Patent Description:
For example, this kind of art is disclosed in <CIT>. In detail, <CIT> discloses a parking control device for an automatic transmission, which includes (<NUM>) a parking lock mechanism, (<NUM>) a parking drive mechanism, and (<NUM>) a regulating mechanism. (<NUM>) The parking lock mechanism locks rotation of a power transmission shaft of the automatic transmission, when the automatic transmission is in a parking range, by setting a parking rod at a locked position on one side in the axial direction of the parking rod. The parking lock mechanism unlocks the rotation of the power transmission shaft of the automatic transmission, when the automatic transmission is in ranges other than the parking range, by setting the parking rod at an unlocked position on the other side in the axial direction. (<NUM>) The parking drive mechanism sets the parking rod at the locked position by biasing the parking rod, and sets the parking rod at the unlocked position using hydraulic pressure generated by an engine. (<NUM>) The regulating mechanism regulates a movement of the parking rod to the unlocked position, when the parking rod is at the locked position.

Here, hydraulic pressure generated by the engine is supplied to the parking drive mechanism described above by using a hydraulic pressure control valve which is an electromagnetic valve (solenoid). Typically, the hydraulic pressure control valve intercepts the supply of hydraulic pressure to the parking drive mechanism when power is supplied, and on the other hand, it supplies hydraulic pressure to the parking drive mechanism when power is not supplied.

If such a hydraulic pressure control valve is used, the following problem may occur when power of the vehicle is turned OFF (in other words, "ignition OFF") while the regulating mechanism regulates the movement of the parking rod at the locked position. When the power of the vehicle is turned OFF, since the supply of power to the hydraulic pressure control valve is stopped, it is left in a state where the hydraulic pressure can be supplied to the parking drive mechanism. Fundamentally, when the power of the vehicle is turned OFF, the hydraulic pressure is not given to the parking drive mechanism because the engine speed is fully lowered. However, the engine speed may be comparatively high for a while after the power of the vehicle is turned OFF, and in such a case, the hydraulic pressure is given to the parking drive mechanism. Thus, when the hydraulic pressure acts to move the parking rod, of which the movement is regulated by the regulating mechanism, from the locked position to the unlocked position, the parking rod may interfere (e.g., collide) with the regulating mechanism, and therefore, the parking rod and the regulating mechanism may be damaged.

On the other hand, also when the power of the vehicle is turned ON (in other words, "ignition ON") while the regulating mechanism regulates the movement of the parking rod at the locked position, the following problem may occur. When the power of the vehicle is turned ON, the supply of power to the hydraulic pressure control valve is started, but the hydraulic pressure control valve may not promptly intercept the hydraulic pressure being supplied to the parking drive mechanism. This is because a certain period of time is required for actually supplying the power to the hydraulic pressure control valve after the power is turned ON, or a certain period of time is required for the hydraulic pressure control valve actually operating by the supply of power after the power is turned ON. On the other hand, after the power of the vehicle is turned ON, the engine speed may rise immediately. In such a case, if the hydraulic pressure control valve does not promptly intercept the hydraulic pressure being supplied to the parking drive mechanism, the hydraulic pressure is given to the parking drive mechanism. Thus, when the hydraulic pressure acts to move the parking rod, movement of which is regulated by the regulating mechanism, from the locked position to the unlocked position, the parking rod may interfere (e.g., collide) with the regulating mechanism, and therefore, the parking rod and the regulating mechanism may be damaged.

<CIT> describes that in a vehicular parking lock device, supplying a hydraulic pressure from pressure regulation of a line pressure by a linear solenoid valve to a hydraulic brake via a switching valve operated by a first solenoid valve enables a transmission to carry out a shift change.

<CIT> describes that when an engine is in an idling stop state, if a selector sensor detects that there is a request for changeover from a NotP-range to a P-range, a control unit of a control device for a vehicle drives a motor pump to supply oil to a hydraulic chamber so that a pressure in the hydraulic chamber is a predetermined pressure as a pressure to allow the generation of moving force greater than the energizing force of a rod energizing spring, and then drives the solenoid to put the stopper into a restriction cancelled state that restrictions on the parking rod is cancelled.

<CIT> describes that that a parking control device for an automatic transmission includes a control unit for performing operation control of the actuator including the supply/discharge of oil to/from a hydraulic chamber.

<CIT> describes that a control apparatus for a vehicle having a parking lock device which is placed in its released state with a hydraulic pressure generated by an oil pump operated by an engine, which control apparatus permits reduction of a risk of unintended releasing of the parking lock device upon occurrence of an operating failure of an ON-OFF switching valve or a switching valve of a hydraulic device provided to supply the hydraulic pressure.

The present invention is made in view of solving the above problems of the conventional art, and one purpose thereof is preventing damage due to an interference of a parking rod with a regulating mechanism, which regulates movement of the parking rod, when power of a vehicle is turned ON or when the power is turned OFF.

The above problems are solved by the invention as defined in claim <NUM> or <NUM>.

Particularly, when the parking rod is at the locked position (i.e., when the regulating mechanism regulates the movement of the parking rod to the unlocked position), the supply of power to the hydraulic pressure control valve is maintained while the engine speed of the engine is higher than the given value even after the power of the vehicle is turned OFF. In other words, the supply of power (supplied current or voltage) in an amount larger than zero to the hydraulic pressure control valve is maintained. Thus, the supply of the hydraulic pressure to the parking drive mechanism can be intercepted. Therefore, when the power of the vehicle is turned OFF, the movement of the parking rod to the unlocked position by the parking drive mechanism can be appropriately reduced, and thereby, an interference of the parking rod with the regulating mechanism can be prevented. As a result, damage to the parking rod and the regulating mechanism can be certainly prevented.

The hydraulic pressure control valve may be an on-off valve. After the power of the vehicle is turned OFF, the controller may supply the power to the hydraulic pressure control valve to maintain an ON state of the hydraulic pressure control valve, while the engine speed of the engine is higher than the given value.

According to this configuration, since the power is supplied to the hydraulic pressure control valve as the on-off valve so as to maintain the ON state of the hydraulic pressure control valve in this situation, the hydraulic pressure is certainly prevented from being supplied to the parking drive mechanism.

After the power of the vehicle is turned OFF, the controller may maintain the supply of power to the hydraulic pressure control valve, while the engine speed of the engine is higher than the given value, and suspend the supply of power to the hydraulic pressure control valve, when the engine speed of the engine becomes the given value or below.

According to this configuration, by suspending the supply of power to the hydraulic pressure control valve when the engine speed becomes the given value or below, the power consumption for supplying the power to the hydraulic pressure control valve can appropriately be reduced.

While the power of the vehicle is OFF, the controller may start the supply of power to the hydraulic pressure control valve, before the power of the vehicle is turned ON (or switched from OFF to ON).

According to this configuration, while the power of the vehicle is OFF, the supply of power to the hydraulic pressure control valve is started before the power of the vehicle is turned ON. Therefore, when the power of the vehicle is turned ON, the supply of power to the hydraulic pressure control valve is completed and the hydraulic pressure control valve is set to be able to certainly intercept the supply of hydraulic pressure to the parking drive mechanism. Thus, even when the engine speed rises immediately after the power of the vehicle is turned ON, the movement of the parking rod to the unlocked position by the parking drive mechanism is prevented, which can prevent the interference of the parking rod with the regulating mechanism. As a result, damage to the parking rod and the regulating mechanism can be certainly prevented.

While the power of the vehicle is OFF, the controller may start the supply of power to the hydraulic pressure control valve, when a door of the vehicle is opened.

