JP2009138820A - Shift controller of variable displacement pump motor type transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten time required for a sudden shift by a variable displacement hydraulic pump motor type transmission. <P>SOLUTION: Torque applied to any switching mechanism engaged before the sudden shift is reduced (Step S2). Any switching mechanism is switched to a power untransmitted state in its state (Step S4). The reduced torque is increased thereafter (Step S8). A rotating speed of mutual rotary members connected by the switching mechanism engaged so as to set the gear ratio after the sudden shift is synchronized (Step S5 and S6) when reducing the torque and/or increasing the torque by a return means. The switching mechanism is operated in an engaging state when synchronization (Step S10) is determined. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes at least two power transmission paths capable of changing the power transmission state in accordance with the extrusion volume of the variable displacement pump motor, and appropriately sets the extrusion volume to the maximum and minimum values and intermediate values thereof. The present invention relates to a device for controlling the shift of a variable displacement pump motor type transmission capable of setting a gear ratio.

  This type of transmission is described in Patent Document 1. In brief, the variable displacement pump motor is connected to the reaction force element in each of the pair of planetary gear mechanisms, and the discharge ports and the suction ports of each variable displacement pump motor are connected to each other and closed. A circuit is formed. Moreover, the power output from a power source such as an engine is input to the input element in each planetary gear mechanism. Furthermore, on the intermediate shaft integral with the output element of each planetary gear mechanism, a drive gear for setting a so-called fixed gear stage or fixed gear ratio is arranged, and the driven gear meshing with each drive gear is connected to the output shaft. Is placed on top. A synchronous coupling mechanism (so-called synchro) is provided as a switching mechanism for switching each gear pair composed of the drive gear and the driven gear between a state where torque can be transmitted and a state where torque is not transmitted.

  Therefore, if one of the variable displacement pump motors is locked and the reaction force element is fixed, the power output from the power source is transmitted to one intermediate shaft through the planetary gear mechanism having the reaction force element. In addition, power is transmitted to the output shaft through a gear pair connected to the intermediate shaft by synchronization. In this case, the gear ratio is a gear ratio according to the gear ratio of the gear pair involved in power transmission.

  The lock of the variable displacement pump motor in this case is set by making the extrusion volume of the other variable displacement pump motor zero, that is, minimize. That is, since each pump motor is communicated by a closed circuit, if the extrusion volume of the other pump motor is made zero, the flow of pressure fluid will not occur, so the extrusion volume of one pump motor is maximized, etc. By making the extrusion volume greater than zero, one of the pump motors is locked and its rotation is prevented.

  In addition, the displacement volume of each variable displacement pump motor is set to be larger than zero, and a predetermined gear pair is set in a state where torque can be transmitted by synchronization on one variable displacement pump motor side, and the other variable displacement pump motor side When the other gear pairs are in a state in which torque transmission is possible by this synchronization, a gear ratio of an intermediate value of the gear ratio determined according to the gear ratio of each gear pair is set. That is, one variable displacement pump motor generates pressure fluid, which is supplied to the other variable displacement pump motor, which operates as a motor, and that power is transmitted to the output shaft through the other gear pair. . As a result, power that is a combination of the power transmitted through such a fluid and the power mechanically transmitted through one variable displacement pump motor appears on the output shaft. The power through the fluid can be changed continuously by continuously changing the extrusion volume of each variable displacement pump motor, so that the transmission gear ratio as a whole is continuously changed. In other words, it can be set steplessly.

  In addition, the vehicle is configured to drive a hydraulic pump by the engine, supply the hydraulic oil generated by the hydraulic pump to the hydraulic motor, drive the hydraulic motor, and transmit the power output from the hydraulic motor to the wheels. A step transmission is described in Patent Document 2. In the transmission described in Patent Document 2, a hydraulic pump and a hydraulic motor are communicated with each other by a closed hydraulic circuit, and a high pressure oil path having a relatively high pressure and a relatively low pressure in the closed hydraulic circuit. A clutch valve is interposed between the low pressure oil passage and the power transmission capacity between the hydraulic pump and the hydraulic motor is controlled according to the opening of the clutch valve.

JP 2007-64269 A Japanese Patent No. 2788569

  In the transmission described in the above-mentioned Patent Document 1, when changing a gear ratio in accordance with the gear ratio of any one of the gear pairs, that is, when changing the speed beyond a fixed gear stage (fixed gear ratio), the synchro is switched. Thus, the gear pair involved in power transmission is changed. More specifically, while maintaining the sync on the one intermediate shaft side in a so-called engaged state, the sync on the other intermediate shaft side is moved to the neutral position and moved to the other gear pair side, depending on the gear. It switches to what is called an engagement state which transmits motive power. In the process of switching, a fixed shift stage is set once, and the sync that is not involved in torque transmission in that state is switched. That is, the synchro connected to the variable displacement pump motor with zero extrusion volume is switched. Then, when the synchro switching operation is completed, the extrusion volume of the variable displacement pump motor whose extrusion volume has become zero is controlled based on the target gear ratio.

  That is, when shifting beyond the fixed gear, the synchro switching operation is accompanied as described above, and the gear ratio is fixed at the fixed gear until the sync switching is completed. It will be in the state which does not shift. Therefore, as described above, the shift with the sync change operation, that is, the shift across the fixed shift step, is the continuous shift without the sync change operation, i.e., the change in the gear ratio at the fixed shift step. The shift time becomes longer compared to a continuously variable shift between fixed shift stages. For this reason, there is a possibility that the required shift speed may not be achieved, especially in the case of a sudden shift that requires a rapid change in the gear ratio, such as a downshift or an upshift that is executed at the time of sudden start or acceleration. there were. In addition, there is a difference in the shift feeling due to the change in the shift speed between the continuously variable shift between the fixed shift stages and the shift across the fixed shift stages. As a result, the driver feels uncomfortable. There was a possibility.

  In addition, when the synchro is engaged, the displacement volume of the variable displacement pump motor is set to zero, and the torque hardly acts on the synchro. Since it is different before and after, the difference in rotational speed is absorbed by the synchro. For this reason, the time until the synchro is completely engaged becomes longer, the amount of energy absorbed to synchronize the rotation speed of these rotating members and the load applied to the synchro are large, the synchro is enlarged, or the capacity is increased. Needed to be.

  The present invention has been made paying attention to the technical problem described above, and in a transmission using a variable displacement pump motor, even if the shift is across a fixed shift stage with a switching operation of the switching mechanism, It is an object of the present invention to provide a speed change control device that enables a quick speed change by shortening the time and enables a smooth speed change without a sense of incongruity.

  In order to achieve the above object, the invention of claim 1 is directed to at least two power transmission paths capable of selectively setting a plurality of different gear ratios between a power source and an output member, Provided for each power transmission path so that the torque transmitted through the transmission path is changed according to the extrusion volume, and when one of the extrusion volumes is zero, the other is prevented from supplying and discharging the pressure fluid. A variable displacement pump motor in which the discharge ports and the suction ports communicate with each other so that they are locked, and when one of the variable displacement pump motors is locked, power from the power source is output to the output member. A first transmission mechanism that transmits power to the output member, a second transmission mechanism that transmits power from the power source to the output member when the other variable displacement pump motor is locked, and each transmission mechanism selected And a switching mechanism that enables power transmission to a fixed transmission stage determined by a gear ratio of each of the transmission mechanisms, and power transmitted between the variable displacement pump motors via pressure fluid In a transmission control device for a variable displacement pump motor type transmission configured to be capable of setting a continuously variable transmission state by continuously changing the transmission ratio, the transmission ratio is changed via the fixed transmission stage. A sudden shift determining means for determining a sudden shift state to be rapidly changed; a torque releasing means for reducing a torque applied to any of the switching mechanisms engaged before the sudden shift; and the torque is reduced. The release means for switching any one of the switching mechanisms to a state in which power is not transmitted in the state, and the torque release means after the switching mechanism is switched to a state in which any one of the switching mechanisms is not transmitted power. And a gear ratio after the sudden shift when the torque is reduced by the torque release means and / or when the torque is increased by the torque return means. Synchronization that controls at least one of the rotational speed of the power source and the extrusion volume of the variable displacement pump motor so as to synchronize the rotational speed of the rotating members coupled by the switching mechanism that is engaged so as to set Control means, synchronization determination means for determining the synchronization of the rotation speeds of the rotating members, and operation of the switching mechanism in the engaged state when the synchronization determination means determines that the rotation speeds of the rotating members are synchronized. And an engagement instruction means.

