JP2000127781A - Shift control method for hydromechanical transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly carry out shifting by allowing shifting in a travel state on the operation of a hydraulic continuously variable transmission and a hydromechanical transmission, and by setting the shift delay time as the total time of an electrical delay and the delay of a mechanical part, and issuing a shifting instruction earlier by the total delay time. SOLUTION: A hydromechanical transmission(HMT) is formed out of a transmission 30 equipped with a hydraulic continuously variable transmission (HST) 21. When output rotation in the forward travel side is gradually increased, an HST mode is switched to an HMT mode at a certain point, and when the output rotation drops to or below a certain point, the HST mode is selected. For speed selection, electrical and mechanical delay times due to the shift with clutches 11, 12 are taken into consideration, and control is made for estimating the arrival point of shifting with the delay times used as a time count in a simulated calculation. Thus, the shifting can be made on optimum timing and a shock or the like does not take place.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission, and more particularly to a transmission used for a tractor front loader, a backhoe, and various other construction machines, and more particularly, to a transmission control mechanism, particularly an electronic control mechanism. The present invention relates to a transmission control method.

[0002]

2. Description of the Related Art Conventionally, a driving mode using HST and HMT
As a method of reducing the shock at the time of switching the traveling mode, the method of increasing the performance of the hydraulic pump for the hydraulic clutch to shorten the clutch fill time or sending a switching instruction before reaching the switching point has been adopted.

[0003]

However, in the prior art, even if the performance of the hydraulic pump for a hydraulic clutch is improved, the cause of an electrical delay or a mechanical delay in a solenoid valve or the like increases, and The method of sending the switching instruction before reaching the switching point also does not accurately predict the arrival of the switching point, and a timing shift occurs, so that a shock has occurred.

[0004]

The above is the problem to be solved by the present invention. Next, means for solving the problem will be described. That is, a hydraulic-mechanical transmission including at least one of a hydraulic transmission unit using a variable-capacity hydraulic continuously variable transmission and a differential mechanism using planetary gears connected to both the hydraulic transmission unit and the mechanical transmission unit. The speed stage can be switched between the traveling state by the hydraulic continuously variable transmission and the traveling state by the hydraulic-mechanical transmission, and the delay time required for switching the speed stage is determined by the electrical delay time and the delay time of the mechanical part. Control is performed so as to issue a speed gear switching instruction earlier by the total delay time as the total time.

In addition, the delay time is set as a time step, an appropriate simulation calculation method corresponding to the required accuracy and the allowable operation time is selected, and the simulation calculation method uses the time step to reach the speed ratio switching point of the speed ratio. Predict the time until.

[0006]

Next, an embodiment of the present invention will be described. FIG. 1 is a front view of a hydraulic-mechanical transmission, and FIG.
FIG. 3 is a block diagram of the hydraulic-mechanical transmission, FIG. 4 is a diagram showing the relationship between the output of the hydraulic-mechanical transmission and the discharge amount of the hydraulic pump and the hydraulic motor, and FIG. FIG. 6 is a flow chart of a clutch switching instruction control, FIG. 7 is a diagram showing a relationship between time and speed ratio, FIG. 8 is a control output diagram of the clutch based on time, and FIG. FIG. 10 is a flowchart of a speed ratio control, FIG. 10 is a flowchart of a volume correction sharing control, FIG. 11 is a diagram illustrating a correspondence relationship between an operation amount of a speed ratio indicating lever and a target speed, FIG. 12 is a control diagram of the controller 100, and FIG. FIG. 14 is a flowchart of the neutral control.

Referring to FIGS. 1 and 2, the construction of a hydraulic-mechanical transmission (hereinafter referred to as HMT) 40 will be described. The HMT 40 is configured by a transmission 30 having an HST (hydraulic continuously variable transmission) 21 and a planetary gear unit 7. The HST 21 includes a hydraulic pump 22 and a hydraulic motor 23 included in an HST case 31 and a center section 32.
Is fixed to the case 33 of the mission 30.

An input shaft 25 is inserted through the HST 21, and a movable swash plate 22a and a cylinder block 22b of the hydraulic pump 22 are inserted into the input shaft 25. The cylinder block 22b is inserted into the input shaft 25 so as not to rotate relatively, and the cylinder block 22b is driven together with the input shaft 25. A plurality of plunger pumps 22c are slidably disposed on the cylinder block 22b. The plunger pump 22
The movable swash plate 22a is in contact with the distal end of the movable swash plate 22a, and the amount of hydraulic oil discharged from the hydraulic pump 22 can be adjusted by adjusting the inclination angle of the movable swash plate 22a.
The hydraulic oil discharged from the hydraulic pump 22 is sent to a hydraulic motor 23 via an oil passage provided in the center section 32.

A hydraulic motor output shaft 26 is inserted into the hydraulic motor 23 of the HST 21.
One end of 6 is rotatably supported by the HST case 31. A movable swash plate 23a of the hydraulic motor 23 and a cylinder block 23b are inserted into the hydraulic motor output shaft 26, and the cylinder block 23b is connected to the hydraulic motor output shaft 26.
, So that relative rotation is impossible. A plurality of plunger pumps 23c are slidably disposed on the cylinder block 23b, and the movable swash plate 23a is in contact with the tip of the plunger pump 23c.
The capacity of the hydraulic motor 23 can be adjusted by adjusting the inclination angle of. With this configuration, the rotation speed for the amount of hydraulic oil fed from the hydraulic pump 22 is adjusted.

Next, the configuration of the mission 30 will be described. The mission 30 is covered by a transmission case 33, and the transmission case 33 has an input shaft 2
5, hydraulic motor output shaft 26, drive shaft 27 and drive shaft 1
8 are provided and supported rotatably. Further, a planetary gear unit 7 including a planetary gear is provided in the transmission case 33, and the planetary gear unit 7 is divided by the clutch unit 35 and the case 34 in the transmission case 33. The planetary gear unit 7 includes a sun gear 1, planetary gears 2 and 3, an input gear 4, and a carrier 6, which will be described later.
And a gear 5 fixed to the carrier 6
Is the clutch part 3 by the case 34 together with the planetary gear part 7.
5 is isolated.

