JPH0136657Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a power transmission device for a wheel loader.

Prior Art Generally, in a wheel loader, it is not possible to change the power distribution between the working machine and the undercarriage because there is only one accelerator pedal.

For this reason, power is transmitted to the undercarriage even when power is not required, such as during excavation, resulting in wasteful energy consumption such as tire slipping.

Purpose of the invention The purpose of the invention is to enable power distribution between the work equipment and the undercarriage in a wheel loader, and prevent power from being transmitted to the undercarriage during excavation, etc., thereby eliminating wasteful energy consumption due to tire slipping, etc. In addition, in the case of a combination of work and running and repeated running only, the clutch mechanism can be controlled from half-clutch to fully engaged by simply switching the solenoid valve.

Structure of the Invention In order to achieve the above object, the present invention is provided between the input shaft 5 of the torque converter 1 connected to the output side of the engine and the pump 8 of the torque converter 1. A clutch mechanism 6 connects, slides connects and disconnects the shaft 5 and the pump 8, and a first
The cylinder part 2 of the clutch mechanism 6 is
The variable pressure reducing valve side circuit A leading to the first oil chamber 27 and the cylinder part 21 of the clutch mechanism 6 from the discharge side of the hydraulic pump 25 via the second pipe line 29 and the third pipe line 31.
A switching valve side circuit B leading to the oil chamber 27, a switching valve 30 provided in the switching valve side circuit B and controlling the set pressure to the clutch mechanism 6 between zero and a predetermined pressure, and a hydraulic pump 25 by the switching operation. A solenoid valve 33 acts on the switching valve 30 by using the discharge pressure from the valve as pilot pressure to switch the switching valve 30, and a solenoid valve 33 is provided in the variable pressure reducing valve side circuit A to change the set pressure to the clutch mechanism 6 from zero to a predetermined pressure. The structure includes a variable pressure reducing valve 28 which performs stepless control until the changeover valve 30 switches and eliminates the pressure reducing effect by receiving the set pressure by the switching valve 30 when the switching valve 30 is switched.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a torque converter, the torque converter 1 is equipped with a case 2, and an input shaft 5 is provided on a shaft support 3 of the case 2 via a bearing 4,
The input shaft 5 is connected to a pump 8 via a clutch mechanism 6. A shaft support 10 is provided on the inner circumference of the pump housing 9 of the pump 8. An output shaft 12 is attached to the shaft support 10 via a bearing 11, and a turbine 13 is connected to the output shaft 12. A stator 15 is attached to the stator shaft 14 , and the stator shaft 14 supports the pump 8 via a bearing 16 .

The clutch mechanism 6 includes an inner shell 17 connected to the pump 8 side and an outer shell 18 connected to the input shaft 5 side.The outer shell 18 has a plate 19, and the inner shell 17 has a disk 20. are connected by splines. Cylinder part 21 of clutch mechanism 6
A press piston 22 is fitted into the plate 19, and the press piston 22 faces the plate 19.

The input shaft 5 of the torque converter 1 is connected to the output shaft 24 of the engine 23, and the output shaft 12 of the torque converter 1 is connected to the input shaft (not shown) of the transmission, which transmits power. It constitutes a mechanism.

The discharge side of the hydraulic pump 25 is connected to the oil chamber 27 of the cylinder portion 21 of the clutch mechanism 6 via a conduit 26, and a variable pressure reducing valve 28 is provided in this conduit 26. This variable pressure reducing valve 28 is operated manually or by electromagnetic force.

Further, the discharge side of the hydraulic pump 25 is connected to a port 30a of a switching valve 30 with modulation via a pipe line 29, and a port 30b of the switching valve 30 is connected to the oil chamber 27 via a pipe line 31. be.

The pipe line 26 constitutes a variable pressure reducing valve side circuit A, and the pipe line 29 and the pipe line 31 constitute a switching valve side circuit B.

Further, the discharge side of the hydraulic pump 25 is connected to a port 33a of a solenoid valve 33 via a conduit 32, and a port 33b of the solenoid valve 33 is connected to a pilot port 30c of the switching valve 30 via a pilot conduit 34.
The tank port 33c is connected to the tank 3.
5.

In the drawing, 36 is a clutch cooling circuit, and 37 is a drain circuit.

Next, the operation will be explained.

By maintaining the variable pressure reducing valve 28 at a predetermined set pressure, the discharge pressure from the hydraulic pump 25 is set to the set pressure, and this set pressure is introduced into the oil chamber 27 and the pressing piston 2
2 to bring the plate 19 and disk 20 into close contact with each other to bring them into the clutch-on state. For this purpose, the output of the engine 23 enters the pump 8 via the output shaft 24, the input shaft 5, and the clutch mechanism 6, and the pump 8 is driven and transmitted to the output shaft 12 via the turbine 13.

In this case, by changing the set pressure of the variable pressure reducing valve 28, the set pressure acting on the oil chamber 27 is changed, and the contact pressure between the plate 19 and the disc 20 is changed, and the capacity of the torque converter 1 is changed by sliding the clutch. , controls power distribution to the work equipment and undercarriage.

