JP2013241984A - Hydromechanical continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydromechanical continuously variable transmission capable of reducing energy loss in driving.SOLUTION: A hydromechanical continuously variable transmission device includes: an input shaft; an HST in which a hydraulic pump and a hydraulic motor are fluidly connected via hydraulic pressure circulation paths and the hydraulic pump is driven by power from the input shaft; a differential mechanism transmitted with power from the hydraulic motor and power from the input shaft; an output shaft transmitted with power from the differential mechanism; a charge pump supplying hydraulic oil to the hydraulic pressure circulation path; a drive stop mechanism capable of stopping drive of an element transmitted with power from the hydraulic motor; and a housing containing at least the HST.

Description

  The present invention relates to a hydraulic mechanical continuously variable transmission.

  In recent years, many hydraulic continuously variable transmissions using HST have been adopted in vehicles and the like, and many hydraulic mechanical continuously variable transmissions (HMTs) combining HST and a differential mechanism have been proposed. The HMT inputs the rotational power from the input shaft to any one of the three elements of the sun gear, the internal gear, and the planet carrier constituting the planetary gear mechanism, and obtains an output from the other element. And it is comprised so that the output or input with respect to HST may be obtained from the remaining one element. This makes it possible to control various reduction ratios that cannot be obtained by HST alone.

JP 2001-355705 A

  By the way, since the HST is a transmission that uses hydraulic pressure, there is a problem that even if a differential mechanism is used, there is a drive energy loss due to oil leakage or the like. Therefore, for example, even when driving that does not require shifting, as long as the HST is used, a loss occurs, which is not efficient. The present invention has been made to solve the above problems, and an object thereof is to provide a hydraulic mechanical continuously variable transmission that can reduce energy loss during driving.

  The hydraulic mechanical continuously variable transmission according to the present invention includes an HST in which an input shaft, a hydraulic pump and a hydraulic motor are fluidly connected by a hydraulic circulation path, and the hydraulic pump is driven by power from the input shaft, and the hydraulic motor A differential mechanism that transmits power from the input shaft and power from the input shaft, an output shaft that transmits power from the differential mechanism, a charge pump that supplies hydraulic oil to the hydraulic circulation passage, The differential mechanism includes a drive stop mechanism capable of stopping the drive of the element to which power from the hydraulic motor is transmitted, and a housing that houses at least the HST.

  According to this configuration, the differential mechanism includes the drive stop mechanism that can stop the driving of the element to which the power from the hydraulic motor is transmitted. Therefore, when the drive stop mechanism is operated, the differential mechanism In contrast, only the power from the input shaft is transmitted, and this is transmitted to the output shaft through the differential mechanism. Therefore, output is possible by transmission of mechanical power without using HST that causes loss due to hydraulic pressure. Therefore, for example, when there is no need for shifting while the vehicle is running, operating the drive stop mechanism can reduce energy loss during driving compared to running using HST.

  In the hydraulic mechanical continuously variable transmission, the input shaft, the hydraulic pump, the hydraulic motor, and the output shaft can be arranged on the same axis, and the differential mechanism can be arranged between the hydraulic pump and the hydraulic motor. Further, the differential mechanism can be constituted by, for example, a planetary gear mechanism having a sun gear, an internal gear, and a planet carrier. In this case, the power from the input shaft can be transmitted to the sun gear, the power from the hydraulic motor can be transmitted to the internal gear, and the power from the planet carrier can be transmitted to the output shaft. Further, since the differential mechanism is disposed between the hydraulic pump and the hydraulic motor, the drive stop mechanism can be configured to stop the rotation of the internal gear using the HST housing.

  The drive stop mechanism can take various forms, for example, a mechanical, electrical, or a combination thereof, and a hydraulic brake driven by hydraulic fluid supplied from a charge pump. can do. When this hydraulic brake is configured to be braked by the biasing force of the spring and to be released by the hydraulic pressure, the hydraulic lock state by HST can be maintained even when the engine is stopped, preventing unexpected aircraft runaway on a slope. become able to.

  The hydraulic mechanical continuously variable transmission may further include a lubricating oil supply unit that supplies lubricating oil to the hydraulic brake. The lubricating oil supply unit supplies lubricating oil at a first supply amount when the hydraulic brake is braked, and at a second supply amount that is smaller than the first supply amount when the braking of the hydraulic brake is released. Lubricating oil can be supplied. Accordingly, the supply amount of the lubricating oil can be adjusted according to the heat generation state of the hydraulic brake, which is more efficient than the case where a constant amount of the lubricating oil is always supplied.

