JP2009079704A - Controller for variable displacement fluid pressure pump motor type transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller capable of carrying out sudden gear change without delay, and capable of improving energy efficiency in a variable displacement fluid pressure pump motor type transmission. <P>SOLUTION: When determination of sudden gear change is established, if pressure accumulation is possible in a pressure accumulation device 41, an input side on/off valve 40 connected to a high pressure side oil pathway 14 is opened to supply pressure oil to the pressure accumulation device 41 from the oil pathway 14 and carry pressure accumulation, the input side on/off valve 40 is closed when the oil pressure of the oil pathway 14 is substantially balanced with an oil pressure of a low pressure side oil pathway 15, and a relief pressure of a relief valve 38 is set to low pressure to lower the oil pressure of the oil pathway 14. Since a second pump motor 13 stops having torque capacity, a second synchro 23 is changed in that state. Gear change can be carried out faster than reducing a pushing volume of a second motor 13 to zero, and energy efficiency can be improved by recovering its energy. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention has at least two power transmission paths capable of changing the power transmission state according to the extrusion volume of the variable displacement fluid pressure pump motor, and sets the extrusion volume to the maximum and minimum values and to an intermediate value therebetween. In particular, the present invention relates to a variable displacement fluid pressure pump motor type transmission that can change gears as appropriate, and more particularly to a control device thereof.

  This type of transmission is described in Patent Document 1. Briefly describing the configuration, variable displacement fluid pressure pump motors are connected to reaction force elements in each of the pair of planetary gear mechanisms, and the discharge ports and the suction ports of the variable displacement fluid pressure pump motors are mutually connected. Connected to form a closed circuit. 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 fluid pressure pump motors is locked and the reaction force element is fixed, the power output from the power source is transferred to one intermediate shaft via the planetary gear mechanism having the reaction force element. Further, power is transmitted to the output shaft via a gear pair that is 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 fluid pressure pump motor in this case is set by making the extrusion volume of the other variable displacement fluid pressure pump motor zero, that is, minimum. That is, since each fluid pressure pump motor is connected by a closed circuit, if the extrusion volume of the other fluid pressure pump motor is reduced to zero, the flow of pressure fluid does not occur. Therefore, the extrusion volume of one fluid pressure pump motor By setting the extrusion volume to be greater than zero, such as maximizing, one of the hydraulic pump motors is locked and prevented from rotating.

  In addition, the displacement volume of each variable displacement fluid pressure pump motor is set to be larger than zero, the predetermined gear pair is set in a state where torque can be transmitted by synchronization on one variable displacement fluid pressure pump motor side, and the other variable displacement When the other gear pairs are allowed to transmit torque by synchronization on the mold fluid pressure pump motor side, a gear ratio that is an intermediate value of the gear ratio determined according to the gear ratio of each gear pair is set. That is, one variable displacement fluid pressure pump motor generates pressure fluid, which is supplied to the other variable displacement fluid pressure pump motor and operates as a motor, and the power is output to the output shaft via the other gear pair. Is transmitted to. 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 fluid pressure pump motor appears on the output shaft. The power through the fluid can be continuously changed by continuously changing the extrusion volume of each variable displacement fluid pressure pump motor. Can be set continuously, i.e. steplessly.

  Conventionally, Patent Document 2 discloses an apparatus having a configuration in which a mechanical transmission mechanism and a hydraulic transmission mechanism are arranged in parallel. This device has a configuration in which a mechanical transmission and a hydrostatic transmission are provided in parallel between an engine and a drive wheel, and is configured to accumulate hydraulic pressure generated in the hydrostatic transmission during deceleration.

JP 2007-64269 A JP-A-11-311330

  In the transmission described in the above-mentioned Patent Document 1, a gear ratio corresponding to the gear ratio of any one of the gear pairs, that is, when shifting beyond (or via) a fixed gear stage (fixed gear ratio), By switching the synchro operation, 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 fluid pressure pump motor with zero extrusion volume is switched. Then, when the synchro switching operation is completed, the extrusion volume of the variable displacement fluid pressure 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.

  The present invention has been made paying attention to the technical problem described above, and in a transmission using a variable displacement fluid pressure pump motor, even if the speed is changed over a fixed shift stage accompanied by a switching operation of a switching mechanism. An object of the present invention is to provide a control device that enables a quick shift by shortening the shift time, and enables a shift with good energy efficiency.