The clutch section 35 is provided with the clutch 11 inserted on the hydraulic motor output shaft 26 and the clutch 12 inserted on the drive shaft 27. The clutch housing of the clutch 11 is fixed on the hydraulic motor output shaft 26, and the clutch box of the clutch 11 is fitted on a rolling bearing inserted on the hydraulic motor output shaft 26. Gear 1 is placed in the clutch box of clutch 11
The gear 14 is driven together with the hydraulic motor output shaft 26 by connecting the clutch 11. The clutch housing of the clutch 12 is fixed on the drive shaft 27, and the clutch box of the clutch 12 is fitted on a rolling bearing inserted on the drive shaft 27. The clutch 16 of the clutch 12 has a gear 16
The gear 16 is driven together with the drive shaft 27 by connecting the latch 12.

Case 3 in the transmission case 33
4, the planetary gear portion 7 is isolated from the clutch portion 35, so that the planetary gear portion 7 can be protected from sludge generated from the clutches 11 and 12, and the durability of the planetary gear portion 7 is improved. are doing.

The sun gear 1 is inserted and fixed to the input shaft 25, and a power transmission pipe 28 integrally formed with the gear 4 is inserted so as to be relatively rotatable. The planetary gear unit 7 is configured to be inserted into the input shaft 25 and the power transmission pipe 28. The gear 5 fixed to the carrier 6 of the planetary gear portion 7 meshes with a gear 9 fixedly fitted to a drive shaft 27, and the gear 9 meshes with a gear 19 fixedly fitted to a drive shaft 18. ing. With this configuration, the driving force of the gear 5 is transmitted to the drive shaft 18 via the gears 9 and 19.

In FIG. 3, the output of the engine 24 is HS
T21, one of the planetary gear units 7 or HST2
1 and to the drive shaft 27 via the planetary gear unit 7. One end of an input shaft 25 is connected to the engine 24, and the output of the engine 24 is connected to the HST through the input shaft 25.
21. The HST 21 includes a hydraulic pump 22 and a hydraulic motor 23.
2 and the hydraulic motor 23 are configured to have variable capacity. Therefore, the hydraulic pump 22 or the hydraulic motor 2
By adjusting the capacity of 3, the drive ratio of the hydraulic motor 23 to the hydraulic pump 22 can be adjusted. The input shaft 25 is connected to the hydraulic pump 22, and the hydraulic pump 22 is driven by the input shaft 25. With the above configuration, the output of the engine 24 is supplied to the HS
The hydraulic pump 22 in T21 is driven, and the hydraulic motor 23 is driven by the hydraulic pump 22. A hydraulic motor output shaft 26 is connected to the hydraulic motor 23 and is configured to be driven by the hydraulic motor 23.

The other end of the input shaft 25 is connected to the planetary gear unit 7. The planetary gear unit 7 includes a sun gear 1, a planetary gear 2, a planetary gear 3, a carrier 6, and an input gear 4. The sun gear 1 is inserted and fixed to the other end of the input shaft 25, and a planetary gear 2 meshes with the sun gear 1. The planetary gear 2 meshes with the planetary gear 3, and the planetary gear 3 meshes with the input gear 4. The planetary gears 2 and 3 are rotatably supported by pivots fixed to the carrier 6 and revolve with respect to the sun gear 1.

In the planetary gear section 7, the planetary gears 2 and the planetary gears 3 are arranged in three pairs, and the planetary gears 2 and the planetary gears 3 are formed so that the center of rotation of the carrier 6 is concentric. It is configured to rotate on the circumference. A planetary gear 2 meshes with the outer periphery of the sun gear 1, and a planetary gear 3 is disposed outside the planetary gear 2 with respect to the center of rotation of the carrier 6. A gear 5 is fixed to the carrier 6, and the rotation centers of the sun gear 1, the input gear 4, the carrier 6, and the gear 5 are arranged on the same straight line. The gear 5 fixed to the carrier 6 meshes with a gear 9 inserted and fixed to one end of a drive shaft 27,
The driving force can be transmitted to the gear 9. The gear 9 meshes with a gear 19 which is inserted and fixed to a drive shaft 18. With this configuration, the driving force of the gear 5 is transmitted to the drive shaft 18 via the gears 9 and 19.

The input gear 4 is integrally inserted and fixed at one end of the power transmission pipe 28 on the outer periphery of the power transmission pipe 28, and the gear 10 is mounted on the outer circumference of the other end of the power transmission pipe 28. Inserted and fixed. The gear 10 is meshed with the gear 14 inserted into the hydraulic motor output shaft 26. The gear 14 is fixed to a clutch box of the clutch 11 fixedly fitted to the hydraulic motor output shaft 26, and the gear 14 is driven together with the hydraulic motor output shaft 26 by operating the clutch 11. It has become. A gear 15 is inserted and fixed on the outer periphery of one end of the hydraulic motor output shaft 26, and the gear 15 meshes with the gear 16 inserted into the drive shaft 27. The gear 16 is fixed to a clutch box of the clutch 12 which is fitted and fixed to a drive shaft 27. When the clutch 12 is operated, a drive force is applied to the drive shaft 27 by the gear 16 and the drive shaft 27 together with the gear 16. 27 is rotated. The drive shaft 27 is fixedly provided with a gear 9, and the gear 9 is engaged with a gear 19 fixedly fitted to the drive shaft 18. The output of the drive shaft 27 is transmitted to the drive shaft 18 via the gears 9 and 19.