According to this configuration, the supply of power to the hydraulic pressure control valve is started when the door of the vehicle is opened while the power of the vehicle is OFF, at which the possibility that the power of the vehicle is turned ON is high. Therefore, the power consumption for supplying the power to the hydraulic pressure control valve can appropriately be reduced.

According to a preferred embodiment of the present invention, after power of a vehicle is turned ON (or switched from OFF to ON), the controller reduces or inhibits an increase in an engine speed of the engine, during a period from an issuance of a power supply command to the hydraulic pressure control valve to a given period of time being elapsed. Particularly, after power of a vehicle is turned ON (or switched from OFF to ON), the controller reduces or inhibits an increase in an engine speed of the engine, during a given period of time from an issuance of a power supply command to the hydraulic pressure control valve.

According to this configuration, after the power of the vehicle is turned ON, the controller reduces the increase in the engine speed, during the period from the issuance of the power supply command to the hydraulic pressure control valve to the given period of time being elapsed. Thus, after the power of the vehicle is turned ON, the generation of the hydraulic pressure by the operation of the engine is prevented until, for example, the hydraulic pressure control valve becomes able to intercept the supply of the hydraulic pressure to the parking drive mechanism so as not to give the hydraulic pressure to the parking drive mechanism. Therefore, when the power of the vehicle is turned ON, the movement of the parking rod to the unlocked position by the parking drive mechanism can be appropriately prevented, which can prevent the interference of the parking rod with the regulating mechanism. As a result, it becomes possible to certainly prevent damage to the parking rod and the regulating mechanism.

The controller may reduce the increase in the engine speed by inhibiting starting of the engine by a starter motor. The controller may control the starter motor so that the starter motor rotates a flywheel to start the engine after determining that the given period of time is elapsed.

Particularly, the control device further includes a shift lever configured to select a shift range.

Further particularly, the switch is configured to turn OFF the power of the vehicle when the switch is turned OFF.

Further particularly, the switch is configured to turn ON the power of the vehicle when the switch is turned ON.

Further particularly, the controller is configured to reduce or inhibit, after the switch is turned ON, the increase in the engine speed of the engine, during the period from the issuance of the power supply command to the hydraulic pressure control valve to the given period of time being elapsed.

Further particularly, the controller is configured to be operable when the switch is OFF.

Further particularly, the controller is configured to be operable when the power of the vehicle is OFF.

Hereinafter, a control device for an automatic transmission is described with reference to the accompanying drawings. All of the features as disclosed in the drawings may not necessarily be essential.

<FIG> is a schematic view illustrating a front part of a vehicle (or an automobile) to which the control device for the automatic transmission according to this embodiment of the present disclosure is mounted. As illustrated in <FIG>, particularly a vehicle <NUM> is of a front-engine front-drive (FF) type. An engine <NUM> is mounted transversely on the front side of the vehicle <NUM>, and an automatic transmission <NUM> is disposed on the left side of the engine <NUM>. An output from the engine <NUM> is transmitted to driven wheels <NUM> through the automatic transmission <NUM> so that the vehicle <NUM> travels. Note that the vehicle <NUM> may be of a front-engine rear-drive (FR) type in which driven wheels (not illustrated) located on the rear side of the vehicle are driven.

A shift lever <NUM> is disposed inside a cabin of the vehicle <NUM>. The shift lever <NUM> is to select a shift range of the automatic transmission <NUM>, and the shift range particularly includes "P" (parking range), "R" (reverse range), "N" (neutral range), and "D" (drive range). An operator or a driver of the vehicle <NUM> operates the shift lever <NUM> to select a desired shift range. Note that in the following, the parking range is suitably referred to as the "P-range," and shift ranges other than the parking range is suitably referred to as the "Non-P-range(s).

The automatic transmission <NUM> is of a shift-by-wire type. The shift range selected by the operation of the shift lever <NUM> is detected by a selector sensor SN2, and an electrical signal based on the detection result of the selector sensor SN2 is inputted into a controller <NUM>. Then, the shift range of the automatic transmission <NUM> is switched by an output signal from the controller <NUM> based on the electrical signal.

Moreover, the automatic transmission <NUM> has a parking device <NUM> which regulates (locks) operation (rotation) of a power transmission shaft <NUM> for transmitting power from the engine <NUM>, when the P-range is selected. Note that the power transmission shaft <NUM> may be directly coupled to the engine <NUM>, or may be indirectly coupled to the engine <NUM> through a torque converter, etc..

Next, referring to <FIG> and <FIG>, a concrete structure of the parking device <NUM> according to this embodiment of the present disclosure is described. <FIG> and <FIG> are cross-sectional views schematically illustrating the parking device <NUM> according to this embodiment of the present disclosure. Particularly, <FIG> is a cross-sectional view schematically illustrating the parking device <NUM> in a locked state, and <FIG> is a cross-sectional view schematically illustrating the parking device <NUM> in an unlocked state.

As illustrated in <FIG> and <FIG>, the parking device <NUM> of the automatic transmission <NUM> is disposed inside a transmission case (not illustrated) of the automatic transmission <NUM>. The parking device <NUM> mainly includes a parking gear <NUM> attached to the power transmission shaft <NUM>, a parking pole <NUM> which engages with the parking gear <NUM> to lock the rotation of the power transmission shaft <NUM> in the P-range, a parking rod <NUM> which moves in the axial direction to switch the locked state (engaged state) and the unlocked state (disengaged state) between the parking pole <NUM> and the parking gear <NUM>, an actuator <NUM> which causes the parking rod <NUM> to move in the axial direction, a stop <NUM> which regulates the axial movement of the parking rod <NUM> in the locked state and the unlocked state, a solenoid <NUM> which cancels the regulation of the parking rod <NUM> by the stop <NUM>, and a rod position sensor SN4 which detects a position of the parking rod <NUM>. Note that in the following description, the parking pole <NUM> side (left side in <FIG> and <FIG>) of the parking rod <NUM> in the axial direction is referred to as a "lock side," and the opposite side from the parking pole <NUM> (right side in <FIG> and <FIG>) is referred to as an "unlock side.

As illustrated in <FIG> and <FIG>, the parking pole <NUM> is supported at an end part on the lock side by the transmission case so as to be rotatable through a pin <NUM>, and a pole pressing part 25a which is pressed by the parking rod <NUM> (in detail, a parking cam <NUM> described later) is formed in an end part on the unlock side. A protrusion 25b which engages with the parking gear <NUM> is formed between the support part supported by the pin <NUM> and the pole pressing part 25a. Moreover, two parking pole biasing springs 25c and 25d which bias the pole pressing part 25a in a disengaging direction (the counter clockwise direction in <FIG> and <FIG>) of the parking gear <NUM> and the protrusion 25b are attached to the parking pole <NUM>. The parking pole biasing springs 25c and 25d are twist coil springs, where the parking pole biasing spring 25c contacts the pole pressing part 25a at an end part on the lock side and contacts the transmission case at an end part on the unlock side. On the other hand, the parking pole biasing spring 25d contacts the pole pressing part 25a at an end part on the lock side and contacts a bracket <NUM> (described later) at an end part on the unlock side.

As illustrated in <FIG>, when the parking rod <NUM> moves to the lock side, the pole pressing part 25a is pressed by the parking rod <NUM>, and the parking pole <NUM> rotates around the pin <NUM> in an engaging direction of the protrusion 25b with the parking gear <NUM> (the clockwise direction in <FIG>), while resisting the biasing force of the parking pole biasing springs 25c and 25d. On the other hand, as illustrated in <FIG>, when the parking rod <NUM> moves to the unlock side, the parking pole <NUM> rotates around the pin <NUM> in a disengaging direction of the protrusion 25b from the parking gear <NUM>, by the biasing force of the parking pole biasing springs 25c and 25d.