  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. The variable displacement fluid pressure pump motor in which the discharge ports and the suction ports communicate with each other so that they are locked together, and the power from the power source when one of the variable displacement fluid pressure pump motors is locked 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 fluid pressure pump motor is locked, A switching mechanism for selectively transmitting power to each transmission mechanism, between a fixed shift stage determined by a gear ratio of each of the transmission mechanisms, and the variable displacement fluid pressure pump motors. In the control device for a variable displacement fluid pressure pump motor type transmission configured to be capable of setting a continuously variable transmission state by continuously changing the power transmitted through the pressure fluid, the discharge Of the oil passage communicating with the outlets and the oil passage communicating with the suction ports, the extrusion volume of the one variable displacement fluid pressure pump motor is set to zero and the other variable displacement fluid pressure is set. A pressure accumulating device that is selectively communicated to an oil passage that is in a high pressure state while the pump motor is locked, and a sudden shift determining means that determines a sudden shift state in which the gear ratio is rapidly changed via the fixed shift stage. And its sudden change Accumulation control for communicating the high-pressure oil passage to a low-pressure location after the high-pressure oil passage is temporarily communicated with the pressure accumulator when pressure is accumulated by the judging means. Means.

  According to a second aspect of the present invention, in the first aspect of the present invention, the pressure accumulation control means includes an on-off valve mechanism interposed between the pressure accumulation device and the high pressure oil passage, and the high pressure oil. A relief valve that is connected to a passage and is capable of controlling a relief pressure, and an oil passage that temporarily opens the on-off valve mechanism when the sudden shift state is determined by the sudden shift determining means, And a valve control means for closing the on-off valve mechanism and reducing the relief pressure of the relief valve to exhaust pressure from the oil passage that is at a high pressure after accumulating pressure by communicating with the accumulator. It is a control apparatus of a displacement type fluid pressure pump motor type transmission.

  Further, the invention of claim 3 is the invention of claim 2, further comprising a pressure sensor for detecting the pressure of the pressure accumulator, wherein the valve control means is configured such that the pressure detected by the pressure sensor is a predetermined reference pressure. In the above case, the variable displacement fluid pressure pump motor includes means for reducing the relief pressure of the relief valve while maintaining the on-off valve mechanism in the closed state, and exhausting the pressure from the oil passage having the high pressure. It is a control apparatus of a type transmission.

  The invention of claim 4 is the invention of claim 2, further comprising differential pressure determination means for determining a pressure difference between the oil passages, wherein the valve control means opens the on-off valve mechanism, Control of a variable displacement fluid pressure pump motor type transmission comprising means for closing the on-off valve mechanism when the differential pressure determined by the differential pressure determination means is not more than a predetermined reference differential pressure. Device.

  According to the first aspect of the present invention, when the gear ratio is changed across the fixed gear stages, that is, when a gear shift involving a switching operation of any one of the switching mechanisms is performed, if the gear shift is a so-called sudden gear shift, A high-pressure oil passage between the pump motor is temporarily connected to the pressure accumulator. Therefore, the pressure fluid flows from the oil passage into the pressure accumulator and accumulates pressure, and at the same time, the pressure in the oil passage decreases. After accumulating in this way, the oil passage is brought into communication with a low-pressure location such as a drain location or an oil pan, and is substantially discharged from the oil passage. As a result, the torque acting on the switching mechanism that the oil pump rapidly loses the torque capacity and should be switched is rapidly reduced, so that the switching mechanism can be switched quickly. As a result, even for a shift that changes the gear ratio across the fixed gear, the shift time is shortened, and a decrease in the shift speed relative to a continuously variable gear that does not cross the fixed gear is avoided or suppressed. Smooth shifts without any problems can be executed. Further, since the pressure fluid in the oil passage can be stored in the pressure accumulator, energy can be recovered and effectively used, and the energy efficiency as a whole can be improved.

  According to the second aspect of the present invention, in the case of the above-described sudden shift, the on-off valve mechanism is temporarily opened to supply high-pressure fluid to the pressure accumulator for accumulating, and after the on-off valve is closed. Then, the set pressure of the relief valve is lowered, and the pressure of the oil passage is lowered. Therefore, as in the first aspect of the invention, in the case of a sudden shift via a fixed shift stage, the shift can be executed smoothly and quickly with good energy efficiency. In addition, since the oil passage can be discharged using a relief valve for avoiding an excessive pressure from acting on the pump motor, an increase in the number of parts can be avoided or suppressed.

  Further, according to the invention of claim 3, when the shift that changes the gear ratio across the fixed shift stage is a so-called sudden shift, if the pressure accumulator is already at a high pressure, the pressure in the oil passage is controlled by the relief valve. Since the speed is lowered immediately, the switching operation of the switching mechanism can be speeded up and a sudden shift according to the request becomes possible.