In the above configuration, the clutch 11 is disengaged, the clutch 12 operates, and the gear 16 and the drive shaft 27 are disengaged.
Is connected, the driving shaft 27 is driven by the driving force of the hydraulic motor output shaft 26 of the HST 21.
The output of the drive shaft 27 is transmitted to the drive shaft 18 via the gears 9 and 19. The output of the engine 24 is H
The speed is changed in ST21 and output from the hydraulic motor output shaft 26. When the hydraulic motor output shaft 26 is driven, the gear 15 is driven, and the gear 16 meshed with the gear 15 is driven. The gear 16 is fixedly provided with a clutch box of the clutch 12. Since the clutch 12 is operated, the gear 16 and the drive shaft 27 are connected. Thus, the output of the hydraulic motor output shaft 26 is
7 is driven. That is, by disconnecting the clutch 11 and operating the clutch 12, the drive shaft 27 is driven only by the driving force shifted by the HST 21. The output of the drive shaft 27 is transmitted to the drive shaft 18 via the gears 9 and 19.

When the clutch 11 is operated, the gear 14 is connected to the hydraulic motor output shaft 26, and the clutch 12 is disconnected, the driving force of the input shaft 25 and the driving of the hydraulic motor output shaft 26 The force is combined in the planetary gear unit 7, and the output combined in the planetary gear unit 7 drives the drive shaft 27. The output of the engine 24 is transmitted to the sun gear 1 via the input shaft 25, and the driving force of the input shaft 25 is introduced to the planetary gear unit 7 by the sun gear 1. The driving force of the hydraulic motor output shaft 26 is transmitted to the gear 10 via the gear 14 by connecting the clutch 11. The power transmission pipe 28 is driven by the gear 10, and the input gear 4 formed integrally with the other end of the power transmission pipe 28 is driven. The driving force of the hydraulic motor output shaft 26 is transmitted to the planetary gear unit 7 by the input gear 4. The driving force of the input shaft 25 and the hydraulic motor output shaft 26 is combined in the planetary gear unit 7 to drive the carrier 6. The driving force of the carrier 6 is transmitted to the gear 9 by the gear 5 fixed to the carrier 6 and transmitted to the drive shaft 27 by the gear 9. Thus, the drive shaft 2 is driven by the drive force transmitted to the planetary gear unit 7 by the input shaft 25 and the drive force shifted by the HST 21.
7 is driven. Further, the drive shaft 2 is connected via the gears 9 and 19.
7 is transmitted to the drive shaft 18.

A power source rotation speed detector 104 is provided near the input shaft 25 so that the rotation speed of the input shaft 25 can be detected. A rotation detector 103 is also provided in the vicinity of the gear 9 fixedly fitted to one end of the drive shaft 27 to detect the number of rotations of the gear 9. The power source rotation speed detector 104 and the rotation detector 103 are connected to the controller 100, and the detection values of the power source rotation speed detector 104 and the rotation detector 103 are input to the controller 100. .

A speed indicator and solenoid valves 105 and 106 are connected to the controller 100, and are controlled by the controller 100. The speed indicator is configured to calculate and display the speed from the detection values of the power source rotation speed detector 104 and the rotation detector 103. Also, the solenoid valve 105 connected to the controller 100
The operation of the clutch 11 and the clutch 12 is controlled by 106. Controller 100
In the above, calculation is performed based on the detection values of the power source rotation speed detector 104 and the rotation detector 103, the solenoid valves 105 and 106 are controlled by the controller 100, and the clutches 11 and 12 are disconnected or connected to switch the driving state. Done. That is, the HM is
The drive state can be automatically switched according to the drive speed of T40, and a smooth shift can be realized.

In the above driving method, the case where the driving shaft 27 is driven by the driving force of the hydraulic motor output shaft 26 of the HST 21 is in the HST mode, and the combined driving force of the driving force of the input shaft 25 and the driving force of the hydraulic motor output shaft 26 is used. The case where the drive shaft 27 is driven by the control is referred to as an HMT mode. In the HST mode, the clutch 11 is disengaged and the clutch 12 is connected as described above. In the HMT mode, the clutch 11 is connected as described above, and the clutch 12 is disengaged. In FIG. 4, a graph 41 shows the hydraulic oil discharge amount of the hydraulic pump 22, a graph 42 shows the hydraulic oil discharge amount of the hydraulic motor 23, and a graph 43 shows the output of the HMT 40.
In the graph 43, the left drive from the neutral point N is the reverse drive, and the right drive is the forward drive. At the neutral point N, the output rotation is 0, and no driving is performed. In this configuration, the motor is driven in the HST mode in the whole range on the reverse side and in the range of low speed rotation on the forward side, and is driven in the HMT mode in the range of medium speed rotation and high speed rotation.

Next, the hydraulic pump 22 corresponding to the graph 43
In the graph 41 showing the hydraulic oil discharge amount of the hydraulic pump 2
The control configuration of the discharge amount of No. 2 will be described. Graph 4
At a point corresponding to the neutral point N of 3, the discharge amount of the hydraulic pump 22 is 0, the discharge amount below the discharge amount 0 is negative, and the discharge amount above the discharge amount is positive. The points P1 and P
2 is the minimum discharge amount of the hydraulic pump 22. That is,
The discharge amount of the hydraulic pump 22 at the points P1 and P2 is the maximum negative discharge amount. In the graph 42, the discharge amount of the hydraulic oil of the hydraulic motor 23 decreases on the reverse side from the point P2 and decreases also on the forward side from the point P1, and the discharge amount is constant between the points P1 and P2. It is kept in.

That is, when increasing the output rotation to the reverse side from the neutral point N, the output rotation for driving the hydraulic motor 23 to the reverse side is increased by increasing the discharge amount of the hydraulic pump 22 to the negative side. That is, the movable swash plate 22 of the hydraulic pump 22
a by inclining the hydraulic pump 2
The second is to increase the discharge of hydraulic oil to the minus side. Since the discharge amount of the hydraulic motor 23 is kept constant, the hydraulic motor 23 is further driven to the minus side by increasing the discharge amount of the hydraulic pump 22 to the minus side.

When the output rotation is further increased to the reverse side and the output rotation is performed to the reverse side beyond the point P2, the hydraulic pump 22
Is maintained at the discharge amount at the point P2, and the discharge amount of the hydraulic motor 23 is reduced. Thereby, the hydraulic pump 2
2 and the discharge amount of the hydraulic motor 23 changes, and the discharge amount of the hydraulic pump 22 increases with respect to the discharge amount of the hydraulic motor 23. That is, the output of the hydraulic motor 23 further increases to the minus side. By adjusting the discharge amount of the hydraulic pump 22 and the hydraulic motor 23 when performing the output control on the reverse side as described above, it is possible to increase the output rotation range on the reverse side.