As illustrated in <FIG> and <FIG>, the parking rod <NUM> is comprised of a piston rod 26a disposed at the actuator <NUM> and a push rod 26b which presses the parking pole <NUM> in the locked state.

The push rod 26b is disposed so that it is supported by the bracket <NUM>, and an end part of the push rod 26b on the lock side is provided with the parking cam <NUM> which presses the pole pressing part 25a in the engaging direction of the protrusion 25b of the parking pole <NUM> with the parking gear <NUM> in the locked state. The parking cam <NUM> has a shape in which a cylindrical body and a truncated cone are combined, and the truncated cone is attached to a surface of the cylindrical body on the lock side so that the diameter is reduced toward the lock side. The parking cam <NUM> serves as guiding the parking pole <NUM> to the parking gear <NUM> side when it rotates the parking pole <NUM> from an unlocked state to a locked state. That is, when the parking rod <NUM> moves to the lock side, the parking pole <NUM> is guided by the diameter-reduced part of the parking cam <NUM> and rotates about the pin <NUM>. Moreover, the bracket <NUM> is provided with a guide <NUM> which guides the movement of the parking cam <NUM>.

An end part of the push rod 26b on the unlock side is curved so as to be substantially perpendicular to the longitudinal direction of the push rod 26b (i.e., the axial direction of the parking rod <NUM>), and this curved part is connected to an end part of the piston rod 26a on the lock side. A piston 26c is formed in the piston rod 26a so that it is fitted in a cylinder 31a (described later).

Moreover, first and second engagement grooves <NUM> and <NUM> which engage with the stop <NUM> are formed in an end part of the piston rod 26a on the unlock side. The first engagement groove <NUM> is a groove with which the stop <NUM> engages when the parking pole <NUM> is in the locked state. On the other hand, the second engagement groove <NUM> is located on the lock side of the first engagement groove <NUM>, and the second engagement groove <NUM> is a groove with which the stop <NUM> engages when the piston rod 26a moves to the unlock side, and the parking pole <NUM> is in the unlocked state. Groove widths of the first and second engagement grooves <NUM> and <NUM> are larger than a thickness of the stop <NUM> in the axial direction of the parking rod <NUM>. Note that the first and second engagement grooves <NUM> and <NUM> may be formed all around the piston rod 26a in the circumferential direction, or may only be formed in a part thereof with which the stop <NUM> engages.

The actuator <NUM> is a hydraulic actuator. The actuator <NUM> has a housing formed by a cylindrical case <NUM> which has the cylinder 31a, and sealing members <NUM> which close openings of the cylinder 31a on both sides. The piston rod 26a extends so that it penetrates the sealing member <NUM> on the lock side, passes through the inside of the cylinder 31a, and penetrates the sealing member <NUM> on the unlock side. As described above, the piston 26c is fitted into the cylinder 31a, and divides the cylinder 31a into two closed spaces. Among the divided closed spaces, in the closed space on the lock side of the piston 26c, a hydraulic pressure chamber <NUM> to which oil is supplied is formed in order to generate a moving force for moving the parking rod <NUM> (in detail, the piston 26c) to one side in the axial direction (i.e., to the unlock side) so that the parking pole <NUM> is made into the unlocked state. On the other hand, in the closed space on the unlock side of the piston 26c, a rod biasing spring <NUM> which biases the parking rod <NUM> to the other side in the axial direction (i.e., to the lock side) is disposed so that the parking pole <NUM> is made into the locked state. The rod biasing spring <NUM> is a compression coil spring, which contacts the piston 26c at an end part on the lock side, and contacts the sealing member <NUM> at an end part on the unlock side.

As described above, the rod biasing spring <NUM> biases the parking rod <NUM> to the lock side. That is, when oil is not supplied to the hydraulic pressure chamber <NUM> and the moving force based on the pressure inside the hydraulic pressure chamber <NUM> does not act on the piston 26c, the parking rod <NUM> moves to the lock side (<FIG>). At this time, the parking rod <NUM> is located at a "locked position. " On the other hand, when oil is supplied to the hydraulic pressure chamber <NUM> and the pressure inside the hydraulic pressure chamber <NUM> is such a pressure that it generates a moving force larger than the biasing force of the rod biasing spring <NUM>, the parking rod <NUM> moves to the unlock side while resisting the biasing force of the rod biasing spring <NUM> (<FIG>). At this time, the parking rod <NUM> is located at an "unlocked position.

The hydraulic pressure chamber <NUM> is connected to an oil passage <NUM> for supplying oil from an oil pump <NUM> into the hydraulic pressure chamber <NUM>. In this embodiment, the oil pump <NUM> is disposed inside the transmission case, generates hydraulic pressure to be supplied to friction engagement elements of the automatic transmission <NUM>, and is driven by the engine <NUM>. The oil passage <NUM> is provided with a hydraulic pressure control valve <NUM> which supplies oil to the hydraulic pressure chamber <NUM> or discharges (drains) oil from the hydraulic pressure chamber <NUM>. The oil supplied from the oil pump <NUM> is supplied to the hydraulic pressure chamber <NUM> after the hydraulic pressure is adjusted by the hydraulic pressure control valve <NUM>. That is, the hydraulic pressure of the hydraulic pressure chamber <NUM> is controlled by the hydraulic pressure control valve <NUM>. Note that the hydraulic pressure control valve <NUM> is, for example, a linear solenoid valve.

Next, the stop <NUM> and the solenoid <NUM> of the parking device <NUM> according to this embodiment of the present disclosure are described concretely with reference to <FIG> is a side view illustrating the stop <NUM> and the solenoid <NUM>, seen from the unlock side.

As illustrated in <FIG>, the stop <NUM> is an elongated plate-like member where an engaging pawl 35a is formed. The stop <NUM> is rotatably supported by the transmission case of the automatic transmission <NUM> at one end side through a pin <NUM>. A stop biasing spring <NUM> for biasing the stop <NUM> in a direction for regulating the axial movement of the parking rod <NUM> (the counter clockwise direction in <FIG>: hereinafter, referred to as the "regulating direction") is attached to the stop <NUM>. When the stop <NUM> rotates around the pin <NUM> in the regulating direction by the biasing force of the stop biasing spring <NUM>, the engaging pawl 35a engages with the first or second engagement groove <NUM> or <NUM> of the parking rod <NUM>. The stop biasing spring <NUM> is a compression coil spring, and contacts the stop <NUM> at one end side and contacts the transmission case at the other end side.

The stop <NUM> regulates the axial movement of the parking rod <NUM> by the engaging pawl 35a engaging with the first or second engagement groove <NUM> or <NUM> provided to the parking rod <NUM> and contacting a side surface of the first or second engagement groove <NUM> or <NUM>. That is, even if the parking rod <NUM> tries to move to the unlock side or the lock side by using the moving force based on the pressure inside the hydraulic pressure chamber <NUM> or the biasing force of the rod biasing spring <NUM>, the stop <NUM> (in detail, the engaging pawl 35a of the stop <NUM>) contacts the side surface of the first or second engagement groove <NUM> or <NUM> so that the movement of the parking rod <NUM> is regulated.

