JP3868257B2 - Gearbox for work vehicle - Google Patents

Gearbox for work vehicle Download PDF

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Publication number
JP3868257B2
JP3868257B2 JP2001323832A JP2001323832A JP3868257B2 JP 3868257 B2 JP3868257 B2 JP 3868257B2 JP 2001323832 A JP2001323832 A JP 2001323832A JP 2001323832 A JP2001323832 A JP 2001323832A JP 3868257 B2 JP3868257 B2 JP 3868257B2
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Japan
Prior art keywords
forward
reverse
gear
transmission
mechanism
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Expired - Fee Related
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JP2001323832A
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Japanese (ja)
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JP2003130174A (en
Inventor
幸雄 久保田
文雄 石橋
康男 野間
Original Assignee
ヤンマー株式会社
ヤンマー農機株式会社
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a speed change device and a speed change operation mechanism for a work vehicle.
More specifically, a hydraulic continuously variable transmission (HST) Hydro Static Transmission ) And a transmission device having a planetary mechanism and an operation device.
[0002]
[Prior art]
Conventionally, a transmission having an HST and a planetary mechanism is known. For example, it is shown by Unexamined-Japanese-Patent No. 2001-108061.
This is because, in a hydraulic-mechanical transmission device that transmits engine power to the planetary gear mechanism on the one hand and to the planetary gear mechanism on the other side via the HST for synthesizing, when the running speed reaches the set speed, The plate actuator 94 and the electronic governor 93 are interlocked to maintain the set speed. Further, in this mechanism, the backward and low-speed forward regions are performed by HST, and the vehicle is driven by the combined driving force by transmitting the driving force of HST to the planetary gear mechanism when moving forward at medium and high speeds.
[0003]
[Problems to be solved by the invention]
However, in the above configuration, it is difficult to increase the reverse speed because the reverse is performed by the driving force of the HST. Furthermore, when the weight of the vehicle is large, the burden on the HST increases, and the speed range that can be traveled by the HST decreases. In addition, swash plate control of HST becomes complicated.
[0004]
[Means for Solving the Problems]
That is, the inventors take the following problem solving means.
[0005]
In claim 1, A planetary mechanism (22) composed of an HST (21) composed of a variable displacement hydraulic pump (31) and a hydraulic motor (32), a ring gear (59), a planetary gear (58) and a sun gear (60). A forward / reverse mechanism (23) that forward / reversely shifts the output shifted by the planetary mechanism (22) by a forward / reverse gear (63/64) and a switching clutch (61), and the forward / reverse mechanism (23). In a transmission for a work vehicle having a sub-transmission mechanism (24) disposed downstream and further shifting, a transmission shaft (51) at the rear end of an output shaft (25) that drives the hydraulic pump (31) A gear (54) is fixed, and the gear (54) meshes with a gear (55) rotatably inserted in a transmission shaft (52) constituting the planetary mechanism (22). Planetary gears (58, 58) constituting the planetary mechanism (22) The gear (56) on the drive shaft (68) of the hydraulic motor (32) meshes with the gear (57) loosely fitted on the transmission shaft (52). The gear (57) rotates integrally with the sun gear (60) of the planetary mechanism (22) loosely fitted on the transmission shaft (52), and the planetary gear (58) is rotated by the transmission shaft (52). ) Side meshes with the sun gear (60), and on the outside meshes with the inner teeth of the ring gear (59) constituting the planetary gear type transmission mechanism (22), and the ring gear (59) is connected to the transmission shaft. A gear (62) which is rotatably fitted to (52) and meshes with one of the forward / reverse gears (63, 64) of the forward / reverse rotation mechanism (23) similarly fitted to the transmission shaft (52). ) And rotate together Is.