Next, a case where the output rotation is increased to the forward side will be described. When increasing the output rotation to the forward side from the neutral point N, the output is increased by increasing the discharge amount of the hydraulic pump 22. Since the discharge amount of the hydraulic motor 23 of the HST 21 is constant, the discharge amount of the hydraulic pump 22 is increased with respect to the discharge amount of the hydraulic motor 23 by increasing the discharge amount of the hydraulic pump 22, and the rotation of the hydraulic motor 23 is increased. Increase. In the HST mode, since the driving is performed only by the HST 21, the output rotation of the hydraulic motor 23 is increased by increasing the output rotation of the hydraulic motor 23. Further, a clutch operation is not required when shifting from the reverse range to the forward range and when shifting from the forward range to the reverse range. HST2 throughout reverse and low speed forward
Since the shift is performed by 1, the clutch operation is not required in the entire reverse range and the forward low speed range. For this reason, a smooth shift operation can be performed in the entire reverse range and the forward low speed range, and the shift is performed by the HST 21 in which fine speed arbitration is easily performed, so that operability is good.

In the forward output range, the hydraulic pump 2
When the discharge amount of No. 2 is further increased, the output rotation in the HST mode at the point X coincides with the output rotation in the HMT mode corresponding to the discharge amount of the hydraulic pump 22. That is, when increasing the output rotation on the forward side, at this point X, H
Switching from the ST mode to the HMT mode is performed. Further, the output rotation is reduced from the state in which the output is performed in the HMT mode.
The mode is switched from the mode to the HST mode.

Switching from the HST mode to the HMT mode is performed by controlling the connection and disconnection of the clutch 11 and the clutch 12 as described above. That is, as shown in FIG. 5, when switching from the HST mode to the HMT mode, the clutch 11 is operated from the disconnected state to the connected state, and the clutch 12 is operated from the connected state to the disconnected state. On the contrary, HMT mode
When switching to the ST mode, the clutch 12 is operated from the disconnected state to the connected state, and the clutch 11 is operated from the connected state to the disconnected state. By controlling the clutches 11 and 12 as described above,
The drive mode can be switched at the point X.

When the output rotation exceeds the point X and driving is performed in the HMT mode, the input shaft 25 to which the rotation supplied to the planetary gear unit 7 by the hydraulic motor 23 and the rotation of the engine 24 are mechanically transmitted. The output rotation is determined by the rotation supplied to the planetary gear unit 7. That is, in the HMT mode, the output rotation increases as the difference between the rotation speeds of the input shaft 25 and the hydraulic motor 23 increases. When the discharge amount of the hydraulic pump 22 is reduced and the output rotation of the hydraulic motor 23 is reduced in the output rotation on the forward side from the point X, the input shaft 2
5, the difference between the output rotation of the hydraulic motor 23 and the output rotation of the input shaft 25 increases. As a result, the output rotation increases.

Further, the discharge amount of the hydraulic pump 22 is reduced, and when the discharge amount of the hydraulic pump 22 reaches P1, the discharge amount of the hydraulic pump 22 is maintained at P1, and the discharge amount of the hydraulic motor 23 is maintained. Decrease. Since the discharge amount of the hydraulic pump 22 is constant and the discharge amount of the hydraulic motor 23 decreases, the discharge amount of the hydraulic pump 22 relative to the hydraulic motor 23 increases relatively. As a result, the speed of the hydraulic motor 23 increases. As shown in graphs 41 and 42, the output rotation of the hydraulic motor 23 is increased in the minus direction, so that the input rotation of the input shaft 25 to the planetary gear unit 7 and the hydraulic motor 2
The difference between the input rotations to the planetary gear unit 7 of No. 3 increases, and the output rotation increases.

As described above, the output of the hydraulic pump 22 is adjusted to control the output of the hydraulic motor 23. When the output is further increased, the output of the hydraulic pump 22 is maintained constant. The output of the hydraulic pump 22 and the hydraulic motor 23 are adjusted, and the output is adjusted by changing the relative discharge of the hydraulic pump 22 and the hydraulic motor 23, thereby increasing the range of output rotation that can be adjusted even in a hydraulic pump and a hydraulic motor with a small discharge. I do. Therefore, the HST 21 can be made compact. Further, at the point X where the output rotations of the HST mode and the HMT mode match, the switching between the HST mode and the HMT mode is performed, so that the switching between the output modes can be performed smoothly.

In the above configuration, the HST 21 outputs power in the entire reverse range and in the forward low speed range, and is driven by the HMT 40 in the middle forward speed range to the high speed range, so that the HMT 40 is mounted on a small vehicle or the like. By doing so, it is possible to perform a gear shift according to the use condition of the small vehicle. Further, since the shift range corresponds to a small vehicle, the handleability of the small vehicle is improved.

In the forward and reverse areas, HST
Since it is driven by the motor 21, fine speed setting can be performed in the double speed range, and the quality of work can be improved. In the middle to high speed range, HMT
Since it is driven by the motor 40, the transmission is smoothly shifted, and at the same time, the loss of the output of the engine is reduced, the output is improved, and the fuel consumption is improved, which is economical. Further, the transmission mechanism can be simply configured.

Hereinafter, a control structure of the controller 100 and the like for shifting, speed change, and braking will be described with reference to FIG. 3 and FIGS. FIG.
As shown in FIG.
0 is provided, and the brake pack 110 is controlled via the mechanical link 141 when the brake pedal 140 is depressed to generate a braking action on the drive shaft 18. The brake switch 111 is configured to output an operation signal to the controller 100 when the brake pedal 140 is depressed.