The solenoid <NUM> is a so-called "push-type solenoid," and as illustrated in <FIG>, it is provided with a solenoid body 40a where a driving coil (not illustrated) is disposed therein, and a movable body 40b which is driven by the coil. When operating, the solenoid <NUM> pushes out the movable body 40b to rotate the stop <NUM> about the pin <NUM> in a direction to cancel the regulating state (the clockwise direction in <FIG>: hereinafter, the "freeing direction") while resisting the biasing force of the stop biasing spring <NUM> so that the stop <NUM> is made into a "freed state" as illustrated by an imaginary line in <FIG>. On the other hand, when not operating, the biasing force of the stop biasing spring <NUM> pushes the movable body 40b into the solenoid body 40a, the solenoid <NUM> rotates the stop <NUM> about the pin <NUM> in the regulating direction, and makes it into a "regulated state" as illustrated by a solid line in <FIG>.

The rod position sensor SN4 is disposed at a position of an end part of the parking rod <NUM> on the unlock side. The rod position sensor SN4 is a magnetic type position sensor, and it is comprised of a substantially C-shaped magnetic sensor 105a, and a slide block 105b which is slidable inside the C-shape of the magnetic sensor 105a. The slide block 105b is provided with an engagement part 105c, and the engagement part 105c engages with the end part of the parking rod <NUM> on the unlock side to integrally couple the slide block 105b to the parking rod <NUM>. Therefore, the slide block 105b slides inside of the C-shape of the magnetic sensor 105a according to the axial movement of the parking rod <NUM>. The slide block 105b has a given magnetic pattern, and by the magnetic sensor 105a detecting the magnetic pattern and detecting the position of the slide block 105b, the position of the parking rod <NUM> is detected.

Note that each of the components used for switching between the locked state and the unlocked state of the rotation of the power transmission shaft <NUM> of the automatic transmission <NUM>, such as the parking gear <NUM>, the parking pole <NUM>, and the parking rod <NUM>, may be an example of a "parking lock mechanism" in the present disclosure. Moreover, the actuator <NUM> which moves the parking rod <NUM> between the locked position and the unlocked position may be an example of a "parking drive mechanism" in the present disclosure. Moreover, each of the stop <NUM>, the stop biasing spring <NUM>, and the solenoid <NUM> may be an example of a "regulating mechanism" in the present disclosure.

Next, a concrete structure of the hydraulic pressure control valve according to this embodiment of the present disclosure is described with reference to <FIG> is a partial cross-sectional view schematically illustrating the hydraulic pressure control valve at the locked state, and <FIG> is a partial cross-sectional view schematically illustrating the hydraulic pressure control valve at the unlocked state.

As illustrated in <FIG>, the hydraulic pressure control valve <NUM> is provided between the oil pump <NUM> which is driven by the engine <NUM> and the oil passage <NUM> connected to the hydraulic pressure chamber <NUM> inside the actuator <NUM> (also see <FIG> and <FIG>). In detail, the hydraulic pressure control valve <NUM> has oil passages 13a and 13b as selectively-used oil supply routes, an oil passage 13c for discharging (draining) oil, a solenoid valve (electromagnetic valve) 13d as an on-off valve which opens when power is supplied and closes when power is not supplied, and a shift valve 13e which is operated by hydraulic pressure from the solenoid valve 13d. Moreover, the shift valve 13e mainly has a case 13f provided with a plurality of ports (representatively, ports A, B, and C), a valve body <NUM> accommodated movably inside the case 13f, and a hydraulic pressure chamber <NUM> to which oil for moving the valve body <NUM> is supplied.

First, in the locked state of the parking device <NUM>, as illustrated in <FIG> (also see <FIG>), the hydraulic pressure control valve <NUM> becomes in an open state by supplying power to the solenoid valve 13d so that oil is supplied to the shift valve 13e through the oil passage 13a. Therefore, oil is supplied to the hydraulic pressure chamber <NUM> of the shift valve 13e and the hydraulic pressure is given to the valve body <NUM> of the shift valve 13e to move the valve body <NUM> as illustrated by an arrow a1. In this case, in the shift valve 13e, the port B is closed by the valve body <NUM>, and the port A and the port C communicate with each other. Therefore, the supply of oil from the oil pump <NUM> to the hydraulic pressure chamber <NUM> inside the actuator <NUM> is intercepted by the shift valve 13e, that is, the hydraulic pressure is no longer given to the hydraulic pressure chamber <NUM>. As a result, the parking rod <NUM> is biased by the rod biasing spring <NUM> inside the actuator <NUM> and is set at the locked position (see <FIG>). Moreover, while the hydraulic pressure is given to the hydraulic pressure chamber <NUM>, when switched to the state illustrated in <FIG> (i.e., when switched from the unlocked state to the locked state), the oil inside the hydraulic pressure chamber <NUM> is discharged through the port A and the port C of the shift valve 13e, and the oil passage 13c.

Next, in the unlocked state of the parking device <NUM>, as illustrated in <FIG> (also see <FIG>), in the hydraulic pressure control valve <NUM>, the solenoid valve 13d becomes in the closed state when power is not supplied, and oil is supplied to the shift valve 13e through the oil passage 13b. In this case, since oil is not supplied to the hydraulic pressure chamber <NUM> of the shift valve 13e, the valve body <NUM> of the shift valve 13e moves as illustrated by an arrow a2. As a result, in the shift valve 13e, the port C is closed by the valve body <NUM>, and the port A and the port B communicate with each other. Therefore, the oil from the oil pump <NUM> is supplied to the hydraulic pressure chamber <NUM> inside the actuator <NUM> through the oil passage 13b and the port A and the port B of the shift valve 13e, that is, the hydraulic pressure is given to the hydraulic pressure chamber <NUM>. Therefore, the parking rod <NUM> is set at the unlocked position by the hydraulic pressure given to the hydraulic pressure chamber <NUM> of the actuator <NUM> (see <FIG>).

Next, a control configuration of the control device for the automatic transmission according to this embodiment of the present disclosure is described with reference to <FIG> is a block diagram illustrating an electric configuration of the control device for the automatic transmission.

As illustrated in <FIG>, a signal from an IG (ignition) switch SN1 for turning ON/OFF the power of the vehicle <NUM>, a signal from the selector sensor SN2 which detects the shift range selected by the operation of the shift lever <NUM>, a signal from an engine speed sensor SN3 which detects an engine speed of the engine <NUM>, a signal from the rod position sensor SN4 which detects the position of the parking rod <NUM> inside the parking device <NUM>, and a signal from a door opening-and-closing sensor SN5 which detects opening/closing of a door of the vehicle <NUM> (particularly, a driver's seat door) are inputted into the controller <NUM>.

The controller <NUM> is comprised of a circuitry, and is a controller based on a well-known microcomputer. The controller <NUM> includes one or more microprocessors 100a, as central processing units (CPU), which execute program(s), memory 100b which is comprised of, for example, RAM (Random Access Memory) and ROM (Read Only Memory) and stores the program(s) and data, and an I/O bus which inputs and outputs electrical signal(s). For example, the controller <NUM> is comprised of an ECU (Electronic Control Unit) and a TCM (Transmission Control Module).

In detail, as illustrated in <FIG>, the controller <NUM> mainly outputs a control signal to the engine <NUM> and the automatic transmission <NUM> based on the signals from the switch SN1 and the sensors SN2-SN5, and controls the engine <NUM> and the automatic transmission <NUM>. Particularly, in this embodiment, the controller <NUM> controls the engine speed of the engine <NUM> and performs a power control to the hydraulic pressure control valve <NUM> inside the parking device <NUM> of the automatic transmission <NUM> and the solenoid <NUM> which drives the stop <NUM>. Note that, strictly, although the controller <NUM> performs the control to the solenoid valve 13d (<FIG>) of the hydraulic pressure control valve <NUM>, controlling of the solenoid valve 13d of the hydraulic pressure control valve <NUM> may simply be described as controlling of the hydraulic pressure control valve <NUM> while omitting the solenoid valve 13d, for simplifying the description.

