches or exceeds the predetermined time Tdref1, thereby suppressing deterioration in controllability of the linear solenoid valve SL over the spool 5 of the valve section 3. During the filling process, as described above, when the current command value increase rate Iup becomes equal to or greater than the threshold value Iupref2 and then falls below the threshold value Iupref1 and the current command value Is* is maintained at a relatively high value, the output oil pressure average value Psav is low and the oil pressure at the feedback port 4f is low, so the stroke amount average value S1av is maintained near the predetermined stroke amount Sref1. From this perspective, it is also meaningful to continue the amplitude reduction process until the duration Td of the amplitude reduction process becomes equal to or greater than the predetermined time Tdref1.

[0058] Furthermore, when the current command value increase rate Iup reaches or exceeds the threshold value Iupref1 during the pressure increase process at time t13, the amplitude reduction process is executed. This suppresses large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve portion 3 when the stroke amount S1 fluctuates around the predetermined stroke amount Sref1 during the pressure increase process, thereby suppressing large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL.

[0059] As described above, when the linear solenoid valve SL is a normally closed linear solenoid valve, the ECU 6 executes normal amplitude processing to set the dither amplitude Adiz to a first amplitude Adiz1 when the current command value increase rate Iup is less than the threshold value Iupref1 (the first condition is not met), and executes amplitude reduction processing to set the dither amplitude Adiz to a second amplitude Adiz2 that is greater than or equal to 0 and smaller than the first amplitude Adiz1 when the current command value increase rate Iup is greater than or equal to the threshold value Iupref1 (the first condition is met).The ECU 6 then supplies to the solenoid unit 2 a current based on the target voltage Vtag based on the current command value Is* based on the hydraulic pressure command value Ps* and the dither command value Vdiz of the dither amplitude Adiz. By this processing, when the stroke amount S1 fluctuates around the predetermined stroke amount Sref1 or on the larger side, the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve section 3 can be prevented from fluctuating significantly, and the output oil pressure from the output port 4o of the linear solenoid valve SL can be prevented from fluctuating significantly.

[0060] In the above-described embodiment, when the amplitude reduction process is started because the current command value increase rate Iup is equal to or greater than the threshold value Iupref1 and less than the threshold value Iupref2 (the first condition is met but the second condition is not met), the vibration reduction process is terminated when the current command value increase rate Iup falls below the threshold value Iupref1 (the first condition is no longer met). However, in this case, the vibration reduction process may also be terminated when a predetermined time has elapsed since the current command value increase rate Iup fell below the threshold value Iupref1. The predetermined time is shorter than the above-described predetermined time Tdref1, for example, a time that is approximately 1 to 3 times the dither period Tdiz.

[0061] In the above-described embodiment, the linear solenoid valve SL is a normally closed linear solenoid valve. However, the linear solenoid valve SL may also be a normally open linear solenoid valve. As an example of the hardware configuration when the linear solenoid valve SL is a normally open linear solenoid valve, a configuration will be described in which the linear solenoid valve SL has the same sleeve 4 and spool 5 as the linear solenoid valve SL in FIG. 1, and the spool 5 is biased to the left in FIG. 1 by a spring SP, and when current is supplied to the solenoid unit 2, the spool 5 moves to the right in FIG. 1 against the biasing force of the spring SP. For ease of explanation, the same reference numerals as those in the linear solenoid valve SL in FIG. 1 will be used.

