JP2893115B2 - Mechanical hydraulic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mechanical hydraulic power transmission device, and more particularly to power transmission for high-speed continuous running in construction machines such as wheel type power shovels and rough terrain cranes. About the system.

(Prior Art) Conventionally, the following method is often used for a transmission device such as a construction machine.

. Mechanical power transmission system. Hydraulic power transmission system (HST) Mechanical hydraulic power transmission system (HMT) Among these, the mechanical hydraulic power transmission system (HMT) is a system that mechanically transmits part of the transmission power and transmits the rest by hydraulic pressure, that is, a power split type hydraulic transmission (hydraulic- Among them, the power split type is well known, as shown in Fig. 17, in which mechanical power transmission is mainly performed at high and medium speeds to avoid a decrease in efficiency, and hydraulic power is mainly used at low speeds. A mechanical hydraulic power transmission system (FIG. 17) that facilitates switching control between forward and reverse operation by performing dynamic power transmission is used in various fields.

In FIG. 17, on the other hand, the power output from the power source 61 to the shaft 62 is transmitted from a gear 64 fixed to the shaft 62 to a variable displacement hydraulic pump 66 and a fixed displacement hydraulic motor 67 via a gear 63. Enter the transmission B. The output of the hydraulic transmission B rotates the ring gear 69-1 of the planetary gear mechanism A via the gear 68 provided on the motor shaft. On the other hand, the power source 61
The power output to 62 rotates the sun gear 65 of the planetary gear mechanism A from the shaft 62. The planetary gear mechanism A is a ring gear 69-1.
A planetary gear 70 is provided between the output gear 72 and the sun gear 65, and a carrier 71 that supports the planetary gear 70 is integrated with the output shaft 72. Therefore, the output shaft 72 is composed of the ring gear 69-1 and the sun gear.
The power combined with 65 is transmitted to the drive wheels 73. Specifically, the sun gear 65 has the number of teeth a and the number of revolutions Na, and the ring gear 69-
If 1 is the gear b, the rotation speed Nb, and the output shaft 72 is the rotation speed Nc, the rotation speed Nb is represented by “Nc = (a · Na + b · Nb) / (a + b)”. Rotate in the opposite direction (-Nb) (that is, "Nc = (a-Na-b-Nb) / (a +
b) "). For simplicity of description, the description will be made in terms of the gradually decreasing control of the number of revolutions -Nb (that is, the pump 66 will be described as being gradually decreased from a large discharge amount to a small discharge amount).
When Nb <0, the vehicle travels in reverse, and then “a · Na−b · Nb =
At "0", the vehicle is stopped, then at "a.Na-b.Nb>0", low speed forward is achieved, and finally, at Nb ≒ 0, medium to high speed forward is achieved.
Subsequently, when the discharge direction of the hydraulic pump 66 is switched to reversely rotate the hydraulic motor 67 (+ Nb), “Nc = (a · Na
+ B · Nb) / (a + b) ”. Then, when the discharge amount of the hydraulic pump 66 is gradually increased next, a higher speed advance can be achieved.

However, the present inventor has disclosed a further improved invention in Japanese Patent Application Laid-Open No. 1-79791, and an example of the mechanical hydraulic transmission has a configuration shown in FIG. In FIG. 18, a power source 1 having speed control means, a hydraulic transmission 10, a control device 40, and a mechanical transmission 50 are provided. The hydraulic power transmission 10 includes a hydraulic power transmission 20 and a speed increasing / decreasing device 30.

(Problems to be Solved by the Invention) However, in JP-A-1-79791, the pump and motor capacities of the hydraulic power transmission device 20 are controlled and the traveling electromagnetic control valve 24A is also controlled. The structure is complicated. In addition, since the traveling electromagnetic control valve 24A is switched by the control current ivf from the control unit 41, the traveling electromagnetic control valve 24A is turned off in a large mechanical hydraulic power transmission system (HMT) requiring high pressure and large capacity. There is a drawback that it does not change or that the response becomes poor.