  According to the invention of claim 4, as a result of accumulating pressure, when the differential pressure of each oil passage communicating with each pump motor becomes a predetermined low pressure such as zero, the on-off valve mechanism is closed and the relief is performed. Since the pressure of the oil passage is lowered by the valve, the delay of closing the on-off valve mechanism can be avoided and the speed change can be speeded up.

  Next, the present invention will be described based on specific examples. First, the variable displacement fluid pressure pump motor type transmission targeted in the present invention will be described. The variable displacement fluid pressure pump motor transmission targeted in the present invention has at least two power transmission paths. The torque is transmitted from the power source to the output member via both power transmission paths, and as a result, the speed ratio, which is the ratio of the rotational speeds of the power source and the output member, is continuously changed. It is a transmission that can.

  More specifically, each power transmission path includes a variable displacement fluid pressure pump motor that functions as a pump and a motor, respectively, and is configured to transmit torque according to the extrusion volume. The variable displacement fluid pressure pump motor is communicated with each other so as to exchange pressure fluid with each other. Therefore, when one of the variable displacement fluid pressure 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 fluid pressure pump motor to the other. Pressure fluid is supplied to the variable displacement fluid pressure pump motor, and the other variable displacement fluid pressure 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, the transmission of power via the pressure fluid does not occur in the state where the fixed gear is set. It becomes. 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 fluid pressure pump motor type transmission targeted by the present invention is configured to transmit power via pressure fluid, the speed ratio is set by mechanical power transmission as described above. It is preferable that it is configured as a hydrostatic mechanical transmission (HMT) having a function. 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 fluid pressure pump motor may be configured to use a variable displacement fluid pressure pump motor as the reaction force means, in addition to the structure in which the variable displacement fluid pressure pump motor is interposed in series between the power source and the output member.

  Next, the configuration of the variable displacement fluid pressure pump motor type transmission targeted in the present invention will be described based on a specific example. The example shown in FIG. 1 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. Therefore, the variable displacement fluid pressure 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 fluid. This is an example of the configuration. That is, in FIG. 1, an input member 2 is connected to a 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. 1 is an example constituted by a single pinion type planetary gear mechanism, and is a sun gear 3S, 4S that is an external gear, and a ring gear 3R that 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 suction ports (suction ports) 12S and 13S are communicated with each other by the oil passage 14, and the discharge ports (discharge ports) 12D and 13D are communicated with each other through the 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, A second speed drive gear 18A of the second speed gear pair 18 is disposed, and the fourth speed drive gear 17A and the second speed drive gear 18A are rotatably fitted to the first intermediate shaft 8. It has been. 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 18B of the second speed gear pair 18 meshed with the second speed drive gear 18A Is attached to the output shaft 16 so as to rotate integrally therewith.

  On the other hand, also on the second intermediate shaft, in order from the second planetary gear mechanism 4 side, the third speed drive gear 19A of the third speed gear pair 19 and the first speed gear pair corresponding to the second transmission mechanism of the present invention. 20 first speed drive gears 20A are arranged. 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 functions as the third speed driven gear 19B of the third speed gear pair 19, and the second speed driven gear 18B also functions as the first speed driven gear 20B of the first speed gear pair 20. ing. 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. The clutch mechanism is a mechanism for selectively transmitting torque, and a conventionally known mechanism such as a dog clutch mechanism or a synchronous coupling mechanism (synchronizer) can be employed. FIG. An example of adopting a Nizer is shown.

  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 of FIG. 1 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 synchronizer 23 connects the first speed drive gear 20A to the second intermediate shaft 10 by moving the sleeve to the left side in FIG. 1, and the first speed gear pair 20 is connected to the second intermediate shaft 10. Torque is transmitted to and from the output shaft 16. On the other hand, the third speed drive gear 19A is connected to the second intermediate shaft 10 by moving the sleeve to the right in FIG. 1, and the third speed gear pair 19 is connected to the second intermediate shaft 10 and the output shaft 16. Torque is transmitted between the two.

  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. 1 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. 1, 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 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 planetary gear mechanism 4 is configured to rotate integrally.

  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. In that case, for example, an appropriate actuator (not shown) for moving the above-described sleeve in the axial direction may be provided, and the actuator may be electrically controlled.

  As described above, in the variable displacement fluid pressure pump motor type transmission TM shown in FIG. 1, the torque output from the engine 1 is applied to the output shaft 16 via any one of the intermediate shafts 8 and 10 or the motor shafts 9 and 11. It is configured to be transmitted. 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 communicated 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.

  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 reduce the relief pressure to zero, the pump motor 12 (or 13) on the side where the relief valve 38 (or 39) is provided is pushed out. Even when the volume is controlled to be greater than zero, the output shaft 16 can be brought into a state not involved in power transmission.