[0062] Hereinafter, the amount of movement of the spool 5 of the valve portion 3 of the linear solenoid valve SL from its initial position will be referred to as the "stroke amount S2." Furthermore, the stroke amount S2 when the end face 52i of the land 52 of the spool 5 on the input chamber 40i side is located at the boundary between the first communication chamber 41 and the output chamber 40o will be referred to as the "predetermined stroke amount Sref2." When the stroke amount S2 is smaller than the predetermined stroke amount Sref2, the amount of communication between the input port 4i and the output port 4o of the sleeve 4 gradually decreases from a second predetermined amount that is larger than the predetermined amount (a slight clearance between the outer peripheral surface of the land 52 and the inner peripheral surface of the sleeve 4 that defines the first communication chamber 41) toward a predetermined amount as the stroke amount S2 increases. When the stroke amount S2 is equal to or larger than the predetermined stroke amount Sref2, the amount of communication between the input port 4i and the output port 4o of the sleeve 4 gradually decreases from a second predetermined amount that is larger than the predetermined amount (a slight clearance between the outer peripheral surface of the land 52 and the inner peripheral surface of the sleeve 4 that defines the first communication chamber 41) toward a predetermined amount. Therefore, when the stroke amount S2 is smaller than the predetermined stroke amount Sref2, the change in the communication amount between the input chamber 40i and the output chamber 40o of the sleeve 4 per unit movement of the spool 5 of the valve section 3, and therefore the change in the output oil pressure from the output port 4o of the linear solenoid valve SL, is greater than when the stroke amount S2 is greater than the predetermined stroke amount Sref2.

[0063] 2 is formed in the ECU 6, just as when the linear solenoid valve SL is a normally-open linear solenoid valve. However, the current command value setting unit 62 sets the current command value Is* for the solenoid unit 2 of each linear solenoid valve SL so that the current command value Is* decreases as the hydraulic pressure command value Ps* for each linear solenoid valve set by the hydraulic pressure command value setting unit 61 increases.

[0064] Furthermore, the dither command value setting unit 72 of the ECU 6 executes the dither amplitude setting process of Fig. 7 instead of the dither amplitude setting process of Fig. 4. The dither amplitude setting process of Fig. 7 is the same as the dither amplitude setting process of Fig. 4 except that the processes of steps S110, S120, S130, S160, S170, S210, and S220 are replaced with the processes of steps S112, S122, S132, 162, 172, S212, and S222. Therefore, the same step numbers are assigned to the steps in the dither amplitude setting process of Fig. 7 that are the same as the dither amplitude setting process of Fig. 4, and detailed descriptions thereof will be omitted.

[0065] 7, when the dither command value setting unit 72 receives the current command value Is* in step S100, it calculates a current command value decrease rate Idn, which is the amount of decrease per unit time of the current command value Is*, based on the received current command value Is* (step S112). Here, the current command value decrease rate Idn is calculated by, for example, subtracting the current command value Is* from the previous current command value (previous Is*) and dividing the result by the input period Δts of the current command value Is*.

[0066] Next, it is determined whether the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is met) (step S122), and if it is determined that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is met), it is determined whether the current command value decrease rate Idn is equal to or greater than a threshold value Idnref2 that is greater than the threshold value Idnref1 (the second condition is met) (step S132).

[0067] Here, the threshold value Idnref1 is a threshold value used to determine whether there is a possibility (hereinafter referred to as the "third possibility") that the stroke amount S2 of the linear solenoid valve SL will change from a side larger than the vicinity of the predetermined stroke amount Sref2 to a side smaller than the predetermined stroke amount Sref2 or that it is already near the predetermined stroke amount Sref2 or smaller, and is determined in advance through experiments and analyses. The threshold value Idnref2 is a threshold value used to determine whether there is a possibility (hereinafter referred to as the "fourth possibility") that the stroke amount S2 of the linear solenoid valve SL will change from a side larger than the vicinity of the predetermined stroke amount Sref2 to a side smaller than the predetermined stroke amount Sref2 in an extremely short time and that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 for only an extremely short time (the first condition will be satisfied for only an extremely short time). If the linear solenoid valve SL is a normally-open linear solenoid valve, the stroke amount S2 decreases as the current supplied to the solenoid section 2 decreases, and when the stroke amount S2 is smaller than the predetermined stroke amount Sref2, the amount of change in the communication between the input chamber 40i and the output chamber 40o of the sleeve 4 per unit movement of the spool 5 of the valve section 3, and therefore the amount of change in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL, becomes larger than when the stroke amount S2 is equal to or larger than the predetermined stroke amount Sref2. The processing of steps S122 and S132 is performed taking this into consideration.