  In the hydraulic mechanical continuously variable transmission, the circuit pressure of the hydraulic circulation path for driving the hydraulic motor can be controlled to be released to the low pressure side before the driving stop of the elements of the differential mechanism by the driving stop mechanism. . When the drive stop mechanism is operated as described above, the drive of the hydraulic pump is stopped. However, since the hydraulic pump is difficult to stop suddenly, the elements of the differential mechanism receiving the power from the hydraulic motor If the operation is stopped first, the hydraulic motor may be damaged. Therefore, if the circuit pressure of the hydraulic circuit that drives the hydraulic motor is released to the low pressure side before the drive stop mechanism operates, the hydraulic motor can be prevented from being damaged.

  The hydraulic mechanical continuously variable transmission according to the present invention can reduce energy loss during driving.

FIG. 1 is a sectional view of a hydraulic mechanical continuously variable transmission according to this embodiment. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is an enlarged view of FIG. It is a figure explaining operation | movement of a planetary gear mechanism. It is a figure which shows schematic structure of the hydraulic circuit of the hydraulic mechanical continuously variable transmission of FIG. It is a schematic block diagram which shows an example of the control system which controls the hydraulic circuit of FIG. It is explanatory drawing which changed the hydraulic brake of FIG. 1 into the spring load type. It is a figure which shows schematic structure of the hydraulic circuit applied to FIG.

  Hereinafter, an embodiment of a hydraulic mechanical continuously variable transmission according to the present invention will be described with reference to the drawings. 1 is a sectional view of a hydraulic mechanical continuously variable transmission according to the present embodiment, FIG. 2 is a sectional view taken along line AA in FIG. 1, FIG. 3 is a sectional view taken along line BB in FIG. FIG. In the following description, the right side in FIG. 1 is referred to as the front and the left side is referred to as the rear, and the vertical direction in FIG. 1 is the vertical direction, and the horizontal direction in FIG.

  As shown in FIG. 1, the hydraulic mechanical continuously variable transmission includes a housing 2 that houses an HST (hydraulic continuously variable transmission) and a planetary gear mechanism 1. The housing 2 includes first and second oil passage plates 3 and 4 arranged in parallel in the front-rear direction, and the rear side of the pump case 2 a and the second oil passage plate 4 is disposed on the front side of the first oil passage plate 3. A motor case 2b is attached to the side. The oil passage plates 3 and 4 are connected by a plurality of connecting bolts 2c extending in the front-rear direction. Below, the space surrounded by the pump case 2a and the first oil passage plate 3, the space between the two oil passage plates 3 and 4, and the space surrounded by the second oil passage plate 4 and the motor case 2b, respectively, These are referred to as first, second, and third accommodation spaces. The first and third spaces S1, S3 are substantially closed spaces, and the second space S2 is open. In the first to third spaces S1 to S3, an HST hydraulic pump 5, a planetary gear mechanism 1, and an HST hydraulic motor 6 are arranged, respectively, together with an input shaft 21 and an output shaft 23 described later. It is arranged on the axis. Moreover, although the charge pump 201 shown in FIG. 6 to be described later is provided on the engine E side, it may be equipped in the HST. As will be described later, the charge pump 201 is supplied with hydraulic oil so as to compensate for leakage of the hydraulic oil circulating between the hydraulic pump 5 and the hydraulic motor 6.

  An input shaft 21 to which a rotational driving force from the engine E or the like is transmitted is disposed at the front portion of the housing 2. The input shaft 21 passes through the first space S1 from the front of the pump case 2a, passes through the first oil passage plate 3, and extends to near the middle of the second space S2. And it is rotatably supported by bearings 22 and 11 disposed on the front end of the pump case 2a and the rear side surface of the first oil passage plate 3, respectively. As described above, the HST hydraulic pump 5 is disposed in the first space S1. The hydraulic pump 5 includes a cylinder block 51 fixed to the input shaft 21 and a plurality of pistons accommodated in the cylinder block 51. 52 and a movable swash plate 53 for reciprocating the piston 52. The piston 52 protrudes from the front portion of the cylinder block 51 so as to be able to reciprocate in the front-rear direction and is in contact with the movable swash plate 53. As will be described later, the movable swash plate 53 is adjustable in inclination angle for shifting. With respect to the hydraulic pump 5 configured in this way, the input shaft 21 acts as a pump shaft, whereby the cylinder block 51 rotates with the rotation of the input shaft 21, and thereby the piston 52 that contacts the movable swash plate 53. Reciprocates. As a result, the hydraulic oil is discharged and the hydraulic oil is sucked from the hydraulic pump 5. This hydraulic oil passes through a hydraulic circulation path described later and circulates between the hydraulic motor 6.

