JP6259798B2 - transmission - Google Patents

Description

  The present invention relates to a transmission equipped with a continuously variable transmission mechanism such as a belt type mounted on a vehicle, and more specifically, an input path for transmitting driving force from a drive source to the continuously variable transmission mechanism and a continuously variable transmission mechanism. The present invention relates to a transmission provided with another input path that reversely rotates and transmits to a drive wheel.

  Conventionally, there is a transmission (automatic transmission) having a continuously variable transmission mechanism such as a belt type as a transmission mounted on a vehicle or the like. A belt type continuously variable transmission mechanism provided in this type of transmission has a configuration in which an endless belt is wound around a pair of pulleys. Further, this type of continuously variable transmission includes a friction clutch configured to engage by bringing friction materials into contact with each other as a power transmission switching mechanism for switching presence or absence of power transmission in the power transmission path. Some have a meshing type fastening mechanism (dog clutch) as a power transmission switching mechanism between the continuously variable transmission mechanism and the final output mechanism. The dog clutch includes a member such as a sleeve that is movable in the axial direction between a gear provided on one rotating element and another gear provided on the other rotating element. Is a mechanism configured to switch the engagement of one rotation element and the other rotation element.

International Publication 2013/175568

  By the way, in the conventional transmission, for example, the hydraulic circuit for controlling the friction type clutch and the meshing type fastening mechanism as described above is provided for each friction engagement according to the shift position selected by the range selector. A manual valve configured to switch a supply destination of hydraulic pressure to a mechanism (clutch) or the like is provided. The manual valve is configured to supply hydraulic pressure only to a predetermined mechanism corresponding to the shift position. Therefore, in a transmission including a hydraulic circuit having a manual valve, switching between a reverse path selection state and a forward path selection state (R → D or D) in a switchback for switching between a reverse state and a forward state of the vehicle. There was a limit to improving the response at the time of (→ R switching).

  On the other hand, in a transmission having a hydraulic circuit that does not have a manual valve, it is possible to control separately supplying hydraulic pressure to a hydraulic mechanism such as each clutch, and the degree of freedom of control is increased. Therefore, by performing appropriate control, it is possible to improve the responsiveness at the time of switching between the selection state of the reverse route and the selection state of the forward route in the switchback for switching between the reverse state and the forward state of the vehicle.

  However, using a hydraulic circuit that does not have a manual valve increases the degree of freedom of control, but if the timing for engaging the dog clutch is not properly set, the teeth of the dog clutch will collide strongly when the dog clutch is engaged. End up. Then, a load is applied to each tooth of the dog clutch, and the durability of the entire transmission is lowered.

  The present invention has been made in view of the above points, and an object of the present invention is to improve the durability of the dog clutch at the time of switching between the selection state of the reverse travel route and the selection state of the forward travel route. It is to provide a transmission.

In order to solve the above problems, a transmission (1) according to the present invention includes an input shaft (13) to which a driving force from a drive source (E) mounted on a vehicle is input, and a drive from the input shaft (13). The first and second input paths (14, 15) for transmitting the force to the continuously variable transmission mechanism (20) and the rotation of the driving force from the input shaft (13) are reversed without passing through the continuously variable transmission mechanism (20). A transmission (1) having a third input path (16) for transmitting to the drive wheels (W) and an input switching mechanism for selectively switching the first to third input paths (14 to 16). the input switching mechanism, the input shaft (13) and the first, the first is provided between the second input path (14, 15), respectively, and the second friction clutch (61, 62), the second friction clutch (62) one of the continuously variable transmission mechanism the driving force transferred (20) and the third input path (16) by engagement of A reverse switching mechanism before having dog clutch (71) for transmitting by switching (70), first, in order to switch the engagement / disengagement of the second friction clutch (61, 62), a hydraulic supply the hydraulic pressure to them And a control unit (102) for controlling at least the forward / reverse switching mechanism (70) and the hydraulic pressure supply mechanism (103). The dog clutch (71) is connected to the continuously variable transmission mechanism (20) . The first receiving tooth (71a) for transmitting the driving force and the second receiving tooth (71b) for transmitting the driving force to the third input path (16), and the control unit (102) is configured by the first receiving tooth (71a). ) And the second receiving tooth (71b) when the differential rotation (ΔND, ΔNR) is less than the predetermined value (ΔNDx, ΔNRx), the forward / reverse switching mechanism (70) causes the vehicle to move backward and forward. It is characterized by switching.

Thus, the first of the dog clutch (71) that transmits the driving force transmitted by the engagement of the second friction clutch (62) by switching between the continuously variable transmission mechanism (20) and the third input path (16) . When the differential rotation (ΔND, ΔNR) between the first receiving tooth (71a) and the second receiving tooth (71b) becomes less than a predetermined value (ΔNDx, ΔNRx), the vehicle is moved backward by the forward / reverse switching mechanism (70). And the forward state can be switched between the backward state and the forward state of the vehicle at a timing when the differential rotation (ΔND, ΔNR) is small, so that the first tooth receiving (71a) or second receiving portion of the dog clutch (71). The vehicle can be switched between forward and backward travel in a state where the impact on the teeth (71b) is reduced. Thereby, the transmission which can aim at the improvement of the durability of the dog clutch at the time of forward / reverse switching can be provided .
In the transmission (1), the control unit (102) switches from the first input path to the third input path and switches from the third input path to the second input path when switching the forward / reverse switching mechanism (70). Only switching to one input path may be performed.
In the transmission (1), when switching the input from the first input path to the third input path, the control unit (102) switches the forward / reverse switching mechanism (70), and then switches the second friction clutch. (62) may be engaged.
In the transmission (1), when switching the input from the third input path to the first input path, the control unit (102) switches the forward / reverse travel after engaging the first friction clutch (61). The mechanism (70) may be switched.

