JP2023114545A - transmission - Google Patents

Abstract

To provide a transmission that has effectively suppressed noise which occurs during switching of a traveling range to a non-traveling range with a simple constitution.SOLUTION: A transmission 20 comprises: a range selector valve 100 which brings a support port 113 and a friction fastening element 114 into communication with each other and blocks a drain port 115 in a traveling range ; a supply control valve 240 arranged between a hydraulic pressure supply source 230 and the supply port; a control unit 210 for controlling the supply control valve in response to switching of the traveling range to a non-traveling range; and parking lock mechanisms 28, 29 which transition from a released state to a locked state in response to switching of the traveling range to the non-traveling range. The range selector valve brings the supply port and the drain port into communication with each other in the non-traveling range, and the control unit holds the supply control valve in a valve-open state until the parking lock mechanisms transition to the locked state after detecting the switching of the traveling range to the non-traveling range.SELECTED DRAWING: Figure 4

Description

The present invention relates to a transmission that transmits power from a power source for running a vehicle to wheels.

2. Description of the Related Art A transmission such as an automatic transmission mounted on a vehicle such as an automobile switches between a forward drive state and a reverse drive state by switching engagement and release of frictional engagement elements such as clutches and brakes.
In a transmission in which an occupant such as a driver manually performs a range selection operation, an oil passage switching valve (manual valve) that interlocks with a range selection operation unit such as a select lever is used to switch between engagement and release of frictional engagement elements.

The transmission is also provided with a parking lock mechanism that mechanically locks the output shaft to prevent the vehicle from moving when the non-driving range (typically the parking range) is selected.
The parking lock mechanism, for example, provides a parking gear on the output shaft or a shaft portion that interlocks with the output shaft, and engages the parking pawl with the recess of the parking gear in response to switching to the non-running range, thereby locking the output shaft. lock.

In the above-described transmission, when the driving range such as the reverse range is switched to the non-driving range in which the parking lock mechanism is activated, there is a problem that the parking gear repels the parking pawl, causing an abnormal noise (tooth rattling). may be.
This type of noise is caused by the rapid rotation of the parking gear due to the release of the reverse frictional engagement element from the state in which various shaft members of the power transmission path are twisted by the torque of the engine while the vehicle is stopped. , occurs when the parking pole is ejected.

As a technology related to a vehicle transmission, for example, Patent Document 1 discloses that a manual valve is arranged in a hydraulic control device of an automatic transmission. It is described that the reverse range is achieved at the parking position, and the reverse range attainment hydraulic circuit and the drain oil passage are communicated at the parking position. Also, when the manual valve shifts from reverse to parking, the oil passage leading to the frictional engagement device involved in generating the reverse range is connected to the drain oil passage, and pressure oil is slowly discharged through this orifice. , that gear rattling noise is suppressed.
In Patent Document 2, a pressure holding valve is provided between the drain oil passages of the forward clutch and the reverse brake and a drain port open to the atmosphere, and the flow rate passing through the orifice is adjusted to appropriately drain the hydraulic oil of the reverse brake. It is described that it is performed quickly and slowly, and that a select shock when selecting from the R range to the P range can be prevented.
In Patent Document 3, a drain port of a manual valve having a supply port communicating with a hydraulic source, a discharge port for generating hydraulic pressure according to range switching for forward or backward movement, and a drain port for opening the drain is disclosed. The provision of an electromagnetic switching valve is described. One end of the electromagnetic switching valve is connected to the first oil drain passage through which the orifice is inserted, and the other end is connected to the second oil drain passage. It is described that when switching from the forward side or reverse side range to the P range, the meshing impact noise of the parking mechanism can be reduced.