The present invention focuses on the above problems, and relates to an improvement in a mechanical hydraulic transmission device having a simple structure and excellent control, operability, and responsiveness.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides, in the first invention,
For one output shaft 35, an input shaft 2 and an output shaft 35 connected to the power source 1 are connected to a gear power transmission means 50 including a clutch 51 provided between the two shafts 2 and 35.
The clutch 51 can be selectively connected by clutch engagement means that engages with operating pressure oil via an electrically controlled clutch pressure control valve 44a to transmit mechanical power in the vehicle forward direction to the output shaft 35. A hydraulic motor 22 having a hydraulic motor rotation control means for controlling a rotation direction, a rotation neutral and a rotation speed, a hydraulic motor 22, and a hydraulic pump 21 and an output shaft 35 connected to the power source 1. The clutch 33 is selectively provided by gear power transmission means including a clutch 33 provided between the output shaft 35 and clutch engagement means engaged by operating pressure oil via an electrically controlled clutch pressure control valve 44. And a hydraulic transmission capable of transmitting hydraulic power in the forward direction of the vehicle or hydraulic power in the reverse direction of the vehicle to the output shaft 35. Shift shift map data that defines the mechanical drive area and the hydraulic drive area from the correlation with the dull operation amount, and the hydraulic drive area when the forward / reverse shift operation input signal is forward or reverse operation and the first speed stage of low speed traveling Make a judgment,
When the forward / reverse speed change operation input signal is a forward or reverse operation, the shift change between the mechanical drive region and the hydraulic drive region is determined by comparing the accelerator pedal opening amount operation input signal, the output shaft rotation speed input signal, and the shift shift map data. A shift change determining unit for determining, clutch engagement pattern data for each mechanical drive or hydraulic drive switching shift, and an output unit for outputting a control signal of a hydraulic drive subroutine when the shift change determination is in the hydraulic drive region; When the change determination is a switch from hydraulic drive to the mechanical drive region, the control current and hydraulic pressure of the clutch pressure control valve for switching from disconnection of the hydraulic power transmission clutch to connection of the mechanical power transmission clutch from the clutch engagement pattern data. The control current to the hydraulic pump and hydraulic motor that invalidates the power is read out, and shift change judgment is performed. When the driving is switched to the hydraulic driving region, the control current of the clutch pressure control valve and the hydraulic drive routine start timing for switching from disconnection of the mechanical power transmission clutch to connection of the hydraulic power transmission clutch from the clutch engagement pattern data. And a control unit having an output unit for reading out and outputting the power, and selectively controlling mechanical power transmission and hydraulic power transmission.

According to a second invention, in the mechanical hydraulic transmission according to the first invention, an accelerator pedal opening amount operation input signal is input to the control device by an accelerator operation amount detecting means 46b provided on the accelerator pedal 46a, and a forward / reverse speed change operation signal is input. Is input to the control device by a shift signal output from the shift shift lever 45, and two manual operations of the accelerator and the shift shift, and the power transmission method of mechanical power transmission and hydraulic power transmission can be switched from the output shaft rotation speed. It is characterized by doing.

According to a third aspect, in the mechanical hydraulic transmission according to the first aspect, the hydraulic motor rotation control means for controlling the rotation direction, the rotation neutral, and the rotation speed includes a rotation direction of the hydraulic motor 22 based on a forward / reverse speed change operation input signal. An electrically operated forward / reverse switching valve 47 that selectively supplies a rotation-neutral command pilot pressure fluid; and a hydraulic motor that is driven by the command pilot pressure fluid from the forward / reverse switching valve 47 and that is driven by the hydraulic pump 21. A hydraulic motor travel control valve 24 to be inserted into the valve 22 and pressure oil supply means 46 for controlling the flow rate of the pilot pressure fluid flowing into the pilot pressure circuit in conjunction with the depression angle of the accelerator pedal 46a.

