JP5073444B2 - Dual clutch transmission - Google Patents

Description

  The present invention includes a first clutch for connecting / disconnecting power to a drive train group required for each odd speed stage, and a second clutch for connecting / disconnecting power to a drive train group required for each even speed stage, Depending on the throttle opening and the vehicle speed, the drive train group is automatically selected by turning on and off the first clutch and the second clutch, and the power from the engine is shifted and transmitted to the axle. The present invention relates to a dual clutch transmission that temporally overlaps one separating operation and the other joining operation of the first clutch and the second clutch at the time of speed stage switching between speed stages.

In the conventional dual clutch transmission, when the vehicle is started and the brake is released and the accelerator pedal is depressed, the clutch pressure of the clutch on the start speed stage side of the first clutch or the second clutch is in accordance with a predetermined pattern. A clutch pressure control technique that automatically increases with time and starts moving after the clutch shifts from the disengaged state to the engaged state is known (see, for example, Patent Document 1).
JP 2007-51764 A

  In the above-described technology, when starting a hill, if the clutch pressure increases before the engine speed sufficiently increases and the clutch shifts to the on state, the start is started with a shortage of output torque, and the load capacity is increased. When the vehicle is heavy and the road surface is heavy or the road surface is inclined, a phenomenon in which the vehicle slides downward (hereinafter referred to as “rollback”) easily occurs against the intention of the operator. Therefore, it is conceivable that an engine speed sensor is provided in the dual clutch transmission and the clutch pressure is controlled by a controller based on the engine speed actually detected by the engine speed sensor. Only, when a malfunction such as failure of the engine speed sensor or disconnection of a signal line from the engine speed sensor to the controller occurs, the clutch pressure signal is not transmitted to the controller. There is a problem that the vehicle falls into an inoperable state without normal increase or decrease of the clutch pressure.

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
In claim 1, the first clutch (C1) for power connection / disconnection to the drive train group required for each odd speed stage and the second clutch for power connection / disconnection to the drive train group required for each even speed stage. A control device (94) including a clutch (C2) and capable of controlling the operation of the first clutch (C1) and the second clutch (C2) by a hydraulic clutch (79, 80). Thus, when the first clutch (C1) and the second clutch (C2) are turned on and off, the drive train group is automatically selected, and the power from the engine (9) is shifted and transmitted to the axle (50/65). At the same time, when the speed stage is switched between the odd speed stage and the even speed stage, one of the first clutch (C1) and the second clutch (C2) is separated in time and the other joint operation in terms of time. In the dual clutch transmission (2) to be overlapped An engine speed sensor (176) for detecting the rotation speed of the output shaft of the engine (9) as an engine speed and an engine speed setting means for setting the engine speed are provided, and the engine (9 ) Actuates the hydraulic clutch (79, 80) in response to the increase in the engine speed, and the clutch of the clutch on the start speed stage side of the first clutch (C1) and the second clutch (C2). A clutch pressure control configuration for increasing the pressure, and an estimation control configuration for estimating the engine speed based on a set amount by the engine speed setting means when detecting a malfunction related to the engine speed sensor (176). , the estimated control configuration, the operation amount of the engine rotational speed setting means, stored in the storage unit of the control device (94) (94a) The engine speed is estimated based on the relationship model with the engine speed, and the engine speed sensor (176) fails or the engine speed sensor (176) to the control device (94). When the signal line is disconnected, the engine speed is estimated by the estimation control configuration, and the first clutch (C1) and the second clutch (C2) are corresponding to the output torque from the engine (9). ) To increase / decrease the clutch pressure .
According to a second aspect of the present invention, in the dual clutch transmission according to the first aspect, the engine speed setting means is a throttle valve provided in an intake system of the engine (9), and an operation amount of the throttle valve is determined as a throttle opening. When it is detected by the degree sensor (178) and it is determined that a malfunction such as a failure of the engine speed sensor (176) has occurred, the throttle opening signal detected by the throttle opening sensor (178) is The throttle opening is detected based on the throttle opening, and the estimated engine is based on the relationship model between the throttle opening and the throttle opening and the engine speed stored in the storage unit (94a) of the control device (94). The number of revolutions is estimated and used as the set amount .
According to a third aspect of the present invention, in the dual clutch transmission according to the first aspect, the engine speed setting means is an accelerator operating tool, and an operation amount of the accelerator operating tool is detected by an accelerator opening sensor (134), When it is determined that a malfunction such as a failure of the engine speed sensor (176) has occurred, the accelerator opening is detected based on the accelerator opening signal detected by the accelerator opening sensor (134), Based on the relationship between the accelerator opening and the accelerator opening and the engine speed stored in the storage unit (94a) of the control device (94), the estimated engine speed is estimated, and the set amount It is what.

Since this invention was comprised as mentioned above, there exists an effect shown below.
In claim 1, the first clutch (C1) for power connection / disconnection to the drive train group required for each odd speed stage and the second clutch for power connection / disconnection to the drive train group required for each even speed stage. A control device (94) including a clutch (C2) and capable of controlling the operation of the first clutch (C1) and the second clutch (C2) by a hydraulic clutch (79, 80). Thus, when the first clutch (C1) and the second clutch (C2) are turned on and off, the drive train group is automatically selected, and the power from the engine (9) is shifted and transmitted to the axle (50/65). At the same time, when the speed stage is switched between the odd speed stage and the even speed stage, one of the first clutch (C1) and the second clutch (C2) is separated in time and the other joint operation in terms of time. In the dual clutch transmission (2) to be overlapped An engine speed sensor (176) for detecting the rotation speed of the output shaft of the engine (9) as an engine speed and an engine speed setting means for setting the engine speed are provided, and the engine (9 ) Actuates the hydraulic clutch (79, 80) in response to the increase in the engine speed, and the clutch of the clutch on the start speed stage side of the first clutch (C1) and the second clutch (C2). A clutch pressure control configuration for increasing the pressure, and an estimation control configuration for estimating the engine speed based on a set amount by the engine speed setting means when detecting a malfunction related to the engine speed sensor (176). , the estimated control configuration, the operation amount of the engine rotational speed setting means, stored in the storage unit of the control device (94) (94a) The engine speed is estimated based on the relationship model with the engine speed, and the engine speed sensor (176) fails or the engine speed sensor (176) to the control device (94). When the signal line is disconnected, the engine speed is estimated by the estimation control configuration, and the first clutch (C1) and the second clutch (C2) are corresponding to the output torque from the engine (9). since the control to increase or decrease the clutch pressure of), or failure the engine speed sensor, even if the signal line from the engine speed sensor to the control device, such as broken, the engine speed Estimating and increasing / decreasing the clutch pressure so as to correspond to the output torque from the engine without any interruption, and reliably avoiding falling into a state where the vehicle cannot start when the vehicle starts In both cases, it is possible to prevent the rollback from occurring even when the load is large and the vehicle weight is heavy or the road surface is inclined when the hill starts.
According to a second aspect of the present invention, in the dual clutch transmission according to the first aspect, the engine speed setting means is a throttle valve provided in an intake system of the engine (9), and an operation amount of the throttle valve is determined as a throttle opening. When it is detected by the degree sensor (178) and it is determined that a malfunction such as a failure of the engine speed sensor (176) has occurred, the throttle opening signal detected by the throttle opening sensor (178) is The throttle opening is detected based on the throttle opening, and the estimated engine is based on the relationship model between the throttle opening and the throttle opening and the engine speed stored in the storage unit (94a) of the control device (94). speed is estimated, since with the set amount, the throttle opening degree which is an operation amount of close throttle valve to the engine during the estimation control You can use, it is possible to obtain high estimation accuracy.
According to a third aspect of the present invention, in the dual clutch transmission according to the first aspect, the engine speed setting means is an accelerator operating tool, and an operation amount of the accelerator operating tool is detected by an accelerator opening sensor (134), When it is determined that a malfunction such as a failure of the engine speed sensor (176) has occurred, the accelerator opening is detected based on the accelerator opening signal detected by the accelerator opening sensor (134), Based on the relationship between the accelerator opening and the accelerator opening and the engine speed stored in the storage unit (94a) of the control device (94), the estimated engine speed is estimated, and the set amount since the, it can use the accelerator opening is an operation amount of readily accelerator operation member access at the estimation control, cost reduction by simplification of the control structure And it is possible to improve the maintainability.

  Next, embodiments of the invention will be described. 1 is a skeleton diagram showing an overall configuration of a work vehicle according to the present invention, FIG. 2 is a skeleton diagram showing a power transmission configuration of a rear axle drive device, FIG. 3 is a hydraulic circuit diagram of the work vehicle, and FIG. FIG. 5 is a time chart illustrating the shift control process, FIG. 6 is a block diagram relating to the shift control of the dual clutch transmission, and FIG. 7 is a flowchart illustrating the shift control. FIG. 8, FIG. 8 is a shift point characteristic model diagram applied to the first speed stop start control, FIG. 9 is a shift point characteristic model diagram applied to the second speed stop start control, and FIG. 10 is a shift control for estimating the engine speed. 11 is a block diagram showing a part of the system, FIG. 11 is a flowchart showing the estimation control of the engine speed, and FIG. 12 is a clutch pressure at the start of the vehicle based on the engine speed / throttle opening information. FIG. 13 is a flow chart showing the throttle opening forced setting control, FIG. 14 is a shift point characteristic model diagram showing the shift state when the throttle opening is forcibly set when a trouble occurs, and FIG. 15 is when the trouble occurs. FIG. 16 is a flowchart illustrating vehicle speed estimation control, and FIG. 17 is a flowchart illustrating shift mode maintenance setting control. The direction indicated by the arrow 71 in FIG. 1 is the aircraft forward direction of the work vehicle 1, and the positions and directions of the members described below are based on the aircraft forward direction 71.

  First, the overall configuration of a work vehicle 1 equipped with a dual clutch transmission 2 according to the present invention will be described with reference to FIGS. A front axle driving device 5 that supports and drives front axles 4 and 4 to which a pair of left and right front wheels 3 and 3 are fixed is disposed at the front portion of the work vehicle 1. A rear axle drive device 8 that supports and drives the rear axles 7 and 7 to which the wheels 6 and 6 are fixed is disposed, and an engine 9 is disposed on the left side of the rear axle drive device 8.

  Then, after the power from the engine 9 is input from the output shaft 11 into the rear axle drive device 8 and is shifted by the dual clutch transmission 2 according to the present invention housed in the rear axle drive device 8. , Output from the output gear 27 and branched through the central differential 28. One branch power is transmitted from the differential yoke shaft 20 and the drive take-out part 24 to the front wheel differential device 25 in the front axle drive device 5 in front, and differentially drives the front wheels 3 and 3, while the other branch power is This is transmitted to the differential yoke shaft 19 and the rear wheel differential device 26 so as to differentially drive the rear wheels 6 and 6.

