JP2008128470A - Parking device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking device for an automatic transmission, changeable over between a release position and a lock position with the rotation of a motor in a single direction. <P>SOLUTION: The parking device comprises: a parking rod 21 to be moved in the axial direction for engaging/disengaging a parking pole 30 with/from a parking gear 35; a parking lock spring 37 for energizing the parking rod to move the parking rod in the direction of engaging the parking pole with the parking gear; a cam follower 26 mounted on the parking rod; the motor 12; a nonreversible reduction mechanism for reducing the rotation of the motor; and a cam member 20 for transmitting the rotation reduced by the reduction mechanism to the cam follower while abutting thereon to move the parking rod in the direction of releasing the parking pole from the parking gear. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a parking device for an automatic transmission, and more particularly to a parking device suitable for a shift-by-wire automatic transmission.
It is about.

  In an automatic transmission of an automobile, a range in which a necessary line pressure circuit is switched among a parking range (P range), a reverse range (R range), a neutral range (N range), a forward range (D range), etc. A switching valve is provided. This range switching valve is generally switched manually by a shift lever in the driver's seat.

  In this type of automatic transmission, a parking mechanism is provided for locking the rotation of the output shaft of the automatic transmission by switching the range switching valve to the P range. Such a parking mechanism comprises a parking gear provided on the output shaft and a parking pole that is detachably engaged with the parking gear. When the selector lever is switched to the P range, the parking rod is connected via a link mechanism or the like. When the parking rod slides, the parking pawl is rotated via the parking cam, whereby the parking pawl is engaged with the parking gear and the rotation of the output shaft is locked. .

By the way, in the so-called shift-by-wire type automatic transmission in which the above-described range switching valve is switched by the operation of a selector switch or a shift button provided in the driver's seat, a separate parking mechanism for locking the rotation of the output shaft of the automatic transmission has a separate function. It is necessary to use driving means. For example, Patent Document 1 describes a device using a motor as a driving unit.
Japanese Laid-Open Patent Publication No. 4-63750 (page 6 <Example 3>, FIG. 7)

  FIG. 7 of the above-mentioned Patent Document 1 moves the rod (65) forward and backward through the rack and pinion mechanism (64, 66) by forward and reverse rotation of the reversible motor (61). When the cam member is disengaged from the lock member by the axial movement of the rod in the forward direction of the motor, the lock member is returned to the unlocked position by the biasing force of the spring.

  However, in the thing of above-mentioned patent document 1, since it is the structure which converts rotation of a motor into the axial direction motion of a rod with a rack and pinion mechanism, a big reduction ratio cannot be obtained and a lock member is unlocked. There is a problem that it is difficult to obtain a large thrust necessary for returning to the position. For this reason, particularly when the vehicle is parked on a slope, if a large reaction force acts on the lock member due to rotational input from the drive shaft of the automatic transmission, the reaction force may cause the cam member to move.

  In addition, in the device described in Patent Document 1 described above, since the motor needs to be rotated forward and backward in order to rotate the lock member to the lock position and the unlock position, the motor drive circuit becomes complicated and the cost is high. There is a problem.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a parking device for an automatic transmission that can be switched between a release position and a lock position by motor rotation in a single direction. Is.

  In order to solve the above-mentioned problem, a feature of the invention according to claim 1 is that parking that restricts movement of a vehicle by engaging a detachable parking pole with a parking gear provided on an output shaft of the automatic transmission. In the device, a parking rod that engages and disengages the parking pole with the parking gear by moving in the axial direction, and biases the parking rod to engage the parking pole with the parking gear. A parking lock spring, a cam follower attached to the parking rod, a motor, a non-reversible speed reduction mechanism for reducing the rotation of the motor, and a rotation reduced by the speed reduction mechanism. In contact with the cam follower to transmit the parking pawl from the parking gear. Serial is that constituted by a cam member for moving the parking rod.

  The invention according to claim 2 is characterized in that, in claim 1, the speed reduction mechanism is a worm mechanism comprising a worm gear fixed to a rotating shaft of a motor and a worm wheel attached to the same drive shaft as the cam member. That is.

