JPH1137250A - Mechano-hydraulic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use oil pressure energy for an actuator of a working machine by minimizing power to be used by a hydraulic pump for driving a hydraulic motor when the rotational speed of an output shaft is large, and merging excess power in the hydraulic pump with power in the other pump. SOLUTION: In a mechano-hydraulic transmission, a second selector valve 15 for switching the rotating direction of a hydraulic motor 21, and a first selector valve 13 for switching communication passages 12b, 14 communicated with a working machine actuator 10 and the second selector valve 15 by a second pump 9 are arranged on pipe liens 12a, 14, 16, 20a, 20b for connecting the second pump 9 and the hydraulic motor 21 to each other, and discharging oil of the second pump 9 and the first pump 8 are joined to each other by switching the first selector valve 13 so as to be used for the actuator 10 of a working machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical hydraulic transmission for driving a vehicle such as a construction machine, and more particularly to a hydraulic pump that effectively utilizes hydraulic energy without losing extra power in a hydraulic pump. .

[0002]

2. Description of the Related Art FIG. 4 shows a conventional mechanical hydraulic transmission of this type. To explain this, this transmission is equipped with an engine (ENG) 1
An input shaft 2 is connected to a power source such as the above. A drive gear 3 is fixed to the input shaft 2, and an end is connected to a planetary gear group 5 via a clutch 4. The driving gear 3 further includes:
Interlocked with the variable displacement pumps 8 and 9 via gears 6 and 7,
The pumps 8 and 9 are driven to rotate. The pump 8 is connected to an actuator 10 of the work machine by a pipe 11, while the pump 9 is connected to a hydraulic motor 21 through pipes 12c and 12d. A gear 22 and a brake disc board 23 are fixed to the main shaft 21a of the hydraulic motor 21. The gear 22 further meshes with the planetary gear group 5 via a gear 24, and the brake disc The board 23 is held by a brake cylinder 25 that operates via a control device (not shown), and the hydraulic motor 2
The rotation of one main shaft 21a is stopped.
The output shaft 5a of the planetary gear group 5 is connected to wheels or the like of a construction machine (not shown) to drive the vehicle body. When the rotation speed of the output shaft 5a is low and low, the clutch 4 is disconnected by a signal from a control unit (not shown), and power from a hydraulic transmission unit including a hydraulic pump, a hydraulic motor, a planetary gear group 5, and the like is output. 5a, output shaft 5
When the rotation speed of the motor a is high, the clutch 4 is connected by a signal from the control unit, and the power from the engine 1 is directly transmitted to the output shaft 5a. Pump 8 while minimizing
Supplies the necessary power to the actuator 10 of the work machine.

[0003]

By the way, in the above-mentioned prior art, when the rotation speed of the output shaft is high, the clutch is connected by a signal from a control unit (not shown) at a high speed, and the power of the hydraulic power transmission device is transmitted to the output shaft. And tell
While the power used by the pump is minimized by a command from the control unit, the other pumps supply hydraulic pressure to the actuator of the work equipment, but the extra power in the hydraulic pump that drives the hydraulic motor is There is a problem that the hydraulic energy is lost without being used, and the hydraulic energy is not effectively used.

Accordingly, the present invention minimizes the power used in the hydraulic pump for driving the hydraulic motor when the rotation speed of the output shaft is large and at high speed, and reduces the excess power in the hydraulic pump for driving the hydraulic motor. Combined with another hydraulic pump, it is supplied to the actuator of the working machine, etc., and the hydraulic energy is used effectively to save energy.