Next, a control executed by the controller <NUM> in the first embodiment of the present disclosure is described.

First, in the first embodiment, a control executed by the controller <NUM> when the power of the vehicle <NUM> is turned OFF (i.e., when the IG switch SN1 is turned OFF) is described. In the first embodiment, when the parking rod <NUM> is at the locked position (i.e., when the movement of the parking rod <NUM> is regulated by the stop <NUM> engaging with the first engagement groove <NUM>), the controller <NUM> maintains the supply of power to the hydraulic pressure control valve <NUM>, in other words, it supplies the power to the hydraulic pressure control valve <NUM> as the on-off valve to maintain the ON state of the hydraulic pressure control valve <NUM>, while the engine speed of the engine <NUM> is higher than a given value, after the power of the vehicle <NUM> is turned OFF (switched to from ON to OFF). That is, even after the power of the vehicle <NUM> is turned OFF, the controller <NUM> continues the supply of power to the hydraulic pressure control valve <NUM> while the engine speed of the engine <NUM> is higher than the given value, and after that, it suspends the supply of power to the hydraulic pressure control valve <NUM> when the engine speed of the engine <NUM> becomes the given value or below.

The reason why doing this is as follows. Since the supply of power to the hydraulic pressure control valve <NUM> is suspended when the power of the vehicle <NUM> is turned OFF, it becomes in a state where the oil from the oil pump <NUM> can be supplied to the hydraulic pressure chamber <NUM> of the actuator <NUM> (see <FIG>). Fundamentally, since the engine speed is fully lowered when the power of the vehicle <NUM> is turned OFF, the hydraulic pressure is often not given to the actuator <NUM>. However, after the power of the vehicle <NUM> is turned OFF, the engine speed may be comparatively high for a while, and in this case, the hydraulic pressure is given to the actuator <NUM>. Thus, the hydraulic pressure acts to move the parking rod <NUM>, in the state where the movement is regulated by the stop <NUM> engaging with the first engagement groove <NUM> (see <FIG>), from the locked position to the unlocked position. Therefore, the stop <NUM> collides the wall which forms the first engagement groove <NUM> (in this case, a backlash between the stop <NUM> and the first engagement groove <NUM> is eliminated), and the stop <NUM> and the first engagement groove <NUM> may be damaged.

Therefore, in the first embodiment, when the parking rod <NUM> is at the locked position, after the power of the vehicle <NUM> is turned OFF, the controller <NUM> maintains the supply of power to the hydraulic pressure control valve <NUM> while the engine speed of the engine <NUM> is higher than the given value so as not to give the hydraulic pressure to the actuator <NUM> (see <FIG>). Therefore, the movement of the parking rod <NUM> caused by the hydraulic pressure in the actuator <NUM> can be reduced, and the collision of the stop <NUM> with the first engagement groove <NUM> can prevented. As a result, it becomes possible to prevent damage to the stop <NUM> and the first engagement groove <NUM>.

Next, a control when switching the power of the vehicle <NUM> from ON to OFF in the first embodiment of the present disclosure is described concretely with reference to <FIG> is a flowchart illustrating a control when switching the power of the vehicle <NUM> from ON to OFF. This control is repeatedly executed at a given interval by the microprocessor 100a in the controller <NUM> based on the program stored in the memory 100b. All of the steps as disclosed in <FIG> may not necessarily be essential.

First, at Step S11, the controller <NUM> acquires variety of information based on or corresponding to the signals from the switch SN1 and the sensors SN2-SN5. Particularly, the controller <NUM> acquires a state of the IG switch SN1, i.e., ON/OFF of the IG switch SN1 (this corresponds to the power ON/OFF of the vehicle <NUM>), the shift range detected by the selector sensor SN2, and the engine speed detected by the engine speed sensor SN3. Then, the controller <NUM> shifts to Step S <NUM>.

Next, at Step S <NUM>, the controller <NUM> determines whether the shift range acquired at Step S <NUM> is the P-range. This determination corresponds to a determination of whether the parking rod <NUM> is at the locked position. As a result, if determined that the shift range is the P-range (Step S12: YES), the controller <NUM> shifts to Step S13. At Step S13, the controller <NUM> determines whether the state of the IG switch SN1 acquired at Step S11 is OFF. As a result, if determined that the IG switch SN1 is OFF (Step S13: YES), that is, if the power of the vehicle <NUM> is turned OFF, the controller <NUM> shifts to Step S14.

On the other hand, at Step S12, if determined that the shift range is not the P-range (Step S12: NO), that is, if the shift range is the Non-P-range, the controller <NUM> exits from the routine according to this control. Moreover, at Step S <NUM>, if determined that the IG switch SN1 is not OFF (Step S13: NO), that is, if the power of the vehicle <NUM> stays ON, the controller <NUM> exits from the routine according to this control. This is because the situation where the shift range is the Non-P-range or the IG switch SN1 is ON does not correspond to the condition to execute the control.

Note that although in the above example it is determined whether the shift range is the P-range (Step S12), it may be determined whether the parking rod <NUM> is at the locked position based on the position of the parking rod <NUM> detected by the rod position sensor SN4.

Next, at Step S14, the controller <NUM> determines whether the engine speed acquired at Step S11 is the given value or below. The given value used for this determination adopts an engine speed at which the hydraulic pressure for moving the parking rod <NUM> is not generated in the actuator <NUM>, in more detail, the hydraulic pressure larger than the biasing force of the rod biasing spring <NUM> inside the actuator <NUM> is not generated. In a suitable example, a value near zero (rpm) is applied to the given value. In one example, zero (rpm) is applied to the given value. According to this example, it can certainly prevent the collision of the stop <NUM> with the first engagement groove <NUM> which occurs by the movement of the parking rod <NUM>.

As a result of Step S14, if determined that the engine speed is not the given value or below (Step S14: NO), that is, if the engine speed is higher than the given value, the controller <NUM> shifts to Step S16. In this case, the engine <NUM> may be possible to generate the hydraulic pressure for moving the parking rod <NUM>. Therefore, at Step S16, the controller <NUM> maintains the supply of power to the hydraulic pressure control valve <NUM> in order to intercept the supply of hydraulic pressure from the oil pump <NUM> of the engine <NUM> to the actuator <NUM> and prevent the movement of the parking rod <NUM> to the unlock side. In more detail, the controller <NUM> continues the supply of power to the solenoid valve 13d and maintains the ON state of the valve 13d in order to maintain the solenoid valve 13d of the hydraulic pressure control valve <NUM> in the open state and maintain the state of the shift valve 13e as illustrated in <FIG> (i.e., a state where the oil path from the oil pump <NUM> to the hydraulic pressure chamber <NUM> of the actuator <NUM> is intercepted).

After Step S16, the controller <NUM> returns to Step S14 and then again performs the determination at Step S14. Thus, while the engine speed is higher than the given value (Step S14: NO), the controller <NUM> continues the supply of power to the hydraulic pressure control valve <NUM> (Step S16).

On the other hand, as a result of Step S14, if determined that the engine speed is the given value or below (Step S14: YES), the controller <NUM> shifts to Step S15. In this case, the engine <NUM> is not in a state where it can generate the hydraulic pressure for moving the parking rod <NUM>. Therefore, at Step S15, the controller <NUM> also suspends the supply of power to the hydraulic pressure control valve <NUM> according to the IG switch SN1 being turned OFF, as usual. That is, the controller <NUM> turns OFF the supply of power to the solenoid valve 13d of the hydraulic pressure control valve <NUM>. Then, the controller <NUM> exits from the routine according to this control.