Registered Utility Model No. 2582881 JP-A-2020-41558 Japanese Utility Model Laid-Open No. 3-125945

As described in Patent Literatures 1 and 2, when an orifice is used to delay oil discharge from a reverse frictional engagement element, the orifice diameter and the like are required in hardware specifications in a region where the speed of oil escape becomes a bottleneck. Due to the restrictions, there is concern that abnormal noise cannot be effectively suppressed in a wide area. For example, if the orifice diameter is made too small, the friction engagement element will not be released properly when the non-running range is selected at low temperatures, and there is concern that a creep phenomenon will occur in the non-running range.
In addition, as described in Patent Document 3, if an electromagnetic switching valve is provided, the structure becomes complicated and the cost increases.
SUMMARY OF THE INVENTION In view of the problems described above, an object of the present invention is to provide a transmission that effectively suppresses abnormal noise when switching from a driving range to a non-driving range with a simple configuration.

In order to solve the above-described problems, a transmission according to one aspect of the present invention provides a driving range in which a frictional engagement element provided in a power transmission path from a driving power source to drive wheels is engaged, and a driving range in which the frictional engagement element is engaged. A transmission switchable to and from a disengaged non-drive range, comprising a supply port connected to a hydraulic supply source, a friction engagement element port connected to a friction engagement element, and a drain for discharging hydraulic fluid returning from the friction engagement element port. a range switching valve having a port, communicating between the supply port and the frictional engagement element port and closing the drain port in the travel range; and a supply provided between the hydraulic supply source and the supply port. a control valve, a range switching detection unit for detecting switching from the driving range to the non-driving range, a control unit for controlling the supply control valve according to the output of the range switching detection unit, a parking lock mechanism that transitions from a released state that allows rotation of the driving wheels to a locked state that locks the rotation of the driving wheels in response to switching to a non-driving range, wherein the range switching valve is configured to switch the range switching valve to the non-driving range. The supply port and the drain port are communicated in the range, and after the control unit detects switching from the travel range to the non-travel range, the parking lock mechanism transitions from the released state to the locked state. It is characterized in that the supply control valve is held in an open state until.
According to this, when the driving range is switched to the non-driving range, the hydraulic fluid continues to flow from the supply port to the drain port, thereby interfering with the hydraulic fluid flowing from the friction engagement element to the drain port via the range switching valve. As a result, the discharge speed of hydraulic oil from the friction engagement element becomes slow.
As a result, it is possible to delay the transition time of the frictional engagement element from the engaged state to the disengaged state, prevent the various shaft members in the transmission from rotating rapidly, and reduce the generation of abnormal noise from the parking lock mechanism. can.

In the present invention, after detecting the switching from the driving range to the non-driving range, the control unit elapses a predetermined delay time longer than the time required for the parking lock mechanism to transition from the released state to the locked state. After that, the opening degree of the supply control valve may be reduced or completely closed.
According to this, by reducing the opening degree of the supply control valve or fully closing it after the parking lock mechanism transitions to the locked state, the hydraulic pressure in the hydraulic circuit other than that related to the range switching valve is continuously reduced. can be prevented.

As described above, according to the present invention, it is possible to provide a transmission that effectively suppresses abnormal noise when switching from the driving range to the non-driving range with a simple configuration.

1 is a diagram showing the configuration of a powertrain of a vehicle having an embodiment of a transmission to which the present invention is applied; FIG. FIG. 2 is a schematic diagram showing a state in which the parking lock mechanism of the transmission in FIG. 1 is viewed from the axial direction of the drive pinion shaft; FIG. 4 is a cross-sectional view of a manual valve provided in the transmission of the embodiment, showing a state in which a reverse range is selected; FIG. 4 is a cross-sectional view of a manual valve provided in the transmission of the embodiment, showing a state in which a parking range is selected; FIG. 4 is a cross-sectional view of a manual valve provided in a transmission that is a comparative example of the present invention, showing a state in which a parking range is selected; FIG. 5 is a diagram showing an example of changes in reverse clutch hydraulic pressure and linear solenoid valve hydraulic pressure when switching from a reverse range to a parking range in the transmissions of the embodiment and the comparative example;