  According to a second aspect of the present invention, in the first aspect of the invention, when the synchronization of the rotational speeds of the rotating members by the synchronization determination unit is not determined for a predetermined time, the shift after the sudden shift is performed. Another torque release means for reducing the torque applied to the switching mechanism to be engaged so as to set the ratio, and the speed ratio after the sudden shift is set in a state where the torque is reduced by the other torque release means The shift control device for the variable displacement pump motor type transmission further includes another engagement instruction means for operating the switching mechanism to be engaged in the engaged state.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, at least one of the torque releasing means and the other torque releasing means is the flow path in which the variable displacement pump motors communicate with each other. A shift control device for a variable displacement pump motor type transmission comprising a discharge valve that discharges pressure from a high-pressure flow path that becomes a high pressure during sudden shift to reduce fluid pressure in each variable displacement pump motor. is there.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the exhaust pressure valve includes a relief valve that communicates with the high pressure oil passage and sets an upper limit pressure of the high pressure oil passage. It is a transmission control device of a motor type transmission.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, when the switching mechanism is switched from the released state to the engaged state, the torque capacity gradually increases, and rotation between the connected rotating members is performed. A shift control device for a variable displacement pump motor type transmission, comprising an engagement mechanism having a synchronization function for gradually synchronizing the number.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the synchronization control means determines the rotation speed of the power source and the displacement volume of the variable displacement pump motor at a speed ratio after shifting. A speed change control device for a variable displacement pump motor type transmission comprising means for controlling the determined rotation speed and extrusion volume.

  According to the first aspect of the present invention, in the case of a sudden shift in which the gear ratio is changed across the fixed gear, the torque is applied to the switching mechanism engaged with the gear ratio before the sudden shift. More specifically, control is performed so that no torque is applied. In this state, the switching mechanism is switched to a release state where no power is transmitted. Therefore, the switching mechanism can be a so-called meshing type. Thereafter, the reduced torque is increased. Therefore, torque is applied to the rotating members connected by the switching mechanism, and the number of rotations increases. At the same time, the rotational speed of the power source and the variable capacity type are synchronized so as to synchronize the rotational speeds of the rotating members connected by the switching mechanism that is engaged so as to set the speed ratio after the sudden speed change. At least one of the extrusion volume of the pump motor is controlled. When the synchronization is determined, the switching mechanism in the released state is operated to the engaged state. Therefore, when the switching mechanism is engaged to achieve the gear ratio after the shift, since the power output from the power source is actively synchronized, the time required until the switching mechanism is engaged is shortened. Even in the case of a sudden shift, a delay in the shift can be prevented or suppressed. In addition, since the synchronization of the rotational speeds of the rotating members connected by the switching mechanism is achieved by the power output from the power source regardless of the switching mechanism, the load on the switching mechanism can be reduced, and the size or capacity can be reduced. Can be achieved.

  According to the invention of claim 2, if the synchronization is not achieved within a predetermined time even by the increase of the reduced torque and the control of the rotational speed of the power source or the extrusion volume of the variable displacement pump motor, the engagement is performed. The torque applied to the switching mechanism to be reduced is reduced, and in that state, the switching mechanism is engaged. Therefore, the switching mechanism can be easily engaged, the load applied to the switching mechanism can be reduced, and the shift delay caused by the synchronization delay can be avoided or suppressed.

  According to the invention of claim 3 or claim 4, the torque applied to the switching mechanism can be reduced by exhausting the pressure from the high-pressure channel among the channels communicating with the variable displacement pump motors. Therefore, torque reduction control is facilitated. In particular, according to the invention of claim 4, torque reduction control can be performed using a relief valve normally used in a fluid pressure circuit. Can be prevented or suppressed to simplify or downsize the overall configuration of the apparatus.

  According to the invention of claim 5, when operating the switching mechanism in the engaged state, the rotational speeds of the rotating members coupled to each other are synchronized by the synchronization function of the switching mechanism. Therefore, the switching mechanism is smoothly switched to the engaged state, and even if the synchronous control is performed by controlling the rotational speed of the power source or the extrusion volume of the variable displacement pump motor, the rotational speeds of the rotating members are completely synchronized. Since the switching mechanism can be operated to the engaged state before the shift, a quick shift can be performed. In addition, since synchronous control is performed by controlling the rotational speed of the power source and the extrusion volume of the variable displacement pump motor, the load on the switching mechanism can be reduced.

  According to the sixth aspect of the present invention, since the rotational speed of the power source and the extrusion volume of the variable displacement pump motor are controlled to the rotational speed and the extrusion volume after shifting, the power source is at the time when the switching mechanism is engaged. , Or the displacement volume of the variable displacement pump motor is the rotation speed or displacement volume after shifting, and therefore no special control is required to complete shifting. Can be improved.

  Next, the present invention will be described based on specific examples. First, the variable displacement pump motor type transmission that is the subject of the present invention will be described. The variable displacement pump motor type transmission that is the subject of the present invention includes at least two power transmission paths. A transmission that is configured to be able to transmit torque from the power source to the output member via the power transmission path, and as a result, can change the speed ratio that is the ratio of the rotational speed of the power source and the output member continuously. Machine.

  More specifically, each power transmission path includes a variable displacement pump motor that functions as a pump and a motor, and is configured to transmit torque according to the extrusion volume. The mold pump motors communicate with each other so as to exchange pressure fluid with each other. Accordingly, when one of the variable displacement pump motors functions as a pump, torque corresponding to the extrusion volume is transmitted from the power source to the output member, and at the same time, from one variable displacement pump motor to the other variable displacement pump. Pressure fluid is supplied to the motor, and the other variable displacement pump motor functions as a motor. That is, power transmission via the pressure fluid is performed in parallel, and the torque is transmitted to the output member via the other power transmission path. As a result, the torque transmitted to the output member is the sum of the torque transmitted through each power transmission path, and the torque transmitted through the pressure fluid changes according to each extrusion volume. Eventually, the gear ratio changes continuously.

  Each power transmission path can be provided with a transmission mechanism such as a gear pair or a winding transmission device having different gear ratios, and when transmitting torque to the output member only through one power transmission path, The speed ratio of the entire machine is determined by the speed ratio of the transmission mechanism in the power transmission path. If such a gear ratio is referred to as a fixed gear, power transmission via pressure fluid does not occur in a state where the fixed gear is set, so power loss is unlikely to occur and power transmission efficiency is good. It becomes a transmission state. Note that a switching mechanism such as a clutch mechanism is preferably included in each transmission mechanism so that only one of the transmission mechanisms is involved in torque transmission, or between the power source or output member and the transmission mechanism. It is preferable to provide a switching mechanism.

  Since the variable displacement pump motor type transmission targeted in this invention is configured to transmit power via pressure fluid, the function of setting the gear ratio by mechanical power transmission as described above is provided. It is preferably configured as a combined hydrostatic mechanical transmission (HMT). The mechanical transmission portion can be appropriately configured as necessary, and a mechanism configured to select a gear pair that is always meshed by a clutch mechanism or a synchronous coupling mechanism, or a plurality of planetary gear mechanisms or compound planetary gears. A configuration in which a plurality of gear ratios can be set by a mechanism can be employed. Further, the variable displacement pump motor may be configured to use a variable displacement pump motor as the reaction force means in addition to the configuration in which the variable displacement pump motor is interposed in series between the power source and the output member.

  Next, the configuration of the variable displacement pump motor type transmission targeted by the present invention will be described based on a specific example. The example shown in FIG. 6 is an example configured as a transmission TM for a vehicle, and uses a differential mechanism as a power distribution mechanism and a plurality of gear pairs as a transmission mechanism. Accordingly, the variable displacement pump motor is an example of a reaction force mechanism, and four forward speeds and one reverse speed are set as so-called fixed shift speeds that can be set by transmitting torque without passing through a fluid. This is an example of the configuration. That is, in FIG. 6, the input member 2 is connected to the power source (E / G) 1, and the torque is transmitted from the input member 2 to the first planetary gear mechanism 3 and the second planetary gear mechanism 4. Has been.

  The power source 1 may be a general power source used in a vehicle such as an internal combustion engine, an electric motor, or a combination of these. In the following description, an example in which an engine 1 such as a gasoline engine, a diesel engine, or an LPG engine is used as the power source 1 will be described. Moreover, you may interpose suitable transmission means, such as a damper, a clutch, and a torque converter, between this engine 1 and the input member 2.