[0005]

According to a first aspect of the present invention, an input shaft connected to a power source, a drive gear and a clutch fixed to the input shaft, a group of planetary gears connected via a clutch, and a drive gear A second pump connected to drive the hydraulic motor and a second pump connected to the actuator of the work machine, and a gear fixed to the main shaft of the hydraulic motor and meshing with the planetary gear group. When the rotation speed of the output shaft from the planetary gear group is low, the clutch is disengaged at low speed and the power from the hydraulic motor is transmitted to the output shaft, and at the high rotation speed of the output shaft, the clutch is joined to output power. In a mechanical hydraulic transmission that transmits power to the shaft and minimizes the power used by the second pump, a hydraulic motor is connected to a pipe connecting the second pump and the hydraulic motor. A second switching valve for switching the direction of rotation and a first switching valve for switching the communication path from the second pump to the working machine actuator or to the second switching valve are provided, and the first switching valve is switched. The discharge oil of the second pump and the first pump are combined and used for the actuator of the work machine.

In the second invention, the first pump is a fixed displacement pump.

In a third aspect, a clutch and a hydraulic transmission unit including a second switching valve, a hydraulic motor, a gear, a planetary gear group, and the like are unitized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1, the mechanical hydraulic transmission according to this embodiment includes a power source such as an engine (ENG) 1, gears 3, 6, and 7 connected to the power source, a clutch 4, and the like. A mechanical transmission unit M and hydraulic pumps 8 and 9 linked to a power source;
The switching valves 13 and 15, the hydraulic motor 21, and the hydraulic transmission H including the planetary gear group 5 and the like are combined and configured.

An input shaft 2 is directly connected to a power source such as an engine 1, and a drive gear 3 is fixed to the input shaft 2.
The end is connected to a planetary gear group 5 via a clutch 4.

The driving gear 3 is further interlocked with first and second variable displacement pumps 8 and 9 (hereinafter referred to as first and second pumps 8 and 9) via gears 6 and 7, Pump 8,
9 is driven to rotate.

The first pump 8 is connected to an actuator 10 of a working machine by a pipe 11, while the second pump 9 is connected to a first switching valve 13 having a three-port two-position via a pipe 12a. Port a.

The port b of the first switching valve 13 is connected to the pipe 12
b, is connected to a pipe 11 communicating with the actuator 10 of the working machine, and a port c is connected to the pipe 1
Second switching valve 1 having 4 ports and 3 positions by 4
5 is connected to port d.

When the first switching valve 13 is in the position A, the second pump 9 is connected to the ports a,
b, communicating with the actuator 10 of the working machine via the pipe 12b, and at the position B, the second pump 9 is connected to the second switch 9 via the ports a, c of the first switching valve 13 and the pipe 14.
To the port d of the switching valve 15.

The port e of the second switching valve 15 is connected to a pipe 16
Is connected to a downstream side of a check valve 19 provided in a pipe 18 communicating with the tank 17 on the suction side of the second pump 9.

The ports f and g of the second switching valve 15 are connected to a fixed displacement hydraulic motor (hereinafter referred to as a hydraulic motor) 21 via pipes 20a and 20b.

When the second switching valve 15 is in the positions C, D, E
, The hydraulic motor 21 rotates forward, reverse, and stops.

A gear 2 is mounted on a main shaft 21a of the hydraulic motor 21.
2 and the brake disc board 23 are fixed,
The gear 22 further meshes with the planetary gear group 5 via a gear 24, and the brake disk board 23 is sandwiched by a brake cylinder 25 operated via a control device (not shown), and a hydraulic motor The rotation of the main shaft 21a of the motor 21 can be stopped.

The output shaft 5a of the group of planetary gears 5 is connected to a wheel or the like of a construction machine (not shown) to drive the vehicle body.

Next, the operation will be described. Now, when the engine 1 is driven, the drive gear 3 fixed to the input shaft 2
Are rotated, and the first and second pumps 8, 9 are driven through gears 6, 7.
Is driven, and the discharge oil of the first pump 8 which is sucked and discharged from the tank 17 is directly supplied to the actuator 10 of the working machine.
In addition, the discharge oil of the second pump 9 which is sucked and discharged from the tank 17 via the check valve 19 is supplied to the ports a and b and the pipe 1 when the first switching valve 13 is at the position A.
Via the 2b, it is joined and supplied to the actuator 10 of the working machine.