  An output shaft 23 for outputting power is disposed at the rear portion of the housing 2. The output shaft 23 passes through the third space S3 from behind the motor case 2b, passes through the second oil passage plate 4, and extends to the vicinity of the middle of the second space S2. And it is rotatably supported by bearings 24 and 12 attached to the rear end portion of the motor case 2b and the front side surface of the second oil passage plate 4, respectively. As described above, the HST hydraulic motor 6 is disposed in the third space S3. The hydraulic motor 6 includes the cylindrical motor shaft 61 disposed so as to cover the outer peripheral surface of the output shaft 23, and the motor. A cylinder block 62 fixed to the outer peripheral surface of the shaft 61 is provided. A plurality of pistons 63 are accommodated in the cylinder block 62 so as to reciprocate in the front-rear direction, and a movable swash plate 64 for reciprocating the pistons 63 is disposed behind the cylinder block 62. Each piston 63 protrudes from the rear part of the cylinder block 62 and contacts the movable swash plate 64. The motor shaft 61 described above can rotate relative to the output shaft 23 and rotates together with the cylinder block 62. The motor shaft 61 extends from the hydraulic motor 6 through the second oil passage plate 4 to the second accommodation space S2. The hydraulic motor 6 configured as described above is driven by the hydraulic oil supplied from the hydraulic pump 5 described above, and rotates the motor shaft 61.

  As shown in FIG. 2, the first oil passage plate 3 has a pair of first oil passages 31 extending in the vertical direction across the through hole of the input shaft 21, and forward from each first oil passage 31. An extending pump oil passage 32 is formed. Each pump oil passage 32 is formed in an arc shape in cross section and is opened on the front surface of the first oil passage plate 3, and is arranged with the input shaft 21 sandwiched in the same manner as the first oil passage 31 and connected to the hydraulic pump 5. Has been. On the other hand, the second oil passage plate 4 is similarly configured, and as shown in FIG. 3, a pair of second oil passages 41 extending in the vertical direction across the through hole of the output shaft 23, and A motor oil passage 42 extending rearward from each second oil passage 41 is formed. Each motor oil passage 42 is formed in an arc shape in cross section and is opened on the rear surface of the second oil passage plate 4. The motor oil passage 42 is disposed with the output shaft 23 interposed therebetween and connected to the hydraulic motor 6. And as shown in FIGS. 1-3, between the lower end part of the 1st oil path 31 board and the 2nd oil path 41, a pair of connection pipe 13 which connects these is attached. The lower ends of the first oil passages 31 and the second oil passages 41 communicate with each other through these connection pipes 13.

  Thereby, the hydraulic oil discharged from the hydraulic pump 5 through the one pump oil passage 32 to the one first oil passage 31 flows into the one second oil passage 41 through the one connection pipe 13, and This hydraulic oil is supplied from one motor oil passage 42 to the hydraulic motor 6 and drives it. The hydraulic oil that has thus driven the hydraulic motor 6 is discharged and supplied to the other second oil passage 41 via the other motor oil passage 42. The hydraulic oil passes through the other connecting pipe 13 and returns to the other first oil passage 31, and then returns to the hydraulic pump 5 through the other pump oil passage 32. As described above, the hydraulic oil circulates between the hydraulic pump 5 and the hydraulic motor 6. At this time, a path through which the hydraulic oil passes is a hydraulic circulation path.

  Next, a path of hydraulic oil supplied from the charge pump 201 shown in FIG. 6 to be described later, that is, a hydraulic circulation path will be described. First, as shown in FIG. 2, a first charge oil passage 33 is formed between the pair of first oil passages 31 in the first oil passage plate 3. The oil passage 33 extends vertically from the upper end of the first oil passage plate 3 to the vicinity of the input shaft 21, and hydraulic oil is supplied from the charge pump 201 to the upper end of the oil passage 33. A branch path 331 is formed near the upper end of the first charge oil path 33. On the other hand, in the vicinity of the lower end of the first charge oil passage 33, a supply port 332 for supplying hydraulic oil as lubricating oil / cooling oil to the planetary gear mechanism 1 side of the second space S2 is formed. Opened on the rear surface of the plate 3. A communication passage 333 that communicates with each first oil passage 31 is formed near the middle of the first charge oil passage 33. Each communication passage 333 is provided with a first check & relief combined valve 34. Each first check & relief combined valve 34 has a check valve body 342 that is pushed into the first charge oil passage 33 from the first oil passage 31 side by a check spring 341, and the communication passage 333 is a first passage. The oil passage 31 is closed from the side. Therefore, when the pressure of the first charge oil passage 33 is larger than the pressure of the first oil passage 31, the check valve body 342 of the first check & relief combined valve 34 is pushed into the first oil passage 31 side, The first oil passage 31 and the first charge oil passage 33 communicate with each other, and hydraulic oil is supplied from the first charge oil passage 33.