[0006]
In claim 2, In the transmission for a work vehicle according to claim 1, a forward / reverse lever (7) provided with a potentiometer 87 capable of recognizing forward, neutral and reverse positions and a potentiometer 88 capable of detecting the position are provided. In addition to being controlled by the main transmission lever (3), a shift target value is generated from the positions of the forward / reverse lever (7) and the main transmission lever (3), so that the forward / reverse rotation mechanism (23) and the HST (21) are The forward / reverse clutch (61) of the forward / reverse rotation mechanism (23) is connected when the forward / reverse lever (7) is switched from the neutral position to the forward position or from the neutral position to the reverse position at time t1. In this case, at time t2, the swash plate of the HST (21) is automatically rotated to a predetermined position at a gear ratio instructed by the main transmission lever (3) with a delay. Is.
[0007]
In claim 3, The transmission device for a work vehicle according to claim 2, wherein the forward / reverse lever (7) and the main transmission lever (3) are constituted by one transmission lever (100), and the forward / reverse mechanism (23) moves forward, neutral and reverse. Control of forward / reverse clutch (61) and speed ratio in HST (21) are performed. Is.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with reference to the drawings.
1 is an overall side view of the work vehicle, FIG. 2 is a schematic diagram showing a shift configuration of the work vehicle, FIG. 3 is a skeleton diagram showing a drive configuration of the work vehicle, FIG. 4 is a skeleton diagram showing a configuration of the HMT, and FIG. FIG. 6 is a diagram showing the relationship between the discharge amount of the hydraulic pump and the transmission ratio, FIG. 7 is a diagram showing the control configuration of the transmission mechanism, and FIG. 8 is a diagram showing the forward / reverse lever and hydraulic pressure. FIG. 9 is a schematic diagram showing a speed change control mechanism using a speed change lever, FIG. 10 is a flowchart showing the structure of speed change control, and FIG. 11 is a speed change when forward / reverse movement and speed change are performed by one lever. FIG. 12 is a diagram showing the configuration of the lever and the groove.
[0009]
In FIG. 1, an embodiment in which a work vehicle is a tractor will be described from the overall configuration.
The front wheel 1 and the rear wheel 2 are supported on the front and rear of the machine, the engine 5 is disposed inside the front bonnet 6, and a steering handle 10 is provided behind the bonnet 6. Is provided with a sheet 11. Further, a main speed change lever 3, a sub speed change lever 4, a height change lever and the like are projected on the side portion of the seat 11, and a forward / reverse changeover lever 7 is arranged as a forward / reverse changeover operation tool on the handle column side portion of the steering handle 10. Has been. The steering handle 10, the seat 11, the levers, and the like are disposed in a driving unit in the cabin 12.
[0010]
A transmission housing is disposed at the rear of the engine 5, a transmission case 9 is disposed at the rear of the transmission housing, and the power from the engine 5 is transmitted to the rear wheels 2 for driving, via a four-wheel drive switching mechanism. Thus, the driving force can be transmitted to the front wheel 1 at the same time.
[0011]
Further, the driving force of the engine 5 is transmitted to the PTO shaft 15 protruding from the rear end of the transmission case 9 and is mounted from the PTO shaft 15 to the rear end of the machine body via a universal joint or the like (not shown) via a work implement mounting device. The working machine is configured to be driven. A brake pedal, a main clutch pedal, a differential lock pedal, and the like are disposed on the step in front of the seat 11.
[0012]
Next, the speed change mechanism will be described with reference to FIG.
In the speed change mechanism of the present invention, the output of the engine 5 is changed by the HST 21 and the planetary mechanism 22. The forward / reverse rotation of the shifted output is controlled by the forward / reverse rotation mechanism 23, and the sub-transmission mechanism 24 is disposed downstream thereof. An output shaft (crankshaft) 25 of the engine 5 extends rearward of the fuselage, and driving force is transmitted to the HST 21 and the planetary mechanism 22. The driving force shifted by the HST 21 and the planetary mechanism 22 is transmitted to the forward / reverse rotation mechanism 23 and the auxiliary transmission mechanism 24.
[0013]
Next, the drive mechanism of the work vehicle will be described in more detail with reference to FIG.