An embodiment of a transmission to which the present invention is applied will be described below.
The transmission of the embodiment is mounted in a vehicle such as a passenger car having an engine vertically mounted as a driving power source, for example.
FIG. 1 is a diagram showing the configuration of a vehicle powertrain having a transmission according to an embodiment.
In order to facilitate understanding, in FIG. 1, only the power transmission path to the front wheels FW (driving wheels) when the transmission is in reverse (when the reverse range (R range) is selected) is shown by a simplified skeleton diagram. Illustrations of the power transmission path at time (when the drive range (D range) is selected), the transmission mechanism, the AWD transfer that distributes the driving force to the rear wheels (not shown), etc. are omitted.

The powertrain 1 has an engine 10, a transmission 20, a drive shaft 30, and the like.
The engine 10 is, for example, an internal combustion engine such as a gasoline engine.
The rotational output of the engine 10 is transmitted to the transmission 20 via a starting device such as a torque converter.

Transmission 20 is a power transmission device that transmits rotational output of engine 10 to front wheels FW via drive shaft 30 .
The transmission 20 has an input shaft 21, a reverse clutch 22, a drive gear 23, a drive pinion shaft 24, a driven gear 25, a pinion gear 26, a ring gear 27, a parking gear 28, a parking pawl 29, and the like.

The input shaft 21 is an input shaft to which the rotational output of the engine 10 is input via a starting device.
The reverse clutch 22 is a frictional engagement element provided in the intermediate portion of the input shaft 21 .
The reverse clutch 22 is engaged when the reverse range is selected and the vehicle travels backward, and is disengaged otherwise.

The drive gear 23 is a helical gear provided at the end of the input shaft 21 opposite to the engine 10 side.
Drive gear 23 cooperates with driven gear 25 to transmit power from input shaft 21 to drive pinion shaft 24 .

The drive pinion shaft 24 is a rotating shaft arranged parallel to the input shaft 21 .
Drive pinion shaft 24 transmits power transmitted from input shaft 21 to ring gear 27 .

Driven gear 25 is a helical gear provided at an intermediate portion of drive pinion shaft 24 .
The driven gear 25 meshes with the drive gear 23 of the input shaft 21 to transmit power.

The pinion gear 26 is provided at the end of the drive pinion shaft 24 on the engine 10 side and meshes with the ring gear 27 .
The pinion gear 26 and the ring gear 27 work together to convert the rotation direction around an axis along the vehicle width direction, and function as a final reduction gear that reduces the speed at a predetermined final reduction ratio.
Rotation of the ring gear 27 is transmitted to the front wheels FW via the drive shaft 30 .
The drive shaft 30 has a CV joint and has a function of transmitting rotation in a bendable state according to the suspension stroke and the steering of the front wheels FW.

The parking gear 28 and parking pawl 29 cooperate to form a parking lock mechanism.
The parking lock mechanism prevents the vehicle from moving by restricting the rotation of the drive pinion shaft 24 when the parking range is selected.
FIG. 2 is a schematic diagram showing a state in which the parking lock mechanism of the transmission in FIG. 1 is viewed from the axial direction of the drive pinion shaft.
FIG. 2(a) shows a state in which the engaging projection of the parking pawl is in contact with the outer peripheral edge of the parking gear (the state immediately before shifting to the locked state), and FIG. 2(b) shows the locked state.
The parking gear 28 is a gear provided at the end of the drive pinion shaft 24 opposite to the pinion gear 26 side (engine 10 side).
Concave portions that engage with the parking pawls 29 are arranged at equal intervals in the circumferential direction on the outer peripheral edge of the parking gear 28 .

The parking pawl 29 restricts (locks) the rotation of the parking gear 28 by inserting and engaging the engagement protrusion 29a into the concave portion of the parking gear 28 in response to the driver's selection operation of the parking range. It prevents movement.
As shown in FIG. 2, the parking pawl 29 is supported so as to be able to swing (rotate) about a rotating shaft 29b.
The rotating shaft 29b is fixed to a housing (transmission case) (not shown) of the transmission 1 .