  The check valve body 342 of each first check & relief combined valve 34 includes a pressing portion 3421 disposed on the first charge oil passage 33 side, a base portion 3422 disposed on the first oil passage 31 side, and a base portion 3422. And a relief valve body 3423 arranged between the pressing portion 3421 and the pressing portion 3421. The tip of the relief valve body 3423 protrudes from the through hole formed in the pressing portion 3421 toward the first charge oil passage 33 and closes the through hole. In addition, a safety spring 3424 is disposed between the base 3422 and the pressing portion 3421, and when the safety spring 3424 contracts, the relief valve body 3423 protrudes toward the first charging oil passage 33, and passes through the pressing portion 3421. A hole is to be opened. Here, the safety spring 3424 is stronger than the check spring 341. Normally, the valve body 342 of the first relief valve 34 blocks the communication path 333 without the safety spring 3424 contracting. However, when the pressure of the hydraulic oil in the first oil passage 31 exceeds a predetermined value, for example, when an excessive load is applied to the HST, the relief valve element 3423 opens by the safety spring 3424 contracting. As a result, hydraulic fluid flows from the first oil passage 31 to the first charge oil passage 33, and the abnormally high hydraulic pressure generated on the high pressure side of the hydraulic circulation path is released.

  A brake oil passage 35 extending upward is formed at the lower end of the first oil passage plate 3. The hydraulic oil from the charge pump 201 is also supplied to the brake oil passage 35. A communication passage 351 that is opened on the rear surface of the first oil passage plate 3 and communicates with the second space S2 is formed at the upper end of the brake oil passage 35. From the communication passage 351 to a hydraulic brake that will be described later. Hydraulic oil is supplied.

  On the other hand, as shown in FIG. 3, the second oil passage plate 4 is configured in substantially the same manner, and a second charge oil passage 43 is formed between the pair of second oil passages 4. The oil passage 43 extends in the vertical direction between the upper end of the second oil passage plate 4 and the output shaft 23. A branch passage 431 is formed at the middle portion in the vertical direction and is opened on the front surface of the second oil passage plate 4. As shown in FIG. 4, the branch passage 431 and the first charge oil passage 33 are formed. The branch pipe 331 is in communication with the branch pipe 331. As a result, hydraulic oil is supplied from the first charge oil passage 33 to the second charge oil passage 43. That is, the hydraulic oil supplied from the charge pump 201 to the first charge oil passage 33 is branched and supplied also to the second charge oil passage 43.

  Further, in the vicinity of the lower end of the second charge oil passage 43, a communication passage 44 communicating with each second oil passage 41 is formed. Each communication passage 432 is provided with a second check valve 44. The second check valve 44 has a valve body 442 that is pushed by the check spring 441 into the second charge oil passage 43 from the second oil passage 41 side, and the communication passage 432 is connected from the second oil passage 41 side. It is blocking. Therefore, when the pressure of the second charge oil passage 43 is larger than the pressure of the second oil passage 41, the valve body 442 of the second check valve 44 is pushed into the second oil passage 41 side, and the second oil passage 41 and the second charge oil passage 43 communicate with each other. Actually, since one of the pair of second oil passages 41 is high pressure and the other is low pressure, the hydraulic oil is supplied from the second charge oil passage 43 to the second oil passage 41 on the low pressure side. . Further, cam bodies 4421 are provided at the tips of the valve bodies 442 of the second check valves 44, and these cam bodies 4421 are slightly spaced apart from each other in the second charge oil passage 43. Has been placed.

  A solenoid 45 is provided at the upper end of the second charge oil passage 43, and a rod-like movable member 46 extending downward is attached to the solenoid 45. The movable member 46 is configured to protrude downward from the position of FIG. 3 when the solenoid 45 is energized. The lower end portion of the movable member 46 extends to the vicinity of the cam body 4421 of the valve body 442 of both the second check valves 44 facing each other. When the movable member 46 is moved downward by the solenoid 45 from this state, the cam bodies 4421 of both the second check valves 44 are pushed toward the second flow path 41 and both the second check valves 44 are opened simultaneously. . As a result, the circuit pressure of the hydraulic circulation path for driving the hydraulic motor 6 can be forced to open the high pressure side of the hydraulic circulation path to the low pressure side. Such an operation of the solenoid 45 (movable member 46) is performed by a controller 301 (see FIG. 7) described later. Here, the low pressure side may be an oil sump (not shown) outside the hydraulic circulation path.

  Next, the planetary gear mechanism 1 in the second space S2 will be described. As shown in FIG. 1, the planetary gear mechanism 1 includes a sun gear 15, an internal gear 16, a plurality of planetary gears 17, and a planetary carrier 18 connected to the rotation shaft of these planetary gears 17. The input shaft 21 described above is connected to the sun gear 15, and the rotation of the input shaft 21 is transmitted to the sun gear 15. A plurality of planetary gears 17 are engaged with the sun gear 15, and a planetary carrier 18 is disposed behind the planetary gears 17 to pivotally support the planetary gears 17 so as to rotate and revolve. An output shaft 23 is connected to the center of the planet carrier 18. The internal gear 16 that meshes with the planetary gear 17 extends rearward, and is connected to the motor shaft 61 of the hydraulic motor 6. Therefore, in the planetary gear mechanism 1, the power from the input shaft 21 and the power from the motor shaft 61 of the hydraulic motor 6 are combined and transmitted to the output shaft 23.