  Furthermore, a mechanism for recovering energy is provided. In other words, a pressure accumulating device 41 is communicated with an oil passage 14 that is high pressure in a so-called power-on state in which the engine 1 outputs power via an input-side on / off valve 40. This pressure accumulator 41 is mainly composed of a cylinder (or tank) that can enclose pressure oil, and is configured to elastically reduce its internal volume and make the internal pressure relatively high as necessary. For example, a gas having a predetermined pressure is enclosed. Between the pressure accumulator 41 and the input side on / off valve 40, a check valve 42 that allows only the flow of pressure oil from the input side on / off valve 40 toward the pressure accumulator 41 is interposed. ing. Furthermore, a pressure sensor 43 that detects the pressure of the pressure oil stored in the pressure accumulator 41 and outputs a signal is provided.

  In addition, an output-side on / off valve 44 is branched from the pressure accumulator 41 and the check valve 42 and communicated with the output side on / off valve 44 from the pressure accumulator 41 to the control circuit 45. It is configured to selectively supply oil. Each of the on / off valves 40 and 44 is a so-called electromagnetic valve that switches between an open state and a closed state when operated by an electrical signal, and constitutes an on-off valve mechanism in the present invention. Further, the control circuit 45 is configured to operate the above-described extrusion volumes of the pump motors 12 and 13, actuators (not shown) for operating the synchros 22, 23, 24 and 25, and reliefs of the relief valves 38 and 39. This is for controlling the pressure, lubricating oil, etc., and is configured to control the hydraulic pressure of each part using the hydraulic pressure of the pressure accumulator 41 or the hydraulic pressure pumped up by a pump (not shown) as a source pressure. Furthermore, hydraulic sensors 46 and 47 for detecting the pressures of the oil passages 14 and 15 and outputting signals are provided.

  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) 48 is provided. The electronic control device 48 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 pre-stores 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. 2 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.

  In addition, “right” and “left” for each of the synchros 22, 23, 24, and 25 indicate the positions of the sleeves in the respective synchros 22, 23, 24, and 25 in FIG. 1, and the parentheses are downshifted. The stand-by state, the brackets indicate the stand-by state for upshifting, and “◯” reduces drag by setting the corresponding synchro 22, 23, 24, 25 to the OFF state (neutral position). “●” 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. 1 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. In other words, the second pump motor 13 gives the reaction torque accompanying the generation of the 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 pressure 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 rotation speed of the engine 1 and the vehicle speed change to the first speed 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 the fixed gear stage, the sleeve of the third sync 24 is moved to the left side in FIG. 1 and the second speed drive gear 18A is connected 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. 2), 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 (indicated as “hydraulic pressure recovery” in FIG. 2), so that the second pump motor 13 and the second planetary gear. 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.

  When the extrusion volume q1 of the first pump motor 12 is substantially maximized and its rotation is stopped or is almost stopped, the motor shaft 9 is substantially fixed. In addition, the second pump motor 13 is set to the OFF state. 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.

  Similarly, the third speed is achieved by moving the sleeve of the second synchro 23 to the right in FIG. 1 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. 1 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 side of FIG. 1, and the sleeve of the R sync 25 is moved to the right side of 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 speed, power is transmitted via hydraulic pressure, and in FIG. 2, this is indicated as “hydraulic pressure recovery” for the first pump motor 12 and “hydraulic pressure generation” for the second pump motor 13.

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

  FIG. 3 is a flowchart for explaining an example of control by the control device of the present invention, and the routine shown in this flowchart is repeatedly executed every predetermined short time. In addition, here, as an example, a downshift 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 taken as an example. I will explain.

  In FIG. 3, first, it is determined whether or not there is a shift request for shifting over a fixed shift stage. Specifically, it is determined whether or not there is a switching request for the second synchro 23 (step S1). For example, as shown in FIG. 4, switching between the synchros 23 and 24 is performed when the target gear ratio (transmission ratio command value) exceeds the synchro change determination line. This sync change judgment line is set for each shift across the second and third fixed gears. In the example shown in FIG. 4, the second change is made during the upshift across the second fixed gear. The “1 → 3 decision line” for switching the synchro 23 from the first speed gear pair 20 to the third speed gear pair 19 and the second synchro 23 in the third speed gear pair at the time of downshift across the second speed fixed gear stage. “3 → 1 decision line” for switching from 19 to the first speed gear pair 20 and the third sync 24 from the second speed gear pair 18 to the fourth speed gear pair 17 at the time of upshifting across the third speed fixed gear. “2 → 4 judgment line” for switching to “4 → 2 judgment line” for switching the third sync 24 from the fourth speed gear pair 17 to the second speed gear pair 18 at the time of downshift across the third speed fixed gear. 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. If there is no switching request for the second sync 23, and if a negative determination is made in step S1, this routine is temporarily terminated without performing the subsequent control.