The controller 100 is linked with a speed ratio indicating lever 120, a pump swash plate controller 121, and a motor swash plate controller 122, which are running operation levers. A position sensor 120a for detecting the operation amount of the speed ratio instruction lever 120 is provided between the two. And the position sensor 12
The controller 100, which has received the detection result of 0a, outputs the inclination angle to the pump / motor swash plate controllers 121 and 122, respectively. Motor 2
2. Adjust the movable swash plates 22a and 22b of the HST2.
1 is controlled.

The controller 100 includes a solenoid valve 1
05 and 106 are linked, and the solenoid valves 105 and 106
To control the connection and disconnection of the clutches 11 and 12. Further, the gear 9 fixed to the drive shaft 27 includes:
A rotation detector 103 is provided so as to be able to detect the number of rotations and the direction of rotation of the drive shaft 27, and the number of rotations and the direction of rotation of the drive shaft 27 are controlled by the controller 100 by the rotation detector 103.
Can be entered.

With the above configuration, a method for controlling the switching of the speed between the HST mode and the HMT mode according to the present invention will be described with reference to FIGS. As described above, if the speed gear is switched at the point X where the output rotation in the HST mode and the output rotation in the HMT mode match, it is possible to reduce the shock due to the switching operation. Solenoid valve 10 according to an instruction from controller 100
Since the operation is performed by operating the clutches 11 and 12 through 5 and 106, an electrical delay time and a mechanical delay time are generated. For this reason, when a speed gear switching instruction is issued after detecting the switching speed ratio Vx at the point X, a timing shift occurs, and a shock due to the switching operation occurs.

A method of controlling speed changeover taking into account the delay time will be described with reference to the flowchart of FIG. First, in process 232, the controller 100 detects and inputs the rotation speed of the engine 24 from the power source rotation speed detector 104 and the hydraulic oil temperature of the hydraulic oil tank 130 for the hydraulic machine from the hydraulic oil sensor 131. Then, the delay time h is calculated from the delay time calculation map using the input engine speed and hydraulic oil temperature as input values. Note that the delay time calculation map includes the engine speed, the operating oil temperature, the clutch 1
This is a mapping in which the electrical and mechanical operation times 1 and 12 correspond to each other.

Then, in the process 233, a simulation calculation is performed using the delay time h as a time interval, and the speed ratio V (t + h) after h seconds at the time t is predicted. Here, the prediction calculation by the Milne's method is performed as an example. However, since the delay time h is set in units of time, various other simulation calculations can be performed. Next, in the conditional branch 234, the speed ratio V (t +
h) is compared with the switching speed ratio Vx at the point X, and if the speed ratio V (t + h) is larger than the speed ratio Vx (that is, it is predicted that the switching point X will be reached after h seconds). In step 235, the clutch 11 is operated.
Thus, the gear 14 described above is connected to the hydraulic motor output shaft 26.
And the motive power in the HMT mode starts to be driven.

Then, in condition branch 236, the current speed ratio V (t) and the switching speed ratio Vx are compared in magnitude.
Here, if the speed ratio V (t) is smaller than the speed ratio Vx, the process returns to the start 231 via the end 238 of the control loop and enters the next control loop. Then, in the process 236, the speed ratio V (t) becomes larger than the speed ratio Vx again.
Proceeding to 37, the clutch 12 is disconnected. As a result, the drive transmission from the hydraulic motor output shaft 26 to the drive shaft 27 via the gears 15 and 16 is cut off, and the power in the HST mode is cut off. If the speed ratio V (t + h) is smaller than the switching speed ratio Vx in the process 234, the process proceeds to the conditional branch 236, where the speed ratio V (t) is determined, and thereafter the loop control is performed.

That is, the delay time h is used as a time interval for the simulation calculation, and a speed ratio V (t + h) after h seconds at a certain time t is predicted and calculated from the time interval. It is determined whether or not the speed ratio Vx which is the optimum speed ratio for the stage switching is reached. If the speed ratio V (t + h) is expected to reach the speed ratio Vx, the clutch 11 is immediately connected, and driving in the HMT mode is started. Then, the control loop is continued, and when the current speed ratio V (t) reaches the speed ratio Vx, the clutch 12 is immediately disconnected, and the drive in the HST mode is cut off. FIG. 7 is a graph showing the relationship between the time and the speed ratio, and FIG. 8 is a diagram showing the connection state of the clutch 11 and the clutch 12 by the speed stage switching control. The time Tx is a predicted time at which the speed ratio reaches Vx, and FIG. 8 shows that the clutch 11 is operated h time before the time Tx, and the clutch 12 is disengaged when the time Tx is reached. I have.

As described above, the speed stage switching of the present invention takes into account the electrical and mechanical delay time due to the speed stage switching by the clutches 11 and 12, and furthermore, the sending time is used as a time step in the simulation calculation. Since the control is performed so as to predict the arrival point of the speed gear switching, even when the speed ratio changes by a higher-order function such as a quadratic function, the prediction can be performed with high accuracy. Because it can be performed at the optimal timing, it is possible to smoothly switch speed stages without causing a shock or the like.

Next, a control method of the HST 21 will be described with reference to FIG.
This will be described with reference to FIG. In the HST mode and the HMT mode, the hydraulic pump / motor 22
By controlling the discharge amount of the pump 23, the acceleration / deceleration can be performed. As described above, the discharge amount is changed between the hydraulic pumps / motors 22/23 on both sides of P1 and P2 shown in FIG. Is configured to switch.

With such a configuration, even if the operator desires rapid deceleration or acceleration, the hydraulic pump 2
Since the control of the discharge amount 2 and the control of the discharge amount of the hydraulic motor 23 are performed sequentially, the acceleration / deceleration time becomes long. Therefore, these problems are solved by performing the instruction speed ratio control as shown in FIG.

First, the case where the speed is rapidly reduced from Pa to Pb in FIG. 4 will be described. At Pa, the operator operates the speed ratio instruction lever 120 to give a speed ratio instruction targeting Pb. At this time, the discharge amounts of the hydraulic pumps / motors 22 and 23 that realize the speed ratio at Pb are determined. Therefore, the controller 100 issues a control command to the pump / motor swash plate controllers 121 and 122 at the same time. Thereby, the movable swash plates 22a and 23a of the hydraulic pumps / motors 22 and 23 are realized to realize the speed ratio in Pb.
At the same time.

