JPS5996016A - Travelling track correcting circuit for hydraulic drive system caterpillar vehicle - Google Patents

Abstract

PURPOSE:To facilitate the correction of deflection during travelling by providing two flow regulating valves and a direction controlling valve for the correction in a travelling hydraulic circuit. CONSTITUTION:A double-throw hydraulic pump consisting of a pair of hydraulic pumps 12, 12' having same dischrge is used for a hydraulic pump for driving hydraulic motors 8, 8' connected through a reduction gear to left and right device wheels, and direction controlling valves 16, 16' for travelling are interposed respectively in pressurized oil supply circuits 15, 15' connected to the discharge ports of the respective pumps. Also, flow regulating valves 22, 22' are connectively branched from the respective circuits 15, 15' to constitute a bleed-off circuit and the outlet side of both valves 22, 22' is connected through a direction controlling valve 23 for electromagnetic correction to an oil return circuit 19. When travelling is deflected during straight travelling, the direction controlling valve 23 for correction is changed over to bleed off a portion of oil pressure to a tank 21 which is applied to the hydraulic motor 8 or 8' at the opposite side to the deflected side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traveling trajectory correction circuit for a hydraulically driven tracked vehicle that can easily correct the trajectory.

Hydraulically driven tracked vehicles generally drive both hydraulic motors by supplying pressure oil from the left and right hydraulic pumps with the same discharge volume to the left and right hydraulic motors with the same capacity. Drive the vehicle forward or backward. If such a tracked vehicle is not provided with an appropriate track correction means, the following factors will cause a difference in the rotational speed of the left and right drive wheels, causing the tracked vehicle to deviate to the left or right.

That is, in this type of tracked vehicle, (a) Although the left and right hydraulic pumps are hydraulic pumps with the same discharge volume, there is a difference in the discharge volume.

(0) Hydraulic motors of the same capacity are used for the left and right hydraulic motors, but there is a difference of 9 in the amount of internal drain between them.

(c) Depending on the condition of the ground on which the vehicle is traveling, the rotational force required of the respective drive wheels that drive the left and right crawlers differs, and this causes a difference in the discharge amount of the left and right hydraulic pumps.

(→ The resistance of the pipeline from one hydraulic pump to one hydraulic motor is different from the resistance of the pipeline from the other hydraulic pump to the other hydraulic motor, and it is impossible to make both pipeline resistances exactly the same.) This is extremely difficult in terms of design.

Due to the synergistic effect of the above factors (a) to (→), a rotation difference occurs between the left and right drive wheels, and you must be prepared for the rotation difference to be normally 6 to 4%. Although it varies slightly, in general, when moving forward by iom, it is 0.3 to 0.4 m, and when moving forward by 5°, it is 1.5 m.
The tracked vehicle will be deflected to the left or right by approximately ~2.0 m. In addition, if there is a certain rotation difference between the left and right drive wheels of a tracked vehicle, the tracked vehicle will turn (deflect) at a constant radius, so as the traveling distance increases, the deflection to the left or right will increase due to acceleration. becomes larger. Therefore, when traveling on a narrow road, it is necessary to drive only one crawler track to correct the direction every time the vehicle travels several meters, making smooth forward (reverse) travel difficult.

Conventionally, as a means to improve the straight-line performance of a tracked vehicle, the driving wheel axles of the left and right tracks are detachably attached using a clutch, and when traveling straight, the clutch is engaged to connect the left and right driving wheel axles. A method of synchronizing the rotational speed of the left and right drive wheel axles, and a rotation detector is installed on the left and right drive wheel axles to detect the rotation error of the left and right drive wheel axles, and the error is fed back to the hydraulic pump that is the power source for each of the left and right drive wheel axles. Accordingly, a method is used in which the rotational speeds of the left and right drive wheel shafts are synchronized by adjusting the discharge amount of the left and right hydraulic pumps.

However, in the former method, it is necessary to mechanically connect the left and right drive wheel axles, so the synchronizer is large and
Since no other equipment can be installed in the occupied space, there are design constraints. Further, in the latter method, the control device becomes complicated, which increases equipment costs and causes problems such as an increase in the number of failure factors.

In view of these points, the present invention has a simple structure that allows the vehicle to travel smoothly in a straight line, and not only controls the straightness of the vehicle, but also freely changes the direction of travel of the vehicle without moving forward. The present invention provides a traveling trajectory correction circuit for a hydraulically driven tracked vehicle that can greatly improve the operation control function.

The present invention provides a traveling circuit for a hydraulically driven tracked vehicle, in which flow rate regulating valves are branched and connected in the middle of each pressure oil supply circuit from the left and right hydraulic pumps to the left and right hydraulic motors, and
A correction directional control valve is connected to the outlet side of both flow rate adjustment valves, and by switching the correction directional control valve, a part of the pressure oil in each pressure oil supply circuit is connected to the flow rate adjustment valve and the correction directional control valve. The feature is that the water is selectively drained into the tank via a valve.