Note that as described above, the controller <NUM> operates, also when the IG switch SN1 is OFF (i.e., if the power of the vehicle <NUM> is OFF). Normally, since the TCM included in the controller <NUM> can operate also when the IG switch SN1 is OFF, the control described above may be executed mainly by this TCM, for example (similar for controls described later).

Next, operation and effects by the control when switching the power of the vehicle <NUM> from ON to OFF in the first embodiment of the present disclosure is described with reference to <FIG> is a time chart illustrating a result of the control when switching the power of the vehicle <NUM> from ON to OFF.

<FIG> illustrates, sequentially from the top, the state (ON/OFF) of the IG switch SN1, the engine speed, the power supply state (ON/OFF) of the hydraulic pressure control valve <NUM>, the hydraulic pressure given to the actuator <NUM>, and the stroke position of the parking rod <NUM> on the basis of the locked position. Moreover, in <FIG>, a solid line graph illustrates a result of the control according to the first embodiment, and a broken line graph illustrates a result of a control according to a comparative example.

First, in the comparative example, when the IG switch SN1 is turned OFF (time <NUM>), the supply of power to the hydraulic pressure control valve <NUM> is turned OFF. In the example illustrated in <FIG>, since the engine speed is comparatively high even after the IG switch SN1 is turned OFF, the hydraulic pressure is given from the oil pump <NUM> to the actuator <NUM> when the supply of power to the hydraulic pressure control valve <NUM> is turned OFF. Thus, by the hydraulic pressure given to the actuator <NUM>, the parking rod <NUM> moves to the unlock side by the amount of backlash between the stop <NUM> and the first engagement groove <NUM>, and the stop <NUM> collides the first engagement groove <NUM>.

On the other hand, in the first embodiment, even after time t11 at which the IG switch SN1 is turned OFF, the supply of power to the hydraulic pressure control valve <NUM> is maintained ON. Therefore, the hydraulic pressure is not given from the oil pump <NUM> to the actuator <NUM>, and the movement of the parking rod <NUM> by the hydraulic pressure is prevented. As a result, the collision of the stop <NUM> with the first engagement groove <NUM> can be prevented. Moreover, in the first embodiment, while the engine speed is higher than the given value (zero in the example illustrated in <FIG>) (time t11-t12), the supply of power to the hydraulic pressure control valve <NUM> is continued, and after the engine speed becomes the given value or below (after time t12), the supply of power to the hydraulic pressure control valve <NUM> is suspended. Thus, by suspending the supply of power to the hydraulic pressure control valve <NUM> when the engine speed becomes the given value or below, the power consumption for supplying the power to the hydraulic pressure control valve <NUM> can appropriately be reduced.

Next, in the first embodiment, a control executed by the controller <NUM> when the power of the vehicle <NUM> is turned ON (i.e., when the IG switch SN1 is turned ON) is described. In the first embodiment, while the power of the vehicle <NUM> is OFF, the controller <NUM> starts the supply of power to the hydraulic pressure control valve <NUM> before the power of the vehicle <NUM> is turned ON. Particularly, while the power of the vehicle <NUM> is OFF, the controller <NUM> starts the supply of power to the hydraulic pressure control valve <NUM> when the door of the vehicle <NUM> is opened. Note that, in order to achieve such a control according to the first embodiment, while the power of the vehicle <NUM> is OFF, the controller <NUM> must be in an active state where it is possible to give the power supply command to the hydraulic pressure control valve <NUM>.

The reason for performing the control is as follows. When the power of the vehicle <NUM> is turned ON, although the supply of power to the hydraulic pressure control valve <NUM> is started, the hydraulic pressure control valve <NUM> may not promptly intercept the supply of hydraulic pressure to the actuator <NUM>. This originates, for example, from a time lag from the power supply command being issued from the controller <NUM> to the power being actually supplied to the solenoid valve 13d of the hydraulic pressure control valve <NUM>, a time lag from the power being supplied to the solenoid valve 13d being actually opened, and a time lag from the solenoid valve 13d being opened to the shift valve 13e being actually operated. On the other hand, after the power of the vehicle <NUM> is turned ON, the engine speed may rise immediately. In this case, if the hydraulic pressure control valve <NUM> does not promptly intercept the supply of hydraulic pressure to the actuator <NUM>, the hydraulic pressure is given to the actuator <NUM>. Thus, the hydraulic pressure acts for moving, from the locked position to the unlocked position, the parking rod <NUM> of which the movement is regulated by the stop <NUM> engaging with the first engagement groove <NUM> (see <FIG>), and the stop <NUM> collides the wall which forms the first engagement groove <NUM> (in this case, the backlash between the stop <NUM> and the first engagement groove <NUM> is eliminated). Therefore, the stop <NUM> and the first engagement groove <NUM> may be damaged.

Therefore, in the first embodiment, the controller <NUM> starts the supply of power to the hydraulic pressure control valve <NUM>, while the power of the vehicle <NUM> is OFF before the power is turned ON. Particularly, in the first embodiment, when the door (particularly, the driver's seat door) is opened while the power of the vehicle <NUM> is OFF, it is considered that the power will be turned ON immediately after that, and therefore, the supply of power to the hydraulic pressure control valve <NUM> is started. Thus, when the power of the vehicle <NUM> is turned ON, the supply of power to the hydraulic pressure control valve <NUM> is completed and the hydraulic pressure control valve <NUM> is set to be able to intercept the supply of hydraulic pressure to the actuator <NUM> certainly (see <FIG>). Therefore, the movement of the parking rod <NUM> caused by the hydraulic pressure in the actuator <NUM> can be prevented, and the collision of the stop <NUM> with the first engagement groove <NUM> can be prevented. Thus, it becomes possible to prevent damage to the stop <NUM> and the first engagement groove <NUM>.

Next, a control when switching the power of the vehicle <NUM> from OFF to ON in the first embodiment of the present disclosure is described concretely with reference to <FIG> is a flowchart illustrating the control when switching the power of the vehicle <NUM> from OFF to ON. This control is also repeatedly executed at a given interval by the microprocessor 100a in the controller <NUM> based on the program stored in the memory 100b.

First, at Step S21, the controller <NUM> acquires variety of information corresponding to the signals from the switch SN1 and the sensors SN2-SN5. Particularly, the controller <NUM> acquires the state of the IG switch SN1, i.e., ON/OFF of the IG switch SN1 (this corresponds to the power ON/OFF of the vehicle <NUM>), and the open/close state of the door of the vehicle <NUM> detected by the door opening-and-closing sensor SN5. Then, the controller <NUM> shifts to Step S22.

Next, at Step S22, the controller <NUM> determines whether the door of the vehicle <NUM> is opened based on the open/close state of the door acquired at Step S21. As a result, if determined that the door of the vehicle <NUM> is opened (Step S22: YES), the controller <NUM> shifts to Step S23. On the other hand, if determined that the door of the vehicle <NUM> is not opened (i.e., if the door of the vehicle <NUM> is closed) (Step S22: NO), the controller <NUM> exits from the routine according to this control. Note that at the Step S22, particularly, it is desirable to determine whether the door of the driver's seat is opened. This is because, if the door of the driver's seat is opened, the possibility that the IG switch SN1 will then be immediately turned ON is high.