The parking pawl 29 is interlocked with a range selection operating portion such as a selector lever to have a released position where the engaging projection 29a is separated from the parking gear 28 and a locked position where the engaging projection 29a is engaged with a concave portion of the parking gear 28. is displaced between
Here, as shown in FIG. 2(a), the parking gear 28 rotates while the engagement projection 29a is in contact with the outer peripheral edge of the parking gear 28, and the engagement projection 29a and the concave portion of the parking gear 28 are aligned. When the positions match, the engaging projection 29a is inserted into the recess as shown in FIG. 2(b), establishing a locked state.
However, when the rotation speed of the parking gear 28 is high, the engagement protrusion 29a does not normally engage with the recess and is repelled by the parking gear 28, generating abnormal noise (tooth rattling noise).
The present embodiment aims to suppress such abnormal noise, and this point will be described later in detail.

The transmission 20 described above has a hydraulic circuit, which will be described below, in order to switch between engagement and release of various frictional engagement elements such as a reverse clutch, and to change the gear ratio of a transmission mechanism, such as a chain-type CVT.
The hydraulic circuit operates with automatic transmission fluid (hereinafter referred to as "oil") that serves as lubricating oil and hydraulic oil (pressure oil).

The hydraulic circuit is a manual valve that is a range switching valve that selects and switches the travel range of the transmission 20 from drive range (D range), neutral range (N range), reverse range (R range), and parking range (P range). It has 100.
The drive range is a travel range used when moving forward.
A neutral range is a non-driving range in which the parking lock mechanism is released.
The reverse range is a driving range used when moving backward.
A parking range is a non-driving range in which the parking lock mechanism is locked.

The manual valve 100 is interlocked with a select lever (not shown) provided in the passenger compartment and used by the driver to select a range by mechanical interlocking means such as a Bowden wire.
FIG. 3 is a cross-sectional view of the manual valve provided in the transmission of the embodiment, showing a state in which the reverse range is selected.
FIG. 4 is a cross-sectional view of the manual valve provided in the transmission of the embodiment, showing a state in which the parking range is selected.
In FIGS. 3 and 4, broken line arrows indicate the flow of oil, and solid line arrows indicate the flow of electrical signals. (The same applies to FIG. 5 described later)

The manual valve 100 includes a sleeve 110, a spool valve 120, and the like.
Sleeve 110 is a tubular member fixed to a transmission case, which is a housing for transmission 20 .
A cylindrical through hole into which the spool valve 120 is inserted is formed on the inner diameter side of the sleeve 110 .
The sleeve 110 is provided with a drain port 111, a forward clutch port 112, a supply port 113, a reverse clutch port 114, a drain port 115, and the like in order from one end side (left side in FIG. 3, etc.) in the axial direction. .

The drain port 111 is a port for discharging oil returning from a forward clutch 250, which will be described later, from the inside of the sleeve 110 (into the transmission case) when the drive range is switched to another range.
Forward clutch port 112 is a port that supplies oil from inside sleeve 110 to forward clutch 250 (to be described later) when a drive range is selected (when the vehicle moves forward).
Further, the forward clutch port 112 functions as a flow path through which oil returns from the forward clutch 250 to the inside of the sleeve 110 according to the transition from the drive range to another range.

The supply port 113 is a port through which the oil pressurized and discharged by the oil pump 230 is introduced into the sleeve 110 .
The reverse clutch port 114 is a port (friction engagement element port) that supplies oil from the inside of the sleeve 110 to the reverse clutch 22 when the reverse range is selected (when the vehicle moves backward).
Also, the reverse clutch port 114 functions as a flow path through which oil returns from the reverse clutch 22 to the inside of the sleeve 110 according to the transition from the reverse range to another range.
The drain port 115 is a port for discharging oil returning from the reverse clutch 22 from the inside of the sleeve 110 (into the transmission case) in response to switching from the reverse range to another range.

