JPS607228Y2 - Crawler type vehicle drive device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drive device for a crawler-type vehicle in which left and right drive devices are driven by independent power lines.

As shown in FIG. 1, a conventional drive device of this type has two independent power lines e and f formed by two hydraulic pumps a and b and two hydraulic motors C and d.

However, in the drive system of such a vehicle, the required capacity of the hydraulic motor is larger than the traction force Ft per hydraulic motor required when driving straight ahead, but the traction force per motor required when turning. Since Fs is larger, it was determined by the latter.

For this reason, there is a drawback that the capacity of the hydraulic pump and motor of the conventional drive device increases, and when applied to large vehicles, the price of the hydraulic pump and motor increases more than the rate of increase in their capacity. Therefore, there is a problem in that very expensive hydraulic pumps and motors must be used, or if suitable products are not available on the market, new large-capacity hydraulic pumps and motors must be developed.

In Fig. 1, g and h are parking brakes, and 1w
j is a speed reducer.

The present invention has been made in consideration of the above-mentioned problems, and it is an object of the present invention to provide a drive system for a crawler-type vehicle that eliminates the need for a specially designed hydraulic pump and motor even in the case of large-sized vehicles.

The configuration will be explained below based on the embodiment shown in FIG.

In the figure, reference numerals 1, 2, and 3 denote left, center, and right hydraulic pumps, which are rotationally driven by an engine 5 via a splitter 4.

6, 7゜8 are left, center, and right hydraulic motors that constitute independent power lines for each of the hydraulic pumps 1, 2, and 3, respectively, and the output shafts of the left and right hydraulic motors 6゜8 serve as parking brakes. 9aw9bJE right reducer 10a
, 10b to the left and right drive wheels 11a, llb.

Also, the output shaft of the central hydraulic motor 7 is connected to the left and right hydraulic motors 6.
．． Left and right clutches 12a and 12b are installed on the output shaft of 8, respectively.
Connect via .

Note that each of the above hydraulic pumps and motors is a reversible and variable displacement pump and motor.

In the above configuration, when the vehicle is traveling straight, the left and right clutches 1
2a and 12b are connected.

(Then, the torque of the three hydraulic motors 6, 7, 8 is divided into left and right halves and transmitted to the left and right drive wheels 11a, llb.

When turning gently to the left or right, release only the clutch on the inside in the turning direction.

In this way, the torque of the two hydraulic motors is transmitted to the drive wheel on the outside of the turn, and the torque of one hydraulic motor is transmitted to the drive wheel on the inside.

In this state, the discharge flow rate of one hydraulic pump that sends pressure oil to the inner hydraulic motor is smaller than the discharge flow rate of the two hydraulic pumps that send pressure oil to the two outer hydraulic motors.

By rotating the vehicle, the rotation speed of the inner hydraulic motor is made smaller than the rotation speed of the two outer hydraulic motors, and the vehicle is rotated slowly to the left or right.

When making a left or right pivot turn (turning around the center of one track of the vehicle body), release the clutch on the inside of the turn in the same way as when making a gentle turn, and in this state send pressure oil to the hydraulic motor on the inside of the turn. This is done by reducing only the supply amount of one hydraulic pump to zero.

When making a left or right spin turn (turning with the center of the vehicle as the turning center), release the clutch on the inside of the turn and reverse only the direction of pressure oil supply from the pump that sends pressure oil to the hydraulic motor on the inside, just like when turning slowly. It is done by making.

The relationship between the engagement/disengagement states of the two clutches and the magnitudes and directions of the supply flow rates of the three pumps in each of the above running states is shown in the table below.

The present invention is as described above, and includes three hydraulic pumps 1, 2.3 and three hydraulic motors 6.3 connected to a common engine 5.
7.8 configures three independent power lines, two of which have two hydraulic motors each.
8 are connected to the left and right drive wheels 11a and llb, respectively, and the output shaft of the hydraulic motor 7 of the other power line and the output shaft of the motor 6.8 that drives the left and right drive wheels 11a and llb are connected to clutches 12a and 8, respectively. 12b to form a drive system for a crawler-type vehicle, when driving straight, the two clutches 12a and 12b are brought into contact, so that the traction force of the hydraulic motor required for each clutch is 2/3 Ft or less. By releasing only one clutch when turning, the traction force of each hydraulic motor is reduced to 17
2FS or less, the required capacity of one hydraulic pump and motor can be reduced to less than half of the conventional case, and even in the case of large vehicles, there is no need to use a hydraulic pump and motor with special specifications, making the entire vehicle cheaper. Obtainable.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. 1.2.3 is a hydraulic pump, 6, 7, 8 are hydraulic motors, 1
1a and 11b are driving wheels, and 12at and 12b are clutches.

Claims (1)

[Scope of utility model registration request] Three variable displacement hydraulic pumps 1, 2.3 connected to a common engine 5 and three hydraulic motors 6.7.8
The hydraulic motors 6.8 of two of these power lines are connected to the left and right drive wheels 11a and 11b, respectively, and the output shafts of the hydraulic motors of the other power lines and the left and right Drive wheels 11a, l
A drive device for a crawler type vehicle, characterized in that the output shaft of a motor 6.8 for driving a motor 6.8 is connected via clutches 12a and 12b, respectively.