As a result, rapid deceleration from Pa to Pb becomes possible, and the operator can quickly obtain the expected speed, thereby improving the operability. Also, from Pb to Pa
In the case of rapid acceleration toward, it is possible to perform the same operation as described above.

Next, a case where the operator instructs rapid deceleration and rapid acceleration and shifts across the speed gear switching point X in FIG. 4 will be described. In the case of rapid acceleration from Pc to Pa in FIG. 4, the operator operates the speed ratio instruction lever 120 at Pc to give a speed ratio instruction targeting Pa. At this time, the discharge amounts of the hydraulic pumps / motors 22 and 23 that realize the speed ratio in Pa are determined. However, when the discharge amount in Pa is instructed to the hydraulic pumps 22 and 23 in Pc, since the stroke crosses the point X as described above, the switching from the HST mode to the HMT mode is performed, and the shock due to the mode switching causes a shock. This may cause damage to parts such as the clutches 11 and 12 in some cases.

Therefore, when the Pa speed ratio is designated in Pc, the controller 100 instructs the pump / motor swash plate controllers 121 and 122 to determine the switching speed ratio Vx at the point X. Thereby, the hydraulic pump / motor 2
2 · 23 is adjusted to the speed ratio at the point X, and at this time, the switching from the HST mode to the HMT mode is performed. Subsequently, the controller 100 instructs the pump / motor swash plate controllers 121 and 122 on the speed ratio in Pa, and simultaneously adjusts the movable swash plates 22a and 23a of the hydraulic pump / motors 22 and 23 to adjust the speed in Pd. You get the ratio.

In this manner, even in the rapid acceleration across the X point, the rapid acceleration can be performed without applying a load to the clutch or the like by once passing through the speed ratio Vx at the X point. It is also possible to accelerate suddenly. Similarly, in the case of rapid deceleration from Pa to Pc, the switching shock from the HMT mode to the HST mode occurs by instructing the speed ratio of Pc after passing through the speed ratio Vx at the point X. Without doing
Rapid deceleration is possible.

The control flow shown in the example of rapid acceleration and rapid deceleration from Pa to Pb and from Pc to Pa will be described with reference to the flowchart of FIG. First, it is determined whether or not the speed ratio indicated in the conditional branch 242 is over the X point. If the vehicle does not cross the point X, speed gear switching (switching between the HST mode and the HMT mode) is not necessary. Therefore, the hydraulic pumps / motors 22 and 23 are simultaneously controlled with the speed ratio designated in the process 244 as the target speed ratio. Shift gears. Also, when the shift is over the X point,
In the process 243, the speed ratio Vx is switched to the provisional target speed ratio.
Is set. Then, in the conditional branch 245, it is determined whether or not the speed gear can be switched, that is, the timing of the speed gear switching described above is determined. And switching is not possible (H
The output rotations of the ST mode and the HMT mode are different. ), The waiting time loop 246 is repeated, and when it becomes possible to switch, the speed gear is switched in step 247, and then in step 248, the operator's designated speed ratio is set to the target speed ratio. The hydraulic pumps / motors 22 and 23 are simultaneously controlled to perform rapid acceleration and rapid deceleration.

Next, the HS in the vicinity of the speed gear switching point X will be described.
The T mode and HMT mode switching restriction control will be described. As described above, the switching from the HST mode to the HMT mode and the switching from the HMT mode to the HST mode are performed at the speed gear switching point X. In some cases, such as when a change occurs, the speed ratio changes due to an external factor and the speed stage is automatically switched. As a result, frequent gear shifts occur near the point X, and the clutch 11.1.
There is a problem that the load on the second and the like becomes large, and vibrations continue to frequently occur.

Therefore, in order to solve these problems,
The following configuration is adopted. That is, the speed ratio switching control is performed at the point X only when the operator gives an instruction from the speed ratio instruction lever 120.
After the shift of the speed ratio or the change of the speed stage according to the instruction of 20, the control is performed so as to maintain the current speed stage. By performing such control, frequent switching of speed stages does not occur, and stable running can be performed even when running with large load fluctuations in, for example, tractor towing work.

Next, the correction sharing control of the volumetric efficiency will be described. In the HST 21 of the speed change portion, since the volume efficiency changes due to the load fluctuation, even if the operator operates the speed ratio indicating lever 120 to control the hydraulic pumps / motors 22 and 23,
In some cases, the expected speed cannot be obtained, and the correction is required. Thus, a control flow of the correction sharing will be described with reference to the flowchart of FIG. First, the conditional branch 252
In, it is determined whether or not the swash plate angle of the movable swash plate 22a of the hydraulic pump 22 is maximum. If the swash plate angle of the movable swash plate 22a is not the maximum, an instruction is sent to the pump swash plate controller 121 to make the movable swash plate 22a tilt and perform correction. If it is detected that the swash plate angle of the movable swash plate 22a is the maximum, the process proceeds to step 253 where the HST
The swash plate angle target value of the movable swash plate 23a of the hydraulic motor 23 is calculated, and an instruction is sent to the motor swash plate controller 122 to control the swash plate angle of the hydraulic motor 23. .

Thus, the correction at the time of load change is
The correction is performed by controlling the movable swash plate 22a of the hydraulic pump 22 within a range that can be corrected by the hydraulic pump 22. After the swash plate angle of the movable swash plate 22a reaches the maximum, the movable swash plate 23a of the hydraulic motor 23 takes over the correction, so that it is possible to make a continuous correction near P1 and P2 in FIG. It can reduce shock and running discomfort.

Next, a description will be given of a method of improving the operation feeling by the speed ratio indicating lever 120. When the speed ratio indicating lever 120 is operated by the operator as described above, the position sensor 120a detects the operation amount (position or rotation angle, etc.) of the speed ratio indicating lever 120, and the controller 100 inputs the detection result. . Here, the controller 100 calculates the target speed 222 of the traveling vehicle from the input value 221.
The relationship 223 between the input value 221 and the target speed 222 is shown in FIG.
As shown in the figure, the input value 221 from the position sensor 120a is
Is changed in several areas. In this embodiment, when the input value 221 is in the low speed range, the slope of the relationship 223 is small, and as the input value 221 is in the middle speed range and the high speed range, the slope of the relationship 223 is increased. I have.