The spool valve 120 is a valve body that is inserted into the inner diameter side of the sleeve 110 and switches each port of the sleeve 110 between opening and closing.
The spool valve 120 is displaced relative to the sleeve 110 in the cylinder axis direction in accordance with a range selection operation of a select lever (not shown).
The spool valve 120 is formed in a shaft shape concentric with the inner peripheral surface of the sleeve 110, and the lands 121, 122, 123 extend axially from the drain port 111 side (left side in FIGS. 3 and 4). They are provided in sequence toward the drain port 115 side (same right side).
The lands 121, 122, 123 are formed in a columnar shape by partially enlarging the outer diameter of the spool valve 120 with respect to the shaft portion other than the lands.
The outer peripheral surfaces of the lands 121, 122, and 123 are opposed to the inner peripheral surface of the sleeve 110 with a small clearance therebetween, so that oil can be sealed.
Between the land 121 and the land 122 and between the land 122 and the land 123, the outer peripheral surface of the spool valve 120 has a gap with the inner peripheral surface of the sleeve 110, and oil can pass through this gap. It's becoming

In the reverse range state shown in FIG. 3 , the land 121 blocks (disconnects) the supply port 113 and the forward clutch port 112 .
The land 122 has an end face on the land 121 side disposed between the reverse clutch port 114 and the drain port 115 in the axial direction of the sleeve 110 . At this time, the supply port 113 and the reverse clutch port 114 are in communication.
As a result, the oil is supplied to the reverse clutch 22 as indicated by the dashed arrow in FIG.
Also, the supply port 113 and the drain port 115 are blocked.

In the parking range state shown in FIG. 4 , the land 122 is arranged at a position overlapping the supply port 113 in the axial direction of the sleeve 110 . Land 122 isolates supply port 113 from drain port 111 and forward clutch port 112 .
The land 121 is provided with a notch 124 formed by recessing the outer peripheral surface portion in a groove shape.
The notch 124 is formed so as to communicate with the outer peripheral surface from the end surface of the land 121 on the land 122 side.
Notch 124 allows supply port 113 and drain port 115 to communicate with each other when the parking range is selected.
The land 122 closes the opening of the end of the sleeve 110 on the drain port 115 side (right end in FIG. 4).
The land 123 is pulled out of the sleeve 110 .

As shown in FIGS. 3 and 4, the transmission 20 further has a transmission control unit 210, a range detection switch 220, an oil pump 230, a linear solenoid valve 240, a forward clutch 250 and the like.
A transmission control unit (TCU) 210 is an electronic control unit (control section) that controls the transmission 20 and its accessories in an integrated manner.
The transmission control unit 210 can be configured as a microcomputer having, for example, an information processing section such as a CPU, a storage section such as a RAM and a ROM, an input/output interface, and a bus connecting them.
The transmission control unit 210 controls the gear ratio of a transmission mechanism (not shown) in the transmission 20, the engagement force of a lockup clutch (not shown), the engagement force of a transfer clutch (not shown) in the case of an AWD vehicle, and the like.
Transmission control unit 210 also has a function of controlling the opening of linear solenoid valve 240 according to the output of range detection switch 220 and the like.

A range detection switch 220 is connected to the transmission control unit 210 .
Range detection switch 220 is a range switching detection unit that detects the range selected by the driver in transmission 20 and outputs a range signal indicating the detected range.
As the range detection switch 220, for example, a physical switch that detects the range based on the position of the spool valve 120 of the manual valve 100 or the position of the select lever can be used.

The oil pump 230 is a hydraulic supply source that pressurizes oil and supplies it to the linear solenoid valve 240 and other hydraulic elements (not shown).
The linear solenoid valve 240 is a supply control valve that supplies the oil pressure-fed from the oil pump 230 to the supply port 113 of the manual valve 100 .
The linear solenoid valve 240 can control the oil pressure and the amount of oil introduced to the supply port 113 of the manual valve 100 by adjusting the degree of opening according to a command from the transmission control unit 210 .