  In the central differential device 28, a hollow differential case 30 supported in the rear axle drive device 8 so as to have the same rotational axis as the differential yoke shafts 19 and 20 is fastened and fixed to the outer peripheral surface on one side of the differential case 30. A ring gear 29 meshed with the output gear 27, a pinion shaft 32 that is disposed orthogonally to the differential yoke shafts 19, 20 in the differential case 30, and rotates integrally with the differential case 30, and is rotatable at both ends of the pinion shaft 32. And pinions 33 and 33 as bevel gears, and differential side gears 34 and 34 as bevel gears fixed to the inner end sides of the differential yoke shafts 19 and 20 and meshed with the pinions 33 and 33.

  As a result, the rotation input from the dual clutch transmission 2 to the ring gear 29 via the output gear 27 can be differentially rotated and appropriately distributed back and forth from the differential yoke shafts 19 and 20.

  The central differential device 28 is provided with a differential lock mechanism 35 for locking the differential rotation. The differential lock mechanism 35 can lock a differential lock slider 36 that is slidably fitted on the outer periphery of the differential yoke shaft 19 and a convex portion 36 a formed on the ring gear 29 side by the differential lock slider 36. The ring gear 29 is formed by an engagement recess (not shown), and the projection 36a is locked to the engagement recess by the sliding operation of the differential lock slider 36, so that the differential case 30 and the differential yoke shafts 19 and 20 are integrated. And the central differential device 28 is locked so that the left and right differential yoke shafts 19 and 20 are driven at the same rotational speed. The differential lock slider 36 is linked to a differential lock lever (not shown) via an arm or a link mechanism (not shown), and the central differential device 28 is locked or unlocked by tilting the differential lock lever. The operation can be performed to improve the straightness of the work vehicle 1 and the runnability in the mud.

  In the drive extraction portion 24, one end of the differential yoke shaft 20 extends to the left and right sides of the body of the transmission case 38, and a transmission shaft 39 is connected to the extended portion via a coupling 37. The transmission shaft 39 is plunged into a drive take-out case 40 provided in a convex shape on the side of the mission case 38, and a bevel gear 41 is fixed to the tip of the plunged portion, and at the front of the drive take-out case 40. A bevel gear 42 is fixed to the rear end of the output shaft 21 supported in the longitudinal direction of the machine body, and the bevel gear 42 is engaged with the bevel gear 41.

  The output shaft 21 protrudes forward from the drive take-out case 40 and is connected to the input shaft 44 of the front axle drive device 5 through the universal joint 22, the transmission shaft 23, and the universal joint 43. The power from the engine 9 can be transmitted to the front wheels 3.

  In the front axle drive device 5, a bevel gear 45 is formed at the front end of the input shaft 44. The bevel gear 45 meshes with the ring gear 46 of the front wheel differential 25, and right and left differential yoke shafts 48 and 49 are fitted in a differential case 47 integral with the ring gear 46. 49 is connected to the front wheel shafts 50 and 50, which are the center axes of the front wheels 3 and 3 that can be steered on the left and right outer sides, via a universal joint 53, a half shaft 52, and a universal joint 51, respectively. Has been. The front wheel differential 25 is also provided with a differential lock mechanism 74 like the central differential 28.

  In the rear wheel differential device 26, similarly to the central differential device 28, a ring gear 55 is engaged with a rear output gear 54 formed outside the yoke shaft 19, and the ring gear 55 is engaged with the differential case 56. The differential case 56 is provided with a pinion shaft 58 having pinions 57 rotatably disposed at both ends thereof, and the pinions 57 and 57 are engaged with differential side gears 59 and 59, respectively. Yes. The differential yoke shafts 60 and 61 for fixing the differential side gears 59 and 59 to the inner end side are universal joints 62 with respect to the rear wheel shafts 65 and 65 that are the central axes of the rear wheels 6 and 6 disposed on the left and right outer sides, respectively. The drive shaft is connected via a half shaft 63 and a universal joint 64. The rear wheel differential 26 is also provided with a diff lock mechanism 66 as in the front wheel differential 25.

  Next, the structure of the dual clutch transmission 2 will be described with reference to FIGS. In the transmission case 38 that houses the dual clutch transmission 2, the output shaft 11, the second clutch output shaft 13, the intermediate shaft 18, the transmission shaft 15, the traveling output shaft 17, and the same shaft on the same axis. The differential yoke shaft 19 and differential yoke shaft 20 on the center, and the differential yoke shaft 60 and differential yoke shaft 61 on the same axis are parallel to each other and horizontally mounted in the left-right direction of the body.

  Among these, the output shaft 11 penetrates into the mission case 38 from the left side of the aircraft so as to penetrate the seal case 67 mounted on the upper outer surface of the mission case 38, and the right part thereof is extended. The second clutch output shaft 13 is rotatably supported by the left end portion. Further, a first clutch output shaft 12 is rotatably fitted on the output shaft 11, and between the first clutch output shaft 12 and the left end of the second clutch output shaft 13, A clutch housing 82a fixed to the output shaft 11 is interposed.

  A plurality of sheets are provided between the clutch housing 82a and the right end of the first clutch output shaft 12, and between the clutch housing 82a and the left end of the second clutch output shaft 13. The friction element is supported so as to be slidable only, whereby a traveling speed change clutch 82 composed of a first clutch part C1 and a second clutch part C2 that can be connected and disconnected is formed. The traveling speed change clutch 82 is configured to be hydraulically operated, and is urged toward the partition wall 82b side of the left and right center of the clutch housing 82a by a return spring 85. The first piston 86 and the second piston 87 of the second clutch part cylinder 80 are moved toward the friction element side by the action of hydraulic pressure, which will be described later, and the clutch is engaged by engaging between the friction elements. Yes.

  Further, with respect to the traveling speed change clutch 82, oil passages 88, 89, and 90 are formed in the output shaft 11, and the left ends of the oil passages 88, 89, and 90 are all outer peripheral surfaces of the left end portion of the output shaft 11. An electromagnetic proportional pressure reducing valve 91 for controlling the hydraulic pressure of hydraulic oil to the first clutch part C1, an electromagnetic proportional pressure reducing valve 92 for controlling the hydraulic pressure of hydraulic oil to the second clutch part C2, respectively. The switch valve 93 communicates with the supply and discharge of the lubricating oil to and from the first clutch part C1 and the second clutch part C2. The right end of the oil passage 88 is communicated with the cylinder chamber 83 between the partition wall portion 82 b and the first piston 86, and the right end of the oil passage 89 is also the cylinder chamber between the partition wall portion 82 b and the second piston 87. Further, the right portion of the oil passage 90 is branched into two and communicated with a gap between the pistons 86 and 87 and the sliding surface.

  In such a configuration, when a shift operation lever 95 as a shift operation tool is operated, a position signal from a lever position detection sensor 113 connected to the shift operation lever 95 is transmitted to the controller 94, and the controller 94 receives the position signal. When a predetermined shift command signal is transmitted to the electromagnetic proportional pressure reducing valve 91 based on the position signal, the solenoid of the electromagnetic proportional pressure reducing valve 91 is excited and passes through the oil path 88 in the cylinder chamber 83 of the first clutch portion C1. The hydraulic oil is supplied to the first piston 86, and the first piston 86 presses between the friction elements against the urging force of the return spring 85, and the first clutch portion C1 is gradually shifted to the on state. Conversely, when the hydraulic oil supply to the cylinder chamber 83 is cut off, the first piston 86 is separated from the friction element by the urging force of the return spring 85, and the first clutch portion C1 gradually shifts to the disengaged state. I will do it. The same applies to the second clutch portion C2. When the controller 94 transmits a predetermined shift command signal to the electromagnetic proportional pressure reducing valve 92 based on the position signal, the solenoid of the electromagnetic proportional pressure reducing valve 92 is excited and the oil passage 89 is excited. The hydraulic oil is supplied to the cylinder chamber 84 of the second clutch portion C2 through the second piston 87, and the second piston 87 presses between the friction elements against the urging force of the return spring 85. Gradually shift to the on state. On the contrary, when the hydraulic oil supply to the cylinder chamber 84 is cut off, the second piston 87 is separated from the friction element by the urging force of the return spring 85, and the second clutch portion C2 is gradually shifted to the disengaged state. I will do it.

  A small-diameter gear 72 is formed on the left outer periphery of the first clutch output shaft 12, and the gear 72 meshes with a large-diameter gear 96 fixed to the left end of the transmission shaft 15. When one clutch portion C1 is in the engaged state, the power from the output shaft 11 can be transmitted to the transmission shaft 15 via the first clutch portion C1, the first clutch output shaft 12, the gear 72, and the gear 96.

  A reduction gear 16, a reverse gear 78, and a gear 77 are fitted into the right half of the speed change shaft 15 in order from the left so that they can rotate relative to each other, and the speed reduction gear 14 can be rotated relative to the second clutch output shaft 13. The gear 73 is fixed to the right side of the reduction gear 14, and the output gear 27 and the large-diameter gear 81 are fixed to the traveling output shaft 17. Each of the reduction gear 14 and the reduction gear 16 is a double gear in which a large-diameter gear and a small-diameter gear are integrally formed. The reduction gear 14 is constituted by a large-diameter gear 14a and a small-diameter gear 14b. The gear 16 includes a large diameter gear 16a and a small diameter gear 16b.

  The aforementioned small diameter gear 72 meshes with the large diameter gear 96 to form a first reduction gear train, and the small diameter gear 14b of the reduction gear 14 meshes with the large diameter gear 16a of the reduction gear 16 to form the second reduction gear train. , And a small-diameter gear 16b of the reduction gear 16 is meshed with a large-diameter gear 81 to form a third reduction gear train. Further, the reverse gear 78 meshes with the idle gear 75 on the intermediate shaft 18, and the idle gear 75 meshes with the large-diameter gear 14 a of the reduction gear 14 to form a reverse gear train, and the gear 77 meshes with the gear 73. The adjustment gear train is formed, and by forming various gear trains having various gear ratios and rotation directions, each speed stage can be made to appear.

  Further, on the transmission shaft 15, a third spline hub 99 is provided on the left side of the reduction gear 16 via a synchronization mechanism 99 b such as synchromesh, and a synchronization mechanism 98 b is provided between the reverse gear 78 and the gear 77. All of the second spline hubs 98 are engaged with each other so as not to rotate relative to each other. On the second clutch output shaft 13, a first spline hub 97 is engaged to the left of the reduction gear 14 via a synchronization mechanism 97b so as not to be relatively rotatable.

  Of these, the first spline hub 97 has a first shifter 97a, the second spline hub 98 has a second shifter 98a, and the third spline hub 99 has a third shifter 99a that can slide in the axial direction. And it is engaged so that relative rotation is impossible. A clutch tooth portion 14c is formed at a portion of the reduction gear 14 toward the first spline hub 97 side, and a clutch tooth portion 16c is formed at a portion of the reduction gear 16 toward the third spline hub 99 side. Clutch tooth portions 77a and 78a are formed at portions facing 78 toward the second spline hub 98, respectively.