  On the other hand, if a positive determination is made in step S1 due to a switching request to the second synchro 23, the process proceeds to step S2 and whether the shift to be executed is a sudden downshift. It is determined whether or not. The sudden shift (sudden downshift, sudden upshift) in this control refers to a shift in which the gear ratio changes greatly. For example, the gear shift when the difference between the actual gear ratio and the target gear ratio is equal to or greater than a predetermined value. That is. This can be determined based on, for example, a depression angle (depression amount) of an accelerator pedal (not shown).

  Therefore, the shift to be executed is an abrupt downshift, that is, a downshift in which the difference between the actual gear ratio and the target gear ratio is equal to or greater than a predetermined value. In this case, the process proceeds to step S3, and it is determined whether or not the pressure accumulator 41 is at a high pressure. This determination is made as to whether or not the pressure accumulating device 41 has a recovery capacity, that is, the pressure value in the pressure accumulating device 41 detected by the pressure sensor 43 described above is the highest pressure value set in the design (the maximum pressure determined in the specification). Value) or not.

  If the pressure accumulating device 41 is still at a low pressure and a negative determination is made in step S3, the pressure accumulating device 41 has a pressure recovery capacity, so that the on / off valves 40 and 44 described above are operated. (Step S4). This is an operation for switching to a so-called pressure accumulation mode, in which the input-side on / off valve 40 is switched to the open state and the output-side on / off valve 44 is set to the closed state. That is, the pressure accumulator 41 is communicated with the oil passage 14 where the pressure is high. This is the control at time T1 shown in the time chart of FIG.

  In this state, the pressure difference (differential pressure) between the oil passages 14 and 15 is determined (step S5). The differential pressure can be obtained from the pressure detected by the hydraulic sensors 46 and 47 described above. In step S5, the pressure oil in the so-called high-pressure side oil passage 14 is sent to the pressure accumulator 41, and the pressure in the oil passage 14 gradually decreases, and the differential pressures in the oil passages 14 and 15 associated therewith are determined in advance. This is to determine whether or not the reference differential pressure has been reached. More specifically, it is determined whether or not the differential pressure has become zero. This can be done by setting the reference differential pressure for determination to a value close to zero and comparing the reference differential pressure with the detected differential pressure.

  If the negative pressure is determined in step S5 because the differential pressure in each of the oil passages 14 and 15 is larger than the reference differential pressure, the flow returns to step S3 to continue the recovery of the hydraulic pressure. On the other hand, when the pressure difference becomes equal to or less than the reference pressure difference, such as when the pressure difference becomes almost zero, and the determination in step S5 is affirmative, the process proceeds to step S6 to turn on / off the so-called pressure accumulation mode. The off valves 40 and 44 are operated. Specifically, the input side on / off valve 40 is closed. This is the control at time T2 shown in the time chart of FIG. In this case, the output-side on / off valve 44 is opened when a hydraulic pressure supply condition such as a request from the control circuit 45 is satisfied.

  In this way, when the so-called pressure accumulation mode ends and high pressure oil in the oil passage 14 is recovered by the pressure accumulator 41, control for further reducing the oil pressure in the oil passage 14 is executed simultaneously (T2 time). That is, the hydraulic pressure of the oil passage 14 that is high in the power-on state where the engine 1 is running with the power output is reduced by the first relief valve 38 that defines the maximum pressure. Specifically, a command for setting the relief pressure (set pressure) of the first relief valve 38 to zero is output (step S7). This is because the pressure acting on the second synchro 23 is reduced by reducing the pressure on the discharge side of the second pump motor 13 that is rotating in reverse to reduce the torque of the motor shaft 11.

  If the determination in step S3 is affirmative, that is, if the pressure accumulating device 41 is already at a high pressure when the determination of a sudden shift is established, the step is immediately performed without executing the so-called pressure accumulation mode. Proceeding to S7, the relief pressure is lowered. This is because the hydraulic pressure cannot be recovered, so that the second synchro 23 can be switched immediately.

  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 S8). 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.

  If the relief pressure of the first relief valve 38 is not yet zero, that is, if the above-described waiting time Tlate has not yet elapsed, a negative determination is made in this step S8, the process returns to the aforementioned step S7, The previous control is continued.

  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 a positive determination is made in step S8, the process proceeds to step S9. The second sync 23 switching command is output.