  According to a third aspect of the invention, there is provided the sensor according to the first or second aspect, further comprising a sensor for detecting that the parking pole is disengaged from the parking gear as the parking rod moves in the axial direction. The motor is driven based on a signal corresponding to the range requested by the driver, and when the signal is a signal for restricting movement of the vehicle, it detects that the parking pole is released from the parking gear. When the motor is stopped and the signal is a signal for releasing the movement of the vehicle from the restriction, it is detected that the parking pole is engaged with the parking gear and the motor is stopped.

  According to the first aspect of the present invention, the parking lock spring for urging the parking rod to move the parking rod in the direction for engaging the parking pole with the parking gear, the cam follower attached to the parking rod, and the motor And a non-reversible deceleration mechanism that decelerates the rotation of the motor, and a cam that moves the parking rod in a direction to release the parking pole from the parking gear by transmitting the rotation decelerated by the deceleration mechanism in contact with the cam follower. Even if a large reaction force is applied from the output shaft of the automatic transmission, for example, when parking on a slope, it is ensured that the parking rod is moved by the irreversible reduction mechanism. Can be prevented.

  In addition, since it is not necessary to rotate the motor forward and backward, the motor driving circuit is simplified, and the driving force of the motor can be amplified by the speed reduction mechanism, so that the motor does not become large and the cost can be reduced.

  According to the second aspect of the invention, the speed reduction mechanism is a worm mechanism comprising a worm gear fixed to the rotating shaft of the motor and a worm wheel attached to the same drive shaft as the cam member. A large reduction ratio can be obtained.

  According to the third aspect of the present invention, it is provided with a sensor for detecting that the parking pole is disengaged from the parking gear as the parking rod moves in the axial direction, and the motor is a signal corresponding to the requested range of the driver. If the signal is a signal that restricts the movement of the vehicle, it detects that the parking pole has been released from the parking gear, stops the motor, and the signal is a signal that releases the movement of the vehicle from the restriction. In some cases, it is detected that the parking pole is engaged with the parking gear and the motor is stopped, so that the parking device can be accurately controlled to the parking release state and the parking lock state based on the signal of the sensor. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a parking device 10 for an automatic transmission. A case body 11 of the automatic transmission is provided with a motor 12 made of, for example, a DC motor that can rotate only in one direction. A rotation shaft 13 is connected to the motor shaft of the motor 12, and the rotation shaft 13 is rotatably supported by a support block 15 attached to the case body 11. A worm gear 16 is fixed to the rotating shaft 13, and a helical toothed worm wheel 17 that meshes with the worm gear 16 is supported by the case body 11 so as to be rotatable about an axis perpendicular to the axis of the rotating shaft 13. It is fixed to the shaft 18. A worm mechanism 19 is constituted by the worm gear 16 fixed to the rotating shaft 13 of the motor 12 and the worm wheel 17 fixed to the driving shaft 18. The worm mechanism 19 reduces the rotation of the motor 12 and amplifies the driving force. Thus, a non-reversible speed reduction mechanism that is transmitted to the drive shaft 18 is configured. A cam member 20 is integrally attached to the drive shaft 18 coaxially with the worm wheel 17, and a cam curve portion 20 a in which the lift amount gradually decreases with rotation over the entire circumference of the cam member 20. Is formed.

  A parking rod 21 parallel to the rotation shaft 13 is supported on the case body 11 by support portions 23 and 24 so as to be movable in a direction parallel to the rotation shaft 13. The parking rod 21 has a cam curve portion of the cam member 20. A cam follower 26 that supports a follower roller 25 that abuts on 20a is integrally attached.

  A parking cam 27 is slidably fitted to one end of the parking rod 21, that is, the right end of FIG. 1, and the parking cam is inserted by a spring 28 inserted between the parking cam 27 and the parking rod 21. 27 is urged to the right in FIG. 1 with respect to the parking rod 21 and is prevented from coming off at a predetermined position on the parking rod 21.

  As shown in FIG. 2, the parking pole 30 has one end 31 supported rotatably, and the other end 32 engaged with the parking cam 27. An engagement portion 33 is provided at the center of the parking pole 30 so as to be detachably engaged with a parking gear 35 mounted on the output shaft of the automatic transmission. The parking pole 30 is rotated in the direction in which the engaging portion 33 is disengaged (released) from the parking gear 35 by the urging force of the spring 34, whereby one end portion 32 is always in contact with the parking cam 27. . In FIGS. 1 and 3, reference numeral 36 denotes a guide member that slidably guides the tip of the parking rod 21.