  Further, in the transmission (1), the predetermined values (ΔNDx, ΔNRx) are set within a safe range based on the number of endurances in the differential rotation (ΔND, ΔNR) of the dog clutch (71). Also good. Thus, if the predetermined value at the time of forward / reverse switching is set within a safe range based on the number of times of durability, the durability can be reliably improved.

  In the transmission (1), the hydraulic pressure supply mechanism (103) includes a first hydraulic circuit (103A) for operating the forward / reverse switching mechanism (70) and a hydraulic mechanism other than the forward / reverse switching mechanism (70). A second hydraulic circuit (103B) for operating the first hydraulic circuit (103B), and the control unit (102) can independently control the first hydraulic circuit (103A) and the second hydraulic circuit (103B). It is good also as featuring. Thus, when the first hydraulic circuit (103A) and the second hydraulic circuit (103B) are provided and the control unit (102) can be controlled independently, the dog clutch (71) and the friction clutch The degree of freedom of the switching timing of (61, 62) is increased, and the switching of the forward / reverse switching mechanism (70) can be performed at a timing that does not impact the forward / reverse switching mechanism (70).

  In the transmission (1), the first and second output paths (17, 18) for outputting the driving force shifted to a predetermined gear ratio by the continuously variable transmission mechanism (20), and the continuously variable transmission mechanism ( 20) and third and fourth friction clutches (63, 64) provided between the first and second output paths (17, 18), respectively, and third and fourth friction clutches (63, 64). ) Is a configuration in which engagement / disengagement is switched by hydraulic control by the hydraulic supply mechanism (103). The third input path (16), the first output path (17), and the second output path ( 18) finally transmits the driving force to the final output mechanism (30) that transmits the drive to the driving wheel (W), and the control unit (102) transmits the first input path (14) to the third input path ( 16) When the input is switched to the forward / reverse switching mechanism (70), the vehicle reverse state and the front After switching the state, when the second friction clutch (62) is engaged and the input is switched from the third input path (16) to the first input path (14), the first friction clutch (61) and After the third friction clutch (63) is engaged, the vehicle may be switched between the reverse drive state and the forward drive state by the forward / reverse switching mechanism (70).

Thus, when the input is switched from the third input path (16) to the first input path (14), the forward / reverse switching is performed after the first friction clutch (61) and the third friction clutch (63) are engaged. When the vehicle is switched between the reverse state and the forward state by the mechanism (70), the first output is obtained at the time when the drive transmission to the first output path (17) and the drive transmission to the third input path (16) are simultaneously performed. Since the path (17) absorbs the driving force in the backward direction, the reduction in the differential rotation (ΔNR) can be accelerated. For this reason, responsiveness can be enhanced while controlling so as not to give an impact to the forward / reverse switching mechanism (70).
In addition, the code | symbol in said parenthesis has shown the code | symbol of the corresponding component of embodiment mentioned later as an example of this invention.

  According to the transmission of the present invention, it is possible to improve the durability of the dog clutch when the vehicle is switched between the reverse route selection state and the forward route selection state.

It is a skeleton figure of the transmission concerning one embodiment of the present invention. It is a schematic diagram explaining the specific structure of a forward / reverse switching mechanism. It is a schematic diagram explaining the specific structure of a hydraulic supply mechanism. It is a figure which shows the power transmission path | route of the LOW mode of a transmission. It is a figure which shows the HI mode power transmission path | route of a transmission. It is a figure which shows the power transmission path | route of the RVS mode of a transmission. It is a timing chart which shows about change of each value at the time of performing switching from RVS mode-> LOW mode. It is a flowchart at the time of switching RVS mode-> LOW mode. It is a graph for determining the value of D side switching prohibition difference rotation speed. It is a timing chart which shows about change of each value at the time of switching from LOW mode-> RVS mode. It is a flowchart at the time of switching LOW mode-> RVS mode. It is a graph for determining the value of R side switching prohibition difference rotation speed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a skeleton diagram of a transmission according to an embodiment of the present invention. As shown in FIG. 1, in a transmission 1 mounted on a vehicle, a torque converter 12 is installed between a crankshaft 11 and an input shaft 13 of an engine (drive source) E. The transmission 1 includes an input shaft 13 connected from the engine E via a torque converter 12, a first input path 14 and a second input path 15 through which driving force from the input shaft 13 is transmitted.

  A continuously variable transmission mechanism 20 is disposed downstream of the first input path 14 and the second input path 15. The continuously variable transmission mechanism 20 includes a second pulley 22 provided at the downstream end of the first input path 14, a first pulley 21 provided at the downstream end of the second input path 15, a first pulley 21, and a second pulley And an endless belt 23 wound around the pulley 22. The groove widths of the first pulley 21 and the second pulley 22 increase or decrease in opposite directions by hydraulic pressure, and continuously change the gear ratio of rotation of the driving force input from the first input path 14 or the second input path 15. .

  On the first input path 14, a first transmission gear train 51 is disposed that decelerates the input from the input shaft 13 and transmits the driving force to the continuously variable transmission mechanism 20. The first transmission gear train 51 includes a first transmission drive gear 51A disposed on the input shaft 13 side of the first input path 14 and a first transmission mechanism gear 51 disposed on the continuously variable transmission mechanism 20 side of the first input path 14. A transmission driven gear 51B. The gear ratio between the first transmission drive gear 51A and the first transmission driven gear 51B is greater than 1. Therefore, the first transmission gear train 51 functions as a reduction gear train that transmits the driving force from the input shaft 13 while decelerating it.