According to a fourth aspect of the present invention, in the mechanical hydraulic transmission according to the third aspect of the present invention, the pilot circuit between the pressurized oil supply means 46 and the forward / reverse switching valve 47 includes the rotational speed control means 48 of the power source 1 as the pilot pressure fluid. Branch connection of the pilot pressure operation circuit
Hydraulic motor 22 for hydraulic power transmission with forward / reverse switching valve 47
And the rotation speed of the power source 1 can be controlled.
It is characterized in that the rotation speed of the power source 1 can be controlled during neutral mechanical power transmission.

(Operation) According to the above configuration, a clutch pressure control valve controlled by a controller at the time of power transmission of the mechanical hydraulic power transmission device is provided, and a machine fixed to the input shaft in a range where the rotation speed of the output shaft is higher than a predetermined value. Connect the clutch of the hydraulic transmission and disconnect the clutch of the hydraulic transmission or transmit the power to the output shaft with a mechanical transmission that minimizes the discharge of the pump and has high transmission efficiency, and the rotation speed of the output shaft is a predetermined value In a smaller range, the clutch of the mechanical transmission fixed to the input shaft is disengaged, and power is transmitted to the output shaft by the hydraulic transmission. For this reason, the transmission efficiency is good at high speed, so the power loss can be reduced, and at low speed, the output rotation speed between forward rotation and reverse rotation can be controlled smoothly.
Further, in the case of the mechanical hydraulic transmission according to the present invention, a traveling control means is provided between the pump and the motor, and when switching between forward and backward and a neutral port is used, power is not transmitted to the output shaft, and the discharge flow rate of the pump is reduced. It can be used for other hydraulic actuators and the like. The hydraulic pressure is used to switch the travel control means, and the hydraulic pressure is controlled by a forward / reverse switching valve that operates according to a command from the control unit. The hydraulic pressure to the forward / reverse switching valve is controlled by a pilot pressure interlocking with the accelerator pedal from the pilot pressure pump. Sent via control valve. At the same time, the hydraulic pressure from the pilot pressure control valve is connected to the speed control means of the power source, and the power source and the hydraulic valve fluctuate according to the operation of the accelerator pedal. Therefore, it can be easily operated even in the case of a large mechanical hydraulic power transmission system (HMT) requiring high pressure and large capacity. Further, when a plurality of hydraulic valves are provided between the pump and the motor, one hydraulic valve switches between forward and backward and controls the rotation speed of the output shaft, and the other hydraulic valve controls the discharge flow rate of the pump. The hydraulic pressure can be used for switching the hydraulic valve. Further, since the pump and the motor are provided side by side with the mechanical transmission, the size of the device can be reduced. In addition, switching between the hydraulic transmission and the mechanical transmission, and switching within each of the mechanical and hydraulic transmissions, also detects changes in output rotation speed, throttle opening, shift position, etc. Since the hydraulic pressure to the clutch is controlled, it can be performed smoothly and quickly.

(Embodiment) Hereinafter, an embodiment of the present invention shown in the drawings will be described. First
FIG. 1 is an overall configuration diagram of a mechanical hydraulic transmission according to a first embodiment of the present invention, in which a power source 1 having speed control means 48,
Hydraulic transmission 10, control device 40, mechanical transmission 50
It is composed of