Next, at Step S23, the controller <NUM> determines that, since the door of the vehicle <NUM> is opened, the possibility that the IG switch SN1 will then be immediately turned ON is high, and it starts the supply of power to the hydraulic pressure control valve <NUM> so that the supply of power to the hydraulic pressure control valve <NUM> is completed when the IG switch SN1 is turned ON. Thus, when the IG switch SN1 is turned ON, the hydraulic pressure control valve <NUM> is certainly set in the state where it can intercept the supply of hydraulic pressure to the actuator <NUM> to prevent the movement of the parking rod <NUM> to the unlock side. In more detail, the controller <NUM> opens the solenoid valve 13d of the hydraulic pressure control valve <NUM>, and starts the supply of power to the solenoid valve 13d so that the shift valve 13e becomes in the state as illustrated in <FIG> (i.e., the state where the oil path from the oil pump <NUM> to the hydraulic pressure chamber <NUM> of the actuator <NUM> is intercepted).

Next, at Step S24, the controller <NUM> determines whether the state of the IG switch SN1 acquired at Step S21 is ON. As a result, if determined that the IG switch SN1 is ON (i.e., if the power of the vehicle <NUM> is turned ON) (Step S24: YES), the controller <NUM> shifts to Step S25 to start the engine <NUM>. For example, the controller <NUM> rotates a flywheel by using a starter motor to start the engine <NUM>. Then, the controller <NUM> exits from the routine according to this control.

On the other hand, if determined that the IG switch SN1 is not ON (i.e., if the power of the vehicle <NUM> stays OFF) (Step S24: NO), the controller <NUM> returns to Step S24 to again perform the determination of Step S24. In this case, the controller <NUM> stands by until the IG switch SN1 is turned ON. Note that after starting the supply of power to the hydraulic pressure control valve <NUM>, even if the IG switch SN1 is not turned ON for a given period of time, the supply of power to the hydraulic pressure control valve <NUM> may be suspended in order to reduce the power consumption.

Next, operation and effects by the control when switching the power of the vehicle <NUM> from OFF to ON in the first embodiment of the present disclosure is described with reference to <FIG> is a time chart illustrating a result of the control when switching the power of the vehicle <NUM> from OFF to ON.

<FIG> illustrates, sequentially from the top, the state of the IG switch SN1 (ON/OFF), the open/close state of the door of the vehicle <NUM>, the engine speed, the power supply state (ON/OFF) of the hydraulic pressure control valve <NUM>, and the hydraulic pressure given to the actuator <NUM>, and the stroke position of the parking rod <NUM> on the basis of the locked position. Moreover, in <FIG>, a solid line graph illustrates a result of the control according to the first embodiment described above, and a broken line graph illustrates a result of the control according to the comparative example.

First, in the comparative example, when a certain period of time is elapsed after the IG switch SN1 is turned ON at time t22, the supply of power to the hydraulic pressure control valve <NUM> is turned ON at time t23. In the example illustrated in <FIG>, the engine speed rises quickly immediately after the IG switch SN1 is turned ON. Therefore, since the supply of power to the hydraulic pressure control valve <NUM> is OFF at least during a period from time t22 to time t23, the hydraulic pressure is given from the oil pump <NUM> to the actuator <NUM>. Thus, by the hydraulic pressure given to the actuator <NUM>, the parking rod <NUM> moves to the unlock side by the amount of backlash between the stop <NUM> and the first engagement groove <NUM>, and therefore, the stop <NUM> collides the first engagement groove <NUM>.

On the other hand, in the first embodiment, when the door of the vehicle <NUM> is opened (time t21) before the IG switch SN1 is turned ON, the supply of power to the hydraulic pressure control valve <NUM> is started, that is, the supply of power to the hydraulic pressure control valve <NUM> is turned ON. Thus, since the supply of power to the hydraulic pressure control valve <NUM> is completed when the IG switch SN1 is turned ON next (time t22), the hydraulic pressure is not given from the oil pump <NUM> of the engine <NUM> to the actuator <NUM>, and therefore, the movement of the parking rod <NUM> by the hydraulic pressure is prevented. As a result, the collision of the stop <NUM> with the first engagement groove <NUM> can be prevented. Moreover, in the first embodiment, since the supply of power to the hydraulic pressure control valve <NUM> is started at the timing when the door is opened while the IG switch SN1 is OFF, at which the possibility that the IG switch SN1 is turned ON is high, the power consumption for supplying the power to the hydraulic pressure control valve <NUM> can appropriately be reduced.

Note that although in the embodiment the timing at which the supply of power to the hydraulic pressure control valve <NUM> is started while the power of the vehicle <NUM> is OFF is the timing at which the door of the vehicle <NUM> is opened, the present disclosure is not limited to this configuration. In another example, while the power of the vehicle <NUM> is OFF, the supply of power to the hydraulic pressure control valve <NUM> may be started at a timing when the door of the vehicle <NUM> is closed after the door is once opened. In another example, while the power of the vehicle <NUM> is OFF, the supply of power to the hydraulic pressure control valve <NUM> may be started at a timing when a seat sensor provided to the driver's seat detects the driver sitting down.

Next, a control executed by the controller <NUM> in the second embodiment of the present disclosure is described.

The control according to the second embodiment relates to a control performed when the power of the vehicle <NUM> is turned ON. Also in the first embodiment, the control described above is performed when the power of the vehicle <NUM> is turned ON. That is, in the first embodiment, the controller <NUM> performs the control for starting the supply of power to the hydraulic pressure control valve <NUM> while the power of the vehicle <NUM> is OFF, before the power of the vehicle <NUM> is turned ON. In the second embodiment, although the control is performed based on a similar reason to the control according to this first embodiment, the control is different from that of the first embodiment.

In detail, in the second embodiment, after the power of the vehicle <NUM> is turned ON, the controller <NUM> performs a control for inhibiting an increase in the engine speed for a given period of time from an issuance of the power supply command to the hydraulic pressure control valve <NUM>. Thus, after the power of the vehicle <NUM> is turned ON, the generation of the hydraulic pressure by the engine <NUM> is prevented until the hydraulic pressure control valve <NUM> becomes able to intercept the supply of hydraulic pressure to the actuator <NUM> so as not to give the hydraulic pressure to the actuator <NUM>. Therefore, the movement of the parking rod <NUM> caused by the hydraulic pressure in the actuator <NUM> can be prevented so as to avoid the collision of the stop <NUM> with the first engagement groove <NUM>. Thereby, it becomes possible to prevent damage to the stop <NUM> and the first engagement groove <NUM>.

Next, a control when switching the power of the vehicle <NUM> from OFF to ON in the second embodiment of the present disclosure is described concretely with reference to <FIG> is a flowchart illustrating the control when switching the power of the vehicle <NUM> from OFF to ON. This control is also repeatedly executed at a given interval by the microprocessor 100a in the controller <NUM> based on the program stored in the memory 100b. All of the steps as disclosed in <FIG> may not necessarily be essential.

First, at Step S31, the controller <NUM> acquires a variety of information corresponding to the signals from the switch SN1 and the sensors SN2-SN5. Particularly, the controller <NUM> acquires the state of the IG switch SN1, i.e., ON/OFF of the IG switch SN1 (this corresponds to the power ON/OFF of the vehicle <NUM>). Then, the controller <NUM> shifts to Step S32.

Next, at Step S32, the controller <NUM> determines whether the state of the IG switch SN1 acquired at Step S31 is ON. As a result, if determined that the IG switch SN1 is ON (i.e., if the power of the vehicle <NUM> is turned ON) (Step S32: YES), the controller <NUM> shifts to Step S33. On the other hand, if determined that the IG switch SN1 is not ON (i.e., if the power of the vehicle <NUM> stays OFF) (Step S32: NO), the controller <NUM> exits from the routine according to this control.