[0068] If it is determined in step S122 that the current command value decrease rate Idn is less than the threshold value Idnref1 (the first condition is not met), it is determined that the third possibility does not exist, and normal vibration processing is executed to set the dither amplitude Adiz to a relatively large first amplitude Adiz1 (step S240), and this processing ends. By executing the normal amplitude processing, the sliding resistance between the spool 5 and sleeve 4 of the valve portion 3 of the linear solenoid valve SL is sufficiently reduced, and deterioration in the responsiveness and response variation of the linear solenoid valve SL can be sufficiently suppressed.

[0069] If it is determined in step S122 that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is met), and if it is determined in step S132 that the current command value decrease rate Idn is less than the threshold value Idnref2 (the second condition is not met), it is determined that the third possibility exists but the fourth possibility does not, and vibration reduction processing is executed to set the dither amplitude Adiz to the second amplitude Adiz2, that is, the process shifts from normal vibration processing to vibration reduction processing (step S140). Compared to the case of normal amplitude processing, executing the amplitude reduction processing suppresses large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve portion 3 when the stroke amount S2 fluctuates around or below the predetermined stroke amount Sref2, and thus it is possible to suppress large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL.

[0070] Next, similarly to the processing of steps S100 and S112, the current command value Is* is input and the current command value decrease rate Idn is calculated (steps S150 and S162). Then, it is determined whether the calculated current command value decrease rate Idn is less than the threshold value Idnref1 (the first condition is no longer satisfied) (step S172). If it is determined that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is not no longer satisfied), the process returns to step S150. In this manner, the process waits until the current command value decrease rate Idn becomes less than the threshold value Idnref1 (the first condition is no longer satisfied). Then, if it is determined in step S172 that the current command value decrease rate Idn is less than the threshold value Idnref1 (the first condition is no longer satisfied), the dither amplitude Adiz is set to the first amplitude Adiz1, that is, the process shifts from the amplitude reduction processing to the normal amplitude processing (step S240), and this process ends.

[0071] If it is determined in step S122 that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is met) and if it is determined in step S132 that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref2 (the second condition is met), it is determined that the third and fourth possibilities exist, and similarly to the processing of step S140, the dither amplitude Adiz is set to the second amplitude Adiz2, that is, the processing shifts from normal amplitude processing to amplitude reduction processing (step S180), and measurement of the duration Td of the amplitude reduction processing begins (step S190). By performing the amplitude reduction processing, as described above, when the stroke amount S2 fluctuates around or below the predetermined stroke amount Sref2, large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve portion 3 can be suppressed, and large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL can be suppressed.

[0072] Next, similarly to the processing of steps S100 and S112, the current command value Is* is input and the current command value decrease rate Idn is calculated (steps S200 and S212). Then, it is determined whether the calculated current command value decrease rate Idn is less than a threshold value Idnref1 (the first condition is no longer satisfied) (step S222), and it is determined whether the duration Td of the amplitude reduction process is equal to or greater than a predetermined time Tdref2 (step S230). If it is determined that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is not no longer satisfied) or if it is determined that the duration Td of the amplitude reduction process is less than the predetermined time Tdref2, the process returns to step S200. In this way, it waits until the current command value decrease rate Idn becomes less than the threshold value Idnref1 (the first condition is no longer satisfied) and the duration Td of the amplitude reduction process becomes equal to or greater than the predetermined time Tdref2. Then, if it is determined in step S222 that the current command value decrease rate Idn is less than the threshold value Idnref1 (the first condition is no longer satisfied) and if it is determined in step S230 that the duration Td of the amplitude reduction process is equal to or longer than the predetermined time Tdref2, the dither amplitude Adiz is set to the first amplitude Adiz1, i.e., the process transitions from the amplitude reduction process to normal amplitude process (step S240), and this process is terminated.

