JPH02213529A - Hill climbing mode circuit of construction equipment - Google Patents

Abstract

PURPOSE:To make it possible to set optimum speed hard to slip, and improve hill climbing end traveling properties and the operability at climbing by inserting a solenoid valve in an oil passage communicating a regulator for a hydraulic pump and an oil pressure source for pilot pressure. CONSTITUTION:A solenoid valve 37 for cutting the maximum flow is inserted in an oil passage communicating regulators 35, 36 for hydraulic pumps 11,12 and a pilot pump 13. A switch 40 for hill climbing mode is installed next. When the switch 40 is turned on, pilot pressure is made to act on the regulators 35,36 by changing over and actuating the solenoid valve 37 with changeover operation signals of running valves 9', 10', and the discharge flow from the hydraulic pumps 11, 12 is reduced. The hydraulic pumps 11, 12 are adjusted to a specified low discharge flow by changing over the solenoid valve 37 when the switch 40 was turned on to let crawlers climb a hill of specified inclination at an optimum speed without causing any slip to them.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a climbing mode circuit for a hydraulically driven vehicle, mainly a construction machine.

Conventional technology Fig. 3 shows the side view of a hydraulic excavator in Fig. 0.
1 is the lower running body of a hydraulic excavator, 2 and 3 are the lower running body 1
4 is the upper rotating body. FIG. 4 is a traveling circuit diagram of the prior art, in which 2.3 is a left and right variable capacity traveling motor, respectively;
5 and 6 are cylinders for adjusting the tilt angles of the travel motors 2 and 3, 7.8 are speed selection switching valves, 9 and 10 are travel valves, respectively, and 11.12 is a hydraulic pump 13, which is a hydraulic source for pilot pressure. There is a pilot pump, 14 is an oil tank, 15 is a solenoid valve for switching between 1st and 2nd speeds, 16 is a solenoid for solenoid valve 15, 17 is a power source, and 18 is a switch for 2nd speed.

Next, a conventional running circuit will be described. When the traveling valves 9 and 10 in FIG. When switching the travel motors 2 and 3 to 1st and 2nd speeds in the 0th order, where either one rotates forward or reverse, the travel motor 2 side (
Since the traveling motor 3 side is the same, only the traveling motor 2 side will be explained. When traveling at low speed, the switch 18 is turned off. At that time, the cylinder 5 is in the oil passage 19, the speed selection switching valve 7 is in the A position,
It communicates with the oil tank 14 via oil passages 20 and 21.

Since the travel motor 2 is tilted to the large capacity side, when the travel valve 9 is operated, the travel motor 2 exerts a strong rotational force and rotates at a low speed, thereby allowing one-way travel.

Next time you drive in two directions at high speed, switch...lchie8
Turn on. Since the solenoid 16 is energized, the solenoid valve 15 is switched from the tank communication oil passage position C to the pilot pressure application oil passage position 2. The pilot pressure from the pilot pump 13 is applied to the oil passage 22, the two positions of the solenoid valve 15, and the oil passage 23.
．． 24, it acts on the pilot pressure receiving portion 25 of the speed selection switching valve 7. The speed selection switching valve 7 is switched from the A position to the Open position. When the travel valve 9 is operated, the pressure oil discharged from the hydraulic pump 11 is transferred to the oil passage 26, 27, the travel valve 9,
The oil is sent to the travel motor 2 via the oil path 28 or 29. At that time, a part of the pressure oil in the oil passage 28 or 29 acts on the cylinder 5 via the oil passage 30 or 31, the shuttle valve 32, the oil passage 33, and the oil passage 19 at the mouth of the speed selection switching valve 7. . Since the piston 34 in the cylinder 5 moves against the spring force of the built-in spring, the travel motor 2 is tilted toward the small capacity side. Since the travel motor 2 rotates at high speed, the hydraulic excavator performs two-way travel.

Problems to be Solved by the Invention When a tracked hydraulic excavator as shown in Fig. 3 climbs up a hill, it normally sets its traveling speed to 1st gear and increases its running traction force.However, the climbing speed is high. In some cases, the track may slip against the board surface, making it impossible to pitch. Therefore, either lower the engine speed of the hydraulic excavator, or
Alternatively, the travel lever was adjusted in the intermediate range without being fully operated. However, when the engine speed is lowered, the engine horsepower also decreases, so the climbing horsepower decreases, and when adjusting the left and right travel levers in the intermediate range, the left and right travel levers must be operated at the same position. Since it cannot be held, the hydraulic excavator may not move straight. In addition, a driver who operates the left and right travel levers in the intermediate range becomes fatigued early because he or she must be careful with the driving operations. In addition, when the above-mentioned operation was performed for a long time, the temperature of the hydraulic oil increased due to oil pressure loss, which adversely affected hydraulic equipment and the like.