  The shifters 97a, 98a, and 99a are moved to predetermined positions by the shifter operating mechanism 143 as follows. The shifters 97a, 98a, and 99a are respectively connected to the rod 100a of the first hydraulic cylinder 100, the rod 101a of the second hydraulic cylinder 101, and the third hydraulic cylinder through connecting arms 128, 129, and 130 from a fork (not shown). 102 is connected to a rod 102a.

  In the first hydraulic cylinder 100, the oil chamber 100 b of the first hydraulic cylinder 100 is connected to the electromagnetic switching valve 103 through the oil passage 107. On the other hand, a return spring 132 is wound around the rod 100a between the right side surface of the piston 100c and the right inner wall of the cylinder chamber 100d, and the piston 100c is biased toward the oil chamber 100b. Similarly, in the third hydraulic cylinder 102, the oil chamber 102 b of the third hydraulic cylinder 102 is connected to the electromagnetic switching valve 106 through the oil passage 110. On the other hand, a return spring 133 is wound around the rod 102a between the right side surface of the piston 102c and the right inner wall of the cylinder chamber 102d, and the piston 102c is biased toward the oil chamber 102b.

  In such a configuration, as shown in FIG. 3, when the electromagnetic switching valves 103 and 106 are in the non-excitation position and the hydraulic cylinders 100 and 102 are in a neutral state, the elastic force of the return springs 132 and 133 The pistons 100c and 102c are abutted and held in a state of being urged by a stopper (not shown), and the corresponding contact position is set to a neutral position N. At this time, the oil chambers 100b and 102b are both communicated from the electromagnetic switching valves 103 and 106 to the oil sump 136 through the common oil passage 115 so that excessive pressure is not applied to the pistons 100c and 102c. The pistons 100c and 102c are accurately positioned at the neutral position.

  When the solenoids of the electromagnetic switching valves 103 and 106 are excited and switched to the excitation position, hydraulic oil is supplied from the common oil passage 114 into the oil chambers 100b and 102b through the electromagnetic switching valves 103 and 106. Then, against the elastic force of the return springs 132 and 133, the piston 100c slides to the position A and the piston 102c slides to the position D, and the shifters 97a and 99a are moved to move the clutch teeth 14c and 14c, respectively. 16c can be engaged.

  In other words, the oil chambers 100b and 102b are provided on one side of the pistons 100c and 102c, and the return springs 132 and 133, which are elastic members, are provided on the other side. Compared to the case where the hydraulic oil is supplied to both the oil chambers and the piston is controlled to slide, the oil chamber and the oil passage for supplying the hydraulic oil to the oil chamber can be reduced, and the oil chamber is sealed. High processing accuracy required for securing, parts such as external piping for oil passages are unnecessary, and devices such as switching valves required for hydraulic control can be switched to inexpensive ones, reducing manufacturing costs And maintainability can be improved.

  In the second hydraulic cylinder 101, a main piston 140 composed of a large diameter portion 140a and a small diameter portion 140b is fixed to one end of the rod 101a, and the small diameter portion 140b is larger than the large diameter portion 140a. A cylindrical sub-piston 141 having an outer diameter is externally fitted on the small-diameter portion 140b so as to be slidable in the axial direction. Oil chambers 101b and 101c are formed on both sides of the cylinder chamber 101d with the piston 139 including the main piston 140 and the sub-piston 141 interposed therebetween, and the oil chambers 101b and 101c are respectively connected to the electromagnetic switching valve 104. -It is connected to 105.

  In such a configuration, as shown in FIG. 3, when the electromagnetic switching valves 104 and 105 are in the non-excitation position and the second hydraulic cylinder 101 is in the neutral state, the electromagnetic switching valves 104 and 105 are connected to the oil passages 108 and 105. The pressure oil is supplied to both oil chambers 101b and 101c through 109, but the pressure receiving area on the oil chamber 101c side of the piston 139 is larger than the pressure receiving area on the oil chamber 101b side. Pushed to the oil chamber 101b side and held at a position where the inner peripheral corner of the sub-piston 141 contacts the shoulder 142 of the cylinder case. This contact position is defined as a neutral position N. Thereby, the piston 139 can be accurately positioned at the position N.

  When only the solenoid of the electromagnetic switching valve 104 is excited and only the electromagnetic switching valve 104 is switched to the excitation position, only the supply of pressure oil to the oil chamber 101b by the electromagnetic switching valve 104 is stopped. The piston 139 is pushed by the oil pressure in the oil chamber 101c toward the oil chamber 101b (to the right in the drawing), leaving only the main piston 140 in a state where the sub-piston 141 is blocked by the shoulder 142 and cannot move. The oil chamber 101b is slid and held up to a position B corresponding to the outermost end of the oil chamber 101b. Conversely, when only the solenoid of the electromagnetic switching valve 105 is excited and only the electromagnetic switching valve 105 is switched to the excitation position, only the supply of pressure oil to the oil chamber 101c by the electromagnetic switching valve 105 is stopped, and the piston 139 is moved to the oil chamber. The oil pressure in the oil chamber 101b is pushed to the oil chamber 101c side (left side of the paper) and held at a position C corresponding to the outermost end of the oil chamber 101c. Accordingly, the second shifter 98a can be moved and engaged with the clutch tooth portion 77a or 78a.

  In the shifter operating mechanism 143 as described above, when a solenoid of a predetermined electromagnetic switching valve among the electromagnetic switching valves 103 to 106 is excited based on the shift command signal from the controller 94, the corresponding piston is moved by the hydraulic oil. Is done. Then, the shifter linked to the piston moves to a predetermined position and engages with the clutch tooth portion via the synchronization mechanism, so that the predetermined gear cannot be rotated relative to the second clutch output shaft 13 or the transmission shaft 15. And the power from the first clutch output shaft 12 or the second clutch output shaft 13 can be smoothly transmitted to the travel output shaft 17 after shifting through the various gear trains. is there.

  Here, a hydraulic circuit configuration for supplying hydraulic oil or lubricating oil to the cylinders 79, 80, 100, 101, and 102 described above will be described. A hydraulic pump 145 is housed in the seal case 67, and a pump shaft 145a of the hydraulic pump 145 extends into the mission case 38 and is rotatably supported. An extension end of the pump shaft 145a includes A pump gear 146 is fixed. The pump gear 146 is engaged with a gear 147 fixed in the middle of the output shaft 11 from the engine 9, and the hydraulic pump 145 is configured as a gear pump that is driven by power from the engine 9.

  The suction port of the hydraulic pump 145 communicates with the oil reservoir 136 from an oil passage 149 through a filter 148 so that oil is supplied from the oil reservoir 136 to the hydraulic pump 145. Further, the discharge port of the hydraulic pump 145 is communicated with an oil passage 150. The oil passage 150 is connected to an oil passage 152 for an external work machine and a power steering or a shift gear at a branching portion 151 having throttles 151a and 151b for pressure adjustment. The oil passage 153 is branched. Of these, the oil passage 152 is connected to a switching valve 154, and the switching valve 154 is connected to a hydraulic lift cylinder 156 via a pipe 155, and by supplying pressure oil from the hydraulic pump 145 to the switching valve 154. The hydraulic lift cylinder 156 is switched to drive the lifting arm 157 for the external work machine. On the other hand, the oil passage 153 is connected to a switching valve 158 in the middle, and the switching valve 158 is connected to a power steering cylinder 159. By supplying pressure oil from the hydraulic pump 145 to the switching valve 158, A switching operation of a power steering cylinder 159 linked to a steering wheel (not shown) is performed so that the front wheels 3 and 3 can be freely steered.

  Further, the oil passage 153 is branched into an oil passage 160 for controlling the traveling shift clutch 82 and an oil passage 114 for controlling the hydraulic cylinders 100, 101, and 102. Of these, the oil passage 114 is connected to the electromagnetic switching valves 103 to 106, and as described above, the hydraulic cylinders 100, 101, 102 are operated via the electromagnetic switching valves 103 to 106, and the shifters 97a, 98a, 99a is moved to a predetermined position so that various gear trains can be freely selected and shifted. On the other hand, the oil passage 160 is further branched into an oil passage 161 and an oil passage 162. The oil passage 161 is branched into two after passing through a check valve 168 and a filter 169, and the electromagnetic proportional pressure reducing valve 91 and 92 are connected to pump ports, respectively. The discharge ports of the electromagnetic proportional pressure reducing valves 91 and 92 are connected to the oil passages 88 and 89, respectively, and the pressure oil from the hydraulic pump 145 is supplied to the cylinder chamber 83 of the first clutch portion C1 and the second clutch portion C2. The cylinder chamber 84 is supplied as hydraulic oil.

  On the other hand, the oil passage 162 is branched into an oil passage 163 and an oil passage 164 via a pressure regulating valve 170, and the oil passage 163 includes lubricating oil for the first clutch portion C1 and the second clutch portion C2. Is connected to the switching valve 93 for controlling the supply and discharge of the gas. The pilot oil passages 93a and 93b of the switching valve 93 are communicated with the oil passages 88 and 89, respectively. When the first clutch portion C1 or the second clutch portion C2 is operated, the oil passage 88 or the oil passage 89 is provided. When the pressure oil flows through, the switching valve 93 is switched by the oil pressure of the pressure oil, and the pump port and the discharge port are communicated. Then, the pressure oil in the oil passage 163 regulated by the pressure regulation valve 171 is supplied as lubricating oil from the switching valve 93 to the first clutch portion C1 and the second clutch portion C2 via the oil passage 90. is there.

  An oil passage 173 branches from a middle portion of the oil passage 164, and the oil passage 173 communicates with a bearing portion 179 including a bearing 180 that supports the left end portion of the output shaft 11, and the hydraulic pump 145 Is forcibly supplied as lubricating oil to the bearing portion 179. Further, the oil passage 164 is communicated with a lubrication circuit 190 including a shaft center oil passage (not shown) provided at the rotation center of the transmission shaft 15 and the second clutch output shaft 13. A discharge port (not shown) that injects lubricating oil toward the transmission clutch 82 is opened, and drilled in the axial radial direction from the axial center oil passage toward the various gear trains, the synchronization mechanisms 97b, 98b, 99b, and the like. Thus, a sufficient amount of lubricating oil can be supplied to the traveling transmission clutch 82, various gear trains, the synchronization mechanisms 97b, 98b, 99b, and the like.

  Next, the power transmission path configuration at the time of shifting in the dual clutch transmission 2 having such a structure will be described with reference to FIGS. 2, 4, and 6. A shift operation tool 111 is provided near the driver's seat (not shown) of the work vehicle 1, and the shift operation lever 95 is rotatably attached to the shift operation tool 111. When the moving operation is performed, at position 116, automatic shifting is performed in which the gears are automatically and continuously shifted up or down to shift to a predetermined forward speed, and the positions 118, 119a, 119b, 119c, and 119d are manually neutral. In addition, it is possible to shift to a normal manual shift that can be arbitrarily set for each speed stage.