  The first planetary gear mechanism 3 is disposed on the same axis as the input member 2, and the second planetary gear mechanism 4 is separated outward in the radial direction of the first planetary gear mechanism 3, and the respective central axes are parallel to each other. Are arranged in parallel. These planetary gear mechanisms 3 and 4 can use planetary gear mechanisms of an appropriate type such as a single pinion type and a double pinion type. The example shown in FIG. 6 is an example constituted by a single pinion type planetary gear mechanism, and is a sun gear 3S, 4S which is an external gear, and a ring gear 3R which is an internal gear arranged concentrically with the sun gear 3S, 4S. , 4R and carriers 3C, 4C holding pinion gears meshed with these sun gears 3S, 4S and ring gears 3R, 4R so as to be rotatable and revolved. The input member 2 is connected to the ring gear 3R in the first planetary gear mechanism 3, and the ring gear 3R serves as an input element.

  A counter drive gear 5 is attached to the input member 2. An idle gear 6 is engaged with the counter drive gear 5, and a counter driven gear 7 is engaged with the idle gear 6. The counter driven gear 7 is arranged on the same axis as the second planetary gear mechanism 4 and is connected to the ring gear 4R of the second planetary gear mechanism 4 so as to rotate together. Therefore, in the second planetary gear mechanism 4, the ring gear 4R serves as an input element. The ring gears 3R and 4R, which are input elements of the planetary gear mechanisms 3 and 4, are configured so that the counter gear pair includes the idle gear 6, and thus rotate in the same direction.

  The carrier 3C in the first planetary gear mechanism 3 serves as an output element, and the first intermediate shaft 8 is connected to the carrier 3C so as to rotate integrally. The first intermediate shaft 8 is a hollow shaft into which a motor shaft 9 is rotatably inserted. One end of the motor shaft 9 is a sun gear that is a reaction force element in the first planetary gear mechanism 3. It is connected to 3S so as to rotate together.

  The second planetary gear mechanism 4 has the same configuration, and the carrier 4C serves as an output element, and the second intermediate shaft 10 is connected to the carrier 4C so as to rotate together. The second intermediate shaft 10 is a hollow shaft into which a motor shaft 11 is rotatably inserted. One end of the motor shaft 11 is a sun gear that is a reaction force element in the second planetary gear mechanism 4. 4S is connected to rotate integrally.

  The other end of the motor shaft 9 is connected to the output shaft of the variable displacement pump motor 12. The variable displacement pump motor 12 is a fluid pressure (hydraulic) pump capable of changing a discharge capacity, that is, an extrusion volume, such as a slant shaft pump, a swash plate pump, or a radial piston pump, and rotates by giving torque to its output shaft. Thus, the pressure fluid (pressure oil) is discharged by functioning as a pump, and the pressure fluid is supplied from the discharge port or the suction port, thereby functioning as a motor. In the following description, the variable displacement pump motor 12 is referred to as a first pump motor 12 and is represented as PM1 in the drawing.

  The other end of the motor shaft 11 is connected to the output shaft of the variable displacement pump motor 13. The variable displacement pump motor 13 has the same configuration as the first pump motor 12 on the motor shaft 9 side, and therefore the discharge capacity, that is, the extrusion volume, of the inclined shaft pump, the swash plate pump, the radial piston pump, or the like can be changed. A simple fluid pressure (hydraulic) pump can be employed. In the following description, the variable displacement pump motor 13 is referred to as a second pump motor 13 and is indicated as PM2 in the figure.

  The pump motors 12 and 13 are communicated with each other by oil passages 14 and 15 so that the pressure oil, which is a pressure fluid, can be transferred to each other. That is, the respective suction ports (suction ports) 12S and 13S are communicated with each other by an oil passage 14 corresponding to the high-pressure channel of the present invention, and the discharge ports (discharge ports) 12D and 13D are relatively low in pressure. Are connected by an oil passage 15. Accordingly, a closed circuit is formed by the oil passages 14 and 15. A mechanism for controlling the hydraulic pressure in the closed circuit will be described later.

  An output shaft 16 corresponding to the output member of the present invention is arranged in parallel with each of the intermediate shafts 8 and 10 described above. A transmission mechanism for setting a predetermined gear ratio is provided between the output shaft 16 and each of the intermediate shafts 8 and 10. The transmission mechanism is not limited to a mechanism that transmits power at a fixed rotation speed ratio (transmission ratio), and a mechanism with a variable transmission ratio can be employed. In the example shown in FIG. A plurality of gear pairs 17, 18, 19, and 20 that transmit power in a ratio are employed.

  Specifically, the first intermediate shaft 8 includes, in order from the first planetary gear mechanism 3 side, a fourth speed drive gear 17A of the fourth speed gear pair 17 corresponding to the first transmission mechanism of the present invention, and The second-speed drive gear 18A of the second-speed gear pair 18 is arranged, and the fourth-speed drive gear 17A and the second-speed drive gear 18A are rotatably fitted to the first intermediate shaft 8. Have been combined. The fourth speed driven gear 17B of the fourth speed gear pair 17 meshed with the fourth speed drive gear 17A and the second speed driven gear of the second speed gear pair 18 meshed with the second speed drive gear 18A. 18B is attached to the output shaft 16 so as to rotate integrally therewith.

  On the other hand, the second intermediate shaft 10 also includes, in order from the second planetary gear mechanism 4 side, the third speed drive gear 19A of the third speed gear pair 19 corresponding to the second transmission mechanism of the present invention, and the first speed. A first speed drive gear 20 </ b> A of the working gear pair 20 is disposed. The third speed drive gear 19A meshes with the fourth speed driven gear 17B, and the first speed drive gear 20A meshes with the second speed driven gear 18B. The third speed drive gear 19 </ b> A and the first speed drive gear 20 </ b> A are rotatably fitted to the second intermediate shaft 10. Accordingly, the fourth speed driven gear 17B also serves as the third speed driven gear 19B of the third speed gear pair 19, and the second speed driven gear 18B is the first speed driven gear 20B of the first speed gear pair 20. Doubles as Here, the rotational speed ratio or gear ratio of each gear pair 17, 18, 19, 20 (ratio of the number of teeth of the driven gear to the number of teeth of each drive gear) will be described. The gear pair 20 for the second gear, the gear pair 18 for the second speed, the gear pair 19 for the third speed, and the gear pair 17 for the fourth speed are configured to become smaller in order.

  Furthermore, a starting gear pair 21 is provided. The starting gear pair 21 is for transmitting the power to the output shaft 16 together with the first speed gear pair 20 so as to increase the driving force at the time of starting sufficiently and sufficiently. A starting drive gear 21A attached to the motor shaft 9 on the motor 12 side and a starting driven gear 21B attached to the output shaft 16 so as to be rotatable are provided.

  A mechanism for allowing each of the gear pairs 17, 18, 19, 20, and 21 described above to selectively transmit torque between any of the intermediate shafts 8 and 10 and the output shaft 16, that is, according to the present invention. A clutch mechanism corresponding to the switching mechanism is provided. In short, this clutch mechanism is a mechanism for selectively transmitting torque, and in addition to the conventionally known friction clutch, a mechanism such as a dog clutch mechanism or a synchronous coupling mechanism (synchronizer) can be adopted. FIG. 6 shows an example in which a synchronizer is employed.

  The synchronizer basically has a sleeve that rotates together with a rotating shaft, a spline provided on another rotating member that rotates relative to the rotating shaft, and is moved by the sleeve toward the other rotating member. And synchronizer ring. Then, in the process of moving the sleeve to the spline side of the other rotating member, the synchronizer ring gradually makes frictional contact with the rotating member to synchronize the rotating shaft and the rotating member, and in that state the sleeve engages with the spline. Thus, the rotating shaft and the rotating member are connected to each other. On the output shaft 16, a first synchronizer (hereinafter referred to as a first synchronizer) 22 is provided at a position adjacent to the starter driven gear 21 </ b> B. The first sync 22 moves its sleeve to the left side in FIG. 6 to connect the starter driven gear 21B to the output shaft 16, and the starter gear pair 21 torques between the motor shaft 9 and the output shaft 16. Is configured to communicate.

  On the second intermediate shaft 10, a second synchronizer (hereinafter referred to as a second synchronizer) 23 is provided between the third speed drive gear 19 </ b> A and the first speed drive gear 20 </ b> A. The second synchro 23 connects the first speed drive gear 20A to the second intermediate shaft 10 by moving the sleeve to the left side in FIG. 6, and the first speed gear pair 20 is connected to the second intermediate shaft 10. And the output shaft 16 are configured to transmit torque. On the other hand, by moving the sleeve to the right in FIG. 6, the third speed drive gear 19A is connected to the second intermediate shaft 10, and the third speed gear pair 19 is connected to the second intermediate shaft 10 and the output shaft. 16 is configured to transmit torque.