[0073] Here, the predetermined time Tdref2 is set in consideration of the controllability of the linear solenoid valve SL. When the current command value decrease rate Idn is equal to or greater than the threshold value Idnref2, there is a possibility that the current command value decrease rate Idn will be equal to or greater than the threshold value Idnref1 for only a very short time (the first condition will only be satisfied for a very short time). For this reason, if the current command value decrease rate Idn becomes less than the threshold value Idnref1 (the first condition will no longer be satisfied), and the process immediately shifts from the amplitude reduction process to the normal amplitude process regardless of the duration Td of the amplitude reduction process, the process will switch to the normal amplitude process, the amplitude reduction process for a very short time, and then the normal amplitude process, and this may result in a deterioration in the controllability of the spool 5 of the valve unit 3 of the linear solenoid valve SL. On the other hand, when the current command value decrease rate Idn reaches or exceeds the threshold value Idnref2 (both the first and second conditions are satisfied) and the process shifts from normal amplitude processing to amplitude reduction processing, the amplitude reduction processing is continued until the current command value decrease rate Idn falls below the threshold value Idnref1 (the first condition is no longer satisfied) and the duration Td of the amplitude reduction processing reaches or exceeds the predetermined time Tdref2. This makes it possible to prevent deterioration in controllability of the spool 5 of the valve unit 3 of the linear solenoid valve SL.

[0074] Next, an operation when engaging a hydraulic engagement element corresponding to the linear solenoid valve SL will be described. Fig. 8 is an explanatory diagram showing an example of the current command value Is*, current command value decrease rate Idn, dither amplitude Adiz, stroke amount S2 and stroke amount average value S2av, hydraulic command value Ps*, output hydraulic pressure Ps, and output hydraulic pressure average value Psav when engaging a hydraulic engagement element when the linear solenoid valve SL is a normally open linear solenoid valve.

[0075] As shown in FIG. 8, when engaging a hydraulic engagement element, the filling process (times t21 to t22), the standby process (times t22 to t23), the pressure increase process (times t23 to t24), and the holding process (from time t24) are executed in this order. The threshold value Idnref1 described above when engaging a hydraulic engagement element is set so that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 during the filling process and the pressure increase process, and is less than the threshold value Idnref1 during the standby process and the holding process. Furthermore, the threshold value Idnref2 when engaging a hydraulic engagement element is set so that the current command value decrease rate Idn is equal to or greater than the threshold value Idnref2 during the filling process, and is less than the threshold value Idnref2 during the standby process, the pressure increase process, and the holding process. Furthermore, the predetermined time Tdref2 is set as the time for the filling process.

[0076] The filling process changes the hydraulic pressure command value Ps* so that hydraulic oil is rapidly filled into the engagement oil chamber of the hydraulic engagement element. Specifically, the hydraulic pressure command value Ps* is increased sharply from zero to a relatively high value and maintained there. At this time, the current command value Is* is decreased sharply from a relatively high value to a relatively low value and maintained there. The current command value decrease rate Idn increases from zero to a threshold value Idnref2 or greater for a very short time as the current command value Is* is decreased sharply from a relatively high value to a relatively low value and then returns to approximately zero. As the current command value Is* is decreased sharply from a relatively high value to a relatively low value and maintained there, the stroke amount average value S1av is decreased sharply from a relatively large value to near the predetermined stroke amount Sref2 and maintained there. The output hydraulic pressure average value Psav gradually increases from zero.

[0077] During the filling process, the output oil pressure average value Psav is low and the oil pressure at the feedback port 4f (feedback chamber 40f) is also low, so when the current command value decrease rate Idn reaches or exceeds the threshold value Idnref2 and then falls below the threshold value Idnref1 and the current command value Is* is maintained at a relatively low value, the stroke amount average value S2av is maintained near the specified stroke amount Sref2.