 Here, the operation of the planetary gear mechanism 1 will be described with reference to FIG. First, when the input shaft 21 is rotated in the direction Z of the arrow shown in FIG. 5 with the movable swash plate 53 of the hydraulic pump 5 in the neutral position, the sun gear 15 also rotates in the same direction. At this time, if the movable swash plate 53 is in the neutral position, the motor shaft 61 does not rotate, and as a result, the rotational speed of the internal gear 16 becomes zero (i0). At this time, the planetary gear 17 rotates and revolves in response to driving from the sun gear 15, and mechanical power rotation R <b> 1 is output from the output shaft 23 via the planet carrier 18.

 When the movable swash plate 53 is tilted in one direction from the neutral position, the motor shaft 61 rotates, and the internal gear 16 rotates from (i0) to one direction (i plus). At this time, the rotation is added to the power rotation R1 of the planetary carrier 18 described above. On the other hand, when the movable swash plate 53 is tilted in the other direction from the neutral position, the motor shaft 61 rotates in the opposite direction, so that the internal gear 16 rotates from (i0) to the other direction (i minus). To do. At this time, the rotation is subtracted from the power rotation R1 of the planetary carrier 18. When the tilt angle of the movable swash plate 53 in the other direction is maximized, the internal gear 16 rotates at the maximum speed. As a result, the rotation of the planet carrier 18 is canceled and becomes zero.

  Returning to FIG. 4, the description of the second space S2 will be continued. As shown in the figure, a plurality of annular first friction plates 101 are attached to the inner peripheral surface of the distal end portion of the internal gear 16 at a predetermined interval in the front-rear direction. An annular second friction plate 102 is disposed between the first friction plates 101, and a hydraulic brake that stops the rotation of the internal gear 16 is configured by the friction plates 101 and 102. Hereinafter, this point will be described in detail. First, a cylindrical base portion 103 is attached to the rear side surface of the first oil passage plate 3 so as to be fitted to the input shaft 21, and the bearing 11 described above is installed inside the base portion 103. The input shaft 21 is rotatably supported. An annular support member 104 for supporting the second friction plate 102 is attached to the rear end portion of the base portion 103. An annular pressing member 105 for pressing the friction plates 101 and 102 is disposed between the support member 104 and the first oil passage plate 3 on the outer peripheral surface of the base portion 103. It is possible to move in the front-rear direction along the outer peripheral surface 103. In the internal gear 16, a friction plate receiving portion 199 is provided on the opposite side of the pressing member 105 with the friction plates 101 and 102 interposed therebetween. A spring 106 is disposed between the pressing member 105 and the support member 104. Normally, the pressing member 105 is separated from the friction plates 101 and 102 by the action (biasing force) of the spring 106. That is, the hydraulic brake is released. A space 107 that communicates with the communication passage 351 of the brake oil passage 35 described above is formed between the base portion 103 and the pressing member 105, and this space is formed from the communication passage 351 (see FIGS. 1 and 2). By supplying hydraulic oil to the portion 107, the pressing member 105 is pushed backward against the spring 106. Accordingly, the pressing member 105 presses the friction plates 101 and 102, and the hydraulic brake performs braking. As a result, the rotation of the internal gear 16 is stopped. In this embodiment, the hydraulic brake is of a hydraulic load / spring unload type.