  In the automatic gear shift, according to the gear shift control configuration described later, each speed is determined from the relationship between the depression amount of an accelerator pedal (not shown) as an engine speed setting means (not shown) and the vehicle speed at that time. The gears are automatically shifted continuously between the steps. This engine speed setting means can be constituted by an accelerator pedal or an accelerator lever as an accelerator operating tool. Then, by operating the accelerator operating tool, the throttle valve provided in the intake system of the engine 9 can be opened and closed, the rack position can be changed, and the fuel injection amount can be changed by the electromagnetic valve. An operation amount such as an accelerator opening by the accelerator operating tool is detected by an accelerator opening sensor 134 described later, and is input to the controller 94 as a set amount. Here, the power transmission path configuration of automatic transmission will be described by taking as an example the case of shifting up in order from the first forward speed to the fourth forward speed.

  At the first forward speed, the first clutch portion C1 is engaged and the second clutch portion C2 is disengaged as described above, and the first shifter 97a is moved to the position A by the shifter operating mechanism 143. Engage with the reduction gear 14, move the second shifter 98 a to the position B and engage with the gear 77, and further move the third shifter 99 a to the position N to disengage from the reduction gear 16.

  As a result, the power from the engine 9 is transmitted to the transmission shaft 15 via the output shaft 11, the first clutch portion C 1, and the first reduction gear trains 72 and 96, and then engaged with the transmission shaft 15. It is transmitted to the second clutch output shaft 13 through the rows 77 and 73, and further, via the second reduction gear trains 14b and 16a and the third reduction gear trains 16b and 81 that engage with the second clutch output shaft 13. The front axles 4 and 4 and the rear axles 7 and 7 are driven to travel through the output gear 27, the central differential 28, and the like as the transmission speed of the first forward speed that is transmitted to the traveling output shaft 17 and the lowest speed. Yes.

  In order to shift from the first forward speed to the second forward speed, the first clutch portion C1 is disengaged and the second clutch portion C2 is merely engaged, and the positions of the shifters 97a, 98a, and 99a remain unchanged. Then, the power from the engine 9 is transmitted to the travel output shaft 17 via the output shaft 11, the second clutch portion C2, the second reduction gear trains 14b and 16a, and the third reduction gear trains 16b and 81, and the second forward speed. The front axles 4 and 4 and the rear axles 7 and 7 are driven to travel as shifting power.

  In order to shift the speed from the second forward speed to the third forward speed, the second shifter 98a is moved from the position B to the position N and the third shifter 99a is moved from the position N to the position D by the shifter operating mechanism 143 in advance. However, the disengaged state of the first clutch portion C1, the engaged state of the second clutch portion C2, and the engaged state of the position A of the first shifter 97a remain unchanged. At this time, since the first clutch portion C1 is in the disengaged state, the shift gears 98a and 99a on the transmission shaft 15 connected to the first clutch portion C1 are not subjected to the shift shock at all by the operator. -It can be freely engaged / disengaged from 16 and moved to a predetermined position.

  Subsequently, the first clutch portion C1 is turned on and the second clutch portion C2 is turned off, so that the positions of the shifters 97a, 98a, and 99a remain unchanged. Then, the power from the engine 9 is transmitted to the transmission shaft 15 through the output shaft 11, the first clutch portion C1, and the first reduction gear trains 72 and 96, and then engaged with the transmission shaft 15. It is transmitted to the travel output shaft 17 through the gear trains 16b and 81, and travels and drives the front axles 4 and 4 and the rear axles 7 and 7 as the third forward speed shifting power.

  In order to shift the speed from the third forward speed to the fourth forward speed, the first shifter 97a is moved from the position A to the position N and the second shifter 98a is moved from the position N to the position B by the shifter operating mechanism 143 in advance. However, the engaged state of the first clutch portion C1, the disengaged state of the second clutch portion C2, and the engaged state of the position D of the third shifter 99a are not changed. At this time, since the second clutch part C2 is in the disengaged state, the operator receives no shift shock at all on the first shifter 97a on the second clutch output shaft 13 connected to the second clutch part C2. The second shifter 98a can be smoothly engaged with the gear 77 in a state where the shift shock is greatly reduced by the synchronization mechanism 98b.

  Subsequently, the first clutch portion C1 is disengaged and the second clutch portion C2 is engaged, so that the positions of the shifters 97a, 98a, and 99a remain unchanged. Then, the power from the engine 9 is transmitted to the second clutch output shaft 13 through the output shaft 11 and the second clutch portion C2, and then transmitted to the transmission shaft 15 through the adjustment gear trains 73 and 77. The transmission is transmitted to the travel output shaft 17 through the third reduction gear trains 16b and 81 engaged with the transmission shaft 15, and the front axles 4 and 4 and the rear axles 7 and 7 are driven to travel as transmission power of the fourth forward speed. .

  In the above description, the case of the power transmission path configuration for shifting up from the first forward speed to the fourth forward speed has been described. However, the same applies to the case of downshifting, and the shifters 97a, 98a, After changing 99a to the downshift position of the next speed stage, the shifting operation is performed so that only the on / off state of the clutch parts C1 and C2 is reversed between the first clutch part C1 and the second clutch part C2. It is.

  In the manual shift, the positions 118, 119a, 119b, 119c, and 119d are set to neutral, forward 1st speed, forward 2nd speed, forward 3rd speed, and forward 4th speed, respectively. As for automatic transmission, the power transmission path of each speed stage in the first speed reduction gear trains 72 and 96, the second reduction gear trains 14b and 16a, the third reduction gear trains 16b and 81, and A gear train group consisting of adjusting gear trains 77 and 73, a second reduction gear train 14b and 16a and a third reduction gear train 16b and 81 at the second forward speed, and a first reduction gear train at the third forward speed. 72, 96, a gear train group consisting of third reduction gear trains 16b, 81, and a gear train group consisting of third reduction gear trains 16b, 81 and adjustment gear trains 73, 77 at the fourth forward speed, respectively. And a power transmission path configuration.

  Further, in both the automatic shift and the manual shift described above, the shift operation lever 95 is put into the position 117 during reverse travel. Then, a shift command signal is transmitted from the controller 94, the first clutch portion C1 is turned on, the second clutch portion C2 is turned off, the second shifter 98a is moved to the position C, and the reverse gear 78 is engaged. Further, the third shifter 99a is moved to the position N, and is brought into a non-engagement state with the reduction gear 16. At this time, since the second clutch portion C2 is in the disengaged state, the first shifter 98a on the second clutch output shaft 13 connected to the second clutch portion C2 is not engaged with the reduction gear 14 at the position N. Even if it is in the state, it may be engaged with the reduction gear 14 at the position A.

  As a result, the power from the engine 9 is transmitted to the transmission shaft 15 via the output shaft 11, the first clutch portion C1, and the first reduction gear trains 72 and 96, and then the reverse gear engaged with the transmission shaft 15. It is transmitted to the travel output shaft 17 via the trains 78, 75, 14a, the second reduction gear trains 14b, 16a, and the third reduction gear trains 16b, 81, and the front axles 4 and 4 and the rear axles 7 are transmitted as reverse speed shifting power.・ 7 is driven to travel. Thus, at the reverse speed, the gear train group consisting of the first reduction gear train 72/96, the second reduction gear train 14b / 16a, the third reduction gear train 16b / 81, and the reverse gear train 78/75 / 14a is selected. Power transmission path configuration.

  Next, a shift control configuration at the time of automatic shift in such a power transmission path will be specifically described with reference to FIGS. First, the shift control process will be described by taking an example in which the current speed stage is the second forward speed and the next speed stage is the third forward speed. As shown in FIGS. 2 to 5, during traveling at the second forward speed, the second clutch portion C2 is connected and in the engaged state as described above. At this time, the rod 100a of the first hydraulic cylinder 100 is held at the position A, the rod 101a of the second hydraulic cylinder 101 is held at the position B, and the rod 102a of the third hydraulic cylinder 102 is held at the position N. Shifters 97a, 98a, and 99a connected to the rods 100a, 101a, and 102a via arms, forks, and the like are also held at positions A, B, and N, respectively, as described above. For this reason, the first shifter 97a is held in the engaged state with the reduction gear 14, the second shifter 98a is held in the engaged state with the gear 77, and the third shifter 99a is held in the neutral state. The first forward speed shifting power is transmitted to the travel output shaft 17 through the travel output shaft 17. On the other hand, the first clutch part C1 is disconnected and in a disconnected state.

  At a time point X, for example, when the shift command signal from the second forward speed to the third forward speed is issued from the controller 94 by depressing the accelerator pedal, the disengaged state of the first clutch portion C1, the engaged state of the second clutch portion C2, The engagement state at the position A of the first shifter 97a remains unchanged, and only the second shifter 98a and the third shifter 99a move from the position B to the position N and from the position N to the position D, respectively. In the neutral state, the third shifter 99a is in the engaged state at the position D. The power transmission path is output shaft 11 → second clutch C2 → second reduction gear train 14b / 16a → third reduction gear train 16b / 81 → travel output shaft 17 and does not change before and after the shift command.

  At a time point Y when a little time has elapsed after the transmission command signal is issued, the clutch connection / disconnection command signal indicating that the first clutch portion C1 is gradually connected and the second clutch portion C2 is gradually disconnected is a controller. It is emitted from 94. Then, the electromagnetic proportional pressure reducing valves 91 and 92 are subjected to proportional pressure reduction control, and the first piston 86 of the first clutch part cylinder 79 and the second piston 87 of the second clutch part cylinder 80 gradually and continuously move, The clutch pressure of the first clutch portion C1 increases and the joining operation proceeds from the current disengaged state to the engaged state, the clutch pressure of the second clutch portion C2 decreases and the separation operation proceeds from the current engaged state to the disengaged state, These joining operation and separation operation are performed in parallel.

  Further, the clutch connection / disconnection command signal continues to be issued until the Z point when time elapses from the Y point, and when the Z point is reached, the first clutch portion C1 reaches the specified pressure and the clutch pressure reaches the specified pressure. In the engaged state, the clutch pressure of the second clutch portion C2 is substantially zero and completely disengaged, and the shift is completed. That is, while this clutch connection / disconnection command signal is issued, the power from the first clutch part C1 is output shaft 11 → first clutch part C1 → first reduction gear train 72/96 → third reduction gear train. 16b and 81 are always connected to the travel output shaft 17, and the power from the second clutch part C2 is also output from the output shaft 11, the second clutch part C2, the second reduction gear train 14b and 16a, and the third reduction gear train 16b. -Since it is always connected to the traveling output shaft 17 via 81, the shifting power from the second clutch portion C2 gradually decreases, while the shifting power from the first clutch portion C1 gradually increases. It will be followed.