  A parking lock spring 37 is inserted between the parking rod 21 and the support portion 23, and the parking rod 21 is urged to the right in FIG. 1 by the parking lock spring 37. The parking lock spring 37 has a spring load necessary for engaging the parking pole 30 with the parking gear 35 via the parking cam 27. Thus, when the parking rod 21 is moved rightward in FIG. 1 by the biasing force of the parking lock spring 37, the parking pawl 30 is rotated by the parking cam 27, and the engaging portion 33 of the parking pawl 30 is moved to the parking gear. The rotation of the output shaft of the automatic transmission is prevented. Further, when the parking rod 21 is moved to the left in FIG. 1 against the urging force of the parking lock spring 37, the parking cam 27 is separated (released) from the parking pole 30. However, the engagement with the parking gear 35 is released by the urging force of the spring 34.

  In FIG. 1, reference numeral 40 denotes a position sensor such as a hall element that detects the position of the end of the parking pole 30. The position sensor 40 causes the parking pole 30 to move as the parking rod 21 moves in the axial direction. It is detected that the parking gear 35 is engaged and disengaged. Based on the detection signal of the position sensor 40, the motor 12 is controlled as described later.

  A switching valve 50 is connected to the other end of the parking rod 12, that is, the left end in FIG. 1, and the switching valve 50 is selected except for the P range, and the parking device 10 is positioned at the release position. In the state, as shown in FIG. 1, the supply port 51 connected to the pump P side is connected to the output port 52, and the discharge port 53 connected to the tank T side is shut off. On the other hand, when the P range is selected and the parking device 10 is positioned at the lock position, the supply port 51 connected to the pump P side is shut off and connected to the tank T side as shown in FIG. The discharged port 53 is connected to the output port 52.

  An input port 67 of the PRND solenoid valve 66 is connected to the output port 52 of the switching valve 50. The PRND solenoid valve 66 mainly includes two solenoid parts 71 and 72, a plunger 73 that is moved by the solenoid parts 71 and 72 in the left-right direction in FIG. 1, a spring 74 that holds the plunger 73 in a neutral position, and a plunger 73. The two solenoid parts 71 and 72 are controlled in accordance with the selected required range.

  In the state where the two solenoid parts 71 and 72 are both demagnetized, the plunger 73 is held in the neutral position by the spring 74, the spool valve 75 closes the input port 67, the D range port 77 and the R range port. 78 are connected to the discharge port 79 respectively. When one solenoid 71 is excited and the plunger 73 is moved in the left direction in FIG. 1 against the spring force of the spring 74, the spool valve 75 communicates the input port 67 with the D range port 77. Operated on. When the other solenoid 72 is excited and the plunger 73 is moved in the left direction in FIG. 2 against the spring force of the spring 74, the spool valve 75 communicates the input port 67 with the R range port 78. Operated to do. The D range port 77 and the R range port 78 of the PRND solenoid valve 66 are connected to a line pressure control circuit 80 of the automatic transmission. When pressure oil is supplied from the D range port 77 to the line pressure control circuit 80, the engagement element 81 including a plurality of clutches and brakes is controlled to establish the D range. When pressure oil is supplied to the line pressure control circuit 80, the engagement element 81 composed of a plurality of clutches and brakes is controlled to establish the R range.

  In addition, since engagement and disengagement of a plurality of clutches and brakes in each range is a well-known technique as described in, for example, Japanese Patent Application Laid-Open No. 2006-105333, detailed description thereof is omitted. .

  As described above, in the state where the P range is selected, the communication between the supply port 51 connected to the pump P side and the input port 67 of the PRND solenoid valve 66 is blocked by the switching valve 50 to Control is performed so that no pressure oil is supplied to the line pressure control circuit 80 so that malfunctions during failure of a solenoid such as the PRND solenoid valve 66 can be prevented.