  Further, on the first intermediate shaft 8, a third synchronizer (hereinafter referred to as a third synchronizer) 24 is provided between the second speed drive gear 18A and the fourth speed drive gear 17A. The third synchronizer 24 moves the sleeve to the left side in FIG. 6 to connect the second speed drive gear 18A to the first intermediate shaft 8, and the second speed gear pair 18 is connected to the first intermediate shaft 8. Torque is transmitted to and from the output shaft 16. On the other hand, the fourth speed drive gear 17A is connected to the first intermediate shaft 8 by moving the sleeve to the right in FIG. 6, and the fourth speed gear pair 17 is connected to the first intermediate shaft 8 and the output shaft 16. Torque is transmitted between the two.

  Furthermore, a reverse synchronizer (hereinafter referred to as “R synchro”) 25 is provided on the motor shaft 11 on the second pump motor 13 side at a position adjacent to the shaft end of the second intermediate shaft 10. The R synchro 25 connects the two rotating elements of the motor shaft 11 and the second intermediate shaft 10, that is, the sun gear 4S and the carrier 4C in the second planetary gear mechanism 4, by moving the sleeve to the right in FIG. The entire second planetary gear mechanism 4 is integrally rotated.

  Each of the synchros 22, 23, 24, and 25 can be configured to be switched by manual operation, but can be configured to perform so-called automatic control instead. When configured for automatic control, for example, an appropriate actuator (not shown) for moving the sleeve described above in the axial direction may be provided, and the actuator may be electrically controlled.

  As described above, in the variable displacement pump motor type transmission TM shown in FIG. 6, the torque output from the engine 1 is transmitted to the output shaft 16 via any one of the intermediate shafts 8 and 10 or the motor shafts 9 and 11. It is comprised so that. That is, a power transmission path from the engine 1 via the first intermediate shaft 8 or the motor shaft 9 to the output shaft 16 and a power transmission from the engine 1 via the second intermediate shaft 10 or the motor shaft 11 to the output shaft 16. Two power transmission paths that can selectively set a plurality of different transmission ratios between the engine 1 and the output shaft 16 by switching operations of the synchros 22, 23, 24, and 25 are configured. Has been. A differential 27 is connected to the output shaft 16 through a transmission means 26 such as a gear mechanism or a winding transmission device such as a chain, from which power is output to the left and right axles 28.

  Further, a sensor for detecting the operating state of the transmission TM is provided. Specifically, the input rotational speed sensor 29 for detecting the rotational speed of the input member 2 or the counter drive gear 5 integrated therewith, the output rotational speed sensor 30 for detecting the rotational speed of the axle 28, and the first pump motor 12. A rotation speed sensor 31 for detecting the rotation speed of the second pump motor 13 and the rotation speed sensor 32 for detecting the rotation speed of the second pump motor 13 are provided.

  Next, a fluid pressure circuit (hydraulic circuit) for controlling the pump motors 12 and 13 will be described. A charge pump (sometimes referred to as a boost pump) 33 for replenishing fluid (specifically oil) is provided in the closed circuits 14 and 15 communicating with the pump motors 12 and 13. ing. The charge pump 33 is used to compensate for the shortage of oil due to leakage from the closed circuit, and is driven by the engine 1 or a motor (not shown) described above to draw oil from the oil pan 34 and close it. The circuit is supplied.

  The discharge port of the charge pump 33 communicates with the oil passage 14 and the oil passage 15 in the closed circuit via check valves 35 and 36, respectively. In addition, these check valves 35 and 36 are comprised so that it may open in the discharge direction from the charge pump 33, and may close in the opposite direction. Further, a relief valve 37 for adjusting the discharge pressure of the charge pump 33 is provided in communication with the discharge port of the charge pump 33. The relief valve 37 is configured to open and discharge oil to the oil pan 34 when a pressure higher than the sum of the elastic force of the spring and the pressure of the pilot pressure or the solenoid is applied. The discharge pressure is set to a pressure corresponding to the pilot pressure.

  Further, a first relief valve 38 is provided between the suction port 12 </ b> S of the first pump motor 12 and the oil passage 15. That is, a first relief valve 38 is provided in parallel with the first pump motor 12 so as to communicate the oil passages 14 and 15. The first relief valve 38 maintains the discharge pressure at a preset pressure when pressure oil is discharged from the suction port 12S of the first pump motor 12 or the suction port 13S of the second pump motor 13. It is configured. In other words, the first relief valve 38 is configured to open and exhaust when the pressure in the oil passage 14 is higher than a preset pressure.

  A second relief valve 39 is provided between the discharge port 13 </ b> D of the second pump motor 13 and the oil passage 14. That is, a second relief valve 39 is provided in parallel with the second pump motor 13 so as to communicate the oil passages 14 and 15. The second relief valve 39 maintains the discharge pressure at a preset pressure when the pressure oil is discharged from the discharge port 13D of the second pump motor 13 or the discharge port 12D of the first pump motor 12. It is configured. In other words, the second relief valve 39 is configured to open and exhaust when the pressure in the oil passage 15 is higher than a preset pressure.

  Each of the relief valves 38 and 39 can adjust the set pressure (that is, the relief pressure) to a predetermined pressure including zero, and reduce the transmission torque acting on each of the power transmission paths (torque). In other words, it is possible to include zero. That is, the first relief valve 38 and the second relief valve 39 are relief valves that function as the exhaust pressure valve of the present invention.

  Therefore, by reducing the relief pressure of any relief valve 38 (or 39) to zero, the oil pressure of the oil passage 14 (or 15) on the side where the relief valve 38 (or 39) is provided is made zero. The pump motor 12 (or 13) can be brought into a free state, that is, a neutral state. In other words, by controlling the relief valve 38 (or 39) to make the relief pressure zero, even if any of the pump motors 12 and 13 functions as a pump, no reaction force appears on the drive shaft. Power is not transmitted to the pump motors 13 and 12 that function as motors, and therefore, no torque appears on the output shafts of the pump motors 13 and 12 that function as motors.

  The pumping capacity of each pump motor 12, 13 and the switching operation of each synchro 22, 23, 24, 25 or the relief pressure of each relief valve 38, 39 can be electrically controlled. An electronic control unit (ECU) 40 is provided. The electronic control unit 40 is configured mainly with a microcomputer, and receives detection signals such as the number of rotations of a predetermined rotating member and the stroke of an operating member, and stores those input signals and prestores them. The calculation is performed based on the information and the program, and the command signal is output according to the calculation result.

  Next, the operation of the transmission TM described above will be described. FIG. 7 is a chart collectively showing the operation states of the pump motors (PM1, PM2) 12, 13 and the synchros 22, 23, 24, 25 when setting the respective gear positions. “OFF” for each of the pump motors 12 and 13 makes the pump capacity substantially zero, does not generate pressure oil even if the output shaft is rotated, and the output shaft is not supplied even if hydraulic pressure is supplied. A state where the rotor does not rotate (free) is indicated, and “LOCK” indicates a state where the rotation of the rotor is stopped. Furthermore, “hydraulic pressure generation” indicates a state in which the pump capacity is made larger than substantially zero and pressure oil is discharged, and thus the corresponding pump motors 12 and 13 function as pumps. “Hydraulic pressure recovery” indicates a state in which pressure oil discharged from one pump motor 13 (or 12) is supplied to function as a motor, and therefore the corresponding pump motor 12 (or 13) has a shaft torque. The generated torque is transmitted to the corresponding motor shafts 9 and 11 and the intermediate shafts 8 and 10.

  The “right” and “left” indications for each of the synchros 22, 23, 24, 25 indicate the positions of the sleeves in the respective synchros 22, 23, 24, 25 in FIG. The standby state for shifting, the brackets indicate the standby state for upshifting, and "○" reduces drag by setting the corresponding synchros 22, 23, 24, 25 to the OFF state (neutral position) In this state, “●” indicates that the corresponding synchro 22, 23, 24, 25 is set to the OFF state (neutral position) and is in the neutral state.

  When the neutral position is selected and the neutral (N) state is set, the pump motors 12 and 13 are set to the “OFF” state, and the sleeves of the synchros 22, 23, 24, and 25 are set to the center positions. The Therefore, none of the gear pairs 17, 18, 19, 20, 21 is in a neutral state that is not connected to the output shaft 16. That is, the pump motors 12 and 13 are controlled so that their extrusion volumes (pump capacity) are substantially zero. As a result, a so-called idling state is established, so that even if torque is transmitted from the engine 1 to the ring gears 3R, 4R of the planetary gear mechanisms 3, 4, no reaction force acts on the sun gears 3S, 4S. Therefore, torque is not transmitted to the intermediate shafts 8 and 10 connected to the carriers 3C and 4C that are output elements.