  On the second input path 15, a second transmission gear train 52 that increases the input from the input shaft 13 and transmits the driving force to the continuously variable transmission mechanism 20 is disposed. The second transmission gear train 52 includes a second transmission drive gear 52A disposed on the input shaft 13 side of the second input path 15 and a second transmission gear 52A disposed on the continuously variable transmission mechanism 20 side of the second input path 15. A transmission driven gear 52B. The gear ratio between the second transmission drive gear 52A and the second transmission driven gear 52B is smaller than 1. Therefore, the second transmission gear train 52 functions as a speed increasing gear train that increases the driving force from the input shaft 13 and transmits it to the continuously variable transmission mechanism 20.

  In the third input path 16 between the second input path 15 and the final output mechanism 30, there is a third transmission gear train 53 that transmits the driving force from the input shaft 13 to the final output mechanism 30 with the rotation direction reversed. Arranged. The third transmission gear train 53 includes a third transmission drive gear 53A disposed on the second input path 15 side of the third input path 16, and a third transmission driven gear 53C disposed on the final output mechanism 30 side. The third transmission idle gear 53B is disposed between the third transmission drive gear 53A and the third transmission driven gear 53C. The third transmission idle gear 53B is supported on the idle shaft 53D. Due to the presence of the third transmission idle gear 53B, the third transmission gear train 53 functions as a gear train that transmits the driving force by reversing the rotational direction of the driving force.

  An intermediate transmission gear train 54 is disposed in the first output path 17 between the first pulley 21 of the continuously variable transmission mechanism 20 and the final output mechanism 30. The intermediate transmission gear train 54 includes an intermediate transmission drive gear 54A disposed on the first pulley 21 side of the first output path 17, an intermediate transmission driven gear 54C disposed on the final output mechanism 30 side, and an intermediate transmission drive. An intermediate transmission idle gear 54B is provided between the gear 54A and the intermediate transmission driven gear 54C. Intermediate transmission idle gear 54B is supported on idle shaft 54D.

  In the present embodiment, the intermediate transmission idle gear 54B is used as the intermediate transmission member that transmits the driving force from the intermediate transmission drive gear 54A to the intermediate transmission driven gear 54C. However, it is not always necessary to use a gear. For example, a configuration may be used in which a driving force is transmitted by passing a chain between the intermediate transmission drive gear 54A and the intermediate transmission driven gear 54C.

  A forward / reverse switching mechanism (reverse selector mechanism) 70 is disposed between the input shaft 13 and the second transmission gear train 52 and the third transmission gear train 53. The forward / reverse switching mechanism 70 includes a dog clutch (meshing clutch) 71 that switches between the second input path 15 and the third input path 16, and this dog clutch 71 transfers the driving force from the input shaft 13 to the second transmission gear train 52. It is configured to selectively switch between transmission and transmission to the third transmission gear train 53. That is, the dog clutch 71 includes a first receiving tooth 71a on the second transmission gear train 52 side, a second receiving tooth 71b on the third transmission gear train 53 side, and the first receiving tooth 71a and the second receiving tooth 71b. And a moving tooth (sleeve) 71c provided so as to be movable (stroke) between them.

  A state in which the driving force from the input shaft 13 is transmitted to the second transmission gear train 52 by moving the moving tooth 71c to the first receiving tooth 71a and meshing with the first receiving tooth 71a (hereinafter, this state is referred to as this state). This is referred to as “D-side selection state”). On the other hand, the moving tooth 71c moves to the second receiving tooth 71b side and meshes with the second receiving tooth 71b, whereby the driving force from the input shaft 13 is transmitted to the third transmission gear train 53 (hereinafter, this The state is referred to as “R-side selection state”). That is, the forward / reverse switching mechanism 70 has the second transmission gear train 52 that accelerates the rotation of the input shaft 13 by selectively engaging the moving tooth 71c with either the first receiving tooth 71a or the second receiving tooth 71b. And the third transmission gear train 53 that reversely rotates the rotation of the input shaft 13.

  As described above, the transmission 1 includes the first friction clutch 61, the second friction clutch 62, and the dog clutch 71 in order to switch the input of the first input path 14, the second input path 15, and the third input path 16. Moreover, in order to switch them, it has the hydraulic pressure supply mechanism 103 which supplies hydraulic pressure to them. Thus, the mechanism for switching the input path is referred to as an input switching mechanism.

  A second output path 18 is disposed on the downstream side of the second pulley 22 of the continuously variable transmission mechanism 20. A final output mechanism 30 that outputs the driving force transmitted to the first output path 17 or the second output path 18 is disposed downstream of the first output path 17 and the second output path 18. . The final output mechanism 30 includes a final drive gear 31 disposed on the upstream side of the power transmission path from the first output path 17 and the second output path 18 to the drive wheels W, and a final driven gear that meshes with the final drive gear 31. (Differential gear) 32 and a drive shaft 35 for transmitting the driving force distributed by the final driven gear 32 to the drive wheels W.

  Moreover, the transmission 1 of this embodiment is provided with four friction clutches as a power transmission switching mechanism. Specifically, a first friction clutch 61 that switches whether power is transmitted from the input shaft 13 to the first transmission gear train 51 is provided on the upstream side of the first transmission gear train 51 in the first input path 14. Further, a second friction clutch 62 that switches the presence or absence of power transmission from the input shaft 13 to the second transmission gear train 52 is provided on the upstream side of the second transmission gear train 52 and the forward / reverse switching mechanism 70 in the second input path 15. In addition, a third friction clutch 63 that switches whether power is transmitted from the first pulley 21 to the final output mechanism 30 is provided between the first pulley 21 on the first output path 17 and the intermediate transmission gear train 54. Further, a fourth friction clutch 64 that switches the presence or absence of power transmission from the second pulley 22 to the final output mechanism 30 is provided between the second pulley 22 on the second output path 18 and the final output mechanism 30.