  As a result, the power from the travel transmission clutch 82 to the travel output shaft 17 is gradually switched from the second forward speed to the third forward speed at the time point Y, and is completely shifted to the third forward speed at the time point Z. The power from the engine 9 is not interrupted. Shift control between other shift speeds is performed in the same process as described above.

  The time point X, which is the transmission timing of the shift command signal, is determined based on the shift point characteristic model 191, the throttle opening degree of the engine 9 and the vehicle speed actually detected by the throttle opening degree sensor 178 and the vehicle speed sensor 135. Is done.

  As shown in FIG. 8, for example, as shown in a general shift up line 191U, when the current speed stage is the first forward speed (hereinafter simply referred to as “first speed”, and the same applies to other speed stages). When only the vehicle speed increases under a certain throttle opening and reaches the diagram 191U12 from the first speed to the second speed, a shift command signal in the shift control process is issued (time point X). When the shift control process proceeds and the transition from the first speed of the current speed stage to the second speed of the next speed stage is completed, the shift completion signal is issued (time Z), and the upshift to the second speed is completed.

  When the vehicle speed increases and reaches the diagram 191U23 from the 2nd speed to the 3rd speed, a shift command signal is similarly issued (at time X), and the shift control process proceeds to change the 2nd speed of the current speed stage to the next speed stage. When the shift to the third speed is completed, the shift completion signal is issued (at time Z), and the upshift to the third speed is completed. Further, when the vehicle speed increases and reaches the diagram 191U34 from the 3rd speed to the 4th speed, a shift command signal is similarly issued (time point X), and the shift control process proceeds to shift the 3rd speed from the current speed stage to the next speed. When the shift to the fourth speed of the stage is completed, the shift completion signal is issued (at time Z), and the shift up to the fourth speed is completed.

  Conversely, as shown in the downshift line 191D, when the current speed stage is the fourth speed, when the vehicle speed decreases under a certain throttle opening and reaches the diagram 191D34, the downshift from the fourth speed to the third speed is performed. When the vehicle speed reaches the diagram 191D23, a downshift from the third speed to the second speed is performed, and when the vehicle speed reaches the diagram 191D12, a shift down from the second speed to the first speed is performed.

  The change in vehicle speed at the time of downshifting (lines 191D12, 191D23, 191D34) is made equal or smaller than that at the time of upshifting (lines 191U12, 191U23, 191U34), and the change in vehicle speed at the time of shifting up is represented by the line 191U34. → In the order of the diagram 191U23 → the diagram 191U12, the lower the speed, the smaller the speed. As a result, an operator's intentional kickdown and automatic deceleration according to a decrease in vehicle speed accompanying an increase in traveling load can be performed smoothly.

That is, the first clutch portion C1, which is a first clutch for power connection / disconnection to the drive train group necessary for each odd speed stage, and the second power connection / disconnection to the drive train group necessary for each even speed stage. A second clutch portion C2 that is a clutch, and the operation of the first clutch portion C1 and the second clutch portion C2 can be controlled by a first hydraulic clutch portion cylinder 79 and a second hydraulic clutch portion cylinder 80 that are actuators, respectively. A controller 94, which is a control device, is provided. The controller 94 automatically selects the drive train group when the first clutch part C1 and the second clutch part C2 are turned on and off, and shifts the power from the engine 9 to change the axle. When transmitting to a certain front wheel shaft 50, 50 and a rear wheel shaft 65, 65, and at the time of speed stage switching between the first speed / third speed as the odd speed stage and the second speed / fourth speed as the even speed stage, Crap Since the one separating operation and the other joining operation of the part C1 and the second clutch part C2 are temporally overlapped, the power transmission from the engine 9 to the front wheel shafts 50 and 50 and the rear wheel shafts 65 and 65 is transmitted. The speed can be changed smoothly without interruption, and the vehicle can be reliably driven without being lowered when starting on a slope, and the running performance can be greatly improved.

  A shift control system 120 for controlling such automatic shift will be described. As shown in FIG. 6, the shift control system 120 includes an electromagnetic proportional pressure reducing valve 91 that operates the first clutch part cylinder 79 for the first clutch part C1, and a second clutch part cylinder 80 for the second clutch part C2. A clutch electromagnetic proportional pressure reducing valve group 137 including an electromagnetic proportional pressure reducing valve 92 for operating the shifter, and electromagnetic switching valves 103 to 106 for operating the hydraulic cylinders 100, 101, 102 for the shifters 97a, 98a, and 99a. An electromagnetic switching valve group 138, and these electromagnetic switching valve groups 137 and 138 are connected to the controller 94. In addition to the lever position detection sensor 113, the throttle opening sensor 178, the vehicle speed sensor 135, and the electromagnetic switching valve groups 137 and 138, the controller 94 includes a transmission mode switch 175, an accelerator opening sensor 134, and An engine speed sensor 176 and the like are connected.

  Of these, the transmission mode switching tool 175 is provided with a switching operation tool 175a such as a dial or a lever for switching the transmission mode during automatic transmission with the transmission operation lever 95 at the position 116, and operates the switching operation tool 175a. By doing so, it is possible to switch between an automatic mode (position 181 to position 183) for automatic shifting at an appropriate stop / start speed and a manual mode (position 184 to position 187) for automatic shifting at the set maximum speed stage.

  In the automatic mode, when any one mode is selected, an automatic mode signal is transmitted from the transmission mode switching device 175 to the controller 94 so as to shift up or down according to the selected mode. On the basis of this, a shift command signal is transmitted from the controller 94 to the electromagnetic switching valve groups 137 and 138, and as described above, the clutch is engaged and disengaged and the shifter and the clutch tooth portion are engaged / disengaged. Is called.

  In this automatic mode, as in the normal shift point characteristic model 191 described above, a work mode (position 181) in which the first speed, which is the lowest speed stage, is selected as the stop / start speed stage to obtain a high torque / low speed output, A driving mode (position 183) in which second speed is selected as the starting speed stage to eliminate inefficient clutch switching immediately after starting or immediately before stopping, and when the driving load is excessive in the driving mode, 1 is set as the starting speed stage. One of the automatic selection modes (position 182) for automatically selecting the speed can be selected.

  In the manual mode, when one of the first speed (position 184), the second speed (position 185), the third speed (position 186), and the fourth speed (position 187) is selected, the selected speed stage is the maximum speed stage. The maximum speed stage signal is transmitted from the shift mode switching device 175 to the controller 94 so that the up to the maximum speed stage can be shifted up or down by the accelerator operation by the accelerator operation tool such as an accelerator pedal. A shift command signal is transmitted from the controller 94 to the electromagnetic switching valve groups 137 and 138 based on the step signal.

  The accelerator opening sensor 134 detects an operation amount of the accelerator operating tool as an opening, and transmits the accelerator opening signal to the controller 94. The throttle opening sensor 178 is connected to the intake system of the engine 9. The opening degree of the throttle valve provided is detected, and the throttle opening degree signal is transmitted to the controller 94. Further, the engine speed sensor 176 detects the speed of the output shaft 11 from the engine 9, and An engine speed signal is transmitted to the controller 94. The vehicle speed sensor 135 detects the rotational speed of the output side of the dual clutch transmission 2, for example, the traveling output shaft 17, and transmits the output shaft rotational speed signal to the controller 94. Based on the above, the vehicle speed is calculated in the controller 94.

  Based on the shift control process, the shift point characteristic model 191 and the shift control system 120 as described above, the following shift control is performed during automatic shift. In the storage unit 94a of the controller 94 shown in FIG. 6, the shift point characteristic model 191 shown in FIG. 8 in which the first speed which is the lowest speed stage is selected as the stop / start speed stage, and the stop / start speed as shown in FIG. A shift point characteristic model 192 in which the second speed is selected as a stage is stored, and any one of the maximum speed stages of the work mode, the running mode, the automatic selection mode, and the manual mode is stored by the switching operation tool 175a. When the speed change mode is selected, the controller 94 selects an optimum gear train for the detected throttle opening and vehicle speed according to the speed change point characteristic model of the selected mode so that automatic speed change can be executed.

  In any model diagram, each diagram is determined by a function of the throttle opening (%) and the vehicle speed (km / h), and the current coordinates in the model diagram (hereinafter referred to as “current shift position”). ) Is determined from the throttle opening actually detected by the throttle opening sensor 178 and the vehicle speed sensor 135 (hereinafter referred to as “current throttle opening”) and the vehicle speed (hereinafter referred to as “current vehicle speed”). The point is determined, and the comparison between the current vehicle speed described below and the vehicle speed on each diagram is performed at the same throttle opening.

  As shown in FIG. 7, when the shift control is started, the automatic mode signal and the maximum speed stage signal from the shift mode switch 175, the accelerator opening signal from the accelerator opening sensor 134, and the throttle opening sensor 178 The throttle opening signal, the engine speed signal from the engine speed sensor 176, and the output shaft speed signal from the vehicle speed sensor 135 are read into the controller 94, and the vehicle speed is calculated by the controller 94 ( Step S1). Then, each mode is determined based on the automatic mode signal and the maximum speed stage signal (steps S2 to S4), and the first speed stop start control in which the first speed which is the lowest speed stage is selected as the stop start speed stage ( Step S9), two-speed stop start control in which the second speed is selected as the stop start speed stage (step S5), and manual control (step S6) for shifting to the set maximum speed stage by the accelerator operation are performed. Is called.

  The first-speed stop start control is performed when the automatic mode is the work mode (step S2, YES) or when the automatic selection mode is selected (step S3, YES) and the traveling load is larger than the set value (step S8, YES). Done.

  The case of the work mode (step S2, YES) will be described. At the time of upshifting, it is determined whether or not the current vehicle speed is higher than the vehicle speed (hereinafter referred to as “first set vehicle speed”) for starting the shift between the first speed and the second speed obtained from the diagram 191U12 in FIG. If the current vehicle speed is lower than the first set vehicle speed, the first speed is selected. If the current vehicle speed is higher than the first set vehicle speed, the vehicle speed (hereinafter, “ It is determined whether it is greater than “second set vehicle speed”. Then, if the current vehicle speed is smaller than the second set vehicle speed, the second speed is selected. If the current vehicle speed is greater than the second set vehicle speed, the vehicle speed for starting the shift between the third speed and the fourth speed obtained from the diagram 191U34 ( Hereinafter, it is determined whether it is greater than “the third set vehicle speed”. If the current vehicle speed is smaller than the third set vehicle speed, the third speed is selected, and if it is larger, the fourth speed is selected and the process is terminated.

  On the other hand, at the time of downshift, it is determined whether or not the current vehicle speed is lower than the third set vehicle speed obtained from the diagram 191D34. If the current vehicle speed is greater than the third set vehicle speed, the fourth speed is selected, and the current vehicle speed is set to the third set speed. If it is lower than the vehicle speed, it is determined whether it is lower than the second set vehicle speed obtained from the diagram 191D23. Then, if the current vehicle speed is larger than the second set vehicle speed, the third speed is selected. If the current vehicle speed is smaller, it is determined whether it is smaller than the first set vehicle speed obtained from the diagram 191D12. If the current vehicle speed is larger than the first set vehicle speed, The second speed is selected, and if it is smaller, the first speed is selected and the process is terminated.