  As shown in FIG. 4, the shift lever 60 includes a P range (parking range) for requesting parking of the vehicle, an R range (reverse range) for requesting reverse travel, an N range (neutral range) for requesting stop, and a forward drive. Characters (P, R, N, D) representing the D range (drive range) requesting traveling are displayed. When the driver operates the shift lever 60, one required range is selected, and an electrical signal corresponding to the selected required range is input from the PRND position sensor 62 to the control unit 61. The P range for requesting parking of the vehicle is a range for restricting the movement of the vehicle, and an electric signal output based on this range is a signal for restricting the movement of the vehicle. Furthermore, the R range for requesting reverse travel of the vehicle, the N range for requesting stop and the D range for requesting forward travel are ranges that restrict the movement of the vehicle, and the electric signal output based on this range is: A signal for releasing the movement of the vehicle from the restriction, that is, a signal for allowing the movement of the vehicle. The control unit 61 is connected to the motor 12, the position sensor 40, the PRND solenoid valve 66, and the like. In the present embodiment, the shift lever 60 is shown as the range selection means. However, if the shift signal corresponding to the requested range selected by the driver can be generated, for example, a selector switch, a shift switch, etc. It may be a button, a voice input device, or the like.

  The parking device 10 of the automatic transmission configured as described above controls the motor 12 based on the selection operation of the shift lever 60 by the driver, and performs parking lock control or parking release control of the parking device 10. Hereinafter, the operation will be described based on the flowcharts of FIGS. 5 and 6 and the time chart of FIG.

  For example, in the parking lock state shown in FIG. 3, when the D range, that is, the NotP range is selected by the driver operating the shift lever 60, the NotP drive flag is established, and the control flow shown in FIG. 5 is executed. First, in step S100, the contents of the counter are reset to 0, and in the subsequent step S102, the timer is reset, and time counting is started at the same time.

  Next, in step S104, energization of the motor 12 is started, whereby the motor 12 is rotated in one direction. The rotation of the motor 12 is decelerated by the worm mechanism 19 and transmitted to the cam member 20, and the cam member 20 is rotated counterclockwise in FIG. With the increase in the lift amount of the cam curve portion 20 a due to the rotation of the cam member 20, the parking rod 21 together with the cam follower 26 is moved in the left direction in FIG. 3 while compressing the parking lock spring 37.

  In step S106, it is determined whether or not the position sensor 40 that detects the position of the parking pole 30 no longer detects the parking pole 30 at the locked position. That is, it is determined whether or not the parking pole 30 is detached (released) from the parking gear 35 and the signal of the position sensor 40 is switched from OFF to ON. If the position sensor 40 does not detect the parking pole 30 at the locked position (the signal of the position sensor 40 changes from OFF to ON), the determination result in step S106 is YES, and the process proceeds to step S108, as shown in FIG. In addition, the power supply to the motor 12 is stopped.

  On the other hand, if the decision result in the step S106 is NO, the process proceeds to a step S110 to determine whether or not the detection by the position sensor 40 has been repeated beyond the specified time, that is, the measurement time by the timer (to the motor 12 It is determined whether or not the energization time) has exceeded the set time T0. If the time measured by the timer, that is, the energization time to the motor 12 does not exceed the set time T0, the determination result in step S110 is NO, the process returns to step S104, and energization to the motor 12 is continued. However, if the determination result in step S110 is YES, since some abnormal state is assumed, it is determined that there is a failure in step S120, the driver is warned of the failure in step S122, and the NotP driving process is terminated.

  In this way, when the motor 12 is rotated by a predetermined angle and the parking rod 21 is moved by a predetermined amount in the left direction in FIG. 3 as the cam member 20 rotates, as shown in FIG. The mating parking pole 30 is separated from the parking gear 35 by the urging force of the spring 34 and the engagement with the parking gear 35 is released. As a result, as shown in FIG. 7, when the signal of the position sensor 45 is switched from OFF to ON, the determination result in step S106 is YES, and energization of the motor 12 is terminated.

  When the energization of the motor 12 is stopped in step S108, it is then determined in step S112 whether or not the inertial rotation of the motor 12 has stopped. When the inertial rotation of the motor 12 stops, the determination result in step S112 is YES, and 1 is added to the contents of the counter in the subsequent step S114.