[0078] The standby process is a process in which the hydraulic pressure command value Ps* is abruptly decreased from the relatively high value of the filling process to a relatively low standby pressure and maintained there. During this process, the current command value Is* abruptly increases from the relatively low value of the filling process to a relatively high value and is maintained there. The absolute value of the current command value decrease rate Idn increases relatively quickly from approximately zero within a negative range for a very short time as the current command value Is* abruptly increases, and then returns to approximately zero. As the current command value Is* increases from the relatively low value of the filling process to a relatively high value and is maintained there, the stroke amount average value S2av increases from near the predetermined stroke amount Sref2 and is maintained there. The output hydraulic pressure average value Psav gradually increases and approaches the hydraulic pressure command value Ps*.

[0079] The pressure increase process is a process for gradually increasing the hydraulic pressure command value Ps* so that the hydraulic engagement element is engaged. Specifically, the hydraulic pressure command value Ps* is increased at a substantially constant rate. At this time, the current command value Is* decreases at a substantially constant rate, and the current command value decrease rate Idn becomes a value equal to or greater than the threshold value Idnref1 and less than the threshold value Idnref2. As the current command value Is* gradually decreases, the stroke amount average value S2av decreases from the relatively large value during the standby process to near the predetermined stroke amount Sref2 and is maintained there, and the output hydraulic pressure average value Psav gradually increases from the relatively small value during the standby process. Note that as the output hydraulic pressure Ps from the output port 4o increases, the hydraulic pressure at the feedback port 4f (feedback chamber 40f) also increases.

[0080] The holding process is a process for holding the hydraulic pressure command value Ps*. At this time, the current command value Is* is held in the same manner as the hydraulic pressure command value Ps*, and the current command value decrease rate Idn is set to approximately zero. In addition, because the current command value Is* is held and the hydraulic pressure in the feedback chamber 40f is increased, the stroke amount average value S2av is increased to a certain extent from near the predetermined stroke amount Sref2 and is held.

[0081] 8, when the current command value decrease rate Idn reaches or exceeds the threshold value Idnref2 during the filling process at time t21 (when the first and second conditions are satisfied), the amplitude reduction process is executed. This prevents large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve section 3 when the stroke amount S2 fluctuates around the predetermined stroke amount Sref2 during the filling process, thereby preventing large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL. Furthermore, when the current command value decrease rate Idn reaches or exceeds the threshold value Idnref2 during the filling process (when the first and second conditions are satisfied), and the amplitude reduction process is started, the amplitude reduction process is continued (from time t21 to t22) until the current command value decrease rate Idn falls below the threshold value Idnref1 (when the first condition is no longer satisfied) and the duration Td of the amplitude reduction process reaches or exceeds the predetermined time Tdref2, thereby preventing a deterioration in the controllability of the linear solenoid valve SL over the spool 5 of the valve section 3. During the filling process, as described above, when the current command value decrease rate Idn becomes equal to or greater than the threshold value Idnref2 and then falls below the threshold value Idnref1 and the current command value Is* is maintained at a relatively low value, the output oil pressure average value Psav is low and the oil pressure at the feedback port 4f is low, so the stroke amount average value S2av is maintained near the predetermined stroke amount Sref2. From this perspective, it is also meaningful to continue the amplitude reduction process until the duration Td of the amplitude reduction process becomes equal to or greater than the predetermined time Tdref2.

[0082] Furthermore, when the current command value decrease rate Idn reaches or exceeds the threshold value Idnref1 during the pressure increase process at time t23, the amplitude reduction process is executed. This suppresses large fluctuations in the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve portion 3 when the stroke amount S2 fluctuates around the predetermined stroke amount Sref2 during the pressure increase process, thereby suppressing large fluctuations in the output hydraulic pressure from the output port 4o of the linear solenoid valve SL.