When driving the vehicle body of a construction machine (not shown), the first switching valve 13 is operated to the position B and the second switching valve 15 is operated to the position C or E. Are supplied to the hydraulic motor 21 via the first and second switching valves 13 and 15, and the hydraulic motor 21 rotates forward or reverse, and is interlocked with the gear 24 fixed to the main shaft 21 a of the hydraulic motor 21. The output shaft 5a rotates through the planetary gear group 5 to drive a vehicle body connected to wheels or the like of a construction machine (not shown).

When the rotation speed of the output shaft 5a is low and low, the clutch 4 provided on the input shaft 2 directly connected to the engine 1 is disconnected by a control device (not shown).
Is transmitted to the output shaft 5a, but only the power from the hydraulic motor by the second pump 9 is transmitted.

When the rotation speed of the output shaft 5a is high and the rotation speed is high, the clutch 4 provided on the input shaft 2 is joined by a control device (not shown), and the direct power from the engine 1 is output via the planetary gear group 5. Power is transmitted to the shaft 5a, and the power used by the second pump 9 is minimized by a control device (not shown).

When the power used by the second pump 9 becomes minimum, the brake disk board 23 is clamped by a brake cylinder 25 operated via a control device (not shown), and the output shaft 21a of the hydraulic motor 21 is rotated. Stop the rotation of
When the second switching valve 15 is switched to the position D and the first switching valve 13 is switched to the position A in a state where the hydraulic motor 21 has stopped rotating, power from the hydraulic motor 21 is not transmitted to the output shaft 5a, Direct power from the engine 1 is transmitted to the output shaft 5 a via the input shaft 2, the clutch 4, and the planetary gear unit 5, and the discharge oil of the first and second pumps 8 and 9 is supplied to the actuator 10 of the working machine. And supplied to

When it is not necessary to rotate the output shaft 5a, and the operation is stopped, the first switching valve 13 is switched to the position A so that the discharge flow rates of the first pump 8 and the second pump 9 can be changed. Can be used for the actuator 10 of the work machine, and when the flow rate used by the actuator 10 of the work machine is small and the first pump 8 is sufficient, the first switching valve 13 is moved to the position. B, the second pump 9 switches the ports a and c of the first switching valve 13 to the second
Is unloaded to the suction side of the second pump 9 through the ports d and e of the switching valve 15, and unnecessary power can be saved.

As described above, in the mechanical hydraulic transmission, the second switching valve 15 for switching the rotation direction of the hydraulic motor 21 to the pipeline connecting the second pump 9 and the hydraulic motor 21 and the second pump 9 from the work machine actuator 1
0 or a second switching valve 15 for switching to the second switching valve 15, the rotation speed of the output shaft 5 a is high, the clutch 4 is connected, and the power of the power source is directly transmitted to the output shaft 5.
a, the power used by the second pump 9 is minimized, and the first switching valve 13 is switched so that the discharge oil of the second pump 9 and the discharge oil of the first pump 8 are joined. Is used for the actuator 10 of the working machine, so that the hydraulic energy can be used effectively, which can be used for energy saving.
The discharge capacity of the first pump 8 for use can be reduced, the size can be reduced, the mounting space can be afforded, assembly adjustment can be facilitated, and the cost can be reduced.

Next, the second embodiment shown in FIG.
Among the plurality of variable displacement hydraulic pumps, the pump which does not need to change the displacement is a fixed discharge pump. Other components are the same as those of the first embodiment, and only different components will be described here. The details of the other components are omitted. Therefore, the hydraulic pump according to the second embodiment is a fixed displacement pump 8a in which the first pump used for the working machine actuator 10 or the like which does not need to change the displacement is a fixed displacement pump 8a. 8a, the second pump 9
A more required amount is merged via the switching valve 13, which has the same operation and effect as the first embodiment, and changes the discharge amount by using the fixed displacement pump 8a. Simpler and less expensive.