An HST 21, a planetary mechanism 22, and a forward / reverse rotation mechanism 23 are disposed behind the engine 5. The hydraulic pump 21 of the HST 21 is driven by the output shaft 25. A gear that is inserted into and fixed to a shaft extending from the output shaft 25 and meshed with the planetary mechanism is also transmitted with a driving force from the output shaft 25. The output shaft 25 is connected to the transmission shaft 41 via a PTO clutch (or damper) 33. The transmission shaft 41 transmits the driving force of the output shaft 25 to the PTO transmission mechanism 34. The driving force transmitted from the output shaft 25 drives the PTO shaft 15 via the PTO transmission mechanism 34 described above.
[0014]
The HST 21 includes a hydraulic pump 31 and a hydraulic motor 32. The driving force shifted by the HST 21 is introduced into the planetary mechanism 22. A gear inserted and fixed on a drive shaft connected to the shaft of the hydraulic motor 32 is connected to the planetary mechanism 22. The driving force shifted by the HST 21 is introduced into the planetary mechanism 22 through this gear. The output from the planetary mechanism 22 is transmitted to the transmission shaft 42 via the forward / reverse rotation mechanism 23. The transmission shaft 42 is connected to the subtransmission mechanism 24, and shifts the driving force transmitted to the front wheels 1 and the rear wheels 2 by the subtransmission mechanism 24. The rear transmission 2 is connected to the auxiliary transmission 22 via a differential mechanism 36, and the drive mechanism of the front wheels 1 is connected via a four-wheel drive switching mechanism 37.
[0015]
Next, referring to FIGS. 4 and 5, the HMT composed of the HST 21 and the planetary mechanism 22. (Hydro Mechanical Transition) The configuration of will be described.
The HMT mechanism mounted on the work vehicle is composed of the HST 21 and the planetary mechanism 22. The hydraulic pump 31 of HST21 Output shaft 25 Driven by Of output shaft 25 The rear end is connected to the transmission shaft 51. A gear 54 is inserted and fixed to the front portion of the transmission shaft 51, and a driving force is transmitted to the planetary mechanism 22 via the gear 54. The gear 54 meshes with the gear 55, and the gear 55 is rotatably fitted on the transmission shaft 52. Further, the gear 55 is connected to a holding body that pivotally supports the planetary gears 58 and 58. Then, the gear 55 and the holding body integrally rotate with respect to the transmission shaft 52. The planetary gears 58 and 58 mesh with the sun gear 60 on the transmission shaft 52 side. The sun gear 60 is rotatably fitted on the transmission shaft 52, Freely fitted on the transmission shaft 52 meshed with the gear 56 on the drive shaft 68 on the hydraulic motor 32 side. It rotates integrally with the gear 57. The planetary gears 58 and 58 mesh with the inner teeth of the ring gear 59. The ring gear 59 is rotatably fitted to the transmission shaft 52 and is configured to rotate integrally with a gear 62 that is similarly fitted to the transmission shaft 52.
[0016]
Gears 63 and 64 of the forward / reverse rotation mechanism 23 are inserted into the central portion of the transmission shaft 51 so as to be rotatable relative to the transmission shaft 51. Note that the gear 63 and the gear 64 rotate integrally. The gear 63 meshes with the gear 62, and a driving force from the gear 63 is meshed with a gear 66 that is rotatably fitted to the transmission shaft 52 via the gear 64 and the gear 65. Note that the gear 65 is pivotally supported by the support shaft 51. The gear 62 and the gear 66 are connected to a clutch 61 disposed on the transmission shaft 52. The clutch 61 controls forward / reverse rotation of the transmission shaft 52. By connecting the gear 62 and the transmission shaft 52 by the clutch 61, the transmission shaft 52 is driven to the forward rotation side. Further, by connecting the gear 66 and the transmission shaft 52, the transmission shaft 52 is driven to the reverse side.
[0017]
By adopting such a speed change mechanism, the planetary mechanism 22 can synthesize a driving force via the HST 21 and a driving force not via the HST 21. For this reason, in forward or reverse travel, speed control can be performed smoothly by performing output control on the HST 21 side. That is, by controlling the swash plate of the hydraulic pump 31, the speed of the work vehicle can be adjusted. Furthermore, even when the HST 21 fails, it is possible to run in an emergency by fixing the drive shaft 68 on the hydraulic motor 32 side.