[0083] As described above, when the linear solenoid valve SL is a normally-open linear solenoid valve, the ECU 6 executes normal amplitude processing to set the dither amplitude Adiz to a first amplitude Adiz1 when the current command value decrease rate Idn is less than the threshold value Idnref1 (the first condition is not met), and executes amplitude reduction processing to set the dither amplitude Adiz to a second amplitude Adiz2 that is greater than or equal to 0 and smaller than the first amplitude Adiz1 when the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 (the first condition is met).The ECU 6 then supplies to the solenoid unit 2 a current based on the target voltage Vtag based on the current command value Is* based on the hydraulic pressure command value Ps* and the dither command value Vdiz of the dither amplitude Adiz. By this processing, when the stroke amount S2 fluctuates around the predetermined stroke amount Sref2 or on the smaller side, the amount of communication between the input chamber 40i and the output chamber 40o of the sleeve 4 of the valve section 3 can be prevented from fluctuating significantly, and the output oil pressure from the output port 4o of the linear solenoid valve SL can be prevented from fluctuating significantly.

[0084] When the amplitude reduction process is started because the current command value decrease rate Idn is equal to or greater than the threshold value Idnref1 and less than the threshold value Idnref2 (the first condition is met but the second condition is not met), the vibration reduction process is terminated when the current command value decrease rate Idn falls below the threshold value Idnref1 (the first condition is no longer met). However, in this case, the vibration reduction process may also be terminated when a predetermined time has elapsed since the current command value decrease rate Idn fell below the threshold value Idnref1. The predetermined time is shorter than the above-mentioned predetermined time Tdref2, for example, a time that is approximately 1 to 3 times the dither period Tdiz.

[0085] In the above-described embodiment, the ECU 6 is configured to include, as functional blocks, the calculation processing unit 60 (hydraulic pressure command value setting unit 61, current command value setting unit 62) and a plurality of valve drive control units 70 (target voltage setting unit 71, dither command value setting unit 72, current supply unit 73 (voltage superimposing unit 74, PWM signal generating unit 75, drive circuit 76), current detecting unit 77, and filter processing unit 78). However, as shown in FIG. 9, the ECU 6 of FIG. 1 may be replaced with an ECU 6B. The ECU 6B of FIG. 9 is the same as the ECU 6 of FIG. 1 except that the target voltage setting unit 71, dither command value setting unit 72, voltage superimposing unit 74, and PWM signal generating unit 75 of the ECU 6 of FIG. 1 are replaced with a target current setting unit 71B, a dither command value setting unit 72B, a current superimposing unit 74B, and a PWM signal generating unit 75B. Therefore, the same parts of the ECU 6B in FIG. 9 as those of the ECU 6 in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0086] The target current setting unit 71B sets the target current Istag by feedback control based on the current command value Is* and a processed current Isf obtained by filtering the current Is. The dither command value setting unit 72B sets the dither amplitude Adiz using a process similar to the dither amplitude setting process shown in FIGS. 4 and 7, and generates a dither command value Idiz for varying the superimposed current command value Is2* (described later) with a dither period Tdiz2 and a dither amplitude Adiz2, for example, in a sinusoidal manner, relative to the target current Itag. The current superimposing unit 74B generates the superimposed current command value Is2* by superimposing the dither command value Idiz on the target current Istag. The PWM signal generating unit converts the superimposed current command value Is2* or a voltage based on the superimposed current command value Is2* and the resistance value of the solenoid unit 2 into a PWM signal and outputs it to the drive circuit 76. Even in this case, by setting the dither amplitude Adiz2 using processing similar to the dither amplitude setting processing of Figures 4 and 7, normal vibration processing can be performed to sufficiently suppress a decrease in the responsiveness of the linear solenoid valve SL and a decrease in response variation, or vibration reduction processing can be performed to suppress large fluctuations in the output oil pressure from the output port 4o of the linear solenoid valve SL.