  As shown in FIG. 4, a housing portion 108 that communicates with the supply port 332 of the first oil passage plate 3 is formed on the front surface of the base portion 103. A charging relief valve 19 is disposed in the housing portion 108, and the valve body faces the supply port 332. When the hydraulic oil from the charge pump 201 exceeds a predetermined value set by the charge relief valve 19, the charge relief valve 19 is opened and the hydraulic oil is supplied into the housing portion 108. ing. In addition, a first discharge path 1081 and a second discharge path 1082 that are in communication with the rear end of the housing portion 108 are formed at the rear portion of the base portion 103. A plurality of first discharge passages 1081 are formed in the radial direction and communicate with an opening groove 1083 formed in an annular shape along the circumferential direction of the base portion 103. And the pressing member 105 is arrange | positioned so that this opening groove | channel 1083 may be covered. A radial through hole 1051 is formed in the pressing member 105, and the opening groove 1083 of the first discharge path 1081 communicates with a part of the through hole 1051 in a state where the hydraulic brake is released. That is, the opening groove 1083 of the first discharge path 1081 does not completely coincide with the through hole 1051, and a part thereof is blocked by the pressing member 105. In this state, the hydraulic oil from the accommodating portion 108 is restricted from being discharged from the through hole 1051, and a small amount (second supply amount) of hydraulic oil is discharged toward the friction plates 101 and 102. Therefore, drag torque due to oil intervening between the friction plates 101 and 102 is reduced, and energy loss is suppressed. On the other hand, in a state where the pressing member 105 moves rearward and is braked by the hydraulic brake, the opening groove 1083 of the first discharge path 1081 and the through hole 1051 coincide with each other and more from the housing portion 108 (first Supply fluid) is discharged toward the friction plates 101 and 102. A large amount of oil that has flowed toward the friction plates 101 and 102 effectively acts as lubricating oil and cooling oil in order to protect the friction plates 101 and 102. Note that, as described above, the through hole 1051 for supplying the working oil to the friction plates 101 and 102, the opening groove 1083, and the structure such as making them coincide with each other correspond to the lubricating oil supply unit of the present invention.

  On the other hand, the first discharge path 1081 is connected to the second discharge path 1082 extending in the axial direction at a plurality of locations. The second discharge path 1082 passes through the base portion 103 and the support member 104 and opens to the rear end side. The planetary gear 17 is disposed at a position facing the opening of the second discharge path 1082 so as to face the opening. As a result, the hydraulic oil discharged from the second discharge passage 1082 is sprayed onto the pivotal support portion of the planetary gear 17 as lubricating oil.

  Next, the configuration of the hydraulic circuit of the hydraulic mechanical continuously variable transmission will be described with reference to FIG. The hydraulic pump 5 and the hydraulic motor 6 are connected by the above-described hydraulic circulation path, and hydraulic oil circulates between them. As shown in FIG. 6, the charge pump 201 is provided with a first supply path 202 and a second supply path 203 for supplying hydraulic oil, and one of the supply paths is selectively selected by the first electromagnetic valve 204. Switching is possible. The first supply path 202 is branched into a plurality of parts, and moves forward and backward in addition to the first charge oil path 33 of the first oil path plate 3 and the second charge oil path 43 of the second oil path plate 4 described above. The hydraulic oil is supplied to the second electromagnetic valve 205 and the third electromagnetic valve 206 for shifting operation. Further, the hydraulic oil supplied to the second electromagnetic valve 205 for forward and backward movement and the shift operation and the third electromagnetic valve 206 is configured to drive the piston 207 in accordance with switching of these electromagnetic valves. The angle of the movable swash plate 53 (see FIG. 1) of the HST hydraulic pump 5 can be changed.

  On the other hand, when hydraulic fluid is supplied to the second supply passage 203 by switching the illustrated first solenoid valve 204 from the I position to the II position, the hydraulic fluid is supplied to the brake fluid passage 35, and the pressing member 105 is The hydraulic brake is operated by driving. Here, a brake pressure regulating relief valve 208 is provided between the second supply passage 203 and the first electromagnetic valve 204, and when the hydraulic oil is supplied to the second supply passage 203, the brake is gradually applied. It is configured to increase the pressure. Therefore, when the first electromagnetic valve 204 is switched, the hydraulic pressure is prevented from acting on the hydraulic clutch suddenly. Note that, as described above, the lubricating oil amount limiting mechanism including the opening groove 1083 of the first discharge passage 1081 formed in the base portion 103 and the through hole 1051 of the pressing member 105 is the first on the hydraulic circuit. 2 is described as a throttle valve 209 that is linked to the supply path 202.

  Next, an example of a control system for controlling the hydraulic circuit configured as described above will be described with reference to FIG. As shown in FIG. 7, this system includes a controller 301 composed of a known computer or the like, to which a forward / reverse switching lever 302 and a signal input potentiometer 304 for a shift pedal 303 are connected. ing. The forward / reverse lever 302 switches between forward and backward movement of a vehicle or the like to which the hydraulic mechanical continuously variable transmission is connected, and can select two positions, the forward position and the reverse position. The controller 301 detects the depression amount of the speed change pedal 303 with the potentiometer 304, and based on this, the second electromagnetic valve 205 and the third electromagnetic valve 206 are switched in combination to tilt the movable swash plate 53 of the hydraulic pump 5. The direction and tilt angle are determined. Further, the controller 301 switches the first electromagnetic valve 204 from the I position to the II position (see FIG. 6) based on this only when the depression amount of the shift pedal 303 is in the region S. As a result, hydraulic oil is caused to flow through the second supply path 203 to operate the hydraulic brake. At this time, the relief oil discharged from the brake pressure regulating relief valve 208 flows to the second supply path 202 via the first electromagnetic valve 204, so that the HST charge oil supply and the hydraulic brake friction plate lubricant supply continue. Done. Reference numeral 304 denotes an indicator for notifying the driver that the shift pedal 303 is in the region S, and reference numeral 305 denotes a cruise control switch, which is provided in the driving section of the vehicle.