Then, the controller 100 sets the relation 223
The calculated target speed 222 is output to the pump / motor swash plate controllers 121 and 122, and the hydraulic pump / motors 22 and 23 are output from the pump / motor swash plate controllers 121 and 122.
Are controlled so that the movable swash plates 22a and 22b output the target speed 222.

As described above, the controller 100
3, the relationship between the operation amount of the speed ratio indicating lever 120 and the target speed 222 is not a simple linear function as in the related art, but the indicated position of the speed ratio indicating lever 120. If the speed is low, the speed is increased slowly. Thus, when the worker wants to perform a delicate movement at a low speed, such as when housing the machine in a warehouse or the like, an operation that matches the sense of the worker can be performed. If the designated position of the speed ratio indicating lever 120 is a high-speed position, the acceleration increases. This allows for effective acceleration and deceleration during high-speed driving that does not require subtle speed changes,
Even when it is desired to increase speed at a stretch from a low speed range, a speed that fits the operator's feeling can be obtained.

Next, a method of controlling the target speed 222 according to the operating speed of the speed ratio indicating lever 120 will be described. As described above, the position sensor 120a detects the operation amount of the speed ratio instruction lever 120, and the controller 100
1 is input, and the speed correction means 224 here
As shown in FIG.
An operation speed (ΔV / Δt) of 0 is calculated, and a correction value (k × ΔV / Δt) obtained by multiplying the operation speed by a coefficient k is output. Then, the target speed 222 is calculated using the value obtained by adding the correction value to the input value 221 as a new input value 221.

By performing such control, conventionally, even if the speed ratio indicating lever 120 is moved quickly, the traveling speed does not increase to an expected speed unless the lever is moved to a position where the operation is increased. When the problem that the ring was deteriorated is solved and the operator operates the speed ratio indicating lever 120 in a fast operation in expectation of increasing the speed quickly, the target speed 222 considering the operation speed is set. Therefore, the traveling speed expected by the worker is set, and an operation feeling suitable for the worker's feeling can be obtained.

Next, the operation state of the brake mechanism will be described with reference to the flowchart of FIG. First, conditional branch 202
In, the controller 100 detects the state of the brake switch 111. And HST mode or HM
If the brake switch 111 is turned on by an operator's operation during traveling in the T mode, the clutch 11 or the clutch 12 is disconnected in step 203. As a result, a braking action is generated on the drive shaft 18 by the brake pack 110, but the clutch 12 is disengaged during traveling in the HST mode, and the clutch 11 is disengaged during traveling in the HMT mode, so that the power to the drive shaft 18 is reduced. Since the transmission is interrupted, the braking action and the driving force do not compete with each other, and the braking action is efficiently generated.
The wear of the clutches 1 and 12 can be prevented, and the durability of the clutches 11 and 12 can be improved.

Next, when the ON signal is not detected from the brake switch 111 in the conditional branch 202, the conditional branch 204 is further executed in the previous conditional branch 20.
2 is determined, and if the brake switch 111 has not previously detected the ON signal, the end 210 of the control loop is determined.
Then, the process proceeds from the start 201 to the next control loop. That is, when the brake switch 111 is maintained in the ON state, the process is not performed and the control loop is repeated.

On the other hand, when the previous conditional branch 202 detects an ON signal in the conditional branch 204, that is, in the previous control loop, the ON signal is detected from the brake switch 111, and in the current control loop, the ON signal is detected from the brake switch 111. If no ON signal is detected, process 2
At 05, the actual speed ratio value is set to the target speed ratio. Here, the actual speed ratio is the speed ratio of the drive shaft 27 detected by the rotation detector 103. And processing 2
At 06, the hydraulic pump / motor 22
The controller 100 controls the swash plate angles of the hydraulic pump motors 22 and 23 via the pump / motor swash plate controllers 121 and 122. And
The target speed ratio and the speed ratio at the point X are compared in a conditional branch 207. If the target speed ratio is larger than the speed ratio at the point X, the clutch 11 is connected in a process 208 to transmit power and perform HMT traveling. If the target gear ratio is smaller than the gear ratio at the point X, the clutch 12 is connected in step 209 to transmit power and perform HST traveling.

In this way, when the drive force is restored by releasing the brake from the power-disengaged state by the clutches 11 and 12, the speed ratio on the power transmission side and the actual speed ratio of the drive shaft 27 must be matched. , HST mode, HMT
After the mode is determined, the clutches 11 and 12 are re-engaged, so that smooth power return is possible and the impact on the components such as the clutches 11 and 12 is reduced to reduce the durability. Can also be improved.

Finally, a control method by the controller 100 and the like at the time of operating the neutral position of the speed ratio indicating lever 120 will be described with reference to the flowchart of FIG. The rotational driving force from the engine 24 depends on the amount of operation of the speed ratio indicating lever 120 by the hydraulic pump / motor 2 of the HST.
The gear ratio is changed and output by adjusting the swash plate angle of 2.23. When the machine is stopped, the speed ratio indicating lever 120 is operated to the neutral position. Therefore, when the controller 100 detects that the speed ratio indicating lever 120 has been operated to the neutral position, first, the conditional branch 2 shown in FIG.
At 12, it is determined whether the swash plate angle of the HST hydraulic pump 22 is near the neutral position.

Here, if the swash plate angle of the hydraulic pump 22 is not at the neutral position, the hydraulic pump 21
The control is performed so that the swash plate angle of 7 becomes the neutral stationary swash plate angle on a flat ground, and the control flow returns from the end 218 to the start 211 to perform the next control loop. On the other hand, if it is detected in the conditional branch 212 that the vehicle is near the neutral position, it is further determined in a conditional branch 213 whether or not the speed ratio is low. Do.