The hydraulic power transmission 10 includes a hydraulic power transmission 20 and an acceleration / deceleration device 30. The variable displacement hydraulic pump 21 (hereinafter referred to as "pump 21") of the hydraulic transmission device 20 passes through a gear 31 of an accelerating / decelerating device 30 having power from a power source 1 fixed to a shaft 2 and a gear 32 meshing with the gear. It is rotated by the pump shaft 3 driven and driven. Variable displacement hydraulic motor 22 (hereinafter referred to as "motor 22")
) Is connected to the pump 21 by the pipe 23, the travel control valve 24, the pipe 25, and the brake valve 61, and receives the hydraulic pressure of the pump 21 to output power to the motor shaft 26. The power of the motor shaft 26 is output to the output shaft 35 via a clutch 33 provided on the motor shaft 26, a gear 34 rotatably inserted into the motor shaft 26, and a gear 36 fixed to the output shaft 35. Clutch 33 is another pump
The oil pressure 43 is received and joined via a clutch pressure control valve 44 controlled by the control unit 41, and the output shaft 35 is rotated. The traveling control valve 24 is provided with forward and backward switching positions 24a and 24b and a neutral position 24c of the vehicle, and returns the oil to the tank 29 when the vehicle is in the neutral position. Further, a pipe 27 and a hydraulic valve 28 are connected to branch from the pipe 23 to supply and discharge oil to another hydraulic actuator (A), and this (A) can be driven freely. Further, the pump 21 and the motor 22 are provided with discharge capacity control valves 11 and 12, respectively. The control current ipd and imd from the control unit 41 control the discharge capacity of the pump 21 and the motor 22.
Discharge capacity is changed. The shaft 2 is provided with a speed sensor 42, and the output shaft 35 is provided with a speed sensor 42a.
A pressure sensor 42b is provided between the pump 21 and the motor 22, and feeds back the oil pressure to the control unit 41.

On the other hand, the mechanical transmission 50 is a clutch fixed to the shaft 2.
51, a gear 52 rotatably inserted into the shaft 2, and a gear 53 meshed with the gear 52 and fixed to the output shaft 35. The clutch 51 receives and joins the hydraulic pressure of another pump 43 via a clutch pressure control valve 44a controlled by the control unit 41, and rotates the output shaft 35.

The control unit 41 including a controller and the like, a switching means 45 such as a shift lever for switching between forward and backward of the construction machine and the like, a pressure oil supply means 46 such as a pilot pressure control valve linked to an accelerator pedal 46a for controlling the vehicle speed, Operation amount detection means 46b such as a positioner for detecting the operation amount of the accelerator pedal 46a
Forward / backward switching means 47, such as a forward / backward switching valve for switching the travel control valve 24 to the switching position 24a, 24b or 24c via the pressure oil supply means 46 with the pressure oil of another pump 43;
A speed control means 48 for controlling the rotation speed of the power source 1 with the hydraulic pressure from 46 is provided and supplied together with the other pump 43, the clutch pressure control valves 44 and 44a, the speed sensors 42 and 42a, the pressure sensor 42b, and the like. The device 40 is configured.