  Further, the controller 301 is configured to switch the second and third electromagnetic valves 205 and 206 and set the inclination of the movable swash plate 53 to the neutral position when the depression amount of the shift pedal 303 is set to the region S. At substantially the same time, the first electromagnetic valve 204 is configured to switch from the I position to the II position and to excite the solenoid 45 to release the circuit pressure in the hydraulic circulation path to the low pressure side.

  Next, the operation of the hydraulic mechanical continuously variable transmission configured as described above will be described. Before the vehicle starts, the shift pedal 301 has not been depressed yet. In this state, first, rotational force is applied to the input shaft 21 from the engine E or the like to rotate the input shaft 21. Thus, when the input shaft 21 rotates, the cylinder block 51 of the hydraulic pump 5 rotates. At this time, the controller 301 receives a signal from the potentiometer 304 that detects the state of the shift pedal 303 so that the movable swash plate 53 of the hydraulic pump 5 is driven in the reverse direction at the maximum rotational speed. Tilt to the maximum angle. Thereby, the planetary gear mechanism 1 does not rotate the output shaft 23 and the vehicle stops.

  When the shift pedal 303 is depressed from this state, a signal is sent from the controller 301 to the second and third solenoid valves 205 and 206, and the movable swash plate 53 is directed toward one direction by an angle corresponding to the operation amount of the shift pedal 303. Tilt. As a result, the amount of oil discharged from the pump for driving the hydraulic motor 6 in the reverse direction is reduced, and the rotational speed of the hydraulic motor 6 in the other direction is reduced. As a result of the decrease in the reverse rotation speed of the internal gear 16 of the planetary gear mechanism 1, the planet carrier 18 starts to rotate in one direction, and the vehicle moves forward.

  Subsequently, when the shift pedal 303 enters the region S, the controller 301 operates the movable swash plate 53 to the neutral position after releasing the circuit pressure of the hydraulic circulation path by the solenoid 45 and operating the hydraulic brake by the first electromagnetic valve 204. The discharge amount of the hydraulic pump 5 is set to zero. As a result, the internal gear 16 is mechanically locked, and mechanical power rotation in the positive direction is output from the planetary gear mechanism 1. When the driver desires economic driving, it is only necessary to control the stepping angle of the shift pedal 303 to be maintained in the region S while checking the display 304. Further, a cruise control mechanism may be provided in order to release the foot from the speed change pedal 303 while maintaining the speed. When the cruise control switch 305 is turned on, the speed change pedal 303 is held at the depression angle by the operation of a friction braking mechanism (not shown).

  When stepping on the speed change pedal 303 is strengthened and deviates from the region S, the controller 301 releases the brake of the hydraulic brake and shuts off the low pressure side opening of the hydraulic circulation path, and then the movable swash plate 53 is depressed beyond the neutral position. The angle according to the angle is inclined to one side. In response to the oil discharged from the hydraulic pump 5, the hydraulic motor 6 further rotates in the forward direction, and the planetary gear mechanism 1 adds the rotation of the hydraulic drive to the mechanical power rotation and outputs it.

  As described above, according to the present embodiment, driving of the internal gear 16 to which power from the hydraulic motor 6 is transmitted in the planetary gear mechanism 1 can be stopped. At this time, only the power from the input shaft 21 is transmitted to the planetary gear mechanism 1, and this is transmitted to the output shaft 23. Therefore, output is possible by transmission of mechanical power without using HST that causes loss due to hydraulic pressure. Therefore, for example, when there is no need for shifting during traveling of the vehicle, stopping driving of the internal gear 16 can reduce energy loss on driving compared to traveling using HST.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, in the above embodiment, the power of the hydraulic pump 5 is transmitted to the internal gear 16 of the planetary gear mechanism 1, the power of the input shaft 21 is transmitted to the sun gear 15, and the power from the planet carrier 18 is transmitted to the output shaft 23. However, the present invention is not limited to this. That is, the power synthesis can be variously combined and is not particularly limited. In the above embodiment, the driving of the internal gear 16 is stopped by the hydraulic clutch, but the planetary gear mechanism that receives the power from the hydraulic motor 6 when the combination of the power combinations is changed as described above. What is necessary is just to be comprised so that the drive of 1 element may be stopped.

  Further, as shown in FIG. 8, the hydraulic brake may be of a spring load / hydraulic unload type. By doing so, even if the hydraulic pump 5 stops operating when the engine E is stopped, the internal gear 16 can be stopped from rotating, and the output shaft 23 can be connected to the engine E via the input shaft 21. Therefore, for example, even when the engine E is stopped on a slope or the like without applying the parking brake, there is no fear of the vehicle falling off.