  Next, a hydraulic pressure supply mechanism and a sensor group related to the transmission 1 will be described. A range selector 101 is provided in the vehicle driver's seat, and the power transmission path in the transmission 1 is switched when the driver selects one of the ranges such as P, R, N, and D. That is, the range selection by the driver's operation of the range selector 101 is transmitted to the hydraulic pressure supply mechanism 103 via the controller (control unit) 102, and the vehicle travels forward or backward. An oil pump 108 that supplies hydraulic oil to the hydraulic pressure supply mechanism 103 is provided. The oil pump 108 is driven by the engine E to pump up the hydraulic oil stored in the reservoir (strainer) 106 and send it to the hydraulic pressure supply mechanism 103. An electric oil pump 105 driven by a motor 109 is also provided.

  The hydraulic pressure supply mechanism 103 supplies hydraulic pressure to the first and second pulleys 21 and 22 and the first to fourth friction clutches 61 to 64 of the continuously variable transmission mechanism 20. The first transmission gear train 51, the second transmission gear train 52, and the intermediate transmission gear train 54 are provided with rotational speed sensors 111, 112, 113, 114, respectively, and the first transmission gear train 51, the second transmission gear train 52, Pulse signals corresponding to the rotation speeds of the third transmission gear train 53 and the intermediate transmission gear train 54 are output. In addition, a vehicle speed sensor (rotational speed sensor) 120 is provided in the vicinity of the final drive gear 31 to output a pulse signal indicating a vehicle speed V that means a traveling speed of the vehicle. Further, a range selector switch 130 is provided in the vicinity of the range selector 101 and outputs a signal corresponding to a range such as P, R, N, D, etc. selected by the driver.

  A stroke sensor 150 that detects a movement amount (stroke) is provided in the vicinity of the first friction clutch 61 and outputs a signal corresponding to the movement amount of the first friction clutch 61. A stroke sensor 140 for detecting the movement amount (stroke) of the moving tooth 71 c is provided in the vicinity of the dog clutch 71 and outputs a signal corresponding to the movement amount of the dog clutch 71.

  The output of each sensor described above is sent to the controller 102 including the output of other sensors (not shown). For this reason, the controller 102 receives the output value of each sensor, and calculates each value from the output value. For example, when an output value of a gear whose rotation speed is directly measured by the rotation speed sensors 111, 112, 113, and 114 is sent to the controller 102, the controller 102 considers the gear ratio of the gear meshing with the gear, For example, the rotation speed of each gear and each shaft of the first input path 14, the second input path 15, the third input path 16, and the first output path 17 can be measured. Note that the positions of the rotation speed sensors 111, 112, 113, and 114 are not limited to the positions and number of the present embodiment.

  Further, the controller 102 calculates a pulley supply hydraulic pressure (side pressure) based on the output of the sensor, and excites and demagnetizes various electromagnetic valves of the hydraulic pressure supply mechanism 103 according to the calculated side pressure. Thereby, the supply and discharge of the hydraulic pressure to and from the piston chamber of the hydraulic actuators of the first and second pulleys 21 and 22 are controlled to control the operation of the continuously variable transmission mechanism 20. Further, the hydraulic pressure supplied to the piston chambers of the first to fourth friction clutches 61 to 64 is controlled to control the engagement of the first to fourth friction clutches 61 to 64. Further, the engagement switching of the dog clutch 71 of the forward / reverse switching mechanism 70 is controlled.

  Here, a specific configuration of the forward / reverse switching mechanism 70 will be described. FIG. 2 is a schematic diagram for explaining a specific configuration of the forward / reverse switching mechanism 70. For convenience of explanation, in FIG. 1, the first and second receiving teeth 71 a and 71 b in the forward / reverse switching mechanism 70 are shown in parallel. However, in the dog clutch 71 of the actual forward / reverse switching mechanism 70, the first receiving teeth 71a and the second receiving teeth 71b are arranged on the same axis. Then, by operating a shift fork (not shown), the sleeve 72 integrated with the moving tooth 71c is moved, and the moving tooth 71c is selectively meshed with either the first receiving tooth 71a or the second receiving tooth 71b. . Accordingly, the driving force is selectively applied to either the second transmission drive gear 52A that rotates coaxially with the first tooth 71a or the third transmission drive gear 53A that rotates coaxially with the second tooth 71b. Communicate.

  Further, the controller 102 obtains the rotational speed ND of the first tooth-receiving tooth 71a using the signal from the rotational speed sensor 112 among the rotational speed sensors 111, 112, 113, and 114, and particularly the rotational speed sensor. Using the signal from 113, the rotational speed NR of the second receiving tooth 71b is obtained. And the controller 102 grasps | ascertains the difference of the rotation speed in the forward / reverse switching mechanism 70 by calculating the difference of these rotation speeds.

  The hydraulic pressure supply mechanism 103 of this embodiment will be described in detail. FIG. 3 is a schematic diagram illustrating a specific configuration of the hydraulic pressure supply mechanism 103. As shown in FIG. 3, the hydraulic supply mechanism 103 includes a first hydraulic circuit 103 </ b> A for operating the forward / reverse switching mechanism 70, and other hydraulic mechanisms other than the friction clutches 61, 62, 63, 64 and the other forward / backward switching mechanism 70. A second hydraulic circuit 103B for operating the motor. The first hydraulic circuit 103A and the second hydraulic circuit 103B are independent hydraulic circuits. For this reason, the timing for moving the sleeve 72 of the forward / reverse switching mechanism 70 and the timing for engaging and disengaging the clutches 61, 62, 63, 64 can be controlled independently.

  In the hydraulic pressure supply mechanism 103, at least the oil path of the first friction clutch 61 is in the first oil pressure sensor D 1, the oil path of the second friction clutch 62 is in the second oil pressure sensor D 2, and the oil path of the third friction clutch 63. The third hydraulic sensor D3 and the fourth hydraulic sensor D4 are arranged in the oil passage of the fourth friction clutch 64, respectively. These output signals corresponding to the hydraulic pressure supplied to the piston chambers (not shown) of the first to fourth friction clutches 61 to 64, respectively, and are sent to the controller 102.

  Next, the power transmission path in each shift mode of the transmission 1 having the above-described configuration will be described. First, the case where the transmission 1 sets the LOW mode (low speed mode) for forward traveling will be described. FIG. 4 is a diagram illustrating a power transmission path of the transmission 1 in the LOW mode. In the LOW mode, the first friction clutch 61 is engaged, while the second friction clutch 62 is not engaged. Therefore, the driving force transmitted from the engine E to the input shaft 13 is transmitted only to the first transmission gear train 51 via the first friction clutch 61, and the second transmission gear on the downstream side of the second friction clutch 62. Not transmitted to column 52. In the LOW mode, the third friction clutch 63 is engaged and the fourth friction clutch 64 is disengaged.

  As a result, as shown in FIG. 4, the driving force of the engine E is as follows: input shaft 13 → first input path 14 → first transmission gear train 51 → second pulley 22 → endless belt 23 → first pulley 21 → first It is transmitted to the drive wheel W through the path of the output path 17 → the third friction clutch 63 → the intermediate transmission gear train 54 → the final drive gear 31 → the final driven gear 32 → the drive shaft 35.

  Next, the case where the HI mode (high speed mode) for forward traveling is set in the transmission 1 will be described. FIG. 5 is a diagram illustrating a power transmission path of the transmission 1 in the HI mode. In the HI mode, the first friction clutch 61 is disengaged while the second friction clutch 62 is engaged. Further, the moving tooth 71c of the dog clutch 71 meshes with the first receiving tooth 71a side (D side). Therefore, the driving force transmitted from the engine E to the input shaft 13 is transmitted only to the second transmission gear train 52 via the second friction clutch 62 and the dog clutch 71, and the first transmission gear train 51 and the third transmission gear. It is not transmitted to the column 53. In the HI mode, the third friction clutch 63 is disengaged while the fourth friction clutch 64 is engaged.

  As a result, as shown in FIG. 5, the driving force of the engine E is as follows: input shaft 13 → second input path 15 → second transmission gear train 52 → first pulley 21 → endless belt 23 → second pulley 22 → second It is transmitted to the drive wheel W through the path of the output path 18 → the final drive gear 31 → the final driven gear 32 → the drive shaft 35.

  Next, the case where the RVS mode (reverse mode) for reverse travel is set in the transmission 1 will be described. FIG. 6 is a diagram illustrating a power transmission path of the transmission 1 in the RVS mode. In the RVS mode, the first friction clutch 61 is disengaged while the second friction clutch 62 is engaged. Further, the moving tooth 71c of the dog clutch 71 meshes with the second receiving tooth 71b (R side). Therefore, the driving force transmitted from the engine E to the input shaft 13 is transmitted only to the third transmission gear train 53 via the second friction clutch 62 and the dog clutch 71, and the first transmission gear train 51 and the second transmission gear. Not transmitted to column 52.

  As a result, as shown in FIG. 6, the driving force of the engine E is such that the input shaft 13 → the second input path 15 → the third transmission gear train 53 → the third input path 16 → the second output path 18 → the final drive gear 31. → The final driven gear 32 → the drive wheel 35 is transmitted to the drive wheel W through the path. Thus, according to the RVS mode of the present embodiment, the continuously variable transmission mechanism 20 is not used.

  Here, a description will be given of control when the transmission 1 configured as described above switches from the RVS mode to the LOW mode when the vehicle travel state shifts from the reverse travel state to the forward travel state. In order to switch from the RVS mode to the LOW mode in the transmission 1, the first friction clutch 61 is switched from the disengaged state to the engaged state, and the second friction clutch 62 is switched from the engaged state to the disengaged state. The first switching control is performed to switch the third friction clutch 63 to the engaged state, and then switch the dog clutch 71 from the R side to the D side.

  FIG. 7 is a timing chart showing changes in values when switching from the RVS mode to the LOW mode. In the timing chart of FIG. 10 and FIG. 10 described later, the shift position (shift position switched by the range selector 101), the vehicle speed V, the stroke of the dog clutch 71 (forward / reverse switching mechanism 70) (the stroke of the moving tooth 71c), the first -The change with respect to the elapsed time T of each supply hydraulic pressure (1st-4th clutch pressure P1-P4) of the 4th friction clutches 61-64 is shown.

  In this case, first, the shift position is switched from R (reverse) to D (drive) at time T11 by the operation of the range selector 101 by the driver, but it is already first before that (during reverse drive before time T11). The hydraulic pressure is supplied to the friction clutch 61, and the first clutch pressure P1 = PM1. The first clutch pressure P1 = PM1 is a predetermined preparation hydraulic pressure that is smaller than the hydraulic pressure with which the first friction clutch 61 is engaged. The invalid stroke of the first friction clutch 61 is reduced by this first clutch pressure P1 = PM1.

  Then, when the shift position is switched from R (reverse) to D (drive) at time T11, further hydraulic pressure is supplied to the first friction clutch 61, and the first clutch pressure P1 rises from PM1. On the other hand, when the hydraulic pressure that has been supplied to the second friction clutch 62 stops, the second clutch pressure P2 decreases from the engagement pressure PX2. Further, when the hydraulic pressure is also supplied to the third friction clutch 63, the third clutch pressure P3, which has been 0 until then, starts to increase.

  Then, when the first clutch pressure P1 reaches the engagement pressure PX1 at time T12, the increase in the first clutch pressure P1 is stopped. Thereby, the engagement of the first friction clutch 61 is completed. Thereafter, at time T3, the third clutch pressure P3 = PM3. The third clutch pressure P3 = PM3 is a predetermined preparation hydraulic pressure that is smaller than the hydraulic pressure with which the third friction clutch 63 is engaged. The invalid stroke of the third friction clutch 63 is reduced by the third clutch pressure P3 = PM3. Then, after time T14, the hydraulic pressure is further supplied to the third friction clutch 63, and the third clutch pressure P3 increases from PM3. Then, when the third clutch pressure P3 reaches the engagement pressure PX3 at time T15, the increase in the third clutch pressure P3 is stopped. Thereby, the engagement of the third friction clutch 63 is completed. Thus, the forward drive force transmission path (LOW mode) is formed.

  Thereafter, the vehicle speed V (R vehicle speed) gradually decreases. The dog clutch 71 is switched from the R side to the D side at time T16 when the vehicle speed V is sufficiently reduced. That is, here, when the differential rotation input to the dog clutch 71 becomes a value smaller than a predetermined value, the R side is switched to the D side. Thereafter, the vehicle speed V becomes 0 at time T17, and thereafter the vehicle speed V (D vehicle speed) increases.

  The switching control from the R side to the D side of the dog clutch 71 will be specifically described in relation to the differential rotation speed ΔN. FIG. 8 is a flowchart when switching from the RVS mode to the LOW mode. When the shift position is switched from R (reverse) to D (drive), control for switching the dog clutch 71 from the R side to the D side is started. First, as shown in FIG. 8, after the second friction clutch 62 is disengaged (step S1), the first friction clutch 61 is engaged (step S2), and then the third friction clutch 63 is engaged. (Step S3).

  Here, in the forward / reverse switching mechanism 70, the controller 102 determines from the signal of the rotational speed ND of the D-side first receiving tooth 71a (see FIG. 2) relative to the rotational speed NR of the R-side second receiving tooth 71b to the R side. A relative rotational speed ΔND of the rotational speed ND on the D side with respect to the rotational speed NR is measured (step S4). When the differential rotation speed ΔND is equal to or greater than a D-side switching prohibition differential rotation speed ΔNDx, which is a predetermined value described later, the dog clutch 71 is not switched. On the other hand, when it becomes less than D side switching prohibition differential rotation speed ΔNDx, the dog clutch 71 is switched from the R side to the D side (step S5).

  In order to determine that the second friction clutch 62 is not engaged, the controller 102 receives a detection signal from the second hydraulic sensor D2 that grasps the supply hydraulic pressure of the second friction clutch 62. By doing. Thereby, the controller 102 starts switching control of the forward / reverse switching mechanism 70 after confirming that the second friction clutch 62 is in the disengaged state.

  Next, a method for setting the D-side switching prohibition differential rotation speed ΔNDx will be described. FIG. 9 is a graph for determining the value of the D-side switching prohibition differential rotation speed ΔNDx. (A) shows the relationship between the difference rotational speed ΔND of the D-side rotational speed ND with respect to the R-side rotational speed NR and the vehicle speed V (D vehicle speed), and (b) shows the endurance number and D with respect to the R-side rotational speed NR. The relationship between the rotational speed ND on the side and the differential rotational speed ΔND is shown.

  When the shift position is switched from R (reverse) to D (drive), as shown in FIG. 9 (a), the vehicle speed V decreases as indicated by an arrow A, and the D-side with respect to the R-side rotational speed is reduced. The difference in rotational speed ΔND of the rotational speed also decreases. Then, after the differential rotation speed ΔND becomes sufficiently small, the dog clutch 71 is switched from the R side to the D side. The threshold value for this switching is the D-side switching prohibition differential rotation speed ΔNDx. That is, the controller 102 switches the dog clutch 71 from the R side to the D side when the above-described differential rotation speed ΔND falls below the D-side switching prohibition differential rotation speed ΔNDx.

  The value of the D-side switching prohibition differential rotational speed ΔNDx is set as follows. As shown in FIG. 9B, first, a graph of the number of times of durability corresponding to the difference number of rotations ΔND of the number of rotations on the D side with respect to the number of rotations on the R side is created, and the number of durability times CDs that can be used is set. Then, the differential rotation speed ΔNDs that can be used can be obtained from the graph. Here, actually, the differential rotation speed ΔNDs is not used, but a value sufficiently smaller than ΔNDs is set as the D-side switching prohibition differential rotation speed ΔNDx in consideration of the safety factor. As shown in FIG. 9B, the ΔNDx of the present embodiment is obtained by changing the D-side switching prohibition difference rotational speed ΔNDx as a predetermined value within a range in which safety is high enough to prevent a reliable endurance count from being measured in a general usage mode. It is set.

  Next, a description will be given of control when switching from the LOW mode to the RVS mode in the transmission 1 configured as described above in the transition from the forward traveling state to the reverse traveling state of the vehicle. When the transmission 1 switches from the LOW mode to the RVS mode, the first friction clutch 61 is switched from the engaged state to the non-engaged state, and the second friction clutch 62 is switched from the non-engaged state to the engaged state. And the second switching control for switching the third friction clutch 63 from the engaged state to the non-engaged state and simultaneously switching the dog clutch 71 from the D side to the R side.

  FIG. 10 is a timing chart showing changes in values when switching from the LOW mode to the RVS mode. Here, first, the shift position is switched from D (drive) to R (reverse) at time T21 by the operation of the range selector 101 by the driver. At this time, switching of the dog clutch 71 from the D side to the R side is started. At the same time, the hydraulic pressure previously supplied to the first friction clutch 61 stops, so that the first clutch pressure P1 decreases from the engagement pressure PX1 and the hydraulic pressure that has been supplied to the third friction clutch 63 until then. Is stopped, the third clutch pressure P3 decreases from the engagement pressure PX3.

  On the other hand, when the hydraulic pressure is supplied to the second friction clutch 62, the second clutch pressure P2 that has been zero until then starts to increase. Thereafter, the switching of the dog clutch from the D side to the R side is completed at time T22. Between this time T22 and time T23, the second clutch pressure P2 is PM0. This PM0 is a predetermined preparation hydraulic pressure that is smaller than the hydraulic pressure with which the second friction clutch 62 is engaged. The invalid stroke of the second friction clutch 62 is reduced by the second clutch pressure P2 = PM0. The predetermined time TM from time T22 to time T23 is a time from when the stroke sensor detects completion of switching of the dog clutch 71 from the D side to the R side until the set time measured by the timer elapses.

  Thereafter, the second clutch pressure P2 rises again, and becomes the second clutch pressure P2 = PM2 (PM2> PM0) from time T24 to time T25. The second clutch pressure P2 = PM2 is another predetermined preparatory hydraulic pressure that is smaller than the hydraulic pressure with which the second friction clutch 62 is engaged. By this second clutch pressure P2 = PM2, the invalid stroke of the second friction clutch 62 is further reduced. Thereafter, the second clutch pressure P2 rises again, and the second clutch pressure P2 reaches the engagement pressure PX2 at time T26, whereby the rise of the second clutch pressure P2 is stopped. Thereby, the engagement of the second friction clutch 62 is completed.

  Thus, the RVS mode is formed. Thereafter, the vehicle speed V (D vehicle speed) gradually decreases, the vehicle speed V becomes 0 at time T27, and thereafter the vehicle speed V (R vehicle speed) increases.

  Here, the preparation hydraulic pressure (PM0) is used as the second clutch pressure P2 after time T21 when the shift position is switched from D (drive) to R (reverse) (switching of the dog clutch 71 from the D side to the R side is started). Alternatively, PM2) is supplied, but it is also possible to supply the preparatory hydraulic pressure (PM0 or PM2) as the second clutch pressure P2 from the stage before time T21.

  The switching control of the dog clutch 71 from the D side to the R side will be specifically described in relation to the differential rotation speed ΔN. FIG. 11 is a flowchart when switching from the LOW mode to the RVS mode. When the shift position is switched from D (drive) to R (reverse), control for switching the dog clutch 71 from the D side to the R side is started.

  First, as shown in FIG. 11, the controller 102 disengages the third friction clutch 63 (step S11) and disengages the first friction clutch 61 (step S12). Next, in the forward / reverse switching mechanism 70, the rotation speed ND on the D side is determined from the signal of the rotation speed NR of the second reception tooth 71b on the R side with respect to the rotation speed ND of the first reception tooth 71a on the D side (see FIG. 2). The relative rotational speed ΔNR of the rotational speed NR on the R side with respect to is measured (step S13). When the differential rotation speed ΔNR is equal to or greater than the R-side switching prohibition differential rotation speed ΔNRx, which is a predetermined value described later, the dog clutch 71 is not switched. On the other hand, when it becomes less than the R side switching prohibition differential rotational speed ΔNRx, the dog clutch 71 is switched from the D side to the R side (step S14). Thereafter, the second friction clutch 62 is engaged (step S15).

  In order for the controller 102 to determine that the switching control of the forward / reverse switching mechanism 70 has been completed, from the stroke sensor 140 that grasps the position of the sleeve 72 integrated with the moving tooth 71c of the forward / reverse switching mechanism 70. This is performed by receiving the detection signal. Thereby, the controller 102 starts the engagement operation of the second friction clutch 62 after confirming that the switching control of the forward / reverse switching mechanism 70 is completed.

  Next, a method for setting the R-side switching prohibition differential rotation speed ΔNRx will be described. FIG. 12 is a graph for determining the value of the R-side switching prohibition differential rotation speed ΔNRx. (A) shows the relationship between the difference rotational speed ΔNR of the R-side rotational speed NR with respect to the D-side rotational speed ND and the vehicle speed V (D vehicle speed), and (b) shows the endurance count and the R with respect to the D-side rotational speed ND. The relationship between the rotational speed NR on the side and the differential rotational speed ΔNR is shown.

  When the shift position is switched from D (drive) to R (reverse), as shown in FIG. 12 (a), the vehicle speed V decreases as shown by an arrow B, and the R-side speed with respect to the D-side rotation speed is reduced. The difference in rotational speed ΔNR also decreases. Then, after the differential rotation speed ΔNR becomes sufficiently small, the dog clutch 71 is switched from the D side to the R side. The threshold value for this switching is the R-side switching prohibition differential rotation speed ΔNRx. That is, the controller 102 switches the dog clutch 71 from the D side to the R side when the above-described differential rotational speed ΔNR falls below the R-side switching prohibited differential rotational speed ΔNRx.

  The value of the R-side switching prohibition differential rotation speed ΔNRx is set as follows. As shown in FIG. 12B, first, a graph of the number of durability times corresponding to the difference rotational speed ΔNR of the rotational speed on the R side with respect to the rotational speed on the D side is created, and the durable number CRs that can be used is set. Then, the available differential rotation speed ΔNRs can be obtained from the graph. Here, actually, the difference rotational speed ΔNRs is not used, but a value sufficiently smaller than ΔNRs is set as the R-side switching prohibition differential rotational speed ΔNRx in consideration of the safety factor. As shown in FIG. 12B, the ΔNRx of the present embodiment is the R-side switching prohibition difference rotational speed ΔNRx as a predetermined value within a range where safety is high enough that the reliable number of durability cannot be measured in a general usage mode. It is set.

  As described above, in the transmission 1 according to the present embodiment, when the differential rotations ΔND and ΔNR between the first receiving teeth 71a and the second receiving teeth 71b of the dog clutch 71 are less than the predetermined values ΔNDx and ΔNRx, the vehicle travels forward and backward. The switching mechanism 70 switches between a reverse traveling state and a forward traveling state of the vehicle. Then, it is possible to switch between the reverse state and the forward state of the vehicle at a timing when the differential rotations ΔND and ΔNR are small. For this reason, it is possible to perform forward / reverse switching of the vehicle in a state where the impact of the dog clutch 71 on the first receiving teeth 71a or the second receiving teeth 71b is reduced. Thereby, the transmission which can aim at the improvement of the durability of the dog clutch at the time of forward / reverse switching can be provided.

  Moreover, in the transmission 1 of this embodiment, the predetermined value at the time of forward / reverse switching is set within a safe range based on the number of durability. Thereby, durability can be improved reliably.

  Further, the transmission 1 of the present embodiment includes the first hydraulic circuit 103A and the second hydraulic circuit 103B, and the control unit 102 can control each independently. Then, the degree of freedom of switching timing between the dog clutch 71 and the friction clutches 61 and 62 is increased, and the forward / reverse switching mechanism 70 can be switched at a timing that does not give an impact to the forward / backward switching mechanism 70.

  Further, in the transmission 1 of the present embodiment, when switching the input from the third input path 16 to the first input path 14, that is, when switching from the RVS mode to the LOW mode, the first friction clutch 61 and the third friction are performed. After engaging the clutch 63, the forward / reverse switching mechanism 70 switches between the reverse state and the forward state of the vehicle. Then, when the drive transmission to the first output path 17 and the drive transmission to the third input path 16 are simultaneously performed, the first output path 17 absorbs the driving force in the reverse direction. For this reason, the reduction of the differential rotation ΔNR can be accelerated. Therefore, it is possible to increase the responsiveness while controlling so as not to give an impact to the forward / reverse switching mechanism 70.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Deformation is possible.

DESCRIPTION OF SYMBOLS 1 ... Transmission 13 ... Input shaft 14 ... 1st input path 15 ... 2nd input path 16 ... 3rd input path 17 ... 1st output path 18 ... 2nd output path 20 ... Continuously variable transmission mechanism 30 ... Final output mechanism 61 ... first friction clutch 62 ... second friction clutch 63 ... third friction clutch 64 ... fourth friction clutch 70 ... forward / reverse switching mechanism 71 ... dog clutch 71a ... first tooth 71b ... second tooth 71c ... moving tooth 102 ... Controller 103 ... Hydraulic supply mechanism 103A ... First hydraulic circuit 103B ... Second hydraulic circuit E ... Engine W ... Drive wheel

Claims (7)

An input shaft for inputting driving force from a driving source mounted on the vehicle;
First and second input paths for transmitting driving force from the input shaft to the continuously variable transmission mechanism;
A third input path that reversely transmits the rotation of the driving force from the input shaft to the driving wheels without going through the continuously variable transmission mechanism;
An input switching mechanism for selectively switching the first to third input paths,
The input switching mechanism is
First and second friction clutches provided between the input shaft and the first and second input paths,
A forward / reverse switching mechanism having a dog clutch that transmits the driving force transmitted by fastening of the second friction clutch to either the continuously variable transmission mechanism or the third input path;
A hydraulic pressure supply mechanism for supplying hydraulic pressure to the first and second friction clutches to switch between engagement and disengagement;
And at least a control unit that controls the forward / reverse switching mechanism and the hydraulic pressure supply mechanism,
The dog clutch includes a first tooth receiving tooth that transmits driving force to the continuously variable transmission mechanism and a second tooth receiving tooth that transmits driving force to the third input path.
The control unit switches between a reverse drive state and a forward drive state of the vehicle by the forward / reverse switching mechanism when a differential rotation between the first tooth and the second tooth becomes less than a predetermined value. A transmission. The controller is
When switching the forward / reverse switching mechanism,
Switching from the first input path to the third input path;
The transmission according to claim 1, wherein only the switching from the third input path to the first input path is performed . The controller is
When switching input from the first input path to the third input path,
After switching the forward / reverse switching mechanism, the second friction clutch is engaged.
The transmission according to claim 1 or 2, characterized by the above . The controller is
When switching input from the third input path to the first input path,
After engaging the first friction clutch, the forward / reverse switching mechanism is switched.
The transmission according to any one of claims 1 to 3, wherein the transmission is characterized . The transmission according to any one of claims 1 to 4, wherein the predetermined value is set in a safe range based on the number of endurances in the differential rotation of the dog clutch. The hydraulic pressure supply mechanism is
A first hydraulic circuit for operating the forward / reverse switching mechanism;
A second hydraulic circuit for operating a hydraulic mechanism other than the forward / reverse switching mechanism,
The transmission according to any one of claims 1 to 5 , wherein the control unit is capable of independently controlling the first hydraulic circuit and the second hydraulic circuit. First and second output paths for outputting the driving force shifted to a predetermined gear ratio by the continuously variable transmission mechanism;
Third and fourth friction clutches provided between the continuously variable transmission mechanism and the first and second output paths,
The third and fourth friction clutches are configured to switch their engagement / disengagement by being hydraulically controlled by the hydraulic pressure supply mechanism,
The third input path, the first output path, and the second output path transmit a driving force to a final output mechanism that finally transmits driving to the driving wheels,
The controller is
When switching the input from the first input path to the third input path, the second friction clutch is engaged after the forward / backward switching mechanism is switched between the reverse state and the forward state of the vehicle,
When switching the input from the third input path to the first input path, after the first friction clutch and the third friction clutch are engaged, the vehicle is moved backward and forward by the forward / reverse switching mechanism. The transmission according to claim 6 , wherein the transmission is switched.

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