  Here, the waiting time Tlate is a time represented by a period from time T2 to time T3 in the time chart of FIG. 5, and therefore, in the time chart of FIG. 5, the first relief valve at the time T2. When the command for setting the relief pressure of 38 to zero is output, the switching command for the second sync 23 is output at the time T3 when the waiting time Tlate has elapsed from the time T2.

  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 transmission torque between the second pump motor 13 and the second synchro 23 arranged on the second pump motor 13 side is reduced to zero, and the power transmission therebetween is interrupted. As a result, the second pump motor 13 is brought into a state in which no reaction force acts on the sun gear 4S of the second planetary gear mechanism 4, and accordingly, the second synchro 23 arranged on the second pump motor 13 side is also powered. In this state, the 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, the switching operation of the second synchro 23 can be performed, and therefore , Promptly, 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 accompanying the switching operation of the second synchro 23 can be shortened. As a result, the shift speed of the shift accompanied by the switching operation of the second synchro 23 can be increased.

Subsequently, the extrusion volume of each pump motor (PM) 12, 13 is controlled to a target value (step S10). The push-out volumes Q1 and Q2 of the pump motors 12 and 13 are set so 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 (ie, “sun gear 3S, 4S teeth number / ring gears 3R, 4R teeth number)) and 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 volumes Q1 and Q2 and the gear ratio γ shown in FIG.

  For example, as shown in FIG. 4, when a sudden downshift from the current actual speed ratio R0 to the target speed ratio R1 beyond the second speed fixed gear stage, the extrusion volumes Q1, Q2 of the pump motors 12, 13 are as follows. The extrusion volume Q1 is controlled so as to change from the current volume q10 to the volume q11 that is the required volume after shifting, and the extrusion volume Q2 is controlled from the current volume q20 to the volume q21 that is the required volume after shifting. The

Further, the rotational speed control of the engine 1 is executed (step S11). 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
Therefore, the engine torque (the throttle opening in the case of a gasoline engine and the fuel injection amount in the case of a diesel engine) is controlled so as to be the engine speed Ne.

  When the control of the extrusion volumes Q1, Q2 of the pump motors 12, 13 and the rotation speed control of the engine 1 are executed, the switching operation of the second synchro 23 is completed and the extrusion volumes Q1, Q of the pump motors 12, 13 are completed. It is determined whether or not Q2 has reached the target value (step S12). This is because at least one of the condition that the switching operation of the second synchro 23 has been completed and the condition that the extrusion volumes Q1 and Q2 of the pump motors 12 and 13 have reached the target values has not been satisfied. If a negative determination is made in step S12, the process returns to step S9 described above, and the previous control is repeatedly executed.

  On the other hand, since both the condition for completing the switching operation of the second synchro 23 and the condition for the extrusion volumes Q1 and Q2 of the pump motors 12 and 13 to reach the target values are satisfied, in step S12. If the determination is affirmative, the process proceeds to step S13, and relief pressure return control is performed to return the relief pressure of the first relief valve 38, which has been made zero, to the normal state. Then, the rotational speed control of the engine 1 is terminated (step S14), and then this routine is temporarily terminated.

  On the other hand, since the speed change to be executed is not a sudden downshift, that is, the difference between the actual speed ratio and the target speed ratio is a normal downshift smaller than a predetermined value, a negative determination is made in step S2. If this is the case, the process proceeds to step S15, and the synchronization in the normal downshift and the control of the extrusion volumes Q1, Q2 of the pump motors 12, 13 are executed after step S15.

  That is, in step S15, the extrusion volumes Q1 and Q2 of the pump motors (PM) 12 and 13 are at the low speed side in the gear pair that is set to the power transmission state at that time, in this example, the second speed fixed shift. It is controlled so that the stage is set. Specifically, the extrusion volume Q1 of the first pump motor 12 is set to the maximum, and the extrusion volume Q2 of the second pump motor 13 is set to zero.

  When the object to which the shift control according to the present invention is applied is an upshift, the extrusion volumes Q1 and Q2 of the pump motors 12 and 13 are at the high speed stage side in the gear pair that is set to the power transmission state at that time, For example, in the case of an upshift across the third speed fixed shift stage, control is performed so that the third speed fixed shift stage is set. Specifically, 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.

  Subsequently, it is determined whether or not the pump motor (PM) on the synchro switching side, in this example, the second pump motor 13 extrusion volume Q2 has become zero (step S16). If the second pump motor 13 extruding volume Q2 has not yet become zero, if a negative determination is made in this step S16, the process returns to the aforementioned step S15 and the previous control is continued.