Hereinafter, the implementation side of the present invention will be explained with reference to the drawings.

First, an overview of a hydraulically driven tracked vehicle will be explained with reference to FIGS. 1 and 2. The tracked vehicle shown in FIG. A driving wheel 6 is pivotally supported at one end, and an idler wheel 5 is pivotally supported at the other end via a track tensioning device 4, respectively.
--.

- A crawler track 6 is stretched over each drive wheel 3 and idler wheel 5, and a hydraulic motor 8 is connected to each drive wheel 6 via a reduction gear 7, and the drive of each hydraulic motor 8 causes Left and right crawler belts 6 are driven via each speed reducer 7 and drive wheels 6. Note that 9 is an upper guide wheel of the crawler belt 6, 10 is a lower rolling wheel, and 11 is a suspension device for the lower rolling wheel 10.

The left and right hydraulic motors 8 of the tracked vehicle are driven by a hydraulic circuit shown in FIG. In FIG. 6, motors with the same capacity are used for the left and right hydraulic motors 8, 8', and as hydraulic pumps for driving both motors 8, 8': a pair of hydraulic pumps 12 and 12' with the same discharge capacity. The dual hydraulic pump 12, 12' is connected to the electric motor 14 via a coupling 15.

Solenoids 16a+1 are connected to pressure oil supply circuits 15 and 15' connected to the discharge ports of both hydraulic pumps 12 and 12', respectively.
61) and 16'a+16''b, the oil is connected to both side circuits 17.18 and 17', 18' of the left and right hydraulic motors 8, 8' through electrohydraulic traveling direction control valves 16,16' switched by 16'a+16''b. It is switchably connected to a return circuit 19. Reference numerals 20 and 20' indicate a leaf valve for preventing overload, and 21 indicates an oil tank.

In the above hydraulic circuit, particularly in the present invention, a bleed-off circuit is constructed by branching and connecting flow rate regulating valves 22 and 22' of the same type in the middle of the side pressure oil supply circuit 15 and 15', and both flow regulating valves 22 and The outlet side of .22' is configured to be selectively communicated with or blocked from the oil return circuit 19 via an electromagnetic correction directional control valve 26 which is switched by solenoids 23a, 231).

Next, the operation will be explained.

By demagnetizing the solenoids 23a and 23b and holding the correction directional control valve 26 in the neutral position, both flow rate adjustment valves 22 and 22
' with the outlet sides of solenoid i blocked.
Exciting 6a+16'a and driving direction control valve 16.16
When ' is switched to the left position in the figure, the oil discharged from the hydraulic pumps 12, 12' driven by the electric motor 14 is guided from each pressure oil supply circuit 15, 15' to the circuit 17, 17', and the left and right hydraulic motors 8, 8', both hydraulic motors 8, 8'
The left and right drive wheels and tracks are driven, and the tracked vehicle moves forward. In addition, on the contrary, solenoid i6b+16'l
:+ is excited and the travel direction control valve 16.16' is switched to the right position in the drawing, the oil discharged from the hydraulic pump 12.12' flows into the circuit 18.18', and both hydraulic motors 8, 8'
is driven in reverse, causing the tracked vehicle to move backward.

By the way, in the above hydraulic circuit, the correction directional control valve 2
6 is neutral and both the outlet sides of the flow rate adjustment valves 22, 22' are blocked, the condition is substantially the same as the conventional product without the flow rate adjustment valves 22, 22' and the correction directional control valve 26, and this When a tracked vehicle is moved forward or backward in such a state, due to the factors (a) to (a) above, there will be a difference in the rotational speed of the left and right drive wheels, causing the tracked vehicle to veer to the left or right. It turns out.

Therefore, when such a travel deflection occurs, the correction directional control valve 26 is switched to the left or right side in the drawing, and the pressure oil supply circuit 15 or 15 is switched to the hydraulic motor 8 or 8' on the opposite side to the side where the deflection is occurring. A portion of the oil at ' is bled off to the oil tank 21 via the flow rate regulating valve 22 or 22'.

That is, in the case where the solenoids 16a and 16'a are energized and the traveling direction control valve 16.16' is switched to the left position in the figure to move the tracked vehicle forward, the tracked vehicle will gradually move to the left. In the case of deflection, the rotation speed of the hydraulic motor 8' that drives the right drive wheel is faster than that of the hydraulic motor 8 that drives the left drive wheel, so the solenoid 23'
b is excited to switch the correction directional control valve 26 to the right position in the drawing, and the pressure oil supply circuit 15' to the right hydraulic motor 8' is activated.
By bleeding off a portion of the oil into the oil tank 21 through the flow rate adjustment valve 22', the speed of the right hydraulic motor 8', which has a high rotation speed, is reduced by that amount, and the deflection is corrected naturally. will move forward. Conversely, if the deflection is to the right, the rotation speed of the hydraulic motor 8 that drives the left drive wheel will be faster than the hydraulic motor 8' that drives the right drive wheel, so in this case, the solenoid 23a is energized. Then, the correction directional control valve 26 is switched to the left position in the drawing, and a part of the oil in the pressure oil supply circuit 15 to the left hydraulic motor 8 is bled off to the oil tank 21 via the flow rate adjustment valve 22. In addition, even when the solenoid 161)j16'b is energized and the travel direction control valve 16+16' is switched to the right position in the drawing to move the tracked vehicle backward, the deflection to the left or right can be corrected by the same operation. I can do it.