[0018]
Next, the relationship between the hydraulic oil discharge amount of the hydraulic pump of the HST 21 and the gear ratio of the work vehicle will be described.
In FIG. 6, when the discharge amount of the hydraulic pump 31 is P0, the gear ratio is 0 (the vehicle speed is 0). Then, by gradually decreasing the discharge amount, the speed ratio increases and the vehicle speed increases. When the discharge amount becomes 0, the speed ratio V1 is obtained. Further, when the transmission ratio is increased, the discharge amount is increased by reversing the hydraulic oil discharge direction of the hydraulic pump 31. That is, it is not necessary to control the clutch during forward or reverse travel (except for the sub-shift operation). During forward travel or reverse travel, since the clutch connection / disengagement associated with the shift is not performed, the transmission oil can be prevented from being deteriorated and the shift operation can be performed smoothly. Furthermore, the shift control can be easily performed, and the reliability of the transmission mechanism is improved. When the vehicle is moving backward, the forward / reverse rotation mechanism 23 reverses the rotation directions of the front wheels 1 and the rear wheels 2, so that the control of the hydraulic pump 31 is the same. The amount of discharge and the speed change rate during reverse travel are determined by the reverse speed reduction ratio of the forward / reverse rotation mechanism 23.
[0019]
Next, the control configuration of the transmission will be described with reference to FIG.
The transmission mechanism is controlled by a controller 81 as shown in FIG. The controller 81 includes an electronic governor 84 disposed in the engine 5, a pickup 85 that detects the rotational speed of the hydraulic pump 31, a potentiometer 88 that recognizes the position of the main transmission lever 3, and the position of the forward / reverse lever 7. A potentiometer 87 that recognizes the position of the auxiliary transmission lever 4, a pickup 89 that detects the rotational speed of the transmission shaft 42, an actuator 86 that controls the swash plate of the hydraulic pump 31, and a clutch 61 connection Solenoid valves 82 and 83 for disconnecting are connected. The potentiometers 87 and 88 can recognize the positions of the main transmission lever 3 and the forward / reverse lever 7 in the controller 81. Then, the swash plate of the hydraulic pump 31 is controlled according to the position, and the clutch 61 is connected / disconnected.
[0020]
As described above, by dividing the forward / reverse lever 7 and the main transmission lever 3 as the shift operation device for the working vehicle amount, it is possible to easily inherit the conventional operation configuration of the vehicle. And it is not necessary for the user of a work vehicle to learn a new operation method, and the conventional operation experience can be utilized. The forward / reverse lever 7 is also effective when operating a work machine such as a loader. It is possible to move forward and backward simultaneously with the operation of the loader, and maintain speed reproducibility of forward and backward movement.
[0021]
Next, the swash plate control configuration of the hydraulic pump 31 in the HST 21 will be described.
A sensor capable of recognizing the position or rotation angle of the main transmission lever 3 is disposed in the vicinity of the main transmission lever 3. In the present embodiment, a potentiometer 88 is disposed at the base of the main transmission lever 3, and the position of the main transmission lever 3 is recognized by the potentiometer 88. Then, the controller 81 recognizes the position of the main transmission lever 3. The controller 81 performs shift control corresponding to the position of the main shift lever 3. A swash plate angle of the hydraulic pump corresponding to the position of the main transmission lever 3 is set inside the controller 81. Based on this setting, the swash plate angle is adjusted by the actuator 86 to correspond to the main transmission lever 3. The shift control is performed.