  The case of the automatic selection mode (step S3, YES) will be described. If the automatic mode is not the work mode (step S2, NO), it is determined whether or not the automatic selection mode is selected (step S3). If the automatic mode is the automatic selection mode (step S3, YES), the traveling load is calculated. (Step S7). The travel load can be a rate of change of the engine speed with respect to the accelerator opening, and can be calculated based on the accelerator opening signal and the engine speed signal read in step S1. Then, a predetermined traveling load (hereinafter referred to as “set load”) is stored in advance in the storage unit 94a of the controller 94, and the set load is compared with the calculated traveling load (step S8). If the traveling load is larger than the set load (step S8, YES), it is determined that the traveling load is large, and the first speed stop transmission control based on the same shift point characteristic model 191 as that in the work mode is performed. The traveling load may be measured by a torque sensor or the like, and the method for determining the traveling load is not particularly limited.

  The second speed stop start control is performed when the automatic mode is the traveling mode (step S4, YES), or when the automatic selection mode is selected (step S3, YES) and the traveling load is equal to or less than the set load (step S8, NO). Done.

  The case of the travel mode (step S4, YES) will be described. If the automatic mode is not the automatic selection mode (step S3, NO), it is determined whether or not it is the travel mode (step S4). If it is the travel mode (step S4, YES), the second speed stop start control is performed. Is called. At the time of shifting up, it is determined whether or not the current vehicle speed is higher than the second set vehicle speed obtained from the diagram 192U23 of FIG. 9, and if the current vehicle speed is lower than the second set vehicle speed, the second speed is selected. If it is greater than the set vehicle speed, it is determined whether or not the current vehicle speed is greater than the third set vehicle speed obtained from the diagram 192U34. If the current vehicle speed is smaller than the third set vehicle speed, the third speed is selected, and if it is larger, the fourth speed is selected and the process is terminated.

  On the other hand, at the time of downshifting, it is determined whether or not the current vehicle speed is lower than the third set vehicle speed obtained from the diagram 192D34. If the current vehicle speed is greater than the third set vehicle speed, the fourth speed is selected, and the current vehicle speed is set to the third set speed. If it is lower than the vehicle speed, it is determined whether it is lower than the second set vehicle speed obtained from the diagram 192D23. If the current vehicle speed is greater than the second set vehicle speed, the third speed is selected. If the current vehicle speed is less than the second set vehicle speed, the second speed is selected and the process is terminated.

  The case of the automatic selection mode (step S3, YES) will be described. If the automatic mode is the automatic selection mode, but the traveling load is equal to or less than the set load (step S8, NO), it is determined that the traveling load is small and 2 based on the same shift point characteristic model 192 as the traveling mode. Performs quick stop transmission control.

  The manual control is performed when the automatic mode is not any of the work mode, the automatic selection mode, and the travel mode (step S4, NO). In the manual control, as described above, the set maximum speed stage is set. Until then, it is possible to shift up or down sequentially by the accelerator operation, but after that, it is not possible to shift to a speed stage exceeding the set maximum speed stage.

  For example, when the switching operation tool 175a is operated to switch the maximum speed stage from the third speed (position 187) to the first speed (position 184) of the current speed stage, the shift point is changed in the same manner as in the work mode. According to the characteristic model 191, the gear is shifted down in order of 3rd speed → 2nd speed → 1st speed by the accelerator operation. Conversely, when the setting of the maximum speed stage is switched from the first speed (position 184) to the second speed (position 185) of the current speed stage, 1 is obtained by operating the accelerator according to the shift point characteristic model in the same manner as in the work mode. The speed is shifted up from the second speed to the second speed. After that, even if the vehicle speed increases and exceeds the second set vehicle speed, the speed is not shifted up to the third speed. The speed can be reliably shifted to the set maximum speed stage.

  In the shift control configuration as described above, by operating the switching operation tool 175a and setting the shift mode to the travel mode, the second speed other than the first speed of the lowest speed stage can be selected as the stop speed stage. Thus, inefficient clutch switching immediately after starting or immediately before stopping is eliminated, transmission and clutch operation efficiency is increased, fuel efficiency is improved, and good driving feeling is obtained. Furthermore, by operating the switching operation tool 175a and setting the shift mode to the automatic selection mode, it is possible to automatically select the first speed or the second speed as the stop / start speed stage according to the value of the traveling load. As a result, when the traveling load becomes excessive, the minimum speed stage with high torque can be automatically selected without the operator having to bother to operate, and it is possible to ensure the situation such as engine stalls caused by operational mistakes and delays. It can be avoided.

  Next, in the dual clutch transmission 2 having the above-described structure and shift control configuration, the engine speed estimation control configuration when a malfunction such as a failure of the engine speed sensor 176 occurs when the vehicle starts. 6, FIG. 10 to FIG.

  As shown in FIG. 10, in the estimation control of the engine speed sensor, a first clutch pressure sensor 165, a second clutch pressure sensor 166, and a brake sensor 194 are newly connected to the controller 94. Of these, the first clutch pressure sensor 165 and the second clutch pressure sensor 166 detect the clutch pressure of the first clutch portion C1 and the second clutch portion C2, respectively, and indicate the clutch pressure. The brake sensor 194 transmits a signal to the controller 94, and the brake sensor 194 operates a brake that operates a hydraulically operated brake device provided in the middle of the power transmission path from the engine 9 to the front wheel shafts 50 and 50 and the rear wheel shafts 65 and 65. The brake signal is connected to the pedal 195, and when the brake pedal 195 is depressed, the brake signal is sent to the controller 94. It is to be transmitted.

  In such a configuration, as shown in FIGS. 6 and 11, when the vehicle is started by turning on the key switch or the like, the depression state of the brake pedal 195 is determined (step S20), and the brake is released. If it is in the operating state (step S20, YES), based on the brake signal from the brake sensor 194, a clutch disconnection command signal is transmitted from the controller 94 to the electromagnetic proportional pressure reducing valve group 137 for clutch, and the clutch is in the disengaged state. The vehicle is not started (step S25). On the other hand, when the depression of the brake pedal 195 is released and the brake is released (step S20, NO), the engine speed is detected based on the engine speed signal from the engine speed sensor 176 (step S20). S21).

  The engine speed signal intensity and waveform are compared with normal signal intensity and waveform data (hereinafter referred to as “normal data”) stored in the storage unit 94a of the controller 94 to determine the engine speed. It is determined whether a failure such as a failure of the sensor 176 has occurred (step S22). If it is determined that the problem has not occurred (step S22, NO), the detected engine speed and the elapsed time between the engine speed and the clutch pressure stored in the storage unit 94a of the controller 94 are kept as they are. Based on the model and the like, the upper limit clutch pressure provided for each engine speed is determined (step S23). For example, the upper limit clutch pressure corresponding to the engine speed R2 in the diagram 197 in FIG. 12 is the clutch pressure P2 in the diagram 196.

  The clutch connection command signal is sent from the controller 94 to the clutch electromagnetic proportional pressure reducing valve group so that the clutch pressure obtained from the clutch pressure signals from the clutch pressure sensors 165 and 166 increases until the upper limit clutch pressure is reached. 137 (step S24), and the vehicle starts when the clutch is engaged.

  Note that the pressure increase speed up to the upper limit clutch pressure for each engine speed is limited to a predetermined specified speed, and even if the brake pedal 195 is stepped on and released again while the engine speed is increasing, The clutch pressure is prevented from increasing rapidly under high engine speed.

  On the other hand, when it is determined that a problem has occurred by comparison with the normal data (YES in step S22), the throttle opening is detected based on the throttle opening signal from the throttle opening sensor 178. At the same time, for the worker, a failure has occurred and the part where the failure has occurred, for example, whether the failure has occurred in the engine speed sensor 176 itself, or a signal line from the engine speed sensor 176 to the controller 94. Is notified by a warning sound from a sound device such as a buzzer or flashing light from an indicator lamp (step S26), thereby enabling an operator to quickly respond to a problem. Then, the engine speed is estimated based on the throttle opening and a relational model between the throttle opening and the engine speed stored in the storage unit 94a of the controller 94 (step S27). Thereafter, the estimated engine speed (hereinafter referred to as “estimated engine speed”) is regarded as the engine speed detected by the engine speed sensor 176, and is the same as when it is determined that no malfunction has occurred. Thus, an upper limit clutch pressure is determined (step S23), and until the upper limit clutch pressure is reached, a clutch connection command signal is transmitted from the controller 94 to the electromagnetic proportional pressure reducing valve group 137 for clutches (step S24), and the clutch is engaged. The vehicle starts.

  In such clutch pressure control, as shown in FIG. 12, the clutch pressure, the engine speed, and the throttle opening change according to the diagrams 196, 197, and 198, respectively. Before time T1, the brake pedal 195 is depressed and the brake device is in an operating state, the engine speed is smaller than R1, the engine 9 is idling, and the throttle opening is set to a predetermined value smaller than B1.

  When the accelerator operating tool is operated while releasing the brake pedal 195 and releasing the brake at time T1, the engine speed R1 is detected according to the process shown in FIG. 11, and the clutch pressure P1 corresponding to the engine speed R1 is detected. Clutch pressure increases rapidly. Here, if the controller 94 determines that a malfunction such as a failure of the engine speed sensor 176 has occurred, the throttle opening B1 is detected, and the estimated engine speed r1 estimated from the throttle opening B1 is set. The clutch pressure increases to the corresponding clutch pressure p1.

  Further, when the accelerator operation tool is operated to increase the engine speed from R1 to R3, the clutch pressure gradually increases from P1 to P3. During this time, according to the process shown in FIG. 11, the clutch pressure increases in response to the increase in the engine speed, and after the engine speed has sufficiently increased, the clutch is shifted to the engaged state and the torque is insufficient. The vehicle can be started in a state where there is no load, and even when the vehicle is heavy and the vehicle weight is heavy or the road surface is steep, the occurrence of rollback can be reliably prevented. During this time, if the controller 94 determines that a malfunction such as a failure of the engine speed sensor 176 has occurred, for example, the throttle opening B2 is detected at the time point T2 and is estimated from the throttle opening B2. The clutch pressure increases to the clutch pressure p2 corresponding to the engine speed r2.

  At time T3, the engine speed is R3, the clutch pressure reaches the set maximum clutch pressure P3, and the transition to the clutch engaged state is completed. Also in this case, if it is determined that a malfunction such as a failure of the engine speed sensor 176 has occurred, the clutch pressure is increased to the clutch pressure p3 corresponding to the estimated engine speed r3 estimated from the detected throttle opening B3. To increase.