Next, the operation of the above configuration will be described. Second
An example of the control operation will be described according to the flowchart of FIG. For example, (step 100) is abbreviated as 100. 100
Then, the throttle again θt and the shift lever position Lp (R, N, 2nd, 1s) are detected by the sensors 46a, 45, 42, 42a, 42b.
t), the rotation speed Ni of the shaft 2, the rotation speed No of the output shaft 35, and the discharge pressure P of the pump 21 are read. Note that R and 1st are hydraulically driven, and 2nd is mechanically driven. In 101, the shift lever position
It is determined whether or not Lp is at the neutral position N. If it is the neutral position N, the data N, Ni, No,
P is read from time to time. On the other hand, if the position is not the neutral position N, 10
In step 3, the shift information is retrieved by giving each data No. and θt to the shift map shown in FIG. 3 (a). FIG. 3 (b) shows the torque To of the output shaft 35 in the example machine which naturally occurs corresponding to FIG. 3 (a) (for reference). At 104, the shift position command obtained from the processing result at 103 and the current gear stage Lp
(R, 2nd or 1st) to determine whether to shift down or up. If it is determined that the shift should not be performed, it is determined again at 105 whether Lp is 1st or R. R
Alternatively, if it is not 1st, that is, if it is 2nd, the process goes to step 200, and the processing result or the initial value of the previous time is output as it is. On the other hand, when Lp is R or 1st, the flow proceeds to a hydraulic drive control subroutine described below at 106. If it is determined at 104 that the shift should be performed, the procedure goes to 107. At 107, the clutch engagement pattern shown in FIG. 4 is read. The clutch engagement pattern is as shown in the example of the shift timing data in FIG.
Control unit 41 provides clutch pressure control valves 44, 44a
The control currents ica and icb are changed to connect or disconnect the clutches 33 and 51. Incidentally, the change of the control currents ica and icb at the time of shifting is determined for each timing time Tf, Tt, etc.
In addition, for each speed stage, it is given by a matrix as shown in FIG. At 108, it is determined whether the shift is from 1st to 2nd. In the case of 1st to 2nd, pump 110 is used as shown in the example of shift timing data in FIG.
The control current ipd from the control unit 41 to the discharge capacity control valve 11 is smoothly changed with respect to the switching time t, and the control current ivf from the control unit 41 to the forward / reverse switching means 47 is changed to the switching time t. On the other hand, it changes abruptly and outputs at 200. Conversely, if it is not from 1st to 2nd at 108, that is, if it is from 2nd to 1st, go to 109 and read the start timing of the hydraulic drive routine. The start timing is the control current ipd from the control unit 41 to the discharge capacity control valve 11 of the pump 21 and the control unit to the discharge capacity control valve 12 of the motor 22 as shown in the example of the shift timing data in FIG. Startup timing when the control current imd changes from 41
A change in the control current ivf from the control unit 41 to the forward / reverse switching means 47 after Ths1 is started after the start timing Ths2, and output at 200. The hydraulic drive control subroutine at 106 is the flow of FIG. 6, and at 121, the target engine speed Ne with respect to the throttle opening θt due to the depression of the accelerator pedal 46a is determined (FIG. 7). At 122, a deviation ei between the target engine rotation speed Ne and the rotation speed Ni of the shaft 2 is obtained. At 123, the rotation speed Ni is differentiated to obtain a differential value Nia of the rotation speed Ni. At 124, the target absorption torque Tpo of the pump 21 with respect to the engine speed Ni is calculated (FIG. 8). In the case of 125, the pump 21 takes into account the rotational speed deviation ei and the differential value Nia of the rotational speed Ni.
In 126, the discharge capacity Dp of the pump 21 with respect to the pump discharge pressure P at the time of the absorption torque Tp is determined. At 127, a pump control current ipd instructed from the control unit 41 to the discharge capacity control valve 11 is obtained from the discharge capacity Dp of the pump 21 (FIG. 9). At 128, a motor control current imd instructed from the control unit 41 to the discharge capacity control valve 12 is obtained from the rotation speed No of the output shaft or the vehicle speed (FIG. 10).

FIG. 11 shows a second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. 1st is the same as that of the first embodiment, but 2nd is rotatable on the clutch 132 of the acceleration / deceleration device 130 provided on the output shaft 35 and the output shaft 35 via the gear 131 fixed to the motor shaft 26. Gear 133 inserted
It is composed of The clutch 132 receives and joins the hydraulic pressure of the other pump 43 via a clutch pressure control valve 145 controlled by the control unit 141, and outputs the power of the motor shaft 26 to the output shaft 35.

The third transmission of the mechanical transmission 150 is configured similarly to the second transmission of the first embodiment. That is, 3rd is composed of a clutch 151 fixed to the shaft 2 of the mechanical transmission 150, a gear 152 rotatably inserted into the shaft 2, and a gear 153 meshed with the gear 152 and fixed to the output shaft 35. The hydraulic pressure of the other pump 43 is received and connected via a clutch pressure control valve 146 controlled by the control unit 141, and the power of the power source 1 is output to the output shaft 35. 4th is the clutch 161 and gear
162, gear 163, clutch pressure control valve 16
6 and more. In this case, the clutch 151,
The 161 and the gears 152 and 162 may be provided on the output shaft 35, and the gears 153 and 163 may be provided on the shaft 2 or may be provided alternately.