[0022]
A potentiometer 87 for recognizing the position of the forward / reverse lever 7 and electromagnetic valves 82 and 83 for connecting and disconnecting the clutch of the forward / reverse rotation mechanism 23 are connected to the controller 81. Then, the electromagnetic valves 82 and 83 are controlled in accordance with the forward (F), neutral (N), and reverse (R) positions of the forward / reverse lever 7, and the clutch 61 is controlled. When the forward / reverse lever 7 is in the forward movement position, the forward gear and the transmission shaft 42 are connected. When in the reverse position, the reverse gear and the transmission shaft 42 are connected. When the forward / reverse lever 7 is in the neutral position, the clutch 61 is disconnected and the transmission shaft 42 is not driven. That is, the clutch 61 is configured to be linked to the forward / reverse lever 7, and the forward side connection, release, and reverse side connection are made corresponding to forward (F), neutral (N), and reverse (R). Is to be done.
[0023]
Next, the swash plate control configuration of the hydraulic pump 31 in conjunction with the forward / reverse lever 7 will be described.
The relationship between the angle of the main transmission lever 3, the position of the forward / reverse lever 7, and the swash plate angle of the hydraulic pump 31 will be described with reference to FIG. The main transmission lever 3 is held in a state of being rotated to a fixed position (D1). At time t1, when the forward / reverse lever 7 is rotated from the neutral position (N) to the forward position (F), the clutch is connected to the forward side by the electromagnetic valve. At the same time, the swash plate is rotated from the predetermined position (θ 0) by the actuator 86 and maintained at the swash plate angle (θ 1) corresponding to the position of the main transmission lever 3 at time t 2. That is, when the forward / reverse lever 7 is set to the forward or reverse position, the clutch 61 is connected, and the swash plate control of the HST 21 is performed at the speed ratio indicated by the main speed change lever 3. At time t3, when the forward / reverse lever 7 is rotated from the forward position (F) to the neutral position (N), the clutch is disengaged by the electromagnetic valve. Is rotated from the swash plate angle (θ1) corresponding to this position, and is maintained at the predetermined position (θ0) at time t4. As a result, the load on the speed change mechanism can be reduced even when a sudden speed change operation is performed. When switching to the forward / reverse lever 7, sudden torque fluctuations and impacts can be suppressed, and a smooth speed change operation can be performed.
[0024]
The swash plate angle θ0 of the hydraulic pump can be set to a swash plate angle at which the gear ratio is 0 (vehicle speed is 0) (a swash plate angle at which the discharge amount shown in FIG. 6 is P0). By setting in this way, the friction plate is stopped or in a low-speed rotation state when the clutch is connected, and no impact is generated when the clutch is connected. Then, the drive speed is increased between t1 and t2 after the clutch is connected. Thereby, durability of a clutch can be improved and smooth operativity can be obtained. The same control is performed at the time of switching from the neutral position (N) to the reverse position (R) and from the reverse position (R) to the neutral position (N), so that a smooth shifting operation can be performed.
[0025]
Next, an example of a control configuration of the HST 21 by the main transmission lever 3 will be described with reference to FIGS. 9 and 10.
In this control example, the rotation angle of the main transmission lever 3 is recognized by the potentiometer 88. The rotational speed of the transmission shaft 42 is set according to the rotational angle of the main transmission lever 3. The rotational speed of the transmission shaft 42 is recognized by the pickup 89. Then, the controller 81 compares the rotation speed corresponding to the rotation angle of the main transmission lever 3 with the rotation speed recognized by the pickup 89.
As a result of the comparison, if the rotational speeds do not match or are outside the allowable range, the actuator 86 controls the hydraulic pump of the HST 21.
[0026]
The control configuration will be described in more detail.