  Next, in step S116, it is determined whether or not the position sensor 40 has yet detected the parking pole 30 at the locked position, that is, whether or not the position sensor 40 is on. In other words, the inertia of the motor 12 causes the cam member 20 to rotate more than necessary, and the position sensor 40 that is in the ON state may change to the OFF state, so that the motor 12 is stopped in a predetermined angle range. It is confirmed whether or not the parking apparatus 10 is held in the released state. If the position sensor 40 is held in the ON state, the determination result in step S116 is YES, and the NotP drive process is terminated.

  However, if the cam member 20 rotates too much and the position sensor 40 is not held in the ON state, the determination result in step S116 is NO, and in the subsequent step S118, the drive of the motor 12 exceeds the specified number of times. It is determined whether or not the process has been repeated, that is, whether or not the content of the counter has exceeded the set value C0. When the content of the counter does not exceed the set value C0, the process returns to the above-described step S102, and the NotP driving process is performed again. However, if this is repeated a predetermined number of times, the determination result in step S118 is YES, and a failure is determined in step S120.

  When the parking rod 12 is moved to the parking release position, the switching valve 50 is switched in conjunction with the movement of the parking rod 12, the supply port 51 is communicated with the output port 52, and the output port 52 and the discharge port 53 are connected. Communication is interrupted. As a result, the pressure oil supplied from the supply port 51 to the output port 52 is supplied to the line pressure control circuit 80 of the automatic transmission via the PRND solenoid valve 66.

  At the time of parking release, since the parking rod 21 can be restrained from moving in the parking lock direction by the urging force of the parking lock spring 37 due to the irreversibility of the worm mechanism 19, there is no need to provide a special holding means. Thus, the parking device 10 can be reliably prevented from being operated in the parking lock direction. The irreversible means that the worm wheel 17 can be rotated from the worm gear 16 fixed to the rotating shaft 13 of the motor 12 as the motor 12 rotates, but the worm gear 16 is rotated from the worm wheel 17. Means you can't.

  On the other hand, when the P range is selected by operating the shift lever 60 by the driver in the parking release state shown in FIG. 1, the P drive flag is established, and the control flow shown in FIG. 6 is executed. First, in step S200, the contents of the counter are reset to 0, and in step S202, the timer is reset and time counting is started.

  Next, in step S204, energization of the motor 12 is started, whereby the motor 12 is rotated in one direction. The rotation of the motor 12 is decelerated by the worm mechanism 19 and transmitted to the cam member 20, and the cam member 20 is rotated counterclockwise in FIG. The rotation of the cam member 20 changes the contact position of the cam follower 26 from the maximum lift position of the cam curve portion 20a to the minimum lift position, so that the parking rod 21 is moved by the biasing force of the parking lock spring 37 as shown in FIG. Moved to the right. As a result, the parking pawl 30 is rotated against the biasing force of the spring 34 by the parking cam 27, the parking pawl 30 is engaged with the parking gear 35, and the rotation of the output shaft of the automatic transmission is prevented. Become.

  In step S206, it is determined whether or not the position sensor 40 that detects the position of the parking pole 30 has detected the parking pole 30 at the locked position. That is, it is determined whether or not the parking pole 30 is detached (released) from the parking gear 35 and the signal of the position sensor 40 is switched from ON to OFF. When the position sensor 40 detects the parking pole 30 at the locked position (the signal of the position sensor 40 changes from ON to OFF), the determination result in step S206 is YES, and the process proceeds to step S208, as shown in FIG. The energization of the motor 12 is stopped.

  On the other hand, when the determination result in step S206 is NO, the process proceeds to step S210, and it is determined whether or not the measurement time by the timer (the energization time to the motor 12) is longer than the set time T0. If the measured time of the timer is smaller than the set time T0, the process returns to step S204, and energization of the motor 12 is continued. However, if the determination result in step S210 is YES, in step S220 it is determined that there is a failure, and in step S222, an operation command is output to an unillustrated electric brake system, and the vehicle is stopped by the electric brake system. Try to keep. Next, in step S224, the driver is warned of the failure and the P drive process is terminated.

