JPH0343576B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a test device for a variable speed steering device for testing a variable speed steering device installed in a tracked vehicle or the like on a bench.

[Conventional technology]

Figure 1 shows a conventional general variable speed steering gear test device (hereinafter referred to as the test device), in which a variable speed steering device 3 as a specimen is driven by a prime mover 1 such as an engine via a torque meter 2. be done. The driving force from the variable speed steering gear 3 is transmitted to power distributors 4, 4', torque meters 5, 5', flywheels 6, 6', brakes 7, 7' such as a hydraulic dynamometer, and a hydraulic pump.
The signal is transmitted to brake/drive devices 8, 8' such as motors. At this time, the brakes 7 and 7' are provided to provide running resistance, and the brake/drive combination devices 8 and 8' are provided to provide turning resistance.

FIG. 2 shows the hydraulic circuit and main equipment of the test equipment. Hydraulic oil is pumped from an oil tank 9 by a boost hydraulic pump 10 to high-pressure hydraulic pumps 11, 11' or hydraulic pump/motor 12, 1.
2'. The pressure control valve 13 is the hydraulic pump 1
Set to low voltage for zero protection. Stop valve 1
4 are manual valves and check valves 15, 15', which hold the hydraulic circuit from the hydraulic pump 10 in the open or closed position;
16, 16', 17, and 17' are used for backflow prevention. The switching valves 18, 18', 19, and 19' can be switched between two positions by remote control for setting various test circuits. Pressure control valves 20, 20' adjust the set pressure to control the torque of the hydraulic pump motors 12, 12'. A cooler 21 is provided to cool the hydraulic oil.

FIG. 3 shows the flow state of hydraulic oil when the variable speed steering gear is subjected to a hill climbing test. 12'. That is, the hydraulic pump motors 12, 12' are operated as hydraulic pumps. When operated as a hydraulic pump, suction hydraulic oil is supplied from the hydraulic pump 10 to the hydraulic pump motors 12, 12' via the stop valve 14 and the check valves 15, 15'. The high pressure oil discharged from the hydraulic pump/motor 12, 12' is transferred to the check valves 16, 16' and the switching valves 18, 1.
After being discharged as low-pressure oil by pressure control valves 20 and 20' which control the pressure to an appropriate pressure for torque control, the oil is returned to the oil tank 9 via a cooler 21. In addition, the hydraulic pump motor 12, 1
2' rotates at a low speed, the pressure control valves 20,
From the characteristics of 20', hydraulic pump motor 12,1
Since it is difficult to maintain the outlet pressure of the pump 2' at a high pressure, the hydraulic pumps 11 and 11' are driven to generate high pressure oil. At this time, the hydraulic pump 11,1
Hydraulic oil discharged from the hydraulic pump 10 is used as the suction oil 1'. In this case, the stop valve 14 is held open.

On the other hand, in the case of the descent test, as shown in FIG. 4, the variable speed steering gear 3 is driven by driving the hydraulic pump motors 12, 12'.

In this way, the hydraulic pump motor 12, 12'
When operated as a drive machine, that is, a hydraulic motor, the hydraulic pump motors 12, 12' are driven by high pressure oil generated from the hydraulic pumps 11, 11', and the suction oil of the hydraulic pumps 11, 11' is driven by the hydraulic pump 10. Provided by boost action. In this case, stop valve 14 is held closed.

Related devices of this type include "Meiden Jiho" published by Meidensha Co., Ltd. (No. 1979).
6).

[Problem to be solved by the invention]

In the above-mentioned conventional technology, it is necessary to open or close the stop valve 14 for each running test item, and there is a risk of malfunction. If a malfunction occurs, the main equipment of the test equipment will be damaged. Further, when the stop valve 14 is open, a large amount of hydraulic oil flows, so a large capacity stop valve is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a test device for a variable speed steering machine which eliminates the need for valve switching operations and prevents malfunctions when performing an uphill running test or a downhill running test.

[Means to solve the problem]

The above purpose is to provide hydraulic pump motors 12 and 12' that are connected to both output shaft sides of the variable speed steering gear 3 and that absorb or drive power, a boost hydraulic pump 10, and the hydraulic pump motors 12 and 12. ′
A pipeline is provided on the discharge side of the boost hydraulic pump 10 and a pipe line that communicates the boost hydraulic pump 10 and the hydraulic pump/motor 12, 12' via check valves 15, 15' when descending and climbing a slope. a first pressure control valve 13; a pipe line that communicates the discharge side of the first pressure control valve 13 with the discharge side of the hydraulic pump/motor 12, 12' and leads oil to the oil tank; The discharge side of the hydraulic pump motor 12, 12' and the first
pressure control valve 13, check valve 17, and switching valve 18.
and a pipe line communicating through the second pressure control valves 20, 20', and the second pressure control valves 20, 20'.
the discharge side of the hydraulic pump/motor 12, 12'
The hydraulic pump connects the discharge side of the boost hydraulic pump 10 and the inlet side of the hydraulic pump/motor 12, 12' when the hydraulic pump motors 12, 12' are connected via a switching valve with the discharge side of the boost hydraulic pump 10 when going downhill. 11, 11' and switching valve 1
9, 19', the discharge side of the second pressure control valve 20, 20' and the downward slope of the hydraulic pump/motor 12, 12'. A third pressure control valve 22, 2 whose set pressure is set higher than the set pressure of the first pressure control valve 13 is provided in the pipe line communicating with the discharge side of the
This is achieved by providing 2'.