First, the rotation position of the main transmission lever 3 is detected by the potentiometer 88. The detected angle is input to the controller 81 as an electronic signal (or voltage). The controller 81 stores a map of a target speed (rotation speed) corresponding to the rotation position (target value a) of the main transmission lever 3. As a result, the target speed A corresponding to the rotational position (target value a) of the main transmission lever 3 is calculated by the controller 81. Further, the rotational speed B of the transmission shaft 42 is recognized by a signal recognized by the pickup 89. Then, the speed A and the speed B are compared, and the control direction of the actuator is determined based on the result. When the speed A and the speed B are equal (A = B), the control of the hydraulic pump swash plate of the HST 21 is not performed. When the speed A is higher than the speed B (A> B), the swash plate is tilted to the speed increasing side from the actuator 86. And when the speed A is smaller than the speed B (A <B), it is tilted to the deceleration side. The amount by which the actuator 86 tilts the swash plate according to an increase / decrease command by the controller 81 can be a fixed amount or an amount corresponding to the difference between the speed A and the speed B. In the case of a certain amount, the swash plate angle is tilted by a certain amount for each comparison, and the speed A and the speed B are controlled to be equal. In this case, the swash plate angle can be adjusted with an easy control configuration. When the amount is in accordance with the difference between the speed A and the speed B, the amount of rotation at a time changes, so that the speed can be adjusted quickly and the speed can be delicately corrected. is there.
[0027]
In the work vehicle having the above-described transmission mechanism, a configuration in which the forward / reverse lever and the main transmission lever are performed by one lever will be described with reference to FIGS. 11 and 12.
In this embodiment, forward and backward speed control is performed by the shift lever 100. A potentiometer 101 is disposed at the base of the transmission lever 100 so that the controller 81 can recognize the angle of the transmission lever 100. As shown in FIG. 12, the transmission lever 100 is inserted into a guide groove having a forward groove 103 configured in the front-rear direction, a neutral groove 104 configured in the left-right direction, and a reverse groove 105 configured in the front-rear direction. . The rotation direction of the speed change lever 100 is regulated by the guide groove. A forward groove 103 is connected to the inside of the neutral groove 104 and a reverse groove 105 is connected to the outside of the neutral groove. Thereby, the shift lever 100 does not move to the reverse position more rapidly than the forward position.
[0028]
The controller 81 recognizes the position of the transmission lever 100 to perform swash plate control of the HST 21 and clutch control of the forward / reverse rotation mechanism 23. When the transmission lever 100 is positioned in the neutral groove 104, the clutch of the forward / reverse rotation mechanism 23 is disengaged and the transmission of the driving force is interrupted. When the shift lever 100 is positioned in the forward groove 103, the forward side of the clutch of the forward / reverse rotation mechanism 23 is connected, and the swash plate of the HST 21 is controlled by the actuator 86 to an angle corresponding to the position of the shift lever 100. . When the speed change lever 100 is positioned in the reverse groove 105, the reverse side of the clutch of the forward / reverse rotation mechanism 23 is connected, and the swash plate of the HST 21 is controlled by the actuator 86 to an angle corresponding to the position of the speed change lever 100. . That is, the controller 81 generates a shift target value from the position of the shift lever 100, and electronically controls the HST swash plate and the clutch for moving forward and backward.
[0029]
As a result, it is possible to switch between shifting and forward / backward movement with a single lever, facilitating operation, and smooth shifting operation. In the speed change mechanism, a part of the output of the engine 5 is changed by the HST, and the acceleration / deceleration of the work vehicle is controlled by the speed ratio of the HST. Thereby, the driving driving force of the vehicle can be controlled by the HST while reducing the burden on the HST. Further, since the shift can be performed by the HST swash plate control, the shift operation mechanism can be simplified. Furthermore, the electronic control of the forward / reverse clutch enables the forward / reverse switching and speed increase / decrease operations to be prepared with a single lever.