Further, the third embodiment shown in FIG.
Only the configuration in which the switching valve 15, the oil motor 21, the gear, the planetary gear group 5, the clutch 4 and the like are integrated into a unit U is different, and the other configuration is the same as that of the first embodiment. The details of the elements will be omitted, and the operation and effect will be the same as those of the first embodiment. In addition, the unitization will facilitate assembly adjustment and reduce the cost.

[0028]

According to the first aspect of the present invention, the power of the power source is directly transmitted to the output shaft by connecting the clutch, and the power used by the pump is minimized at a high speed where the rotation speed of the output shaft is high. In such a mechanical hydraulic power transmission device, a second switching valve for switching the rotation direction of the hydraulic motor to a pipeline connecting the second pump and the hydraulic motor, and an actuator of a working machine or a second switching valve from the second pump. A first switching valve for switching the communication path to the second switching valve, and switching the first switching valve to merge the second pump and the discharge oil of the first pump so as to actuate an actuator of a working machine, etc. The hydraulic pump can be used effectively, which can save energy, and can reduce the discharge capacity of the first pump for the actuator of the work machine, making it smaller in size and mounting space. Can afford the over scan, assembling adjustment becomes easy and the effect of the cost can be reduced.

According to the second aspect of the present invention, since the first pump is a fixed displacement hydraulic pump, there is no mechanism for changing the discharge amount, and the pump is simple and inexpensive.

According to the third aspect of the present invention, the clutch and the hydraulic transmission unit including the second switching valve, the hydraulic motor, the gears, the planetary gear group, and the like are unitized, so that the assembly and adjustment are easy and the cost is reduced. I can do it.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a mechanical hydraulic transmission according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a mechanical hydraulic transmission according to a second embodiment.

FIG. 3 is a hydraulic circuit diagram of a mechanical hydraulic transmission according to a third embodiment.

FIG. 4 is a hydraulic circuit diagram of a mechanical hydraulic transmission showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 engine 2 input shaft 3 drive gear 4 clutch 5 planetary gear group 5a output shaft 6,7 gear 8,9 variable displacement pump 8a fixed displacement pump 11 piping 12a, 12b piping 13 first switching valve 14 piping 15 second Switching valve 16 piping 17 tank 18 piping 19 check valve 20a, 20b piping 21 hydraulic motor 21a main shaft 22 gear 23 brake disc board 24 gear 25 brake cylinder a, b, c port of first switching valve d, e, f, g Ports of the second switching valve A, B Positions of the first switching valve C, D, E Positions of the second switching valve H Hydraulic transmission unit M Mechanical transmission unit U Unit

Claims (3)

[Claims] An input shaft connected to a power source, a drive gear and a clutch fixed to the input shaft, a group of planetary gears connected via the clutch, and an actuator of a work machine driven in conjunction with the drive gear And a second pump connected to drive a hydraulic motor and a second pump connected to the hydraulic pump, and a gear fixed to a main shaft of the hydraulic motor and meshing with the planetary gear group, and an output shaft from the planetary gear group. At low rotation speeds, the clutch is disengaged and the power from the hydraulic motor is transmitted to the output shaft at low speeds. At high rotation speeds of the output shaft, the clutch is engaged and power is transmitted to the output shaft. In a mechanical hydraulic transmission configured to minimize power to be used, a second switching valve for switching a rotation direction of a hydraulic motor to a pipeline connecting the second pump and a hydraulic motor; The first of more than 2 pumps switches the communication path to the actuator or the second switching valve of the working machine
And a switching valve for switching the first switching valve so that the discharge oil of the second pump and the discharge oil of the first pump are merged and used for an actuator of a work machine. Transmission. 2. The mechanical hydraulic transmission according to claim 1, wherein said first pump is a fixed displacement pump. 3. The mechanical hydraulic transmission according to claim 1, wherein said clutch and a hydraulic transmission unit comprising a second switching valve, a hydraulic motor, a gear, a planetary gear group and the like are unitized. .