The operation of the above configuration will now be described with reference to the flowchart of FIG. In the case of the same operation as the flow chart of FIG. 2, the same reference numerals are given and the description is omitted. In the case of the second embodiment, the shift lever position Lp is
R2, R1 for reverse 1st gear, N for neutral, 1 for forward 1st to 4th,
2, 3, D. Shift lever position Lp in Fig. 13 at 203
Data N in the shift map showing the shift pattern for
The shift information is retrieved from o and θt. At 104, the shift position command obtained from the processing result at 203 is compared with the current speed stage to determine whether to shift down or up. If the shift should not be performed at 104, it is determined at 205 whether the current gear position is in the hydraulically driven position 1st, 2nd, R1st, R2nd. If it is at 1st, 2nd, R1st, or R2nd at 205, the subroutine of the hydraulic drive control
Go to 6. At this time, as compared with step 106 of the first embodiment, the discharge capacity of the hydraulic motor 22 changes with respect to the output shaft rotation speed in accordance with 1st, 2nd or R1st, R2nd as shown in FIG. At this time, the rotation speed of the motor shaft 26 may be detected instead of the output rotation speed as shown in FIG. If the shift should be made at 104, go to 207 and check the clutch engagement pattern (No. 16).
Figure) is read. Fig. 5 (a) shows the clutch engagement pattern.
As shown in the example of the shift timing data, any one of the control currents ica, icb, icc, and icd from the control unit 41 to the clutch pressure control valves 44, 145, 146, and 166 is changed, and the clutches 33, 132, 151, and 161 are changed. Is bonded or cut. The control current ic when there is a shift change
The changes of a, icb, cc, and icd are based on the timing times Tf, Tt.
For example, for each speed stage, the values are given by a matrix as shown in FIG. At 208, it is determined whether the shift change is a change in the direct connection from the hydraulic drive to the mechanical transmission 150. If the shift is a direct connection from the hydraulic drive, at 209, the pump 21 is switched as shown in the example of the shift timing data in FIG. The control current ipd from the control unit 141 to the discharge capacity control valve 11 is smoothly changed with respect to the switching time t, and the control current ivf from the control unit 141 to the forward / reverse switching means 47 is changed with respect to the switching time t. Change rapidly and output at 200. If it is not a change from hydraulic drive to mechanical transmission
At 210, it is determined whether the change from the mechanical transmission device 150 to the hydraulic drive has been changed, and if not, the process proceeds to step 200 and is output as it is. In the case of direct connection, as in the case of the first embodiment, at 211, as in the example of the shift timing data in FIG.
Control unit for the discharge capacity control valve 11 of the pump 21
Changes in the control current ipd from the controller 141 and the control current imd from the controller 141 to the displacement control valve 12 of the motor 22 are controlled after the start timing Ths1 and the forward / reverse switching means 47.
Of the control current ivf from the control unit 141 to the start after the start timing Ths2 and output at 200.

In the first embodiment, the hydraulically-driven gear stage is one stage and the mechanically-driven gear stage is one stage, and in the second embodiment, the hydraulically-driven gear stage is two stages and the mechanically-driven gear stage is two stages. However, the first and second embodiments may be appropriately combined. Although one or two hydraulic valves are provided between the pump and the motor, a large number of hydraulic valves may be provided, and the hydraulic circuit may use a tandem, series, parallel, or composite circuit. Furthermore, although only the open circuit has been described for the hydraulic circuit of the hydraulic drive device, it goes without saying that a closed circuit may be used.