[0030]
【The invention's effect】
As described in claim 1 A planetary mechanism (22) composed of an HST (21) composed of a variable displacement hydraulic pump (31) and a hydraulic motor (32), a ring gear (59), a planetary gear (58) and a sun gear (60). A forward / reverse mechanism (23) that forward / reversely shifts the output shifted by the planetary mechanism (22) by a forward / reverse gear (63/64) and a switching clutch (61), and the forward / reverse mechanism (23). In a transmission for a work vehicle having a sub-transmission mechanism (24) disposed downstream and further shifting, a transmission shaft (51) at the rear end of an output shaft (25) that drives the hydraulic pump (31) A gear (54) is fixed, and the gear (54) meshes with a gear (55) rotatably inserted in a transmission shaft (52) constituting the planetary mechanism (22). Planetary gears (58, 58) constituting the planetary mechanism (22) The gear (56) on the drive shaft (68) of the hydraulic motor (32) meshes with the gear (57) loosely fitted on the transmission shaft (52). The gear (57) rotates integrally with the sun gear (60) of the planetary mechanism (22) loosely fitted on the transmission shaft (52), and the planetary gear (58) is rotated by the transmission shaft (52). ) Side meshes with the sun gear (60), and on the outside meshes with the inner teeth of the ring gear (59) constituting the planetary gear type transmission mechanism (22), and the ring gear (59) is connected to the transmission shaft. A gear (62) which is rotatably fitted to (52) and meshes with one of the forward / reverse gears (63, 64) of the forward / reverse rotation mechanism (23) similarly fitted to the transmission shaft (52). ) And rotate together Therefore, the speed change operation mechanism can be simply configured. And it becomes possible to take the reverse speed large.
Further, since the shift is performed by the hydraulic transmission in the entire shift range, fine speed adjustment can be performed in a wide speed range.
Further, it is not necessary to switch the clutch according to the shift range except during forward / reverse switching, and smooth shifting is possible. For this reason, shift control can be performed by simple electronic control.
[0031]
As claimed in claim 2, In the transmission for a work vehicle according to claim 1, a forward / reverse lever (7) provided with a potentiometer 87 capable of recognizing forward, neutral and reverse positions and a potentiometer 88 capable of detecting the position are provided. In addition to being controlled by the main transmission lever (3), a shift target value is generated from the positions of the forward / reverse lever (7) and the main transmission lever (3), so that the forward / reverse rotation mechanism (23) and the HST (21) are The forward / reverse clutch (61) of the forward / reverse rotation mechanism (23) is connected when the forward / reverse lever (7) is switched from the neutral position to the forward position or from the neutral position to the reverse position at time t1. In this case, at time t2, the swash plate of the HST (21) is automatically rotated to a predetermined position at a gear ratio instructed by the main transmission lever (3) with a delay. Therefore, the operation configuration of the conventional work vehicle can be diverted, and the operation configuration suited to the worker can be taken.
Also, when operating a work machine such as a loader, the work can be efficiently performed by using the forward / reverse lever. And the speed reproducibility of the forward / reverse movement becomes easy.
Further, a smooth speed change operation can be performed, and the impact applied to the clutch can be minimized. Thereby, the durability of the transmission mechanism can be improved.
[0032]
As claimed in claim 3, The transmission device for a work vehicle according to claim 2, wherein the forward / reverse lever (7) and the main transmission lever (3) are constituted by one transmission lever (100), and the forward / reverse mechanism (23) moves forward, neutral and reverse. Control of forward / reverse clutch (61) and speed ratio in HST (21) are performed. Therefore, it is possible to operate forward / reverse movement and speed change with one lever, and it is possible to effectively use the space of the driving part of the work vehicle. In addition, it is easy to operate and realizes a smooth shifting operation.
[Brief description of the drawings]
FIG. 1 is an overall side view of a work vehicle.
FIG. 2 is a schematic diagram showing a shift configuration of a work vehicle.
FIG. 3 is a skeleton diagram showing a drive configuration of a work vehicle.
FIG. 4 is a skeleton diagram showing the configuration of an HMT.
FIG. 5 is a development view showing configurations of a planetary mechanism and a forward / reverse mechanism.
FIG. 6 is a diagram showing a relationship between a discharge amount of a hydraulic pump and a gear ratio.
FIG. 7 is a diagram showing a control configuration of a transmission mechanism.
FIG. 8 is a diagram showing a relationship between a forward / reverse lever and a hydraulic pump swash plate.
FIG. 9 is a schematic diagram showing a shift control mechanism using a shift lever.
FIG. 10 is a flowchart showing the configuration of shift control.
FIG. 11 is a control configuration diagram of the speed change mechanism in a case where the forward / reverse movement and the speed change are performed by one lever.
FIG. 12 is a diagram showing a configuration of a lever and a groove.