Forward clutch 250 is a friction engagement element provided in the middle of a power transmission path (not shown) during forward movement.
Forward clutch 250 is engaged when the drive range is selected and the vehicle travels forward, and is disengaged otherwise.

In the embodiment, transmission control unit 210 keeps linear solenoid valve 240 open (typically fully open) for a predetermined period of time after range detection switch 220 detects switching from the reverse range to the parking range. , after the parking gear 28 and the parking pawl 29 are engaged and the parking lock mechanism transitions to the locked state, delay control is performed to reduce the opening of the linear solenoid valve 240 (typically to fully close). there is
Here, the predetermined time is, for example, the time from when the parking pawl 29 is started to engage with the parking gear 28 in response to switching to the parking range until the engagement is completed (parking lock mechanism set to be longer than the time required to transition from the released state to the locked state).

The effects of the above-described embodiment will be described below in comparison with comparative examples of the present invention described below.
In the comparative example, the same reference numerals are given to the parts common to the embodiment, and the description is omitted, and mainly the differences will be described.
FIG. 5 is a cross-sectional view of a manual valve provided in a transmission that is a comparative example of the present invention, showing a state in which the parking range is selected.
In the transmission of the comparative example, the notch 124 is not formed in the land 121, and the supply port 113 and the drain port 115 are blocked when the parking range is selected.
In the comparative example, the transmission control unit 210 immediately fully closes the linear solenoid valve 240 in response to detection of switching to the parking range.

FIG. 6 is a diagram showing an example of changes in the reverse clutch hydraulic pressure and the linear solenoid valve hydraulic pressure during switching from the reverse range to the parking range in the transmissions of the embodiment and the comparative example.
In FIG. 6, the horizontal axis indicates time, and the vertical axis indicates the range selection state (output of range detection switch 220), the oil pressure of reverse clutch 22, and the discharge oil pressure of linear solenoid valve 240 in order from the top.
Further, each hydraulic pressure in the embodiment is indicated by a solid line, and each hydraulic pressure in the comparative example is indicated by a broken line.
In order to facilitate understanding, dashed lines are slightly offset at locations where the hydraulic pressures of the embodiment and the comparative example are substantially the same, but in practice the difference in these hydraulic pressures can be ignored. .

In the comparative example, upon detection of switching from the reverse range to the parking range, no delay time is provided, the linear solenoid valve is immediately fully closed, and the discharge hydraulic pressure is set to zero.
At this time, in the manual valve 100, as shown in FIG. 5, the supply port 113 is closed and the reverse clutch port 114 and the drain port 115 are in communication.
The oil Or returned from the reverse clutch 22 to the reverse clutch port 114 passes through the inside of the sleeve 110 and is discharged from the drain port 115 .
As a result, the hydraulic pressure of the reverse clutch 22 drops in a short period of time, and the reverse clutch 22 rapidly changes from the engaged state to the disengaged state.
At this time, when the input shaft 21, the drive pinion shaft 24, etc., which have been twisted by the torque of the engine 10, suddenly rotate in the direction of untwisting, the parking gear 28 engages the parking pawl 29. By flipping the protrusion 29a, an abnormal noise (rattling noise) may be generated.

On the other hand, in the embodiment, as shown in FIG. 4, the supply port 113 and the drain port 115 communicate with each other via the notch 124 when the parking range is selected.
Furthermore, after switching to the parking range, the transmission control unit 210 maintains the linear solenoid valve 240 in an open state for a predetermined period of time, so that the oil pump 230, the supply port 113, and the sleeve 110 are released from the oil pump 230 during this period. The oil O continues to flow to the drain port 115 through the interior.
At this time, the oil Or returning from the reverse clutch 22 to the reverse clutch port 114 interferes with the flow of the oil O, thereby slowing down the discharge speed from the drain port 115 .
For this reason, in the embodiment, the rate of decrease in the oil pressure of the reverse clutch 22 (the rate of decrease in engagement force) after switching to the parking range is slower than in the comparative example, and the drag friction of the reverse clutch 22 causes the torsion The rotation of the input shaft 21 and the drive pinion shaft 24 due to the torque becomes slow.
This prevents the parking gear 28 from flipping the engagement projection 29a of the parking pawl 29, and suppresses the noise associated with the operation of the parking lock mechanism.