  When the shift position is switched to a travel position such as a drive position, the sleeve of the first sync 22 is moved to the left in FIG. 6 and the sleeve of the second sync 23 is moved to the left in FIG. Therefore, the starting drive gear 21A is connected to the motor shaft 9, the first pump motor 12 and the output shaft 16 are connected, and the first speed drive gear 20A is connected to the second intermediate shaft 10 to be the second planetary gear mechanism. 4 is the output element 4 and the output shaft 16 is coupled. That is, the first speed, which is a fixed gear, is set. At the same time, the extrusion volume of each pump motor 12, 13 is controlled to be larger than zero.

  Therefore, the second pump motor 13 is driven by the power of the engine 1 distributed by the second planetary gear mechanism 4 and functions as a pump. Along with this, the second pump motor 13 applies reaction force torque generated by generating hydraulic pressure to the motor shaft 11 and the sun gear 4S. This is described as “hydraulic pressure generation” in FIG. Therefore, the torque is transmitted to the carrier 4C by the differential action of the second planetary gear mechanism 4, and the torque is transmitted to the output shaft 16 via the first speed gear pair 20.

  On the other hand, the hydraulic pressure generated by the second pump motor 13 is discharged from the suction port 13S and supplied to the suction port 12S of the first pump motor 12. As a result, the first pump motor 12 functions as a motor. This is described as “hydraulic recovery” in FIG. In this way, the power transmitted to the first pump motor 12 is transmitted to the output shaft 16 via the starting gear pair 21. Therefore, in the driving state from the start to the first speed, both so-called mechanical power transmission via the second planetary gear mechanism 4 and power transmission via the hydraulic pressure are generated, and the combined power of these powers is generated. Appears on the output shaft 16. Further, the gear ratio in this process becomes a value larger than the first speed which is the fixed gear stage, and the gear ratio changes continuously or steplessly.

  Thus, when the speed of the engine 1 and the vehicle speed change to the first gear ratio, the extrusion volume q1 of the first pump motor 12 is set to zero, and the extrusion volume q2 of the second pump motor 13 is set to the maximum. As a result, the rotation of the second pump motor 13 is substantially locked. That is, the motor shaft 11 and the second pump motor 13 connected thereto are fixed. At the same time, the first sync 22 is set to the OFF state. As a result, the sun gear 4S of the second planetary gear mechanism 4 is fixed, and the first planetary gear mechanism 3 is not involved in the transmission of power to the output shaft 16, so that the power output from the engine 1 is the second planetary gear mechanism. 4 and the first speed gear pair 20 are transmitted to the output shaft 16. That is, a fixed speed determined by the gear ratio of the first speed gear pair 20 is set. In this case, since the first pump motor 12 and the motor shaft 9 connected thereto are idled, no torque appears on the first intermediate shaft 8.

  In the case of upshifting from the first speed, which is a fixed gear stage, the sleeve of the third sync 24 is moved to the left side in FIG. 6 to connect the second speed drive gear 18A to the first intermediate shaft 8. The R synchro 25 is kept in a neutral state. Further, when the sleeve of the third synchro 24 is engaged with the second speed drive gear 18A, synchronous control is performed so that the rotation speed of the sleeve of the third synchro 24 matches the rotation speed of the second speed drive gear 18A. The synchronization control is performed in the same manner when the sleeves of the synchros 22, 23, 24, and 25 are engaged with the mating members.

  In this state, the extrusion volume q1 of the first pump motor 12 is gradually increased toward the maximum. In the upshift standby state to the second speed, the first pump motor 12 rotates in the reverse direction, and thus functions as a pump by gradually increasing the extrusion volume q1. That is, hydraulic pressure is generated (indicated as “hydraulic pressure generation” in FIG. 7), and at the same time, a reaction force torque associated therewith appears on the motor shaft 9. As a result, transmission of power through the first planetary gear mechanism 3 and the second speed gear pair 18 is gradually performed. Further, the hydraulic pressure generated by the first pump motor 12 is supplied to the second pump motor 13 and functions as a motor (denoted as “hydraulic pressure recovery” in FIG. 7). Power is transmitted through the gear mechanism 4 and the first speed gear pair 20. Therefore, the speed ratio in the process of shifting from the first speed to the second speed is a value between the speed ratio of the first speed and the speed ratio of the second speed, and is a continuously changing speed ratio. . That is, a continuously variable transmission state in which the gear ratio continuously changes is obtained. This is the same during the period from the start to the speed ratio of the first speed and between the fixed shift speeds. Therefore, the above-described transmission can function as a continuously variable transmission.

  In the state where the first speed, which is a fixed speed, is set, the extrusion volume q1 of the first pump motor 12 is set to zero (or less than a predetermined value close to the minimum), and the extrusion volume q2 of the second pump motor 13 is set. Is greater than or equal to a predetermined value that is at or near the maximum. Accordingly, the first pump motor 12 and the motor shaft 9 connected to the first pump motor 12 run idle, and the pressure oil cannot flow from the second pump motor 13 to the first pump motor 12. Therefore, the second pump motor 13 becomes locked. From this state, the extrusion volume q1 of the first pump motor 12 is first gradually increased. As a result, hydraulic pressure is generated in the first pump motor 12, and this is supplied to the second pump motor 13, so that the second pump motor 13 acts as a motor. That is, power is transmitted between the pump motors 12 and 13 via the pressure oil.

  Thus, when the extrusion volume q1 of the first pump motor 12 is maximized, the extrusion volumes q1 and q2 of the pump motors 12 and 13 are both maximized or more than a predetermined value close to this. Thereafter, the extrusion volume q2 of the second pump motor 13 is gradually reduced while maintaining the extrusion volume q1 of the first pump motor 12 at a maximum or close to a predetermined value close to this. And the 2nd speed which is a fixed gear stage is set because the extrusion volume q2 of the 2nd pump motor 13 becomes zero (or below predetermined value near the minimum). That is, power is transmitted only through the second speed gear pair 18 of each gear pair, and a gear ratio according to the rotation speed ratio of the second speed gear pair 18 is set.

  As the second pump motor 13 is set to the OFF state, the extrusion volume q1 of the first pump motor 12 is substantially maximized, and the rotation stops or is almost stopped. Fixed. Accordingly, since the sun gear 3S is fixed in the first planetary gear mechanism 3, the power input to the ring gear 3R is output from the carrier 3C to the second speed drive gear 18A via the first intermediate shaft 8. On the other hand, the second pump motor 13 is in the OFF state, and the R synchro 25 and the second synchro 23 arranged coaxially with the second pump motor 13 are in the OFF state and the sleeve is in the neutral position. The motor 13 and the second planetary gear mechanism 4 are not involved in power transmission. Accordingly, the second speed, which is a fixed shift stage determined by the gear ratio of the second speed gear pair 18, is set.

  Hereinafter, similarly, the third speed is achieved by moving the sleeve of the second synchro 23 to the right in FIG. 6 to connect the third speed drive gear 19A to the second intermediate shaft 10, and the second pump motor 13 push-out volume. By maximizing q2, as in the case of the first speed, the motor shaft 11 and the second pump motor 13 are fixed, and the other synchros 22 and 24 are set to the OFF state. Accordingly, the power is transmitted to the output shaft 16 via the third speed gear pair 19, and the third speed, which is a fixed gear stage, is set. For the fourth speed, the sleeve of the third synchro 24 is moved to the right in FIG. 6 to connect the fourth speed drive gear 17A to the first intermediate shaft 8, and the extrusion volume q1 of the first pump motor 12 is maximized. As a result, as in the case of the second speed, the motor shaft 9 and the first pump motor 12 are fixed, and the other synchros 23 and 25 are set to the OFF state. Accordingly, the power is transmitted to the output shaft 16 via the fourth speed gear pair 17, and the fourth speed, which is a fixed gear stage, is set.

  Further, the reverse gear will be described. When the reverse position is selected, the sleeve of the first sync 22 is moved to the left in FIG. 6, and the sleeve of the R sync 25 is moved to the right in FIG. Further, the other syncs 23 and 24 are set to the OFF state. Therefore, when the second intermediate shaft 10 and the motor shaft 11 are connected by the R synchro 25, the sun gear 4S of the second planetary gear mechanism 4 and the carrier 4C are connected, and the entire second planetary gear mechanism 4 is substantially the same. Integrated. The start drive gear 21 </ b> A is connected to the motor shaft 9, that is, the rotor of the first pump motor 12.