[Explanation of symbols]
1 front wheel
2 Rear wheels
3 Main transmission lever
7 Forward / backward lever
15 PTO axis
21 HST
22 Planetary mechanism
23 Forward / reverse mechanism
24 Sub-transmission mechanism
31 Hydraulic pump
32 Hydraulic motor
61 Clutch
81 controller
82 Solenoid valve
83 Solenoid valve
85 pickup
86 Actuator
89 pickup

Claims (3)

  1. A planetary mechanism (22) composed of an HST (21) composed of a variable displacement hydraulic pump (31) and a hydraulic motor (32), a ring gear (59), a planetary gear (58) and a sun gear (60). A forward / reverse mechanism (23) that forward / reversely shifts the output shifted by the planetary mechanism (22) by a forward / reverse gear (63/64) and a switching clutch (61), and the forward / reverse mechanism (23). In a transmission for a work vehicle having a sub-transmission mechanism (24) disposed downstream and further shifting, a transmission shaft (51) at the rear end of an output shaft (25) that drives the hydraulic pump (31) A gear (54) is fixed, and the gear (54) meshes with a gear (55) rotatably inserted in a transmission shaft (52) constituting the planetary mechanism (22). Planetary gears (58, 58) constituting the planetary mechanism (22) The gear (56) on the drive shaft (68) of the hydraulic motor (32) meshes with the gear (57) loosely fitted on the transmission shaft (52). The gear (57) rotates integrally with the sun gear (60) of the planetary mechanism (22) loosely fitted on the transmission shaft (52), and the planetary gear (58) is rotated by the transmission shaft (52). ) Side meshes with the sun gear (60), and on the outside meshes with the inner teeth of the ring gear (59) constituting the planetary gear type transmission mechanism (22), and the ring gear (59) is connected to the transmission shaft. A gear (62) which is rotatably fitted to (52) and meshes with one of the forward / reverse gears (63, 64) of the forward / reverse rotation mechanism (23) similarly fitted to the transmission shaft (52). ) To rotate integrally with the work vehicle.
  2. In the transmission for a work vehicle according to claim 1, a forward / reverse lever (7) provided with a potentiometer 87 capable of recognizing forward, neutral and reverse positions and a potentiometer 88 capable of detecting the position are provided. In addition to being controlled by the main transmission lever (3), a shift target value is generated from the positions of the forward / reverse lever (7) and the main transmission lever (3), so that the forward / reverse rotation mechanism (23) and the HST (21) are The forward / reverse clutch (61) of the forward / reverse rotation mechanism (23) is connected when the forward / reverse lever (7) is switched from the neutral position to the forward position or from the neutral position to the reverse position at time t1. when, at time t2, delay main shift lever (3) by transmission of a working vehicle, characterized in that the swash plate of the HST (21) is rotated automatically to a predetermined position in the gear ratio indicated
  3. The transmission device for a work vehicle according to claim 2, wherein the forward / reverse lever (7) and the main transmission lever (3) are constituted by one transmission lever (100), and the forward / reverse mechanism (23) moves forward, neutral and reverse. A transmission for a work vehicle, characterized by controlling the forward / reverse clutch (61) and the speed ratio in the HST (21) .
JP2001323832A 2001-10-22 2001-10-22 Gearbox for work vehicle Expired - Fee Related JP3868257B2 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106678318A (en) * 2015-11-10 2017-05-17 熵零股份有限公司 Torque converter

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5027521B2 (en) * 2007-02-05 2012-09-19 株式会社クボタ Variable speed transmission
JP4889600B2 (en) * 2007-09-05 2012-03-07 ヤンマー株式会社 Transmission device for work vehicle
JP2010076748A (en) 2008-08-29 2010-04-08 Kanzaki Kokyukoki Mfg Co Ltd Traveling system transmission structure of vehicle
CN101856972B (en) * 2010-05-20 2013-01-02 北京科技大学 Vehicle hydraulic mechanical transmission system for mine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106678318A (en) * 2015-11-10 2017-05-17 熵零股份有限公司 Torque converter

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