As described above, according to this embodiment, the following effects can be obtained.
(1) When the reverse range is switched to the parking range, the oil O continues to flow from the supply port 113 to the drain port 115 for a predetermined period of time, so that it flows from the reverse clutch 22 to the drain port via the inside of the sleeve 110. It interferes with the oil Or, and the discharge speed of the oil Or from the reverse clutch 22 slows down.
As a result, it is possible to delay the time required for the reverse clutch 22 to transition from the engaged state to the disengaged state, prevent the drive pinion shaft 24 and the like from suddenly rotating, and reduce the generation of abnormal noise from the parking lock mechanism. can.
(2) By fully closing the linear solenoid valve 240 after the parking lock mechanism (parking gear 28, parking pawl 29) transitions to the locked state, the hydraulic pressure in the hydraulic circuit other than that related to the manual valve 100 continues. can be prevented from deteriorating to

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, which are also within the technical scope of the present invention.
(1) The configurations of the transmission, power train, vehicle, etc. are not limited to the above-described embodiments, and can be changed as appropriate.
The shape, structure, material, manufacturing method, function, arrangement, quantity, etc. of each member and constituent elements constituting these can be changed as appropriate.
(2) The configuration of the flow path that communicates the oil supply source and the drain port when the parking range is selected is not limited to the notch formed in the land of the spool valve as in the embodiment, and may be other configurations.
(3) In the embodiment, switching from the reverse range to the parking range has been described, but the present invention can also be applied to switching from the drive range to the parking range.

Reference Signs List 1 power train 10 engine 20 transmission 21 input shaft 22 reverse clutch 23 drive gear 24 drive pinion shaft 25 driven gear 26 pinion gear 27 ring gear 28 parking gear 29 parking pawl 29a engagement projection 29b rotating shaft 30 drive shaft FW front wheel 100 manual valve 110 sleeve 111 Drain port 112 Forward clutch port 113 Supply port 114 Reverse clutch port 115 Drain port 120 Spool valve 121, 122, 123 Land 124 Notch 210 Transmission control unit 220 Range detection switch 230 Oil pump 240 Linear solenoid valve 250 Forward clutch O Oil

Claims (2)

A transmission capable of switching between a driving range in which a frictional engagement element provided in a power transmission path from a driving power source to drive wheels is engaged and a non-driving range in which the frictional engagement element is released,
It has a supply port connected to a hydraulic supply source, a friction engagement element port connected to a friction engagement element, and a drain port for discharging hydraulic fluid returning from the friction engagement element port. a range switching valve that communicates with the element port and closes the drain port;
a supply control valve provided between the hydraulic supply source and the supply port;
a range switching detection unit that detects switching from the running range to the non-running range;
a control unit that controls the supply control valve according to the output of the range switching detection unit;
a parking lock mechanism that transitions from a released state that allows rotation of the driving wheels to a locked state that locks the rotation of the driving wheels in response to switching from the driving range to the non-driving range,
The range switching valve communicates the supply port and the drain port in the non-running range,
The controller keeps the supply control valve open until the parking lock mechanism transitions from the released state to the locked state after detecting the switching from the running range to the non-running range. A transmission characterized by: After detecting the switching from the driving range to the non-driving range, the control unit detects a predetermined delay time longer than the time required for the parking lock mechanism to transition from the released state to the locked state. 2. The transmission according to claim 1, wherein the opening degree of the supply control valve is reduced or fully closed.

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