  When the energization of the motor 12 is stopped in step S208 described above, it is then determined in step S212 whether or not inertial rotation of the motor 12 has stopped. If the inertial rotation of the motor 12 stops, 1 is added to the contents of the counter in the subsequent step S214. Next, in step S216, it is determined whether or not the position sensor 40 is held in the OFF state. That is, it is determined whether or not the cam member 20 is not rotated too much due to inertial rotation of the motor 12, and if not, the P drive process is terminated.

  When the shift lever 60 is operated to the P range while the vehicle is running, the motor 12 is rotated in the same manner as described above, and the parking rod 21 is moved by the biasing force of the parking lock spring 40 as shown in FIG. However, since the parking pawl 30 is repelled by the rotating parking gear 35 and the engagement is prevented, the parking cam 27 moves over the parking rod 21 against the biasing force of the spring 28. Relative sliding. When the vehicle is stopped, the parking pole 30 is engaged with the parking gear 35 by the urging force of the spring 28.

  When the parking rod 21 is moved to the parking lock position, the switching valve 50 is switched in conjunction with the movement of the parking rod 21, the communication between the supply port 51 and the output port 52 is shut off, and the output port 52 is connected to the discharge port. 53 is communicated. Thus, the switching valve 50 blocks the supply of the pressure oil supplied to the supply port 51 to the PRND solenoid valve 66.

  In the above-described embodiment, the rotation of the motor 12 is decelerated by the worm mechanism 19, but the decelerating mechanism can be changed to another decelerating mechanism having irreversibility.

  In the above-described embodiment, the switching valve 50 is connected to the parking rod 21, but the switching valve 50 is not necessarily a requirement for the present invention, and the switching valve 50 may be switched by another drive source. The switching valve 50 can be omitted.

  Thus, the specific configuration described in the above-described embodiment is merely an example of the present invention, and the present invention is not limited to such a specific configuration. Of course, various embodiments can be employed without departing from the scope.

1 is a schematic diagram of a parking device for an automatic transmission showing an embodiment of the present invention. It is a perspective view which shows the relationship between the parking pole and parking gear in FIG. It is a schematic diagram of the parking apparatus of the automatic transmission which shows the operation state figure of FIG. It is a control block diagram of a shift-by-wire automatic transmission. It is a figure which shows the flowchart which performs the parking release operation | movement in embodiment. It is a figure which shows the flowchart which performs the parking lock operation | movement in embodiment. It is a figure which shows the time chart in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Parking apparatus, 11 ... Case main body, 12 ... Motor, 13 ... Rotating shaft, 18 ... Drive shaft, 16 ... Worm gear, 17 ... Worm wheel, 20 ... -Cam member, 21 ... Parking rod, 26 ... Cam follower, 27 ... Parking cam, 30 ... Parking pole, 35 ... Parking gear, 37 ... Spring for parking lock, 40 ... Position sensor, 50 ... switching valve, 60 ... shift lever, 66 ... PRND solenoid valve.

Claims (3)

  In a parking device that regulates the movement of a vehicle by engaging a detachable parking pawl with a parking gear provided on an output shaft of an automatic transmission, the parking pawl is moved to the parking gear by moving in an axial direction. A parking rod to be engaged and disengaged, a parking lock spring for urging the parking rod and moving the parking rod in a direction to engage the parking pole with the parking gear, and a cam follower attached to the parking rod; A motor, an irreversible speed reduction mechanism that decelerates the rotation of the motor, and a direction in which the rotation decelerated by the speed reduction mechanism is transmitted in contact with the cam follower to release the parking pole from the parking gear. And a cam member for moving the parking rod. Parking device for an automatic transmission, characterized in that the.   2. The automatic transmission according to claim 1, wherein the speed reduction mechanism is a worm mechanism including a worm gear fixed to a rotation shaft of a motor and a worm wheel attached to the same drive shaft as the cam member. Parking device.   3. The sensor according to claim 1, further comprising: a sensor that detects that the parking pole is disengaged from the parking gear as the parking rod moves in the axial direction. And when the signal is a signal for restricting movement of the vehicle, the motor is stopped by detecting that the parking pole is released from the parking gear, and the signal is A parking device for an automatic transmission, which detects that the parking pole is engaged with the parking gear and stops the motor when the signal is a signal for releasing the movement of the vehicle from regulation.

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