  The spring loaded / hydraulic unloaded hydraulic brake shown in FIG. 8 will be described in detail. The friction plates 101 and 102 respectively engaged with the internal gear 16 and the base 103 are provided on the opening end side of the internal gear 16. The axial movement is restricted by the friction plate receiving portion 199. On the other hand, a disc spring 106a is disposed on the opposite side of the friction plate receiving portion 199 across the friction plates 101 and 102, and the friction plates 101 and 102 are brought into close contact with each other via the pressing plate 200a so that the internal gear 16 is mounted on the base portion. Locked to 103. That is, the hydraulic brake is in a braked state. Further, a release plate 200c is connected to the pressing plate 200a via an interlocking pin 200b, and one end of the brake release piston 105a is brought into contact with the front side thereof. Since the front end surface of the brake release piston 105a faces the pressure receiving chamber 107a, when hydraulic oil is supplied to the pressure receiving chamber 107a, the brake release piston 105a brings the release plate 200c and the pressing plate 200a together with a disc spring. Push backward against the urging force of 106a. As a result, the friction plates 101 and 102 are separated from the friction plate receiving portion 199, and the braking of the hydraulic brake is released.

  FIG. 9 shows a hydraulic circuit corresponding to the embodiment shown in FIG. According to the figure, it is a figure which shows schematic structure of the hydraulic circuit which supplies / stops hydraulic fluid to the pressure receiving chamber 107a. With respect to the first supply path 202 connected to the pressure receiving chamber 107a, the first solenoid valve 204a is operated (excited) at a brake release position I for supplying the discharge oil of the charge pump 201 when not operated (not excited). The brake position II is sometimes connected to the tank 2041a side to discharge the oil in the pressure receiving chamber 107a.

  In the above embodiment, the hydraulic brake is used as the drive stop mechanism. However, the mechanical and electrical methods are particularly limited as long as the driving of the element receiving the power from the hydraulic motor 6 in the planetary gear mechanism 1 can be stopped. Not. Also, a differential mechanism other than the planetary gear mechanism can be used, and there is no particular limitation as long as at least power from the input shaft 21 and the hydraulic motor 6 can be input and output to the output shaft 23.

1 planetary gear mechanism 15 sun gear 16 internal gear 18 planet carrier 21 input shaft 23 output shaft 5 hydraulic pump 6 hydraulic motor 201 charge pump

Claims (6)

An input shaft;
An HST in which a hydraulic pump and a hydraulic motor are fluidly connected by a hydraulic circulation path, and the hydraulic pump is driven by power from the input shaft;
A differential mechanism for transmitting power from the hydraulic motor and power from the input shaft;
An output shaft to which power from the differential mechanism is transmitted;
A charge pump for supplying hydraulic oil to the hydraulic circulation passage;
In the differential mechanism, a drive stop mechanism capable of stopping the drive of the element to which power from the hydraulic motor is transmitted;
A housing containing at least the HST;
A hydraulic mechanical continuously variable transmission. The input shaft, the hydraulic pump, the hydraulic motor, and the output shaft are arranged on the same axis,
The differential mechanism is disposed between the hydraulic pump and the hydraulic motor;
The differential mechanism is a planetary gear mechanism having a sun gear, an internal gear, and a planet carrier,
The power from the input shaft is transmitted to the sun gear,
Power from the hydraulic motor is transmitted to the internal gear,
Power from the planet carrier is transmitted to the output shaft,
The hydraulic mechanical continuously variable transmission according to claim 1, wherein the drive stop mechanism is configured to stop rotation of the internal gear with respect to the housing.   The hydraulic mechanical continuously variable transmission according to claim 1, wherein the drive stop mechanism is configured by a hydraulic brake that is driven by hydraulic oil supplied from the charge pump. The hydraulic brake includes a spring,
The hydraulic mechanical continuously variable transmission according to claim 3, wherein braking is performed by an urging force of the spring and braking is released by the hydraulic oil. The hydraulic brake includes a friction plate that performs braking, and a lubricating oil supply unit that supplies lubricating oil to the friction plate.
The lubricating oil supply unit supplies lubricating oil at a first supply amount when the hydraulic brake is braked, and the first smaller than the first supply amount when braking of the hydraulic brake is released. The hydraulic mechanical continuously variable transmission according to claim 3 or 4, wherein lubricating oil can be supplied at a supply amount of 2.   6. The hydraulic machine according to claim 1, wherein the hydraulic circulation path is controlled to be opened to a low pressure side before driving of the elements of the differential mechanism is stopped by the drive stop mechanism. Type continuously variable transmission.