  Therefore, the motive power transmitted from the engine 1 to the second planetary gear mechanism 4 is transmitted to the second pump motor 13 as it is, and this is driven, and hydraulic pressure is generated by the second pump motor 13. Since the second synchro 23 is in the OFF state, power is not transmitted from the second planetary gear mechanism 4 or the second intermediate shaft 10 to the output shaft 16. On the other hand, the extrusion volume q1 of the first pump motor 12 is controlled to a volume larger than zero, for example, the maximum volume. As a result, the first pump motor 12 functions as a motor by the hydraulic pressure supplied from the second pump motor 13 and outputs torque to the motor shaft 9. In that case, since the hydraulic pressure is supplied to the first pump motor 12 from the discharge port 12D, the first pump motor 12 rotates in the reverse direction. Then, the torque is transmitted to the output shaft 16 via the starting gear pair 21, so that a reverse state is established. That is, in the reverse gear, power is transmitted via the hydraulic pressure, and in FIG. 7, this is indicated as “hydraulic pressure recovery” for the first pump motor 12 and “hydraulic pressure generation” for the second pump motor 13.

  The shift control device according to the present invention for the variable displacement pump motor type transmission TM configured as described above is capable of shifting even when shifting over a fixed shift stage, that is, a shift with a sync switching operation. In order to prevent a decrease in speed and enable a smooth shift without a sense of incongruity, the following control is executed. An example of the control will be described below.

  FIG. 1 is a flowchart for explaining an example of control by the control device of the present invention. The routine shown in this flowchart is repeatedly executed every predetermined short time. Further, here, an example of downshifting across the second speed fixed shift stage, that is, a shift in which the second sync 23 on the second pump motor 13 side is switched from the third speed gear pair 19 to the first speed gear pair 20 is exemplified. Will be described.

  In FIG. 1, first, it is determined whether or not there is a request for an abrupt shift across the fixed shift speed (step S1). The shift across the fixed shift speed is a shift in which at least one of the second sync 23 and the third sync 24 described above is switched from the engaged state to the released state and continuously switched from the released state to the engaged state. Yes, for example, when changing from a gear ratio between the second speed and the third speed, which is a fixed stage, to a gear ratio between the second speed and the first speed, a switching request to the second synchro 23 is made. It is determined whether or not there is. Switching between the synchros 23 and 24 is executed when the target gear ratio (the command value of the gear ratio) exceeds the synchro switching determination line, for example, as shown in FIG.

  This sync change judgment line is set for each shift across the second and third fixed gears, and in the example shown in FIG. 2, the second shift is performed during the upshift across the second fixed gear. “1 → 3 decision line” for switching the sync 23 from the first speed gear pair 20 to the third speed gear pair 19 and the second sync 23 at the third speed at the time of downshift across the second speed fixed gear stage. “3 → 1 decision line” for switching from the gear pair 19 for the first speed to the gear pair 20 for the first speed, and the third sync 24 from the second speed gear pair 18 to the second gear during the upshift across the third speed fixed gear. “2 → 4 decision line” for switching to the 4-speed gear pair 17 and the third sync 24 from the fourth-speed gear pair 17 to the second-speed gear pair 18 during the downshift across the third-speed fixed gear. “4 → 2 decision line” to be switched to is set. Control hunting is prevented between “1 → 3 decision line” and “3 → 1 decision line” and between “2 → 4 decision line” and “4 → 2 decision line”. Hysteresis is provided for this purpose.

  In this way, the presence / absence of a switching request for the second synchro 23 can be determined based on the actual gear ratio (that is, the actual gear ratio) and the target gear ratio at that time. Further, it is determined whether or not the shift to be executed is a sudden downshift. The sudden shift (sudden downshift, sudden upshift) in this control means a shift in which the gear ratio changes greatly. For example, a shift when the difference between the actual gear ratio and the target gear ratio is a predetermined value or more. That is. If it is determined in this step S1 to be negative because the shift is not accompanied by sync switching or is not a sudden shift, this routine is temporarily terminated without performing the subsequent control.

  On the other hand, if an affirmative determination is made in step S1 due to a request for a sudden shift accompanied by switching of the second synchro 23, the process proceeds to step S2 and a command to set the relief pressure to zero is output. The This control is a control for reducing the torque applied to the synchro for executing the shift, and therefore, the pressure is discharged from the oil passage 14 which is a high-pressure passage for transmitting the power between the pump motors 12 and 13. Thus, the command signal is output so that the relief pressure of the first relief valve 38 becomes zero.

  When a command for reducing the relief pressure of the first relief valve 38 is output, it is determined whether or not the relief pressure has become zero (step S3). Whether the relief pressure has become zero is determined by setting, for example, a waiting time Tlate from the time when a command to set the relief pressure to zero is output, and when the waiting time Tlate has elapsed, the relief pressure is reduced. It can be determined that it has become zero. Further, the waiting time Tlate in that case can be set based on, for example, a map based on a preset oil temperature.

  When the relief pressure of the first relief valve 38 is not yet zero, that is, when the above-described waiting time Tlate has not yet elapsed, a negative determination is made in this step S3, the process returns to the above-described step S2. The previous control is repeatedly executed.

  On the other hand, if the relief pressure of the first relief valve 38 has become zero, that is, if the above-described waiting time Tlate has elapsed and the determination is affirmative in step S3, the process proceeds to step S4. A command to switch the second synchro 23 to the released state is output.

  As described above, by setting the relief pressure of the first relief valve 38 to zero, the second pump motor 13 is brought into a free state and is not involved in power transmission. In other words, the torque applied to the second sync 23 arranged on the second pump motor 13 side is reduced to zero, and a switching operation can be executed. Therefore, regardless of the state of the extrusion volume of the second pump motor 13, by making the relief pressure of the first relief valve 38 zero, it is possible to make the switching operation of the second synchro 23 executable. Immediately, in other words, without waiting for the extrusion volume to become zero, the switching operation of the second synchro 23 can be started, and the shift time of the shift accompanied by the switching operation of the second synchro 23 can be shortened, As a result, the shift speed of the shift accompanying the switching operation of the second sync 23 can be increased.

Subsequently, the extrusion volumes of the pump motors 12 and 13 are controlled to target values (step S5). The pumping capacity of each pump motor 12 and 13 is such that the gear ratio is γ, and the gear ratio between the sun gears 3S and 4S and the ring gears 3R and 4R of each planetary gear mechanism 3 and 4 (that is, “the teeth of the sun gears 3S and 4S”). Number / the number of teeth of the ring gears 3R, 4R ”) is ρ, and the gear ratios in the power transmission paths on the pump motors 12 and 13 side are κ1 and κ2, respectively.
γ = {(1 + ρ) × (κ1 × q1 + κ2 × q2)} / (q1 + q2)
Are controlled so as to satisfy the relationship between the extrusion volume and the gear ratio γ shown in FIG.

  For example, as shown in FIG. 2, when a sudden downshift is performed from the current actual speed ratio R0 to the target speed ratio R1 beyond the second speed fixed gear stage, the extrusion volumes of the pump motors 12 and 13 are as follows. The extrusion volume is changed from the current volume q10 to the volume q21 which is the necessary volume for setting the gear ratio after the shift, so that the volume q11 which is the necessary volume for setting the gear ratio after the gear shift is changed to the volume q21 which is the necessary volume for setting the gear ratio after the gear shift. It is controlled to become.

Further, the rotational speed control of the engine 1 is executed (step S6). Specifically, the engine rotational speed Ne is determined by the output shaft rotational speed Nout and the speed ratio after shifting, that is, the target speed ratio R1, where the rotational speed of the output shaft 16 is Nout.
Ne = R1 × Nout
It is controlled to become.

  Control of the extrusion volumes of the pump motors 12 and 13 and rotation speed control of the engine 1 are executed, and it is determined whether or not the switching operation (release) of the second synchro 23 has been completed in the process (step S7). . If a negative determination is made in step S7 because the two syncs 23 have not yet been released, the process returns to step S4 described above, and the previous control is repeatedly executed.

  On the other hand, if a positive determination is made in step S7 due to the completion of the switching operation of the second synchro 23, the process proceeds to step S8, where the relief pressure of the first relief valve 38 that has been set to zero is set. Relief pressure return control for returning to the normal state is executed. This control is a control for ensuring the pressure in the oil passage 14 and restoring the transmission of power between the pump motors 12 and 13, and therefore functions as a pump when the relief pressure return control is executed. Torque appears on the drive shaft of the second pump motor 13 and a reaction force acts on the sun gear 4S of the second planetary gear mechanism 4, and the rotational speed of the input side member of the second synchro 23, specifically, the sleeve The number of rotations changes toward the synchronous number of rotations. That is, torque from the engine 1 side acts on the second synchro 23, and in this case, the engine speed and the extrusion volume of each pump motor 12, 13 are controlled to the rotation speed and the extrusion volume at the speed ratio after the shift. Therefore, when torque is applied to the second synchro 23 from the engine 1 side, the rotation speed of the second synchro 23 changes so as to be synchronized with the rotation speed after the shift.