(Effects of the Invention) As described above, according to the present invention, the mechanical hydraulic transmission, which is divided into a mechanical transmission and a hydraulic transmission, can be used in a range in which the rotation speed of the output shaft is larger than a predetermined value. Efficiency is improved because power is transmitted by the type transmission,
In a range smaller than the predetermined value, power is transmitted by the hydraulic power transmission device, so that the output rotation speed between forward rotation and reverse rotation can be smoothly controlled. Switching between the hydraulic transmission and the mechanical transmission, and switching within each of the mechanical and hydraulic transmissions, also detects changes in output rotation speed, throttle opening, shift position, etc. Because the hydraulic pressure is controlled, the operation can be performed smoothly and quickly. Also,
Hydraulic pressure is used for switching the travel control valve, and the hydraulic pressure is controlled by a forward / reverse switching valve that operates according to a command from the control unit.
Hydraulic pressure to the forward / reverse switching valve is sent from the pump via pressure oil supply means linked to the accelerator pedal, so the power source, pump and hydraulic valve operate according to the change in the accelerator pedal, so high pressure and large capacity are required. It can be easily operated even in the case of the required large mechanical hydraulic power transmission system (HMT). Further, since a planetary gear mechanism having a complicated mechanism is not used, the structure is simplified, and the apparatus can be made compact and inexpensive. Further, by switching the hydraulic circuit, the discharge flow rate of the hydraulic pump can be supplied to another actuator, so that an excellent effect that hydraulic energy can be used without losing extra power can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a mechanical hydraulic transmission according to a first embodiment of the present invention. FIG. 2 is a flowchart of the first embodiment of the present invention. FIG. 3 is a diagram showing an output shaft rotation speed and a throttle opening. FIG. 4 is a diagram showing a clutch engagement pattern. FIG. 5 is a time chart of shift timing. FIG. 6 is a flowchart of hydraulic drive control. FIG. 7 is a diagram showing throttle opening. Fig. 8 shows the relationship between the engine speed and the target absorption torque of the hydraulic pump. Fig. 9 shows the relationship between the displacement of the hydraulic pump and the control current. Fig. 10 shows the output shaft. FIG. 11 is a diagram showing the relationship between a rotational speed and a control current. FIG. 11 is an overall configuration diagram of a mechanical hydraulic transmission showing a second embodiment of the present invention. FIG. 12 is a flow chart of a second embodiment of the present invention. Is the output shaft for each shift lever position FIG. 14 shows the relationship between the rotation speed, the throttle opening, the output shaft torque, and the shift speed. FIG. 14 shows the relationship between the output shaft rotation speed and the discharge capacity of the hydraulic motor. FIG. 15 shows the relationship between the hydraulic motor shaft rotation speed and the hydraulic motor. FIG. 16 is a table showing a clutch engagement pattern. FIG. 17 is an overall configuration diagram of a mechanical hydraulic power transmission system showing a conventional embodiment. FIG. 18 is a conventional embodiment. Overall configuration of mechanical hydraulic transmission 1: Power source, 2: Shaft, 3: Pump shaft, 10: Hydraulic transmission, 20:
Hydraulic power transmission device, 21: variable displacement hydraulic pump, 22: variable displacement hydraulic motor, 24: travel control means, 26: motor shaft, 30: acceleration / deceleration device, 31, 32, 34, 36, 52, 53, 130 , 131, 152, 1
53, 162, 163: gear, 33, 51, 132, 151, 161: clutch, 44, 145, 146, 166: clutch pressure control valve, 40: control device, 41, 141: control unit, 42, 42a: Speed sensor, 45: switching means, 46: pressure oil supply means, 47: forward / backward switching valve, 48: speed control means, 50, 150: mechanical transmission

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 61/38-61/46 F16H 47 / 02

Claims (4)