[Operation] By setting the set pressure of the third pressure control valve higher than the set pressure of the first pressure control valve, the pressure pump can be rotated and the hydraulic pump
Even if the motor is driven as a motor, the hydraulic pump/
The discharge pressure of the motor becomes higher than the discharge pressure of the boost hydraulic pump, and as a result, there is no flow of pressure oil from the boost hydraulic pump toward the hydraulic pump/motor via the check valve. It is necessary to provide an on-off valve in the discharge side pipe of the hydraulic pump.

〔Example〕

An embodiment of the apparatus of the present invention will be described below with reference to the drawings.

In FIG. 5, the difference from FIG. 2 is that the stop valve 14 is removed and new pressure control valves 22, 2 are added.
2' was provided.

The pressure control valves 22, 22' are provided on the discharge side of the hydraulic pump/motor 12, 12', and the set pressure of the pressure control valves 22, 22' is set slightly higher than the set pressure of the pressure control valve 13. has been done.

FIG. 6 shows the flow state of hydraulic oil when performing a hill-climbing test. In the case of the hill-climbing test, the power from the variable speed steering gear 3 is absorbed by the hydraulic pump motors 12, 12'. . That is, the hydraulic pump motors 12, 12' operate as hydraulic pumps. In this case, the check valves 15, 15' are open because the pressure on the inflow side is higher than the pressure on the outflow side. Therefore, suction hydraulic oil is supplied from the hydraulic pump 10 to the hydraulic pump motors 12, 12' via the check valves 15, 15'. The high pressure oil discharged from the hydraulic pump motors 12 and 12' is
The oil is returned to the oil tank 9 via the check valves 16, 16', the switching valves 18, 18', the pressure control valves 20, 20', and the cooler 21. At this time, the set pressure of the pressure control valve 13 is set higher than the suction pressure to the hydraulic pump/motor 12, 12'.

In addition, in the case of a downhill running test, the hydraulic pump motors 12, 12' are
In other words, it operates as a hydraulic motor. In this case, the reverse valves 15, 15' are closed because the pressure on the outflow side is higher than the pressure on the inflow side. Therefore, the hydraulic pump/motor 12, 12' is driven by the suction oil of the hydraulic pump 11, 11', and the suction oil of the hydraulic pump/motor pump 11, 11' is supplied by the boost action of the hydraulic pump 10. be done. The low pressure oil discharged from the hydraulic pump motors 12, 12' is returned via the switching valves 19, 19', the pressure control valves 22, 22' and the cooler 21. At this time, the set pressures of the pressure control valves 22, 22' are set higher than the set pressure of the pressure control valve 13.

〔Effect of the invention〕

It is possible to prevent troubles caused by malfunctions when performing various tests without using a stop valve as in the past.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram for explaining the test equipment for variable speed steering machines, Fig. 2 is a diagram showing the hydraulic circuit in the conventional test equipment for variable speed steering machines, and Fig. 3 is a diagram for explaining the conventional test equipment for variable speed steering machines. A diagram to explain the flow of hydraulic oil when the test device is used for a hydraulic circuit uphill running test. Figure 4 shows the operation when the hydraulic circuit is used for a downhill running test in a conventional test equipment for variable speed steering gear. A diagram for explaining the flow of oil, FIG. 5 is a diagram showing a hydraulic circuit in a test device for a variable speed steering machine according to the present invention, and FIG. 6 is a diagram showing a hydraulic circuit in a test device for a variable speed steering device according to the present invention. FIG. 7 is a diagram for explaining the flow of hydraulic oil when used in a running test. It is a figure for explaining. 10, 11, 11'...Hydraulic pump, 12, 1
2'...Hydraulic pump motor, 13, 20, 2
0', 22, 22'...Pressure control valve.

Claims (1)

[Claims] 1 A hydraulic pump/motor that is connected to both output shaft sides of the variable speed steering gear and that absorbs or drives power, a boost hydraulic pump, and the hydraulic pump/motor that absorbs or drives power.
a conduit that communicates the boost hydraulic pump and the hydraulic pump/motor via a check valve when the motor is lowered and raised; a first pressure control valve provided on the discharge side of the boost hydraulic pump; A conduit that communicates the discharge side of the first pressure control valve and the discharge side of the hydraulic pump/motor to lead oil to the oil tank, and connects the discharge side of the hydraulic pump/motor and the first pressure control valve. A pipe line communicating through a check valve, a switching valve, and a second pressure control valve, and a discharge side of the second pressure control valve and a discharge side of the hydraulic pump/motor at the time of dismounting are connected via the switching valve. and a pipe line that communicates the discharge side of the boost hydraulic pump and the inlet side of the hydraulic pump/motor at the time of dismounting via a hydraulic pump and a switching valve. A third pressure control valve is provided with a set pressure higher than the set pressure of the first pressure control valve in a conduit communicating between the discharge side of the second pressure control valve and the discharge side of the hydraulic pump/motor at the time of dismounting. A test device for a variable speed steering machine, characterized by being equipped with a pressure control valve.