The extrusion volume of the pump motors 12 and 13 can also be controlled by changing the extrusion volume so that the difference between the detected value of the rotation speed of the first pump motor 12 and the synchronous rotation speed becomes small. That is, the rotational speed difference with respect to the synchronous rotational speed is
NP1-{(1 + ρ) · G1st · No-Ne} / ρ
Is required. Here, NP1 is the rotational speed of the first pump motor 12, G1ST is the gear ratio of the first speed gear pair 20, No is the output shaft rotational speed, and Ne is the engine rotational speed. When the rotation speed difference thus obtained is a positive value, the extrusion volume of the first pump motor 12 is increased or the extrusion volume of the second pump motor 13 is decreased so that the rotation speed difference is reduced. Operate (to approach zero). On the contrary, when the value of the rotational speed difference is negative, the above-mentioned rotational speed difference is increased by increasing the extrusion volume of the second pump motor 13 or decreasing the extrusion volume of the first pump motor 12. To operate (to approach zero).

Therefore, the synchronization determination is performed after the relief pressure return control is executed (step S9). This is because both the difference between the actual engine speed and the target engine speed in the gear ratio after the shift, and the difference between the actual extrusion volume of the pump motors 12 and 13 and the target extrusion volume in the gear ratio after the shift. Can be determined by determining whether or not is within a predetermined allowable range. Alternatively, the determination can be made by determining whether or not the engine speed Ne, the output shaft speed No, and the actual speed NP1 of the first pump motor 12 satisfy the following formula.
G1st · No− {NP1 + (Ne−NP1) / (1 + ρ)} <predetermined threshold The predetermined threshold is a value determined in advance so that synchronization determination is possible.

  If a negative determination is made in step S9 because synchronization has not been established, the process returns to step S8 to continue the previous control state. On the other hand, if synchronization is established and the determination in step S9 is affirmative, an engagement command for the second synchro 23 is output (step S10). That is, the sleeve of the second synchro 23 in the neutral state is moved to the first speed gear pair 20 side (left side in FIG. 6), and the drive gear 20A of the first speed gear pair 20 is moved to the second intermediate shaft 10. Control to connect to is started. In the subsequent step S11, it is determined whether or not the completion of the engagement of the second synchro 23 and the extrusion volumes of the pump motors 12 and 13 have reached target values (step S11). If a negative determination is made in step S11, the process returns to step S10 and the previous control state is continued. On the other hand, if the determination in step S11 is affirmative, the second sync 23 is engaged with the first speed gear pair 20 side, and the push-out volume of the pump motors 12 and 13 is the post-shift volume. Therefore, the control of the engine speed for executing the requested sudden shift is ended, a shift end signal is output (step S12), and the process returns.

  FIG. 3 shows a time chart when the above shift control is executed. When the above-described state where the sudden shift should be performed is established at time T21, a command signal for reducing the relief pressure is output at time T22 when a predetermined time has passed for confirmation. This is the control in step S2 described above. At time T23 when the predetermined waiting time Tlate has elapsed, a determination that the relief pressure is zero is established, and a command signal for switching the second synchro 23 from the third speed gear pair 19 side to the neutral state is output. At the same time, a command signal for engine speed control and a control command signal for the extrusion volume of the pump motors 12 and 13 are output, and the control is started.

  Thereafter, when the second sync 23 is switched to the released state, the completion determination is established (at time T24). This is a case where an affirmative determination is made in step S7 described above. At the same time, the relief pressure return control is started, the oil pressure in the oil passage 14 gradually increases, and the power is gradually transmitted between the pump motors 12 and 13 accordingly. In this process, the relief pressure returns to the normal pressure, that is, the pressure before the start of shifting. Further, the rotational speed (NP3) of the second pump motor 13 that has been reversely rotated before shifting is changed to the rotational speed (NP1) after shifting. At time T25 when the synchronization is thus established, a command signal for engaging the second synchro 23 with the first speed gear pair 20 side is output. This is the control in step S10 described above. When the determination of engagement is established (time T27), the engagement command is released. Thereafter, the control command for controlling the engine speed during the shift is released, and the engine 1 is controlled based on the traveling state such as the accelerator opening and the vehicle speed.

  Therefore, according to the control device of the present invention, when the relief pressure once lowered so as to release the torque applied to the synchro to be switched is restored, the engine rotational speed control and the pumping capacity of the pump motors 12 and 13 are restored. Since synchronization control is executed by this control and the synchronization is established, the synchronization is engaged, so even if the synchronization has a synchronization function, the synchronization is engaged with almost no synchronization. To do. Therefore, the load applied to the synchro at the time of engagement is small, the durability can be improved, or the synchro can be made small or have a small capacity. Further, since the restoration of the relief pressure and the synchronization of the rotation speed proceed at the same time, the time required for the sudden shift becomes shorter. In particular, the relief pressure only needs to be lowered once to release the synchro, and then returned to it, and control such as lowering or returning again is not necessary. In this respect as well, the time required for shifting can be shortened. This makes it possible to perform a sudden shift without a sense of incongruity.

  By the way, in the above control, the engine speed is controlled and the extrusion volume of the pump motors 12 and 13 is controlled to synchronize with the speed after the shift. However, the control of the engine speed and the control of the extrusion volume of the pump motors 12 and 13 may be restricted due to various temperatures or the running state of the vehicle. In such a case, the synchronization determination is performed. It takes time to be established, and as a result, there is a possibility that the time until the end of shifting becomes longer. In order to avoid such an inconvenience, the present invention can be configured to perform the following explanation control.

  FIG. 4 is a flowchart for explaining the control example, and is an example in which synchronization is forcibly performed by synchronization when it takes time until the synchronization determination is established in the control shown in FIG. 1 described above. . Therefore, since the control example shown in FIG. 4 is a partial modification of the control example shown in FIG. 1, the same control steps as those in FIG. Omitted.

  In FIG. 4, after the relief pressure return control is started in step S8, the synchronization determination is performed in step S9. If the determination in step S9 is negative, that is, if the synchronization is not synchronized, the relief pressure is determined. It is determined whether or not the elapsed time Tsyn since the start of the return control is equal to or greater than a predetermined reference time Tlimit (step S13). This reference time Tlimit is a time required for the synchronization when the engine speed is smoothly controlled by the engine speed control or the extrusion volume control of the pump motors 12 and 13, or a time slightly longer than that. It is time that can be set. Or the time set as a map according to oil temperature etc. may be sufficient. If a negative determination is made in step S13, the process returns to step S8 because the engine speed control and the synchronous control by controlling the extrusion volumes of the pump motors 12 and 13 are in progress. On the other hand, when the above-described reference time Tlimit has elapsed and the determination in step S13 is affirmative, synchronous control by controlling the engine speed and the extrusion volume of the pump motors 12 and 13 proceeds as expected. As a result, the relief pressure is lowered again (step S14). This is the same control as step S2 described above, and a command signal for reducing the relief pressure to almost zero is output. The decreasing gradient may be the same as the control in step S2, or may be more gradual than the control in step S2.

  Next, it is determined that the relief pressure has been lowered (step S15). If it is determined that the relief pressure has not been reduced, the process returns to step S14. On the other hand, if the determination in step S15 is affirmative, the relief pressure is reduced to almost zero, and the torque applied to the second sync 23 is sufficiently reduced. Is transmitted to the first speed gear pair 20 side to be engaged (step S16). Thereafter, determination of completion of engagement is made (step S17), and if negative determination is made in step S17 because engagement has not been completed, the process returns to step S16 to continue the previous control. On the contrary, when the engagement is completed and the determination in step S17 is affirmative, a command signal for restoring the relief pressure is output (step S18). In this case, since the second synchro 23 is engaged with the first speed gear pair 20 side and is capable of transmitting torque to the output shaft 16, the rising slope of the relief pressure is set relatively gently. In addition, it is preferable to prevent or suppress a sudden change in driving torque or occurrence of a shock. Then, when the relief pressure is restored, the control of the engine speed associated with the shift is finished (step S19), and the process returns.

  FIG. 5 shows a time chart when the control shown in FIG. 4 is performed. The situation from time T31 to time T34 in FIG. 5 is the same as the situation from time T21 to time T24 in the time chart of FIG. When the reference time Tlimit described above elapses before the synchronization is established after the time T34 when the relief pressure return control is started, a command signal for reducing the relief pressure again is output at the time T35. When the reduction of the relief pressure is completed (at time T36), a command signal for engaging the second synchro 23 with the first speed gear pair 20 side is output. As a result, the second sync 23 is gradually engaged while synchronizing the rotational speeds of the input side and the output side. Since the inertial force accompanying it arises, the rotation speed of the 2nd pump motor 13 falls for a while temporarily.

  When the determination of the completion of engagement of the second synchro 23 is thus established (at time T39), the engagement command for the second synchro 23 is released, and relief pressure return control is started at time T310 thereafter. Further, when the return of the relief pressure is completed (at time T311), the engine speed control command is canceled.

  Therefore, by performing the control as shown in FIG. 4, the synchronization is forcibly engaged when the synchronization due to the engine speed control or the extrusion volume control of the pump motors 12 and 13 is delayed. Synchronization is achieved by the synchronization function included in, and the shift is completed. Therefore, since the shift can be advanced without waiting for the completion of the synchronization by the delayed engine speed control or the pump volume control of the pump motors 12 and 13, the delay of the shift can be avoided or suppressed. Also, when engaging the synchro, the relief pressure is lowered to reduce the torque applied to the synchro, so the time required for synchronization by the synchro can be shortened, and the load on the synchro can be reduced to increase its durability. It is possible to improve or use a small-sized or small-capacity sync.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means of step S1 described above corresponds to the sudden shift determination means of the present invention, and the functional means of step S2 is the present invention. The functional means of step S4 corresponds to the release means of the present invention, the functional means of step S8 corresponds to the torque return means of the present invention, and further, the step S5 and step S6 of FIG. The functional means corresponds to the synchronization control means of the present invention, the functional means of step S9 corresponds to the synchronization determination means of the present invention, and the functional means of step S10 corresponds to the engagement instruction means of the present invention. Equivalent to. The functional means in step S14 shown in FIG. 4 corresponds to another torque releasing means of the present invention, and the functional means in step S16 corresponds to other engagement instruction means of the present invention.

  The present invention is not limited to the above specific example, and the target transmission may be other than the configuration shown in FIG. 6, for example, HST in parallel with a transmission mechanism mainly composed of a gear mechanism. The transmission may be configured such that a (hydrostatic transmission) is provided so that the overall speed can be changed continuously. Further, in the example shown in FIG. 6, it is configured to be able to set fixed forward speeds of 4 forward speeds and 1 reverse speed. It may be more or less.

  Also, when the pump motor is used as a reaction force mechanism for a differential mechanism such as a single pinion type planetary gear mechanism or a double pinion type planetary gear mechanism, it is a so-called one-way swing type that can increase its pushing volume only in one direction from zero. Not limited to this, a so-called double swing type pump motor that can be changed in both positive and negative directions can also be used. In that case, the gear mechanism may have a configuration different from that shown in FIG.

  Further, the arrangement of transmission mechanisms such as a pump motor, a differential mechanism, and a gear pair can be appropriately changed as necessary, and may be configured to be suitable for a so-called FR vehicle. Furthermore, the power source may be connected to the idle gear of the counter gear pair described above instead of being directly connected to one of the differential mechanisms. Further, a mechanism such as a belt or a chain may be used instead of the gear pair. The power source in the present invention does not have to be an engine, and may be an electric motor or a hybrid drive device that combines an internal combustion engine and an electric motor.

  Furthermore, the exhaust pressure valve in the present invention is not limited to the relief valve described above, and may be a valve provided so as to primarily exhaust pressure from the high-pressure flow path at the time of shifting. Further, the means for temporarily reducing the torque applied to the switching mechanism that performs the switching operation at the time of shifting is not configured to cut the torque by reducing the pressure of the pump motor, but temporarily transmits torque such as a clutch. It may be a mechanism for automatically blocking.

It is a flowchart for demonstrating the example of control by the control apparatus of this invention. It is a figure which illustrates typically the change state of a gear ratio and synchro at the time of performing control by the control device of this invention, and the state of the extrusion volume of each pump motor. It is a time chart at the time of performing control shown in FIG. It is a flowchart for demonstrating the other control example by the control apparatus of this invention. It is a time chart at the time of performing control shown in FIG. It is a skeleton figure which shows typically an example of the transmission made into object by this invention. FIG. 7 is a chart collectively showing operating states of pump motors and synchros when setting gear ratios in the transmission shown in FIG. 6.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power source (engine, E / G), 2 ... Input member, 3 ... 1st planetary gear mechanism, 4 ... 2nd planetary gear mechanism, 12 ... Variable pump motor (1st pump motor, PM1), 13 ... Variable Pump motor (second pump motor, PM2), 14 ... first oil passage, 15 ... second oil passage, 16 ... output member (output shaft), 17, 18, 19, 20 ... transmission mechanism (gear pair), 22 , 23, 24, 25 ... switching mechanism (first sync, second sync, third sync, R sync), 38 ... first relief valve, 39 ... second relief valve, 40 ... electronic control unit (ECU), TM ... Variable displacement pump motor type transmission.

Claims (6)

At least two power transmission paths capable of selectively setting a plurality of different gear ratios between the power source and the output member, and the torque transmitted through each of the power transmission paths varies according to the extrusion volume. The discharge ports and the suction ports are connected to each other so that when the pushing volume of one of the power transmission paths is zero and the other is locked by blocking the supply and discharge of the pressure fluid, A variable displacement pump motor in communication, a first transmission mechanism that transmits power from the power source to the output member when one of the variable displacement pump motors is locked, and the other variable displacement pump A second transmission mechanism that transmits power from the power source to the output member when the motor is locked; and a switching mechanism that selectively enables the power transmission mechanisms to transmit power. A fixed shift stage determined by the transmission gear ratio of each of the transmission mechanisms, and a continuously variable transmission state by continuously changing the power transmitted via the pressure fluid between the variable displacement pump motors. In a shift control device for a variable displacement pump motor type transmission configured to be settable,
Sudden shift determining means for determining a sudden shift state in which the gear ratio is rapidly changed via the fixed shift stage;
Torque release means for reducing the torque applied to any of the switching mechanisms engaged before the sudden shift;
Release means for switching any of the switching mechanisms to a state in which power is not transmitted in a state where the torque is reduced;
Torque return means for increasing the torque reduced by the torque release means after any one of the switching mechanisms is switched to a state where no power is transmitted;
A switching mechanism that engages so as to set a gear ratio after the sudden shift when the torque is being reduced by the torque release means and / or when the torque is being increased by the torque return means Synchronization control means for controlling at least one of the rotational speed of the power source and the extrusion volume of the variable displacement pump motor so as to synchronize the rotational speed of the rotating members to be coupled;
Synchronization determination means for determining the synchronization of the rotational speeds of the rotating members;
A variable displacement pump motor type comprising: an engagement instructing means for operating the switching mechanism in an engaged state when the synchronization determining means determines that the rotation speeds of the rotating members are synchronized. A transmission control device for a transmission. Torque applied to the switching mechanism that is engaged so as to set the gear ratio after the sudden shift when the synchronization of the rotational speeds of the rotating members by the synchronization determining means is not determined for a predetermined time. Other torque release means for reducing
And another engagement instruction means for operating the switching mechanism to engage the engagement mechanism so as to set the gear ratio after the sudden shift while the torque is reduced by the other torque release means. The shift control apparatus for a variable displacement pump motor type transmission according to claim 1, wherein   At least one of the torque release means and the other torque release means is configured to discharge pressure from a high-pressure flow path that becomes a high pressure during the sudden shift among the flow paths connecting the variable displacement pump motors. The shift control device for a variable displacement pump motor type transmission according to claim 1 or 2, further comprising a discharge valve that reduces a fluid pressure in each variable displacement pump motor.   The shift control device for a variable displacement pump motor type transmission according to claim 3, wherein the exhaust pressure valve includes a relief valve that communicates with the high pressure oil passage and sets an upper limit pressure of the high pressure oil passage. .   The switching mechanism includes an engagement mechanism having a synchronization function in which the torque capacity gradually increases when switching from the released state to the engaged state, and the rotational speeds of the connected rotating members are gradually synchronized. The shift control device for a variable displacement pump motor type transmission according to any one of claims 1 to 4.   The synchronous control means includes means for controlling the rotation speed of the power source and the extrusion volume of the variable displacement pump motor to a rotation speed and an extrusion volume determined by a speed ratio after shifting. A shift control device for a variable displacement pump motor type transmission according to any one of 1 to 5.

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