If the rotation direction is forward, the process 21
In 6, the swash plate angle of the hydraulic pump 22 is reduced by the minimum operation swash plate angle (the minimum unit in which the angle of the inclined plate of the hydraulic pump 22 can be adjusted). If the rotation direction is reverse, in step 215, the swash plate angle of the hydraulic pump 22 is increased by the minimum operation swash plate angle. That is, when the vehicle is traveling forward at a low speed, the vehicle slightly accelerates in the reverse direction, and when the vehicle is traveling backward at a low speed, the vehicle slightly accelerates in the forward direction.

Then, the above processing 215 or processing 2
At the end of 16, the process returns from the end 218 of the neutral control flow to the start 211 and repeats the next control loop. Then, by repeating the above-described processing, the aircraft that is moving forward at low speed gradually decelerates, and eventually runs backward at low speed. Then, the aircraft in the low-speed reverse traveling state gradually increases in speed, and eventually shifts to forward traveling at a low speed. Similarly, the aircraft traveling at low speed reversely repeats low-speed forward motion and reverse motion.

By performing such neutral control, if the speed ratio indicating lever 120 is operated to the neutral position,
The aircraft repeatedly moves forward and backward slightly at low speed, but the speed increase or deceleration in the processes 215 and 216 is performed in the minimum unit in which the angle of the swash plate can be adjusted. It is only slightly moving back and forth, and can maintain a substantially stopped state. In the stop state by the neutral control, since power is transmitted to the drive shaft 27, even when the vehicle stops on an inclined surface or a slope, a reliable stop state can be maintained. Also, the speed ratio indicating lever 1 again
When the speed ratio 20 is operated to the forward or reverse speed ratio, the operation such as the connection of the clutch is unnecessary, so that the delay time at the time of starting is eliminated, and the operation feeling of the worker is improved,
Neutral control with excellent operability is realized.

[0069]

The present invention is configured as described above and has the following effects. That is, a hydraulic-mechanical system including a hydraulic transmission unit using at least one of a variable displacement hydraulic continuously variable transmission and a differential mechanism using planetary gears connected to both the hydraulic transmission unit and the mechanical transmission unit. In the transmission, the speed stage can be switched between a traveling state by a hydraulic continuously variable transmission and a traveling state by a hydraulic-mechanical transmission, and a delay time required for switching the speed stage is an electrical delay time and a delay time of a mechanical part. Is controlled so as to issue a speed gear switching instruction earlier by the total delay time, thereby taking into account the electrical and mechanical delay time caused by speed gear switching by a clutch or the like, and reaching the speed gear switching end point. Is controlled so as to be expected, so that the speed change can be performed at the optimum timing, so that the speed change can be smoothly performed without causing a shock or the like.

Further, an appropriate simulation calculation method corresponding to the required accuracy and the allowable operation time is selected by using the delay time as a time step, and the simulation step calculation method uses the time step to reach the speed ratio switching point of the speed ratio. Since the time until is predicted, various simulation calculations can be used, and even when the speed ratio changes with a higher-order function such as a quadratic function, the prediction can be performed with high accuracy. Since the speed change can be performed at the optimum timing, smooth speed change can be performed without causing any shock or the like.

[Brief description of the drawings]

FIG. 1 is a front view of a hydraulic-mechanical transmission.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a block diagram of a hydraulic-mechanical transmission.

FIG. 4 is a diagram showing the relationship between the output of a hydraulic-mechanical transmission and the discharge rates of a hydraulic pump and a hydraulic motor.

FIG. 5 is a diagram illustrating an operation state of a clutch corresponding to a shift state.

FIG. 6 is a flowchart of a clutch switching instruction control.

FIG. 7 is a relationship diagram between time and speed ratio.

FIG. 8 is a control output diagram of a clutch with respect to time.

FIG. 9 is a flowchart of an instruction speed ratio control.

FIG. 10 is a flowchart of a volume correction sharing control.

FIG. 11 is a diagram illustrating a correspondence relationship between an operation amount of a speed ratio indicating lever and a target speed.

FIG. 12 is a control diagram of a controller.

FIG. 13 is a flowchart of a brake control.

FIG. 14 is a neutral control flowchart.

[Explanation of symbols]

 Reference Signs List 22 hydraulic pump 22a (hydraulic pump) movable swash plate 23 hydraulic motor 23a (hydraulic motor) movable swash plate 100 controller 103 rotation detector 104 engine speed detector 105 solenoid valve 106 solenoid valve 110 brake pack 111 brake switch 120 speed ratio instruction Lever 120a Position sensor 121 Pump swash plate controller 122 Motor swash plate controller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Osamu Yasuda, Inventor 1-32 Chaya-cho, Kita-ku, Osaka, Japan Inside Yanmar Diesel Co., Ltd. (72) Inventor Yuji Kitasaka 1-32, Chaya-cho, Kita-ku, Osaka, Osaka F-term (reference) in Yanmar Diesel Co., Ltd. 3D042 AA08 AB12 BA02 BA05 BA08 BA14 BA19 BA20 BB03 BC01 BC07 BC08 BC17 BD03 BD04 BD09

Claims (2)

[Claims] 1. A hydraulic system comprising: a hydraulic transmission unit using at least one variable-capacity hydraulic continuously variable transmission; and a differential mechanism using planetary gears connected to both the hydraulic transmission unit and the mechanical transmission unit. -In a mechanical transmission, the speed stage can be switched between a traveling state by a hydraulic continuously variable transmission and a traveling state by a hydraulic-mechanical transmission, and the delay time required for switching the speed stage is determined by an electrical delay time and a mechanical part. A speed-gear switching instruction for a hydraulic-mechanical transmission, wherein the speed-gear switching instruction is issued earlier by the total delay time as the total time of the delay time. 2. The method according to claim 1, wherein the delay time is a time step, an appropriate simulation calculation method corresponding to the required accuracy and the allowable operation time is selected, and the simulation calculation method uses the time step to reach a speed stage switching point of a speed ratio. 2. The method according to claim 1, further comprising estimating a time until the speed is changed.