In the above hydraulic circuit, the capacity required for the flow rate regulating valve 22.22' is sufficient to compensate for the difference in rotational speed between the left drive wheel and the right drive wheel.
It is sufficient that it can flow about 10% of the rated discharge amount of '. Note that if the flow rate regulating valves 22, 22' are made variable as shown in FIG. 6, the deflection correction speed can be changed arbitrarily.

The traveling direction control valve 16, 16' and the correction direction control valve 26 may be of a hydraulic pilot type or a manual type, but as in the above embodiment, they may be of an electrohydraulic type or an electromagnetic type, and as shown in FIG. If the switching operation can be performed using the operating lever shown in FIG. 5, the operability can be improved.

That is, in FIGS. 4 and 5, the operating lever 24 operated with the left hand and the operating lever 24' operated with the right hand are of the same type, and both operating levers 24, 24'
are A, B, C, D, E and A' respectively
, B', C', DI, and E', each solenoid 16a of the traveling direction control valve 16zi6' shown in FIG.

16b and 16'a+16'b, and the solenoids 23al and 25b of the correction directional control valve 26 are electrically connected.

Contact A: Solenoid 16a of left side travel direction control valve 16
1161) respectively.

Contact B: Energizes the solenoid 16a of the same valve 16.

Contact C: Energizes the solenoid 16b of the same valve 16.

Contact, E: Solenoid 25b of correction directional control valve 26
Excite.

Contact A': Solenoid i of the right-hand travel direction control valve 16'
Demagnetize 6-'a+16'b, respectively.

Contact B': Energizes solenoid 16'a'i of valve 16'.

Contact point C' excites the solenoid 16'b of the double valve 16'.

Contacts DI and E/ energize the solenoid 23a of the correction directional control valve 26.

Therefore, when moving the tracked vehicle forward, the left and right operating levers 24, 24' may be switched to contacts B and B', respectively, and when moving the tracked vehicle backward, they may be switched to contacts c and c'. If the tracked vehicle veers to the left while moving forward with the left and right operating levers 24 and 24' switched to contacts B and B', the right-hand operating lever 24' is still held at contact B'. , switch the left hand operating lever 24 to the contact point. The tracked vehicle will then move forward while correcting its deflection to the left. On the other hand, if the vehicle is deflected to the right, the right-hand operating lever 24' is switched to contact B while the left-hand operating lever 24 is held at contact B, thereby allowing the vehicle to move forward while correcting the deflection to the right. Become. Further, when moving backward, the same operation may be performed using the contact C2E of the left-hand operating lever 24 and the contacts Cr and 3r of the right-hand operating lever 24'.

As explained above, by simply adding two flow rate adjustment valves and - correction directional control valves to the driving hydraulic circuit, it is possible to correct the deflection while driving and achieve straight-line driving without any practical problems. Therefore, it is highly reliable, has few failures, and is economical. In addition, the vehicle driving control function can be greatly improved because it is not only possible to simply control the straightness of the vehicle, but also to freely change the width direction of the vehicle while moving forward or backward.

[Brief explanation of drawings]

Fig. 1 is a core view showing an example of a hydraulically driven tracked vehicle, Fig. 2 is a front view thereof, Fig. 6 is a hydraulic circuit diagram showing an embodiment of the track correction circuit according to the present invention, and Fig. 4. , FIG. 5 is an operation explanatory view showing an example of an operating lever for switching each directional control valve shown in FIG. 6. 6 Drive wheel, 6...Crawler track, 8,8'...Hydraulic motor, 12.12'--Hydraulic pump, 15.15'--Pressure oil supply circuit, 16.16'--Driving direction control Valve, 22° 22'...Flow rate adjustment valve, 26...Directional control valve for correction. Patent applicant: Kobe Steel, Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 89-

Claims (1)

[Claims] 1. Hydraulic drive type equipped with left and right hydraulic motors that drive the left and right drive wheels separately, and left and right hydraulic pumps that supply pressure oil to each of the left and right hydraulic motors separately via a travel direction control valve. In the traveling circuit of the width of the tracked vehicle, a flow rate adjustment valve is branched and connected in the middle of each pressure oil supply circuit from the left and right hydraulic pumps to the left and right hydraulic motors, and a correction directional control is installed on the outlet side of both flow rate adjustment valves. A valve is connected, and by switching the correction directional control valve, a part of the pressure oil in each pressure oil supply circuit is selectively bleed off to the tank via the flow rate adjustment valve and the correction directional control valve. A travel trajectory correction circuit for a hydraulically driven tracked vehicle, characterized in that: