JP5520850B2 - Vehicle drive device - Google Patents

Description

  The present invention relates to a vehicle drive device including an engine that is automatically stopped under a predetermined stop condition and automatically restarted under a predetermined start condition.

  In recent years, idling stop vehicles have been developed in which the engine is automatically stopped when the vehicle stops to reduce the fuel consumption of the engine. The idling stop vehicle automatically stops the engine when a predetermined stop condition is satisfied, and automatically restarts the engine when a predetermined start condition is satisfied. Further, even in a hybrid vehicle equipped with an engine and an electric motor, it is common to automatically stop the engine when the vehicle is stopped.

  Incidentally, an automatic transmission equipped with a plurality of hydraulic clutches and hydraulic brakes (hereinafter referred to as hydraulic clutches including the hydraulic brakes) is mounted in the power transmission system of the vehicle. An oil pump driven by the engine is connected to the automatic transmission in order to supply the control oil pressure for the clutch to the automatic transmission. However, in an idling stop vehicle, the engine is stopped when the vehicle is stopped, and accordingly, the oil pump is stopped and the hydraulic clutch being engaged is released. When the oil pump is driven again by restarting the engine, the released hydraulic clutch is rapidly switched to the engaged state, and an engagement shock is generated when the clutch is engaged. Thus, the occurrence of the fastening shock accompanying the stop / restart of the engine is a factor that deteriorates the vehicle quality.

  In order to avoid the release of the hydraulic clutch when idling is stopped, it may be possible to avoid a decrease in hydraulic pressure when the engine is stopped by installing an electric oil pump or accumulator. This is a factor in increasing the cost of the idling stop vehicle. For this reason, a power transmission device has been developed in which a spring is assembled to the piston of the hydraulic clutch so that the hydraulic clutch is not completely released even when the control hydraulic pressure of the hydraulic clutch is lowered. (For example, refer to Patent Document 1). Thus, by energizing the piston of the hydraulic clutch with the spring, the friction plate in the clutch can be kept in contact at all times. That is, even when the control hydraulic pressure is lowered, the hydraulic clutch is not completely released, and the engagement shock of the hydraulic clutch when the engine is restarted can be suppressed.

Japanese Patent Laid-Open No. 2006-9973

  However, since the power transmission device of Patent Document 1 has a structure in which the piston of the hydraulic clutch is urged by a spring, the hydraulic clutch is provided with a cancel oil chamber that supplies hydraulic oil when released. By supplying hydraulic oil to the cancel oil chamber, the piston can be moved in a direction against the spring force, and the hydraulic clutch can be switched to the released state. In other words, in order to completely release the hydraulic clutch, it is necessary to supply hydraulic oil to the cancellation oil chamber. Therefore, the hydraulic clutch cannot be released when the engine stops when the oil pump stops, and the vehicle is neutral. It was impossible to control the state. Thus, when the engine is stopped, even if the driver operates the select lever to the neutral range, the hydraulic clutch is held in the slipping state or the engaged state by the spring force. It was impossible to completely disconnect.

  An object of the present invention is to suppress the occurrence of a fastening shock when the engine is restarted and to control the vehicle drive device to a neutral state according to the driver's selection operation even when the engine is stopped.

  A vehicle drive device according to the present invention is a vehicle drive device including an engine that is automatically stopped under a predetermined stop condition and automatically restarted under a predetermined start condition. Provided in the power transmission path between the wheels, the hydraulic piston is moved in the engagement direction to bring the friction plate into the engagement state, and the hydraulic piston is moved in the release direction to release the engagement state of the friction plate. A friction engagement mechanism, an oil pump that is driven by the engine and supplies hydraulic oil that moves the hydraulic piston in an engagement direction and a release direction to the friction engagement mechanism, and is provided in the power transmission path. An input clutch that is switched between a disengaged state in which the power transmission path is disconnected and a fastening state in which the power transmission path is connected based on a hand select operation, and biases the hydraulic piston toward an engagement direction; An urging means is provided in the friction engagement mechanism, the friction engagement mechanism is held in a slipping state or a fastening state when the engine is stopped when the oil pump is stopped, and the input clutch is released when a selection operation is performed to a neutral position. By switching to, the engine and the driving wheel are separated even when the engine is stopped when the friction engagement mechanism is in a slipping state or a fastening state.

  In the vehicle drive device of the present invention, the input clutch is a meshing clutch.

  The vehicle drive device of the present invention is characterized in that the input clutch is switched between an engaged state and a released state electrically or manually.

  In the vehicle drive device of the present invention, the input clutch is arranged on the engine side with respect to the friction engagement mechanism.

  In the vehicle drive device of the present invention, the input clutch is arranged on the engine side with respect to a speed change mechanism provided in the power transmission path.

  According to the present invention, a friction engagement mechanism that is held in a sliding state or a fastening state by an urging member even when the engine is stopped when the oil pump is stopped is provided in the power transmission path, and the power transmission path is released by a select operation. An input clutch that can be switched to is provided. Thereby, the fastening shock of the friction engagement mechanism when the engine is restarted can be suppressed, and the vehicle drive device can be controlled to the neutral state even when the engine is stopped.

It is the schematic which shows the vehicle drive device which is one embodiment of this invention. It is the schematic which shows a part of drive device for vehicles with a control system. It is a flowchart which shows the procedure of the switching control of the input clutch performed in a stop state. It is a flowchart which shows the procedure of the switching control of the input clutch at the time of engine operation. It is the schematic which shows the vehicle drive device which is other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a vehicle drive apparatus according to an embodiment of the present invention. As shown in FIG. 1, the vehicle drive device 10 includes an engine 11, a torque converter 12, a continuously variable transmission (transmission mechanism) 13, and a forward / reverse switching mechanism 14. A continuously variable transmission 13 is connected to the engine 11 via a torque converter 12 and an input clutch 15. The continuously variable transmission 13 is connected to a front wheel (drive wheel) via a forward / reverse switching mechanism 14 and a front differential mechanism 16. ) 19f is connected. The forward / reverse switching mechanism 14 is connected to a rear wheel (drive wheel) 19r via a transfer clutch 17. That is, the input clutch 15 and the forward / reverse switching mechanism 14 are provided in the power transmission path 18 between the engine 11 and the drive wheels 19f and 19r, and the engine 11 is connected via the input clutch 15 and the forward / reverse switching mechanism 14. Power is transmitted to the drive wheels 19f and 19r.

  The illustrated vehicle drive device 10 has an idling stop function, and automatically stops the engine 11 when a predetermined stop condition is satisfied, and automatically restarts the engine 11 when a predetermined start condition is satisfied. It is starting. The stop condition of the engine 11 includes a stop state (vehicle speed = 0 km / h) and depression of a brake pedal. Further, the starting condition of the engine 11 includes releasing the brake pedal and depressing the accelerator pedal. The starter motor for starting and rotating the engine 11 may be a starter motor that engages with a ring gear (not shown) of the engine 11 that protrudes at the time of starting, or a starter motor that always engages with the ring gear via a one-way clutch. It may be a motor. Further, the alternator may function as a starter motor.

  The torque converter 12 connected to the engine 11 includes a pump impeller 21 connected to the crankshaft 20, and a turbine runner 23 facing the pump impeller 21 and connected to the turbine shaft 22. The torque converter 12 is provided with a lockup clutch 25 that directly connects the front cover 24 and the turbine runner 23. The continuously variable transmission 13 includes a primary shaft 30 and a secondary shaft 31 that is parallel to the primary shaft 30. A primary pulley 32 is provided on the primary shaft 30, and a primary oil chamber 33 is defined on the back side of the primary pulley 32. The secondary shaft 31 is provided with a secondary pulley 34, and a secondary oil chamber 35 is defined on the back side of the secondary pulley 34. Further, a drive chain 36 is wound around the primary pulley 32 and the secondary pulley 34. By adjusting the hydraulic pressure of the primary oil chamber 33 and the secondary oil chamber 35, the pulley groove width can be changed to change the winding diameter of the drive chain 36, and the continuously variable transmission from the primary shaft 30 to the secondary shaft 31 is possible. It becomes.

  In order to transmit engine power from the torque converter 12 to the continuously variable transmission 13, a gear train 40 and an input clutch 15 are provided between the torque converter 12 and the continuously variable transmission 13. The gear train 40 includes a drive gear 40 a that is fixed to the turbine shaft 22 of the torque converter 12, and a driven gear 40 b that is rotatably provided on the secondary shaft 31. The input clutch 15, which is a meshing clutch (dog clutch), includes a drive disc portion 41 that is provided so as to be movable in the axial direction with respect to the hollow shaft 40 c of the driven gear 40 b, and a driven disc portion that is fixed to the primary shaft 30. 42. Further, an uneven portion 41 a is formed on the outer peripheral portion of the drive disc portion 41, and an uneven portion 42 a facing the uneven portion 41 a is formed on the outer peripheral portion of the driven disc portion 42. Further, an electric actuator 44 is connected to the drive disc portion 41 via a fork member 43, and the drive disc portion 41 can be slid in the axial direction by the electric actuator 44. Then, by moving the drive disc portion 41 toward the driven disc portion 42, the concave / convex portion 41a of the drive disc portion 41 and the concave / convex portion 42a of the driven disc portion 42 can be meshed, and the input clutch 15 is switched to a fastening state in which the power transmission path 18 is connected. On the other hand, by disengaging the driving disc portion 41 from the driven disc portion 42, the engagement between the concave and convex portion 41a of the driving disc portion 41 and the concave and convex portion 42a of the driven disc portion 42 can be released, and the input clutch 15 Is switched to a release state in which the power transmission path 18 is cut.

  Further, the forward / reverse switching mechanism 14 is connected to the secondary shaft 31 via a gear train 45 in order to output engine power from the continuously variable transmission 13 toward the drive wheels 19f and 19r. The gear train 45 includes a drive gear 45 a fixed to the secondary shaft 31 and a driven gear 45 b fixed to the forward / reverse input shaft 46 of the forward / reverse switching mechanism 14. Further, the forward / reverse switching mechanism 14 includes a double pinion planetary gear train 47, a forward clutch 48, and a reverse brake 49. The planetary gear train 47 of the forward / reverse switching mechanism 14 includes a sun gear 50 that is fixed to the forward / reverse input shaft 46 and a ring gear 51 that is rotatably provided radially outward of the sun gear 50. Between the sun gear 50 and the ring gear 51, a plurality of paired planetary pinion gears 52 and 53 are provided. Planetary pinion gears 52 and 53 that connect the sun gear 50 and the ring gear 51 are rotatably supported by a carrier 54, and the carrier 54 is fixed to a forward / reverse output shaft 55.

  The forward clutch (friction engagement mechanism) 48 of the forward / reverse switching mechanism 14 includes a clutch drum 60 fixed to the forward / reverse input shaft 46 and a clutch hub 61 fixed to the carrier 54. A plurality of friction plates 60 a, 61 a are provided between the clutch drum 60 and the clutch hub 61, the friction plate 60 a is supported on the inner peripheral surface of the clutch drum 60, and the friction plate 61 a is the outer periphery of the clutch hub 61. Supported by the surface. A hydraulic piston 62 that presses the friction plates 60a and 61a is slidably provided in the clutch drum 60. A fastening oil chamber 63 is defined on one side of the hydraulic piston 62 accommodated in the clutch drum 60, and a release oil chamber 64 is defined on the other side of the hydraulic piston 62. Further, a spring member (biasing means) 65 is incorporated in the fastening oil chamber 63, and the hydraulic piston 62 is biased in the engaging direction by the spring member 65. The engagement direction is the direction in which the hydraulic piston 62 approaches the friction plates 60a and 61a, and the release direction to be described later is the direction in which the hydraulic piston 62 moves away from the friction plates 60a and 61a.

  The hydraulic piston 62 can be moved in the engagement direction by supplying the hydraulic oil to the fastening oil chamber 63 of the forward clutch 48 and discharging the hydraulic oil from the release oil chamber 64. Thus, the hydraulic piston 62 can be pressed to bring the friction plates 60a and 61a into the engaged state, and the forward clutch 48 is brought into an engaged state in which the clutch drum 60 and the clutch hub 61 are rotated together. On the other hand, by discharging the hydraulic oil from the fastening oil chamber 63 and supplying the hydraulic oil to the release oil chamber 64, the hydraulic piston 62 can be moved in the release direction. As a result, the hydraulic piston 62 can be released to release the engaged state of the friction plates 60 a and 61 a, and the forward clutch 48 is in a released state in which the clutch drum 60 and the clutch hub 61 are disconnected. Further, even when the hydraulic oil is discharged from both the fastening oil chamber 63 and the release oil chamber 64, the hydraulic piston 62 is urged in the engagement direction by the spring member 65. It is controlled to a sliding state or a fastening state. The sliding state of the forward clutch 48 is a state where there is no play set between the friction plates 60a and 61a, and is a state before the friction plates 60a and 61a are completely fastened. That is, the sliding state of the forward clutch 48 is a state in which the friction plates 60a and 61a are in light contact with each other, and is a state in the process of the forward clutch 48 shifting from the released state to the engaged state.

  Further, the reverse brake 49 of the forward / reverse switching mechanism 14 has a brake drum 70 fixed to a case (not shown) and a brake hub 71 fixed to the ring gear 51. A plurality of friction plates 70 a, 71 a are mounted between the brake drum 70 and the brake hub 71, the friction plate 70 a is supported on the inner peripheral surface of the brake drum 70, and the friction plate 71 a is the outer periphery of the brake hub 71. Supported by the surface. A hydraulic piston 72 that presses the friction plates 70a and 71a is slidably accommodated in the brake drum 70. Further, a fastening oil chamber 73 is defined on one surface side of the hydraulic piston 72. By supplying hydraulic oil to the fastening oil chamber 73, the hydraulic piston 72 can be moved in the engagement direction and moved backward. The brake 49 can be switched to the engaged state. A return spring (not shown) is assembled to the hydraulic piston 72 of the reverse brake 49, and when the hydraulic oil is discharged from the fastening oil chamber 73, the reverse brake 49 is switched to the released state by the spring force.

  During forward travel, the forward clutch 48 is engaged with the reverse brake 49 released. As a result, the forward / reverse input shaft 46 and the forward / reverse output shaft 55 are directly connected, so the engine power input to the forward / reverse input shaft 46 is transmitted to the forward / reverse output shaft 55 in the same rotational direction. On the other hand, during reverse travel, the reverse brake 49 is engaged with the forward clutch 48 released. Thereby, since the ring gear 51 is fixed, the engine power input to the forward / reverse input shaft 46 is transmitted to the forward / reverse output shaft 55 in the reverse rotation direction. Thus, by controlling the forward clutch 48 and the reverse brake 49 provided in the power transmission path 18, it is possible to switch the rotational direction of the forward / reverse output shaft 55.

  Here, FIG. 2 is a schematic view showing a part of the vehicle drive device 10 together with a control system. As shown in FIG. 2, the vehicle drive device 10 is provided with an oil pump 74 such as a trochoid pump in order to supply hydraulic oil to the forward / reverse switching mechanism 14 and the like. Further, in order to supply and control the working oil to the fastening oil chamber 63 and the release oil chamber 64 of the forward clutch 48 and the fastening oil chamber 73 of the reverse brake 49, a valve unit provided with a plurality of solenoid valves in the vehicle drive device 10. 75 is provided. The oil pump 74 and the valve unit 75 are connected via an oil passage 76, and hydraulic oil discharged from the oil pump 74 is supplied to the forward clutch 48, the reverse brake 49, etc. via the valve unit 75. A driven sprocket 77 b is connected to the oil pump 74, and a drive sprocket 77 a is connected to the pump impeller 21 of the torque converter 12. The driving sprocket 77a and the driven sprocket 77b are connected via a chain 77c. Thus, the engine 11 and the oil pump 74 are directly connected, and the oil pump 74 is operated in conjunction with the driving state of the engine 11. Needless to say, the hydraulic oil discharged from the oil pump 74 is supplied to the torque converter 12 and the continuously variable transmission 13 via the valve unit 75.

  Further, a control unit 80 is provided in the vehicle drive device 10 to control the engine 11, the electric actuator 44, the valve unit 75, and the like. The control unit 80 includes an inhibitor switch 82 for detecting the operation position (select operation) of the select lever 81, an accelerator pedal sensor 83 for detecting the operation state of the accelerator pedal, a brake pedal sensor 84 for detecting the operation state of the brake pedal, A vehicle speed sensor 85 that detects the vehicle speed, an ignition switch 86 that is operated by the driver, and the like are connected. The control unit 80 determines a vehicle state based on information from various sensors and outputs a control signal to the engine 11, the valve unit 75, the electric actuator 44, and the like. The select lever 81 operated by the driver can be operated in the P range (parking range), N range (neutral range, neutral position), D range (forward travel range), and R range (reverse travel range). ing. The control unit 80 includes a CPU that calculates control signals and the like, and also includes a ROM that stores control programs, arithmetic expressions, map data, and the like, and a RAM that temporarily stores data.

  Subsequently, switching control of the input clutch 15 will be described. FIG. 3 is a flowchart showing a procedure for switching control of the input clutch 15 executed in a stopped state. As shown in FIG. 3, in step S1, it is determined whether or not the engine 11 is stopped. If the engine 11 is stopped during idling stop or when the ignition switch 86 is turned off in step S1, the process proceeds to step S2 where the operation position of the select lever 81 by the driver is determined. If it is determined in step S2 that the select lever 81 is operated to the P range or N range, the process proceeds to step S3, where the electric actuator 44 is driven and the input clutch 15 is switched to the released state. On the other hand, if it is determined in step S2 that the select lever 81 is operated to the D range or R range other than the P range or N range, the process proceeds to step S4, where the electric actuator 44 is driven and the input clutch 15 is driven. Is switched to the engaged state. Thus, even when the engine is stopped when the oil pump 74 is stopped, when the P range or N range is selected, the input clutch 15 is released, while when the D range or R range is selected. The input clutch 15 is engaged.

  Then, it progresses to step S5 and it is determined whether there exists a starting request | requirement of the engine 11. FIG. That is, when the engine is stopped due to idling stop, it is determined whether or not a predetermined start condition is satisfied, and when the engine is stopped due to ignition switch operation (hereinafter referred to as ignition operation), the ignition is It is determined whether or not the switch 86 is turned on. If it is determined in step S5 that there is no start request, the process returns to step S2 and the routine is repeated. On the other hand, if it is determined in step S5 that there is a start request, the process proceeds to step S6, where it is determined whether or not idling is stopped. If the engine is idling stopped, the process proceeds to step S7 and travels. The engine 11 is restarted in preparation for resumption. Here, since the forward clutch 48 is provided with a spring member 65 that urges the hydraulic piston 62 in the engagement direction, the forward clutch 48 is held in a slipping state or an engaged state even if the control hydraulic pressure is reduced when the engine is stopped. It is possible to suppress the engagement shock of the forward clutch 48 that accompanies the engine restart.

  On the other hand, if it is determined in step S6 that the engine is started by an ignition operation, the process proceeds to step S8, where the operation position of the select lever 81 is determined. If it is determined in step S8 that the select lever 81 is operated to the P range or the N range, the input clutch 15 is switched to the released state, so that the process proceeds to step S8 and the engine 11 is started. The On the other hand, if it is determined in step S8 that the select lever 81 is operated to the D range or the R range, the input clutch 15 is switched to the engaged state, so that the routine returns to step S2 again and the routine starts. Repeated. As described above, when the engine is started by the ignition operation, it is assumed that the control hydraulic pressure of the continuously variable transmission 13 or the like is greatly reduced. Therefore, from the viewpoint of preventing the drive chain 36 and the like from slipping, the input clutch 15 is The engine 11 is started under the released state.

  Next, switching control of the input clutch 15 during engine operation will be described. FIG. 4 is a flowchart showing a procedure for switching control of the input clutch 15 during engine operation. As shown in FIG. 4, in step S11, it is determined whether or not the select lever 81 has been switched to the R range. If it is determined in step S11 that the range has been switched to the R range, the process proceeds to step S12 to switch the input clutch 15 to the engaged state, and the forward clutch 48 and the reverse brake 49 are switched to the released state. Then, after the input clutch 15 is switched to the engaged state in step S13, the reverse brake 49 is switched to the engaged state in step S14. Thus, during engine operation, the forward clutch 48 and the reverse brake 49 are released and the switching control of the input clutch 15 is executed, so that the input clutch 15 can be smoothly switched to the engaged state. It is possible to improve the vehicle quality by suppressing the fastening shock.

  If it is determined in step S11 that the range has not been switched to the R range, the process proceeds to step S15 to determine whether or not the select lever 81 has been switched to the P range or the N range. If it is determined in step S15 that the range has been switched to the P range or the N range, the process proceeds to step S16 to switch the input clutch 15 to the released state, and the forward clutch 48 and the reverse brake 49 are switched to the released state. In step S17, the input clutch 15 is switched to the released state. As described above, during the engine operation, the forward clutch 48 and the reverse brake 49 are released, and the switching control of the input clutch 15 is executed. Therefore, the input clutch 15 can be smoothly switched to the released state. This makes it possible to suppress the release shock and improve the vehicle quality.

  If it is determined in step S15 that the P range or N range has not been switched, that is, if it is determined that the select lever 81 has been switched to the D range, the input clutch 15 is switched to the engaged state. Therefore, the process proceeds to step S18, and the forward clutch 48 and the reverse brake 49 are switched to the released state. In step S19, the input clutch 15 is switched to the engaged state, and in step S20, the forward clutch 48 is switched to the engaged state. Thus, during engine operation, the forward clutch 48 and the reverse brake 49 are released and the switching control of the input clutch 15 is executed, so that the input clutch 15 can be smoothly switched to the engaged state. It is possible to improve the vehicle quality by suppressing the fastening shock.

  As described so far, since the spring member 65 for urging the hydraulic piston 62 in the engaging direction is incorporated in the forward clutch 48, the forward clutch 48 even when the control hydraulic pressure is reduced due to the idling stop. Can be held in the slipping state or the engaged state, and the engagement shock of the forward clutch 48 accompanying the engine restart can be suppressed. Further, since the input clutch 15 linked to the selection operation is provided in the power transmission path 18, even when the engine is stopped, the input clutch 15 is released to operate the engine 11 by operating the selection lever 81 to the N range. And the drive wheels 19f and 19r can be separated. That is, since the forward clutch 48 is held in a slipping state or an engaged state by a spring force, the forward clutch 48 cannot be released when the engine cannot be obtained, and the vehicle drive is not possible. It was impossible to switch the device 10 to the neutral state. Therefore, in the vehicle drive device 10 of the present invention, the input clutch 15 that is released by the selection operation is provided in the power transmission path 18 between the engine 11 and the drive wheels 19f and 19r. As a result, even when the control hydraulic pressure for releasing the forward clutch 48 cannot be obtained, the input clutch 15 can be released and the vehicle drive device 10 can be controlled to the neutral state. Etc. can be performed safely.

  In the above description, the forward / reverse switching mechanism 14 is disposed on the drive wheels 19f, 19r side of the continuously variable transmission 13, but the present invention is not limited to this, and other positions on the power transmission path 18 are provided. Alternatively, the forward / reverse switching mechanism 14 may be disposed. Here, FIG. 5 is a schematic view showing a vehicle drive device 90 according to another embodiment of the present invention. In FIG. 5, the same members as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 5, in the vehicle drive device 90, the forward / reverse switching mechanism 14 is disposed on the power transmission path 18 between the input clutch 15 and the primary pulley 32. Thus, even when the forward / reverse switching mechanism 14 is disposed on the engine 11 side of the continuously variable transmission 13, the forward clutch 48 and the input clutch 15 are disposed on the power transmission path 18. The invention can be applied effectively.

  Further, as shown in FIGS. 1 and 5, the input clutch 15 is disposed on the engine 11 side with respect to the forward clutch 48. Alternatively, the input clutch 15 may be disposed. Further, the input clutch 15 is disposed on the engine 11 side of the continuously variable transmission 13, but the present invention is not limited to this, and the input clutch 15 is disposed on the drive wheels 19f and 19r side of the continuously variable transmission 13. You may do it. The forward clutch 48 and the input clutch 15 may be disposed on the power transmission path 18 between the engine 11 and the drive wheels 19f and 19r, and the positional relationship before and after other mechanisms is not questioned. When considering engine start by an ignition operation, it is desirable to dispose the input clutch 15 close to the engine 11 in order to improve the startability by separating the rotating body from the engine 11. In particular, when the speed change mechanism is the continuously variable transmission 13, the continuously variable transmission 13 is prevented from rotating when the engine is started by an ignition operation so that the continuously variable transmission 13 whose control hydraulic pressure is greatly reduced is not rotated. It is preferable to arrange the input clutch 15 on the engine 11 side.

  In the above description, the spring member 65 is assembled to the forward clutch 48 of the forward / reverse switching mechanism 14. However, the present invention is not limited to this, and the reverse brake (friction engagement mechanism) of the forward / backward switching mechanism 14 is not limited thereto. A spring member that urges the hydraulic piston 72 in the engaging direction with respect to 49 may be assembled. Thereby, even in a vehicle in which idling stop control is executed during reverse travel, it is possible to suppress the engagement shock of the reverse brake 49 when the engine is restarted. A spring member 65 that urges the hydraulic pistons 62 and 72 in the engaging direction may be assembled to both the forward clutch 48 and the reverse brake 49.

  In the above description, the vehicle drive device 10 is equipped with the chain drive type continuously variable transmission 13 as a speed change mechanism, but the present invention is not limited to this, and the speed change mechanism may be a belt drive type or a traction drive. A continuously variable transmission of a type may be mounted, and a planetary gear type or a parallel shaft type automatic transmission may be mounted as a speed change mechanism. When an automatic transmission is employed as the speed change mechanism, the hydraulic piston is engaged with a friction clutch (friction engagement mechanism) or a friction brake (friction engagement mechanism) that is engaged at the time of forward start or reverse start. A spring member that urges in the opposite direction is assembled.

  In the above description, the input clutch 15 is switched between the engaged state and the released state by using the electric actuator 44. However, the structure is not limited to the structure in which the input clutch 15 is switched electrically, and hydraulic control is performed. If it is not, any structure may be used. For example, the input clutch 15 may be manually switched between the engaged state and the released state by connecting the select lever 81 and the fork member 43 via a link mechanism. That is, a structure in which a selection operation by the driver is directly transmitted to the input clutch 15 may be employed. Furthermore, from the viewpoint of reducing costs and increasing durability, the input clutch 15 is configured by a meshing clutch, but the present invention is not limited to this, and the input clutch 15 may be configured by a friction clutch or an electromagnetic clutch. good.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above description, a trochoid pump is used as the oil pump 74, but the present invention is not limited to this, and other types of internal gear pumps or external gear pumps may be used. Further, although the select lever 81 is used as the range operation unit, the present invention is not limited to this, but is not limited to this. It may be an expression. The illustrated vehicle drive device 10 is a vehicle drive device for four-wheel drive, but is not limited thereto, and may be a vehicle drive device for forward drive or rear wheel drive.

DESCRIPTION OF SYMBOLS 10 Vehicle drive device 11 Engine 13 Continuously variable transmission (transmission mechanism)
15 Input clutch (meshing clutch)
18 Power transmission path 19f Front wheel (drive wheel)
19r Rear wheel (drive wheel)
48 Forward clutch (friction engagement mechanism)
60a, 61a Friction plate 62 Hydraulic piston 65 Spring member (biasing means)
74 Oil Pump 90 Vehicle Drive Device

Claims (5)

A vehicle drive device including an engine that is automatically stopped under a predetermined stop condition and automatically restarted under a predetermined start condition,
Provided in the power transmission path between the engine and the drive wheel, the hydraulic piston is moved in the engagement direction to bring the friction plate into the engaged state, and the hydraulic piston is moved in the release direction to engage the friction plate A friction engagement mechanism for releasing the state;
An oil pump that is driven by the engine and supplies hydraulic oil to the friction engagement mechanism that moves the hydraulic piston in an engagement direction and a release direction;
An input clutch that is provided in the power transmission path and is switched between a release state that cuts the power transmission path and a fastening state that connects the power transmission path based on a driver's selection operation;
An urging means for urging the hydraulic piston toward the engagement direction is provided in the friction engagement mechanism, and the friction engagement mechanism is held in a sliding state or a fastening state when the engine is stopped when the oil pump is stopped.
When the select operation is performed at a neutral position, the engine and the driving wheel are separated even when the engine is stopped when the friction engagement mechanism is in a slipping state or an engagement state by switching the input clutch to a released state. A vehicle drive device. The vehicle drive device according to claim 1,
The vehicle drive device, wherein the input clutch is a meshing clutch. The vehicle drive device according to claim 1 or 2,
The vehicle drive apparatus according to claim 1, wherein the input clutch is switched between an engaged state and a released state electrically or manually. In the vehicle drive device according to any one of claims 1 to 3,
The vehicle drive device according to claim 1, wherein the input clutch is disposed closer to the engine than the friction engagement mechanism. In the vehicle drive device according to any one of claims 1 to 4,
The vehicle drive apparatus according to claim 1, wherein the input clutch is disposed closer to the engine than a speed change mechanism provided in the power transmission path.

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