  Conversely, when the engine speed is decreased from R3 to R1, the clutch pressure gradually increases from P3 to P1, and when the engine speed is idling below R1, the brake pedal 195 is depressed. The brake device is activated. During this time, if it is determined that a malfunction such as a failure of the engine speed sensor 176 has occurred, the clutch pressure is reduced to the clutch pressure corresponding to the estimated engine speed estimated from the detected throttle opening. .

  Instead of the throttle opening signal from the throttle opening sensor 178, it is also possible to use an accelerator opening signal from the accelerator opening sensor 134 that is easy to access and has a simple structure. That is, when it is determined that a malfunction such as a failure of the engine speed sensor 176 has occurred, the accelerator opening is detected based on the accelerator opening signal, and the accelerator opening and the storage unit of the controller 94 are detected. The estimated engine speed is estimated based on the relational model between the accelerator opening and the engine speed stored in 94a.

That is, the first clutch portion C1, which is a first clutch for power connection / disconnection to the drive train group necessary for each odd speed stage, and the second power connection / disconnection to the drive train group necessary for each even speed stage. A second clutch portion C2 that is a clutch, and control that can control the operation of the first clutch portion C1 and the second clutch portion C2 by a first hydraulic clutch portion cylinder 79 and a second hydraulic clutch portion cylinder 80 that are actuators. A controller 94 which is a device is provided, and the controller 94 automatically selects the drive train group when the first clutch portion C1 and the second clutch portion C2 are turned on and off, and shifts the power from the engine 9 to form an axle. One of the first clutch part C1 and the second clutch part C2 is transmitted to the front wheel shafts 50, 50 and the rear wheel shafts 65, 65, and at the time of speed stage switching between the odd speed stages and even speed stages. Engine speed sensor 176 for detecting the rotational speed of the output shaft 11 of the engine 9 as an engine rotational speed in the dual clutch transmission 2 that temporally overlaps the separation operation of the engine and the other joint operation, and the engine A throttle valve provided in the intake system of the engine 9, which is an engine speed setting means for setting the engine speed, is provided. When the vehicle starts, the controller 94 responds to the increase in the engine speed. A clutch pressure control structure for operating the clutch part cylinder 79 and the second clutch part cylinder 80 to increase the clutch pressure of the clutch on the start speed stage side of the first clutch part C1 and the second clutch part C2, When a malfunction related to the engine speed sensor 176 is detected, the throttle valve Since the estimation control configuration for estimating the engine speed based on the throttle opening which is a fixed amount is provided, the engine speed sensor 176 fails or the signal line from the engine speed sensor 176 to the controller 94 is disconnected. Even in such a case, the engine speed is estimated and the clutch pressure is increased or decreased without interruption so as to correspond to the output torque from the engine 9 to ensure that the vehicle cannot run when starting the vehicle. In addition to avoiding this, it is possible to prevent the rollback from occurring even when the load is large and the vehicle weight is heavy or the road surface is inclined when the hill starts. In particular, in this way, the engine speed setting means is a throttle valve, and the throttle opening of the throttle valve is the set amount of the engine speed setting means. Can be used during estimation control of the engine speed, and high estimation accuracy can be obtained.

  Furthermore, when the engine speed setting means is an accelerator operating tool such as an accelerator pedal, and the accelerator opening of the accelerator operating tool is set to the engine speed setting means, the operation of the accelerator operating tool that is easy to access is performed. The accelerator opening, which is the amount, can be used during the estimation control of the engine speed, and the cost can be reduced and the maintainability can be improved by simplifying the control configuration.

  Next, a throttle opening force setting control configuration in the event of a malfunction such as a failure of the throttle opening sensor 178 during automatic shifting during traveling will be described with reference to FIGS. .

  As described above, the automatic shift during traveling is performed when the current shift position determined from the current vehicle speed and the current throttle opening exceeds each diagram for starting the shift to each speed stage in the shift point characteristic model. However, when troubles such as failure of the throttle opening sensor 178 in FIG. 6 for detecting the throttle opening or disconnection of the signal line from the throttle opening sensor 178 to the controller 94 occur, The throttle opening signal is not transmitted to the controller 94, the throttle opening becomes 0%, and normal shifting is not performed.

  For example, as shown in the up-shift line 202 of FIG. 15, when the current speed stage is the third speed and only the vehicle speed increases from V1 to V4 under a constant throttle opening B5, the current shift position is the position 202a (vehicle speed). V1) or position 202c (vehicle speed V4) and outside the region 204, even if a malfunction such as a failure of the throttle opening sensor 178 occurs, the throttle opening signal is not transmitted to the controller 94 and the throttle opening becomes Even if it becomes 0%, the speed stage remains at the 3rd speed at the position 202a and remains at the 4th speed at the position 202c, and no speed change is performed.

  On the other hand, if the current shift position is the position 202b (vehicle speed V3) in the region 204, a trouble such as a failure of the throttle opening sensor 178 occurs and the throttle opening becomes 0%. Even though the appropriate speed stage is 3rd gear on the lower vehicle speed side, the vehicle is suddenly shifted up from 3rd gear to 4th gear, and the vehicle suddenly accelerates and stable running is difficult. It was. Therefore, the throttle opening is forcibly set so that the throttle opening does not become 0% even if a trouble such as a failure of the throttle opening sensor 178 occurs, so that sudden acceleration is prevented.

  In the throttle opening forced setting control, as shown in FIG. 13, the throttle opening is detected based on the throttle opening signal from the throttle opening sensor 178 (step S30). The throttle opening signal intensity and waveform are compared with normal data stored in the storage unit 94a of the controller 94 to determine whether or not a trouble such as a failure of the throttle opening sensor 178 has occurred (step). S31). If it is determined that the problem has not occurred (step S31, NO), the detected throttle opening, the vehicle speed detected from the output shaft rotational speed signal from the vehicle speed sensor 135, and the storage unit of the controller 94 Based on the shift point characteristic model 119 of FIG. 8 stored in 94a, the next speed stage is determined as described above (step S32), and the shift operation is performed according to the shift control process described above (step S33). .

  On the other hand, when it is determined that a problem has occurred by comparison with the normal data (step S31, YES), the throttle opening is forcibly set from 0% to 100% (step S34). For example, as shown in the up-shift line 199 of FIG. 14, when the current speed stage is 3rd and only the vehicle speed increases from V1 to V3 under a certain throttle opening B4, the current shift position is the position 199a (vehicle speed V1 ), The speed stage remains at 3rd speed regardless of whether the throttle opening is 0% or 100%, while the current shift position is position 199b (vehicle speed V2) and the throttle opening If 0 is forcibly set from 0% to 100%, the third speed is maintained without shifting up from the third speed to the fourth speed. Furthermore, if the current shift position is a position 199c (vehicle speed V3) in the region 201 and the throttle opening is forcibly set from 0% to 100%, the gear is shifted down from the fourth speed to the third speed. In addition, at the same time that the throttle opening is forcibly set to 100%, for the worker, as in the case of the engine speed estimation control described above, the trouble has occurred and the part where the trouble has occurred, for example, the trouble Whether the alarm is generated in the throttle opening sensor 178 itself or in the signal line from the throttle opening sensor 178 to the controller 94 by a warning sound by an acoustic device such as a buzzer or flashing light by an indicator light In addition, the operator can quickly respond to the malfunction.

  Then, after setting the throttle opening to 100%, the throttle opening set to 100% and the output shaft rotational speed signal from the vehicle speed sensor 135 are used as is, as in the case where it is determined that no trouble has occurred. The next speed stage is determined based on the detected vehicle speed and the shift point characteristic model 119 (step S32), and a shift operation is performed according to the shift control process (step S33).

  That is, when a malfunction related to the throttle opening sensor 178 is detected, the throttle opening is forcibly set to 100%, for example, so that the next speed stage is maintained at the current speed stage or shifts to the lower speed stage side. Therefore, the throttle opening sensor 178 malfunctions in an automatic shift that automatically shifts up or down and shifts to a predetermined forward speed step according to the throttle opening and the vehicle speed. Even if the signal line from the throttle opening sensor 178 to the controller 94 is broken, the vehicle is not shifted up at least suddenly, and the vehicle is prevented from sudden acceleration and stable running is performed. be able to.

  The set value of the throttle opening is not limited as long as it can maintain the next speed stage at the current speed stage by forcibly setting the throttle opening or shift to the low speed stage side. It is not limited to.

  In addition, it is also possible to create a shift point characteristic model using the accelerator opening instead of the throttle opening representing the running load, and to perform automatic shift control based on the accelerator opening and the vehicle speed. When a malfunction related to the accelerator opening sensor 134 is detected, the accelerator opening is forcibly set to 100%, for example.

  Next, a vehicle speed estimation control configuration in the event of a malfunction such as a failure of the vehicle speed sensor 135 during automatic shifting during traveling will be described with reference to FIGS. 6, 10, and 16. FIG.

  As described above, the automatic shift during traveling is performed when the current shift position determined from the current vehicle speed and the current throttle opening exceeds each diagram for starting the shift to each speed stage in the shift point characteristic model. However, if the vehicle speed sensor 135 shown in FIG. 6 for detecting the vehicle speed breaks down or a signal line from the vehicle speed sensor 135 to the controller 94 is broken, the controller 94 outputs the output shaft. The rotation speed signal is not transmitted, the vehicle speed suddenly becomes zero, the vehicle suddenly decelerates, and stable running is difficult. Therefore, even if a failure such as a failure of the vehicle speed sensor 135 occurs, vehicle speed estimation control is performed to estimate the vehicle speed from the engine speed, speed stage, and the like, thereby preventing sudden deceleration.

  In the vehicle speed estimation control, as shown in FIG. 16, the vehicle speed is detected based on the output shaft rotation speed signal from the vehicle speed sensor 135 (step S40). The output shaft rotational speed signal strength, waveform, and the like are compared with normal data stored in the storage unit 94a of the controller 94 to determine whether or not a malfunction such as a failure of the vehicle speed sensor 135 has occurred (step S41). ). If it is determined that the problem has not occurred (step S41, NO), the detected vehicle speed, the throttle opening detected from the throttle opening signal from the throttle opening sensor 178, and the controller 94 Based on the shift point characteristic model 119 stored in the storage unit 94a, the next speed stage is determined as described above (step S42), and a shift operation is performed according to the shift control process described above (step S43).

  On the other hand, when it is determined that a problem has occurred by comparison with the normal data (step S41, YES), the clutch engagement is determined from the clutch pressure obtained from the clutch pressure signal from the clutch pressure sensors 165 and 166 in FIG. The off state is detected, the current speed stage is detected from the immediately preceding shift command signal stored in the storage unit 94a of the controller 94, and the engine speed is detected from the engine speed signal from the engine speed sensor 176. At the same time, as in the case of the engine speed estimation control described above, for the worker, whether a problem has occurred and the part where the problem has occurred, for example, the problem has occurred in the vehicle speed sensor 135 itself, or the vehicle speed Whether or not it has occurred in the signal line from the sensor 135 to the controller 94 is notified by a warning sound from a sound device such as a buzzer or flashing light from an indicator lamp (step S44), enabling the operator to quickly respond to the malfunction. Yes. If the clutch is in the engaged state, the output shaft speed is obtained by dividing the engine speed by the reduction ratio obtained from the current speed stage, and the vehicle speed is estimated from the output shaft speed (step S45). .