(57) [Claims] An input shaft and an output shaft connected to a power source are connected to one output shaft.
Gear power transmission means 50 including a clutch 51 provided between 35,
A machine capable of transmitting mechanical power in the forward direction of the vehicle to the output shaft 35 by selectively connecting the clutch 51 with clutch engagement means engaged by operating pressure oil via an electrically controlled clutch pressure control valve 44a. A hydraulic motor 22 having a hydraulic motor rotation control means for controlling a rotation direction, a rotation neutral and a rotation speed, a hydraulic motor 22 having an output shaft 35 and a hydraulic pump 21 and an output shaft 35 connected to the power source 1. The clutch 33 is selectively connected by gear power transmission means including a clutch 33 provided between the clutch 33 and clutch engagement means engaged by hydraulic oil via a clutch pressure control valve 44 of electric control. A hydraulic transmission capable of transmitting hydraulic power in the forward direction of the vehicle or hydraulic power in the reverse direction of the vehicle to the output shaft 35, wherein the output shaft rotation speed and the accelerator pedal Shift shift map data that defines the mechanical drive area and the hydraulic drive area from the correlation with the operation amount, and the hydraulic drive area when the forward / reverse shift operation input signal is the forward or reverse operation and the 1st speed stage of low speed traveling Judgment, when the forward-reverse speed change operation input signal is forward or reverse operation, the comparison between the accelerator pedal opening amount operation input signal, the output shaft rotation speed input signal and the shift shift map data and the mechanical drive area and the hydraulic drive area A shift change judging unit for judging a shift change of the clutch, clutch engagement pattern data for each mechanical drive or hydraulic drive switching shift, and an output for outputting a hydraulic drive subroutine control signal when the shift change judgment is in the hydraulic drive range. When the shift change determination is a switch from the hydraulic drive to the mechanical drive region, the hydraulic power transmission clutch is determined from the clutch engagement pattern data. Reads the control current of the clutch pressure control valve that switches between the disconnection of the latch and the connection of the mechanical power transmission clutch and the control current to the hydraulic pump and hydraulic motor that invalidates the hydraulic power, and determines the shift change from mechanical drive to hydraulic drive. When the switching is to be performed, the control current of the clutch pressure control valve for switching between the disconnection of the mechanical power transmission clutch and the connection of the hydraulic power transmission clutch and the hydraulic drive routine start timing are output from the clutch engagement pattern data. A mechanical-hydraulic power transmission device comprising: a control device having an output unit; and selectively controlling mechanical power transmission and hydraulic power transmission. 2. The mechanical hydraulic transmission according to claim 1, wherein the accelerator pedal opening amount operation input signal is transmitted to the accelerator pedal.
Input to the control device by the accelerator operation amount detecting means 46b provided in 46a, the forward / reverse shift operation signal is transmitted to the shift shift lever.
The shift signal output from 45 is input to the control device to enable two manual operations of the accelerator and the shift shift, and to switch the power transmission method between mechanical power transmission and hydraulic power transmission from the output shaft rotation speed. Mechanical hydraulic transmission. 3. The mechanical hydraulic power transmission according to claim 1, wherein the hydraulic motor rotation control means for controlling the rotation direction, the rotation neutral and the rotation speed includes a rotation direction of the hydraulic motor 22 based on a forward / reverse speed change operation input signal. An electrically operated forward / reverse switching valve 47 that selectively supplies a rotation-neutral command pilot pressure fluid; and a hydraulic motor that is driven by the command pilot pressure fluid from the forward / reverse switching valve 47 and that is driven by the hydraulic pump 21. A hydraulic motor travel control valve 24 to be inserted into the pump 22; and hydraulic oil supply means 46 for controlling the flow rate of pilot pressure fluid flowing into the pilot pressure circuit in conjunction with the depression angle of the accelerator pedal 46a. Transmission. 4. The mechanical hydraulic transmission according to claim 3, wherein the pilot circuit between the pressure oil supply means 46 and the forward / reverse switching valve 47 includes the rotational speed control means 48 of the power source 1 as the pilot pressure fluid. When the hydraulic power transmission of the forward / reverse switching valve 47 is operated, the rotational speed of the hydraulic motor 22 and the power source 1 can be controlled, and the mechanical power transmission of the forward / reverse switching valve 47 is neutralized. In this case, the rotation speed of the power source 1 can be controlled.