Next, at Step S33, the controller <NUM> issues the power supply command to the hydraulic pressure control valve <NUM> so that the hydraulic pressure control valve <NUM> becomes in the state where it can intercept the supply of hydraulic pressure to the actuator <NUM>. Then, the controller <NUM> shifts to Step S34.

Next, at Step S34, the controller <NUM> determines whether the given period of time is elapsed after issuing the power supply command to the hydraulic pressure control valve <NUM>. This given period of time is set in consideration of a time from the issuance of the power supply command to the power being actually supplied to the solenoid valve 13d of the hydraulic pressure control valve <NUM>, a time from the power supply to the solenoid valve 13d being actually opened, a time from the solenoid valve 13d being opened to the shift valve 13e being actually operated, etc..

As a result of Step S34, if determined that the given period of time is not elapsed (Step S34: NO), the controller <NUM> shifts to Step S36. In this case, it is thought that the hydraulic pressure control valve <NUM> has not been able to intercept the supply of hydraulic pressure to the actuator <NUM>. Therefore, at Step S36, the controller <NUM> inhibits the increase in the engine speed to prevent the generation of the hydraulic pressure by the engine <NUM> so that the hydraulic pressure is not to be given to the actuator <NUM>. For example, the controller <NUM> stands by a startup of the engine <NUM> by the starter motor.

After Step S36, the controller <NUM> returns to Step S34 to again perform the determination of Step S34. Thus, until the given period of time is elapsed (Step S34: NO), the controller <NUM> continues inhibiting the rise of the engine speed (Step S36).

On the other hand, as a result of Step S34, if determined that the given period of time is elapsed (Step S34: YES), the controller <NUM> shifts to Step S35. In this case, it is thought that the hydraulic pressure control valve <NUM> becomes able to intercept the supply of hydraulic pressure to the actuator <NUM>. Therefore, at Step S35, the controller <NUM> starts the engine <NUM> according to the IG switch SN1 being turned ON. For example, the controller <NUM> rotates the flywheel by the starter motor to start the engine <NUM>. Then, the controller <NUM> exits from the routine according to this control.

Next, operation and effects by the control when switching the power of the vehicle <NUM> from OFF to ON in the second embodiment of the present disclosure is described with reference to <FIG> is a time chart illustrating a result of the control when switching the power of the vehicle <NUM> from OFF to ON.

<FIG> illustrates, sequentially from the top, the state (ON/OFF) of the IG switch SN1, the engine speed, the power supply state (ON/OFF) of the hydraulic pressure control valve <NUM>, the hydraulic pressure given to the actuator <NUM>, and the stroke position of the parking rod <NUM> on the basis of the locked position. Moreover, in <FIG>, a solid line graph illustrates a result of the control by the second embodiment described above, and a broken line graph illustrates a result of the control by the comparative example.

First, in the comparative example, when a certain period of time is elapsed after the IG switch SN1 is turned ON at time t31, the supply of power to the hydraulic pressure control valve <NUM> is turned ON at time t33. In the example illustrated in <FIG>, the engine speed rises quickly immediately after the IG switch SN1 is turned ON. Therefore, at least during a period from time t31 to time t33, since the supply of power to the hydraulic pressure control valve <NUM> is OFF, the hydraulic pressure is given from the oil pump <NUM> to the actuator <NUM>. Thus, the hydraulic pressure given to the actuator <NUM> moves the parking rod <NUM> to the unlock side by the amount of backlash between the stop <NUM> and the first engagement groove <NUM>, and therefore, the stop <NUM> collides the first engagement groove <NUM>.

On the other hand, in the second embodiment, the power supply command is issued to the hydraulic pressure control valve <NUM> at time t31 when the IG switch SN1 is turned ON. Then, until the given period of time is elapsed after power supply command is issued, in detail, a period from time t31 to time t32, the increase in the engine speed is inhibited, and therefore, the generation of the hydraulic pressure by the engine <NUM> is prevented. Therefore, the hydraulic pressure is not given to the actuator <NUM>, and the movement of the parking rod <NUM> by the hydraulic pressure is prevented. As a result, the collision of the stop <NUM> with the first engagement groove <NUM> can be prevented.

Note that although in the embodiment the increase in the engine speed is inhibited until the given period of time is elapsed after the power supply command is issued to the hydraulic pressure control valve <NUM>, after the power of the vehicle <NUM> is turned ON, the present disclosure is not limited to inhibiting the increase in the engine speed. In another example, instead of inhibiting the increase in the engine speed, the increase in the engine speed is reduced, while permitting the increase in the engine speed. For example, a rate of increase in the engine speed may be regulated, that is, a slope of the increase in the engine speed may be more gentle than usual.

In the above embodiments, the hydraulic pressure control valve <NUM> is comprised of the on-off valve which can take the two states of the open state (fully open) and the closed state (fully close) by switching between the "power supplied state" and the "power not supplied state. " However, the present disclosure is not limited to the application to such an on-off valve, but it may also be applied to a valve which is adjustable of a valve opening by changing the amount of power supplied (current or voltage). In this case, while the engine speed is higher than a given value after the power of the vehicle <NUM> is turned OFF, the controller <NUM> may maintain a given amount of power (the amount of power supplied to achieve the state illustrated in <FIG>) larger than zero to the hydraulic pressure control valve <NUM>.

Moreover, in the above embodiments, the parking rod <NUM> is set at the unlocked position by using the hydraulic pressure from the oil pump <NUM> which is driven by the engine <NUM>, in other words, by using the hydraulic pressure generated by the rotation of the engine <NUM>. In another example, if the engine <NUM> is provided with a turbocharger, the hydraulic pressure may be generated by rotation of a turbine of the turbocharger, and the parking rod <NUM> may be set at the unlocked position by using the hydraulic pressure.

Claim 1:
A vehicle (<NUM>) comprising an engine (<NUM>) and an automatic transmission (<NUM>), wherein
the automatic transmission (<NUM>) comprises a control device, and
the control device comprises:
a parking lock mechanism (<NUM>, <NUM>), provided with a parking rod (<NUM>), configured to lock rotation of a power transmission shaft (<NUM>) of the automatic transmission (<NUM>) by setting the parking rod (<NUM>) at a locked position on one side in an axial direction of the parking rod (<NUM>), when the automatic transmission (<NUM>) is in a parking range, and unlock the rotation of the power transmission shaft (<NUM>) by setting the parking rod (<NUM>) at an unlocked position on the other side in the axial direction, when the automatic transmission (<NUM>) is in ranges other than the parking range;
a parking drive mechanism (<NUM>) configured to set the parking rod (<NUM>) at the locked position by biasing the parking rod (<NUM>), and set the parking rod (<NUM>) at the unlocked position by supplying hydraulic pressure generated by operating an engine (<NUM>);
a hydraulic pressure control valve (<NUM>) configured to intercept the supply of the hydraulic pressure to the parking drive mechanism (<NUM>) when power is supplied thereto, and supply the hydraulic pressure to the parking drive mechanism (<NUM>) when power is not supplied thereto;
a regulating mechanism (<NUM>) configured to regulate the movement of the parking rod (<NUM>) to the unlocked position when the parking rod (<NUM>) is at the locked position;
a controller (<NUM>); and
an ignition switch (SN1) configured to turn ON/OFF power of the vehicle (<NUM>),
characterized in that
the controller (<NUM>) is configured to control the supply of power to the hydraulic pressure control valve (<NUM>), and configured to maintain, when the parking rod (<NUM>) is at the locked position, after the ignition switch (SN1) is turned OFF, the supply of power to the hydraulic pressure control valve (<NUM>), while an engine speed of the engine (<NUM>) is higher than a given value.