Note that by switching the solenoid valve 33 and removing the pressure acting on the pilot port 30c of the switching valve 30, the switching valve 30 is switched and the discharge pressure of the hydraulic pump 25 is directly introduced into the oil chamber 27. Make it clutch.

This is to transmit driving power from the torque converter to the transmission when no work is being done without controlling the clutch slippage.

In addition, when working and traveling together, the variable pressure reducing valve 28
operates the clutch mechanism 6 at the reduced pressure set by
In the case of only traveling, the solenoid valve 33 is switched and the switching valve 30 is switched, and the pressure set by the switching valve 30 eliminates the pressure reducing action of the variable pressure reducing valve 28 and operates the clutch mechanism 6 to fully engage. be able to.

Effects of the Invention As described in detail above, the present invention is provided between the input shaft 5 of the torque converter 1 connected to the output side of the engine and the pump 8 of the torque converter 1. A clutch mechanism 6 connects, slides connects and disconnects the pump 8 and the first pipe line 2 from the discharge side of the hydraulic pump 25.
6 to the oil chamber 27 of the cylinder portion 21 of the clutch mechanism 6, and the hydraulic pump 2.
5 from the discharge side to the second pipe line 29 and the third pipe line 31
The oil chamber 2 of the cylinder part 21 of the clutch mechanism 6
7, a switching valve 30 provided in the switching valve side circuit B and controlling the set pressure to the clutch mechanism 6 to be switched between zero and a predetermined pressure, and a switching valve 30 that controls the pressure set to the clutch mechanism 6 to be set to zero or a predetermined pressure, and the discharge from the hydraulic pump 25 due to the switching operation. A solenoid valve 33 is provided in the variable pressure reducing valve side circuit A to act on the switching valve 30 by applying pressure as pilot pressure to the switching valve 30, and a solenoid valve 33 is provided in the variable pressure reducing valve side circuit A to set the pressure to the clutch mechanism 6 steplessly from zero to a predetermined pressure. This power transmission device for a wheel loader is characterized in that it is equipped with a variable pressure reducing valve 28 which receives a set pressure by the switching valve 30 and eliminates the pressure reducing effect when the switching valve 30 is switched.

Therefore, by switching the solenoid valve 33 and switching the switching valve 30, the set pressure to the clutch mechanism 6 can be controlled to zero or a predetermined pressure, which reduces the running power when not working. The purpose is to obtain transmission from the torque converter through the transmission without clutch slip control.

Further, the clutch mechanism 6 is controlled by changing the set pressure by controlling the variable pressure reducing valve 28, and the torque converter 1
Since the capacity of the wheel loader can be changed, it is possible to change the power distribution to the work equipment and the undercarriage in the wheel loader. Therefore, when power is not required in the undercarriage, such as during excavation, power is not transmitted to the undercarriage, thereby eliminating wasteful energy consumption such as tire slip.

In addition, when working and traveling together, the variable pressure reducing valve 28
operates the clutch mechanism 6 at the reduced pressure set by
In the case of only traveling, the solenoid valve 33 is switched and the switching valve 30 is switched, and the pressure set by the switching valve 30 eliminates the pressure reducing action of the variable pressure reducing valve 28 and operates the clutch mechanism 6 to fully engage. be able to.

For this reason, when both working and traveling and only traveling are repeated, the clutch mechanism 6 can be controlled from a half-clutch state to a fully engaged state simply by switching the solenoid valve 33.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted structural explanatory diagram of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a torque converter. 1 is a torque converter, 5 is an input shaft, 6 is a clutch mechanism, 8 is a pump, and 28 is a variable pressure reducing valve.

Claims (1)

[Scope of utility model registration request] Input shaft 5 of torque converter 1 connected to the output side of the engine and pump 8 of torque converter 1
and the input shaft 5 depending on the degree of set pressure.
and a clutch mechanism 6 that performs connection, sliding connection, and disconnection with the pump 8, and a variable pressure reducing valve that connects from the discharge side of the hydraulic pump 25 to the oil chamber 27 of the cylinder portion 21 of the clutch mechanism 6 via the first pipe line 26. Side circuit A
and the second pipe line 2 from the discharge side of the hydraulic pump 25.
9. A switching valve side circuit B leading to the oil chamber 27 of the cylinder portion 21 of the clutch mechanism 6 via the third pipe line 31;
A switching valve 30 is provided in the switching valve side circuit B and controls the set pressure to the clutch mechanism 6 to be switched between zero and a predetermined pressure.
, an electromagnetic valve 33 which acts on the switching valve 30 by using the discharge pressure from the hydraulic pump 25 as pilot pressure to switch the switching valve 30; A wheel loader characterized in that it is equipped with a variable pressure reducing valve 28 which continuously controls the set pressure of from zero to a predetermined pressure and eliminates the pressure reducing effect by receiving the set pressure by the switching valve 30 when the switching valve 30 is switched. Power transmission device.