  On the other hand, if the second pump motor 13 extrusion volume Q2 has become zero, and a positive determination is made in step S16, the process proceeds to step S17, and a switching command for the second synchro 23 is output. .

  Then, it is determined whether or not the switching operation of the second sync 23 has been completed (step S18). If a negative determination is made in step S18 because the switching operation of the second sync 23 has not yet been completed, the process returns to step S17 described above, and the previous control is continued.

  On the other hand, if a positive determination is made in step S18 due to the completion of the switching operation of the second synchro 23, the process proceeds to step S19, and each pump motor (PM) is similar to step S10 described above. The extrusion volumes of 12 and 13 are controlled to the target values. Thereafter, this routine is once terminated.

  When the control example by the control device of the present invention described above is compared with the conventional control example in which the control by the control device of the present invention is not performed, first, in the conventional control example shown in the time chart of FIG. In the case of a downshift accompanied by the switching operation of the synchro 23, at time T11, after a command to set the extrusion volume Q2 of the second pump motor 13 to zero is output, the extrusion volume Q2 becomes zero at time T12. At that time, in other words, after the extrusion volume Q2 becomes zero, a switching command for the second synchro 23 is output. Then, at the time T13 when the second sync 23 is switched and the completion of the switching operation is determined, the extrusion volume Q2 of the second pump motor 13 that has been made zero is set to the target value q21 after shifting, that is, the maximum. A command to set to is output. Then, after the extrusion volume Q2 reaches the target value volume q21, that is, the maximum, a command for setting the extrusion volume Q1 of the first pump motor 12 to the target value q11 after the shift is output, and the extrusion volume Q1 is the target value. This downshift is completed at the time T14 when the volume reaches q11.

  As described above, the shift time in the downshift accompanied by the switching operation of the second synchro 23 by the conventional control is the switching time Tsw required for the switching operation of the second synchro 23 represented by the period from the time T12 to the time T13 in FIG. And a time from time T11 to time T14, which includes the time for controlling the extrusion volumes Q1 and Q2 of the pump motors 12 and 13 (ie, the time from time T11 to time T12 and the time from time T13 to time T14). Become.

  On the other hand, the shift time in the downshift accompanied by the switching operation of the second sync 23 by the control of the present invention is the switching required for the switching operation of the second sync 23 represented by the period from time T3 to time T4 in FIG. At time Tsw, the pressure accumulation mode time and the waiting time Tlate at which the relief pressure of the first relief valve 38 is zero, and the time from time T4 to time T5 at which the relief pressure of the first relief valve 38 is returned to the normal level. Is the time from time T1 to time T5.

  Compared with the pump motors 12 and 13 having relatively high pressure and large capacity, the input side on / off valve 40 and the first relief valve 38 which can be constituted by electromagnetic valves have better control responsiveness. The time for controlling the valves 40, 38 may be shorter than the time for controlling the extrusion volumes Q1, Q2 of the pump motors 12, 13. In contrast to the conventional control in which switching of the second synchro 23 is started after the extrusion volume Q2 of the second pump motor 13 becomes zero, in the control of the present invention, the relief pressure of the first relief valve 38 is changed. When the waiting time Tlate of the command to zero is elapsed, the switching of the second synchro 23 can be started without waiting for the extrusion volume Q2 to become zero. Therefore, by executing the shift control by the control device of the present invention, the shift speed of the shift accompanied by the sync change operation is shortened compared to the conventional shift control, and the shift speed of the shift accompanying the sync change operation is increased. be able to. In addition, the hydraulic pressure in the oil passage 14 on the high pressure side is not simply drained, but the hydraulic pressure is recovered in the pressure accumulator 41, so that energy can be recovered and used effectively in the form of hydraulic pressure, resulting in improved energy efficiency. Can be made.

  As described above, according to the control apparatus for a variable displacement fluid pressure pump motor type transmission of the present invention, for example, when changing the gear ratio across the second speed fixed gear, that is, switching the second synchro 23 When performing a shift with an operation, the transmission torque of the power transmission path on the side where the second synchro 23 is disposed is reduced. Specifically, the first relief valve 38 is opened, that is, its relief pressure is made zero, and the transmission torque of the power transmission path on the side where the second synchro 23 is arranged is made zero. Therefore, the second synchro 23 can be brought into a state in which it is not involved in power transmission and the switching operation can be executed. As a result, the switching operation of the second synchro 23 can be executed immediately, and even in the case of a shift across the fixed shift stage, the shift time is shortened, that is, the decrease in the shift speed is avoided or suppressed, Smooth shift without any discomfort can be executed.