  Thereafter, the estimated vehicle speed (hereinafter referred to as “estimated vehicle speed”) is regarded as the vehicle speed detected by the vehicle speed sensor 135, and the estimated vehicle speed The next speed stage is determined based on the throttle opening detected from the throttle opening signal from the throttle opening sensor 178 and the shift point characteristic model 119 (step S42), and the shift operation is performed according to the shift control process (step S42). Step S43).

  That is, when a malfunction related to the vehicle speed sensor 135 is detected, an estimation control configuration for estimating the vehicle speed based on the current speed stage and the engine speed is provided. Even when the vehicle speed sensor 135 breaks down or the signal line from the vehicle speed sensor 135 to the controller 94 is disconnected in the automatic shift that shifts down to a predetermined forward speed stage, at least suddenly Without being downshifted, it is possible to prevent the vehicle from suddenly decelerating and perform stable running.

  It is also possible to create a new shift point characteristic model using the accelerator opening instead of the throttle opening representing the driving load, and to perform automatic shift control based on the accelerator opening and the vehicle speed. When a malfunction related to the vehicle speed sensor 135 is detected, the current shift position in the newly created shift point characteristic model is determined from the estimated vehicle speed and the current accelerator opening.

  Next, a shift mode maintenance setting control configuration in the case where a malfunction such as a failure of the shift mode switch 175 occurs during automatic shift will be described with reference to FIGS. 6, 7, and 17.

  At the time of automatic shifting, as described above, by operating the switching operation tool 175a of the shifting mode switching tool 175, any one of the maximum speed stages of the work mode, the running mode, the automatic selection mode, and the manual mode is selected. Is selected, the controller 94 selects the optimum gear train for the detected throttle opening and vehicle speed in accordance with the shift point characteristic model of the selected shift mode so that the shift can be performed automatically.

  However, when a problem such as a failure of the transmission mode switching device 175 or a disconnection of a signal line from the transmission mode switching device 175 to the controller 94 occurs, the controller 94 receives the automatic mode signal or The maximum speed stage signal is not transmitted, or an automatic mode signal or a maximum speed stage signal different from the selected shift mode is transmitted, making it difficult for the operator to travel as intended. Therefore, even if a malfunction such as a malfunction of the transmission mode switching tool 175 occurs, the maintenance mode control of the transmission mode is performed so that it does not greatly change from the previous traveling state, and the vehicle is suddenly moved to an unexpected transmission mode. I try to prevent it.

  In the shift mode maintenance setting control, as shown in FIG. 6, in the storage unit 94a of the controller 94, the automatic mode signal and the maximum speed stage signal can be always overwritten and recorded as shift data (hereinafter, “ 94b "is provided, and the overwrite recording area 94b is overwritten from the oldest shift data so that recording can be continued.

  In such a configuration, as shown in FIG. 17, the automatic mode signal and the maximum speed stage signal from the transmission mode switch 175, the accelerator opening signal from the accelerator opening sensor 134, and the throttle opening from the throttle opening sensor 178. The degree signal, the engine speed signal from the engine speed sensor 176, and the output shaft speed signal from the vehicle speed sensor 135 are read into the controller 94, and the vehicle speed and the like are calculated by the controller 94 (step S1). .

  Then, the automatic mode signal and the maximum speed stage signal from the shift mode switch 175 are compared with normal data stored in the storage unit 94a of the controller 94, and a failure such as a failure of the shift mode switch 175 has occurred. Whether or not (step S50). If it is determined that the problem has not occurred (NO in step S50), each shift mode is determined based on the automatic mode signal and the maximum speed stage signal as is, after step S2 shown in FIG. (Steps S2 to S4), first speed stop start control in which the first speed, which is the lowest speed stage is selected as the stop start speed stage (Step S9), and second speed stop start control in which the second speed is selected as the stop start speed stage ( In step S5), any one of the manual control (step S6) for shifting the speed by the accelerator operation to the set maximum speed stage is performed.

  On the other hand, if it is determined that a problem has occurred by comparison with the normal data (step S50, YES), the previous shift data is read from the overwrite recording area 94b. At the same time, for the worker, as in the case of the engine speed estimation control described above, whether a problem has occurred and the part where the problem has occurred, for example, the problem has occurred in the shift mode switch 175 itself, or Whether or not the signal has occurred in the signal line from the speed change mode switch 175 to the controller 94 is notified by a warning sound from a sound device such as a buzzer or a blinking light by an indicator lamp (step S51). The correspondence is possible. Then, the content of the previous shift mode is confirmed based on the shift data, and the previous shift mode is set to be maintained as the next shift mode (step S52). After the next shift mode is set, one of the first speed stop start control, the second speed stop start control, and the manual control is performed in the same manner as when it is determined that no problem has occurred (step S1). S2-S9).

  That is, when a malfunction related to the shift mode switch 175 is detected, a maintenance setting control configuration for maintaining and setting the shift mode to the immediately preceding shift mode is provided. In the automatic shift that shifts down and shifts to a predetermined forward speed stage, problems such as a failure of the shift mode switch 175 and a disconnection of the signal line from the shift mode switch 175 to the controller 94 occur. Even in such a case, it is possible to perform stable running while preventing the vehicle from suddenly moving to an unexpected shift mode without changing significantly from the previous running state.

  In this embodiment, the previous shift data is used as the shift data read from the overwrite recording area 94b. However, the shift data suitable for the operator is read by reading a plurality of recorded shift data and performing statistical analysis or the like. A mode may be selected.

The present invention includes a first clutch for connecting / disconnecting power to a drive train group required for each odd speed stage, and a second clutch for connecting / disconnecting power to a drive train group required for each even speed stage, A control device capable of controlling the operation of the first clutch and the second clutch by a hydraulic clutch is provided, and the drive is performed by turning the first clutch and the second clutch on and off according to the throttle opening and the vehicle speed. A group of trains is automatically selected, the power from the engine is shifted and transmitted to the axle, and one of the first clutch and the second clutch is selected when the speed stage is switched between the odd speed stage and the even speed stage. The present invention can be applied to all dual clutch transmissions in which the separating operation and the other joining operation are temporally overlapped.

1 is a skeleton diagram showing an overall configuration of a work vehicle according to the present invention. It is a skeleton figure which shows the power transmission structure of a rear-axle drive device. It is a hydraulic circuit diagram of a work vehicle. It is explanatory drawing which shows the on / off of the travel transmission clutch and the position of a shifter in each speed stage. It is a time chart figure which shows a shift control process. It is a block diagram regarding the shift control of the dual clutch transmission. It is a flowchart figure which shows transmission control. It is a shift point characteristic model figure applied to 1st-speed stop start control. It is a shift point characteristic model figure applied to 2nd speed stop start control. It is a block diagram which shows a part of shift control system for engine speed estimation control. It is a flowchart figure which shows the estimation control of an engine speed. It is a time chart figure of the clutch pressure at the time of vehicle starting based on engine speed and throttle opening information. It is a flowchart figure which shows the forced setting control of a throttle opening. FIG. 6 is a shift point characteristic model diagram showing a shift state when a throttle opening is forcibly set when a failure occurs. It is a shift point characteristic model diagram showing a normal shift situation at the time of occurrence of a malfunction. It is a flowchart figure which shows the estimation control of a vehicle speed. It is a flowchart figure which shows the maintenance setting control of transmission mode.

2 Dual clutch transmission 9 Engine 11 Output shaft 50/65 Axle 79/80 Hydraulic clutch 94 Control device 176 Engine speed sensor
C1 1st clutch C2 2nd clutch

Claims (3)

A first clutch (C1) for connecting / disconnecting power to the drive train group required for each odd speed stage and a second clutch (C2) for connecting / disconnecting power to the drive train group required for each even speed stage A control device (94) capable of controlling the operation of the first clutch (C1) and the second clutch (C2) by a hydraulic clutch (79, 80), and the control device (94) (C1) · The drive train group is automatically selected by turning on and off the second clutch (C2), the power from the engine (9) is shifted and transmitted to the axle (50, 65), and the odd speed stage A dual clutch type that temporally overlaps one separating operation and the other joining operation of the first clutch (C1) and the second clutch (C2) at the time of speed stage switching between even speed stages. In the transmission (2), the engine (9) An engine rotation speed sensor (176) for detecting the rotation speed of the output shaft as the engine rotation speed and an engine rotation speed setting means for setting the engine rotation speed are provided, and the engine rotation speed is set by the engine (9) when starting the vehicle. The clutch pressure that increases the clutch pressure of the clutch at the start speed stage of the first clutch (C1) and the second clutch (C2) by operating the hydraulic clutch (79, 80) in response to the increase in the number. with a control arrangement, wherein when the engine rotational speed sensor (176) associated fault detection, based on the set amount by the engine rotational speed setting means comprises an estimation control arrangement for estimating the engine speed, the estimation control arrangement The operation amount of the engine speed setting means and the engine speed stored in the storage unit (94a) of the control device (94), Based on the model, the estimated engine speed is estimated. The engine speed sensor (176) is broken or the signal line from the engine speed sensor (176) to the control device (94) is disconnected. In such a case, the engine speed is estimated by the estimation control configuration, and the clutch pressures of the first clutch (C1) and the second clutch (C2) are increased or decreased corresponding to the output torque from the engine (9). A dual clutch type transmission apparatus characterized by performing control . 2. The dual clutch transmission according to claim 1, wherein the engine speed setting means is a throttle valve provided in an intake system of the engine (9), and an operation amount of the throttle valve is determined by a throttle opening sensor (178). If it is detected and it is determined that a malfunction such as a failure of the engine speed sensor (176) has occurred, the throttle opening is determined based on the throttle opening signal detected by the throttle opening sensor (178). The estimated engine speed is estimated based on the detected throttle opening and a relational model between the throttle opening and the engine speed stored in the storage unit (94a) of the control device (94). A dual clutch transmission having the set amount . 2. The dual clutch transmission according to claim 1, wherein the engine speed setting means is an accelerator operating tool, an operation amount of the accelerator operating tool is detected by an accelerator opening sensor (134), and the engine speed sensor ( 176), when it is determined that a malfunction such as a failure has occurred, the accelerator opening is detected based on the accelerator opening signal detected by the accelerator opening sensor (134), and the accelerator opening; The estimated engine speed is estimated based on the relationship model between the accelerator opening and the engine speed stored in the storage unit (94a) of the control device (94), and the set amount is used. Dual clutch transmission.

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