[0087] The above describes the forms for implementing the present disclosure, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0088] The present disclosure is applicable to industries such as the manufacturing industry of control devices for linear solenoid valves. [Explanation of symbols]

[0089] 2 solenoid unit, 4 sleeve, 4i input port, 4o output port, 5 spool, 6 ECU (control device), 61 hydraulic pressure command value setting unit, 62 current command value setting unit, dither command value setting unit 72, 73 current supply unit, SL linear solenoid valve.

Claims

1. a solenoid unit that moves the spool within the sleeve to a side where a communication amount between the input port and the output port increases as a current supplied thereto increases, and wherein when the communication amount is equal to or greater than a predetermined amount, a change in the communication amount per unit movement amount of the spool is greater than when the communication amount is less than the predetermined amount, a hydraulic pressure command value setting unit that sets a hydraulic pressure command value for the linear solenoid valve; a current command value setting unit that sets a current command value of the solenoid unit so that the current command value increases as the hydraulic pressure command value increases; a dither command value setting unit that sets a dither command value of a first amplitude when a first condition that a current command value increase rate, which is an increase amount of the current command value per unit time, is equal to or greater than a first threshold value is not satisfied, and that sets the dither command value of a second amplitude, which is equal to or greater than 0 and smaller than the first amplitude, when the first condition is satisfied; a current supply unit that supplies a current based on the current command value and the dither command value to the solenoid unit; Equipped with the dither command value setting unit, when both the first condition and a second condition that the current command value increase rate is equal to or greater than a second threshold value that is greater than the first threshold value, are satisfied, sets the dither command value to the second amplitude until the first condition is no longer satisfied and a predetermined time has elapsed. Linear solenoid valve control device.

2. a solenoid unit that moves the spool within the sleeve to a side where a communication amount between the input port and the output port decreases as a current supplied thereto increases, and wherein when the communication amount is equal to or greater than a predetermined amount, a change in the communication amount per unit movement amount of the spool is greater than when the communication amount is less than the predetermined amount, a hydraulic pressure command value setting unit that sets a hydraulic pressure command value for the linear solenoid valve; a current command value setting unit that sets a current command value of the solenoid unit so that the current command value decreases as the hydraulic pressure command value increases; a dither command value setting unit that sets a dither command value of a first amplitude when a first condition that a current command value decrease rate, which is an amount of decrease in the current command value per unit time, is equal to or greater than a first threshold value is not satisfied, and that sets the dither command value of a second amplitude, which is equal to or greater than 0 and smaller than the first amplitude, when the first condition is satisfied; a current supply unit that supplies a current based on the current command value and the dither command value to the solenoid unit; Equipped with the dither command value setting unit, when both the first condition and a second condition that the current command value decrease rate is equal to or greater than a second threshold value that is greater than the first threshold value, are satisfied, sets the dither command value to the second amplitude until the first condition is no longer satisfied and a predetermined time has elapsed. Linear solenoid valve control device.

3. 3. The linear solenoid valve control device according to claim 1, the linear solenoid valve is a valve that supplies hydraulic pressure to a hydraulic engagement element of a transmission, the sleeve further includes a feedback port communicating with the output port via an oil passage; the hydraulic pressure command value setting unit executes, in order when engaging the hydraulic engagement element, a filling process that changes the hydraulic pressure command value so that hydraulic oil is rapidly filled into an engagement oil chamber of the hydraulic engagement element, a standby process that holds the hydraulic pressure command value at a standby pressure, and a pressure increase process that gradually increases the hydraulic pressure command value so that the hydraulic engagement element is engaged; the first threshold value and the second threshold value are set so that the first condition is satisfied but the second condition is not satisfied during the pressure increasing process, and the second condition is satisfied only at the time of a rise in the hydraulic pressure command value during the filling process. Linear solenoid valve control device.

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