  Since the shift control as described above is executed particularly when a sudden shift determination that requires a rapid change in the gear ratio is established, a change in the gear ratio at the fixed gear stage during the sudden shift is performed. The stagnation of the vehicle can be eliminated, the speed can be increased, and a smooth and quick sudden speed change can be executed without any sense of incongruity. Moreover, energy efficiency can be improved.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means of step S2 described above corresponds to the sudden shift determination means of the present invention, and the functional means of steps S4 to S7 are: It corresponds to the pressure accumulation control means of this invention. The input side on / off valve 40 corresponds to the on-off valve mechanism of the present invention, and the functional means in step S5 corresponds to the differential pressure determination 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. 1, for example, in parallel with a transmission mechanism mainly composed of a gear mechanism. A transmission may be provided that is provided with a hydrostatic transmission (HST) so that the entire transmission can be changed continuously. Further, in the example shown in FIG. 1, it is configured to be able to set fixed forward speeds of four forward speeds and one reverse speed, but the transmission targeted by the present invention has a number of fixed gear speeds higher than that. It may be more or less. Furthermore, the sudden shift is not limited to a downshift, but may be an upshift.

  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.

It is a skeleton figure which shows typically an example of the transmission made into object by this invention. FIG. 2 is a chart collectively showing operation states of pump motors and synchros when setting respective gear ratios in the transmission shown in FIG. 1. FIG. 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 a synchro, and the state of the extrusion volume of each pump motor at the time of performing control by the control device of this invention. It is a time chart for demonstrating the example of control by the control apparatus of this invention. It is a time chart for demonstrating the example of the conventional control.

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 displacement pump motor (1st pump motor, PM1), 13 ... variable displacement pump motor (second pump motor, PM2), 14, 15 ... 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 ... input side on / off valve, 41 ... pressure accumulator 44 ... Output side on / off valve, 48 ... Electronic control unit (ECU), TM ... Variable displacement hydraulic pump motor type transmission.

Claims (4)

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 fluid pressure pump motor communicated; a first transmission mechanism that transmits power from the power source to the output member when one of the variable displacement fluid pressure pump motors is locked; When the variable displacement fluid pressure pump motor is locked, a second transmission mechanism that transmits power from the power source to the output member and a state in which the power transmission mechanism can selectively transmit power. A fixed speed determined by the gear ratio of each of the transmission mechanisms and the power transmitted via the pressure fluid between the variable displacement fluid pressure pump motors is continuously changed. In a control device for a variable displacement fluid pressure pump motor type transmission configured to be able to set a continuously variable transmission state by
Of the oil passage communicating with the discharge ports and the oil passage communicating with the suction ports, the extrusion volume of the one variable displacement fluid pressure pump motor is set to zero and the other variable displacement A pressure accumulator that is selectively communicated to an oil passage that is at a high pressure while the fluid pressure pump motor is locked;
Sudden shift determining means for determining a sudden shift state in which the gear ratio is rapidly changed via the fixed shift stage;
When the sudden shift state is determined by the sudden shift determining means, the high pressure oil passage is temporarily connected to the pressure accumulator to perform pressure accumulation, and then the high pressure oil passage is connected to a low pressure location. And a pressure-accumulating control means for controlling the variable displacement fluid pressure pump motor type transmission.   The pressure accumulation control means includes an on-off valve mechanism interposed between the pressure accumulator and the high pressure oil passage, a relief valve connected to the high pressure oil passage and capable of controlling a relief pressure, When the sudden shift state is determined by the sudden shift determining means, the open / close valve mechanism is temporarily opened to perform pressure accumulation by connecting the high pressure oil passage to the pressure accumulator, and then the on / off valve mechanism 2. The variable displacement fluid pressure pump motor type transmission according to claim 1, further comprising: valve control means for closing the valve and reducing the relief pressure of the relief valve so as to exhaust pressure from the oil passage having the high pressure. Control device. A pressure sensor for detecting the pressure of the pressure accumulator;
When the pressure detected by the pressure sensor is equal to or higher than a predetermined reference pressure, the valve control means lowers the relief pressure of the relief valve while maintaining the on-off valve mechanism in a closed state, so that the oil becomes the high pressure. 3. The control apparatus for a variable displacement fluid pressure pump motor type transmission according to claim 2, further comprising means for exhausting pressure from the road. A pressure difference determining means for determining a pressure difference between the oil passages;
The valve control means includes means for closing the opening / closing valve mechanism when the differential pressure determined by the differential pressure determination means is equal to or lower than a predetermined reference differential pressure after opening the opening / closing valve mechanism. The control device for a variable displacement fluid pressure pump motor type transmission according to claim 2.

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