Power plants – Pressure fluid source and motor – Having condition responsive control in a system of distinct...
Patent
1996-12-20
1999-01-12
Richter, Sheldon J.
Power plants
Pressure fluid source and motor
Having condition responsive control in a system of distinct...
60468, 91447, F15B 1306
Patent
active
058573305
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a travelling control circuit for a hydraulically driven type of travelling control apparatus. In addition, the travelling control apparatus is for use in a construction machine and other similar types of equipment.
BACKGROUND ART
A hydraulically driven type of travelling apparatus is designed to be driven with a pair of hydraulic motors. The hydraulic motors are disposed at right and left hand sides for right and left hand side driving wheels, respectively. In addition, the hydraulic motors are for moving a vehicle. The right and left hand side traveling purpose hydraulic motors are supplied with a pressurized discharge fluid from a hydraulic pump, by right and left hand side directional control valves, respectively.
A travelling control circuit for such a hydraulically driven type of travelling apparatus is known in the prior art, as shown in FIG. 1, in which a single hydraulic pump is provided.
In such a travelling control apparatus, a hydraulic pump 1 has a discharge path 2 that is provided with a left hand side directional control valve 3 and a right hand side directional control valve 4 which are disposed in parallel to each other. A pair of first circuits 7 and a pair of second circuits 8, arranged at the left and right hand side, couple the left and right hand side directional control valves 3 and 4 with left and right hand side hydraulic motors 5 and 6. The hydraulic motors 5 and 6 are used for moving the machine. A pressure compensating valve 9 is provided in each of the first circuits 7 and each of the second circuits 8 to respond to the higher of load pressures of the left and right hand side hydraulic motors 5 and 6.
More specifically, each of the pressure compensating valves 9 is pushed in a direction to disconnect an inlet port 12 from an outlet port 13 by a spring 10 and by a maximum load pressure that acts on a first pressure receiving portion 11. Furthermore, each of the pressure compensating valves 9 may also be pushed in a direction to place the inlet port 12 into communication with the outlet port 13 under its own load pressure that acts on a second pressure receiving portion 14. Hence, the area of opening between the inlet port 12 and the outlet port 13 of each of the pressure compensating valves 9 will decrease as the difference between the maximum load pressure and its own load pressure is increased, thus compensating for a pressure in the inlet side.
Since this causes the pressurized discharge fluid from a single hydraulic pump to be supplied simultaneously to the left and right hand side hydraulic motors 5 and 6 while also compensating for a pressure with the pressure compensating valves 9, a pressurized discharge fluid can be supplied to the left hand side hydraulic motor 5 and the right hand side hydraulic motor 6 even if the left and right hand side traveling purpose hydraulic motors 5 and 6 have different load pressures.
At this point, it should be noted that a first auxiliary circuit 15 and a second auxiliary circuit 16 are each designed to control communication between the outlet port side of the pressure compensating valve 9 and a reservoir port of the left and right hand side directional control valves 3 and 4. Also, it should be noted that a capacity control unit la is provided for controlling the capacity of the hydraulic pump 1 in accordance with a load pressure.
Assume now that the foregoing travelling control arrangement is adopted. Then, if the left and right hand directional control valves 3 and 4 are switched to the first position A as shown in FIG. 2, to travel linearly, and if the supply flows to the left and right hand travelling purpose hydraulic motors 5 and 6 are different, the apparatus will travel in a curve. Then, as shown in FIG. 1. it is configured that the left and right hand side first circuits 7 and the left and right hand side second circuits 8 are each short circuited with a short circuit path 17. Each short circuit path 17 is provided with a travelling communicating path 18. The travelling communi
REFERENCES:
patent: 4769991 (1988-09-01), Johnson
patent: 5138837 (1992-08-01), Obertrifter et al.
patent: 5251444 (1993-10-01), Ochiai et al.
patent: 5259192 (1993-11-01), Karakama et al.
patent: 5447093 (1995-09-01), Budzich
patent: 5560204 (1996-10-01), Ishihama et al.
patent: 5699665 (1997-12-01), Coolidge
Ishizaki Naoki
Takano Toshiro
Komatsu Ltd.
Richter Sheldon J.
LandOfFree
Travelling control circuit for a hydraulically driven type of tr does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Travelling control circuit for a hydraulically driven type of tr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Travelling control circuit for a hydraulically driven type of tr will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1504981