This invention solves the above-mentioned problems and provides a climbing mode circuit for construction machinery that allows climbing at an optimum speed at which the crawler track is unlikely to slip by setting the discharge flow rate of the hydraulic pump lower than the normal discharge flow rate. The purpose is to

Means for Solving the Problems The means of the present invention taken to solve the above problems are as follows: (a) a solenoid valve is interposed in the oil passage that communicates the hydraulic pump regulator and the pilot pump; A climbing mode switch is provided, and when the switch is turned on, the travel valve switching operation signal switches the above solenoid valve to enable pilot pressure to be applied to the above regulator, and also to control the discharge flow rate of the hydraulic pump. It was configured to reduce the amount of

Operation A6 When the climbing mode switch is in the OFF state, the climbing mode function is not performed.In this case, the same function as the conventional technology traveling circuit only works.

B. When the climbing mode switch is turned on and the travel valve is switched, the maximum flow rate cut solenoid valve is switched. Then, the pilot pressure acts on the regulator of the hydraulic pump, and the hydraulic pump is adjusted to a predetermined low discharge flow rate.

This allows the hydraulic excavator to climb a slope with a predetermined inclination angle at an optimal speed without slipping.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a climbing mode circuit diagram of a first embodiment of the present invention. In FIG. 35. 36 is a mechanically operated left and right travel valve, 35 is a regulator for adjusting the tilt angle of the hydraulic pumps 11 and 12, and 37 is a mechanically operated left and right traveling valve.
is a solenoid valve for cutting the maximum flow rate, 38 is a solenoid for the solenoid valve 37, 39 is an electric circuit, 40 is a climbing mode switch, and 41 is an interlock that is turned on by one or both of travel valves 9' and 10'. The switch 42 is a relay. When the climbing mode function is activated in this circuit, the relay 42 indicates that the 2nd speed switch 18 is closed and the travel 1/2nd speed switching solenoid valve 15 is in the pilot pressure oil path position 2. This is provided to automatically avoid this.

Next, the configuration of a climbing mode circuit according to a first embodiment of the present invention will be described with reference to FIG. Hydraulic pump regulator 35
．． A maximum flow rate cut electromagnetic valve 37 is provided in the filler oil passage that communicates the pilot pump 36 with the pilot pump 13. In addition, electric circuit 3
When the climbing mode switch 40 in 9 is turned on, the travel valve 9'.

In conjunction with the switching operation 10', the interlocking switch 41 is turned on, and the maximum flow rate cut solenoid valve 37 is switched. At the same time, it is configured to apply pilot pressure to the regulators 35, 36 of the hydraulic pumps 11, 12.

Next, the functions of the climbing mode circuit according to the first embodiment of the present invention will be described. When the climbing mode switch 40 is turned off, the solenoid 38 of the solenoid valve 37
has become a sad news. In this case, the same function as the conventional driving circuit works, but the function of the climbing mode is not exhibited.

However, when the climbing mode switch 40 is turned on and the traveling valves 9' and 10' are switched, the solenoid 3
8 is energized. The maximum flow rate cut solenoid valve 37 is switched from the tank communication oil passage position E to the pilot pressure application oil passage position. Therefore, the pilot pressure from the pilot pump 13 is applied to the oil passages 22', 43, the solenoid valve 37 position, and the oil passage 4
4. Through the throttle part 45 and oil passage 46, the regulator 35.3
6. Thereby, the hydraulic pumps 11, 12 are adjusted to a predetermined low discharge flow rate. Therefore, the tracks of the hydraulic excavator can climb a slope having a predetermined inclination angle at an optimum speed without slipping. FIG. 2 is a climbing mode circuit diagram of a second embodiment of the present invention. In Figure 9, 47 and 48 are pilot pressure operated left and right traveling valves, 4
9. 50 is the left and right remote control valve, 51 is the pressure switch, 5
2 is an electric circuit, and 40' is a climbing mode switch. The running valves 47, 48 in this circuit are then operated by the pilot valve 53 by operating the remote control valve 49, 50.
Alternatively, the pilot pressure derived from 54, 55 or 56 acts on the pilot pressure receiving portion 57, 58, 59 or 60 of the travel valve 47, 48, respectively, to perform the switching operation.

Next, the differences between the climbing mode circuit of the second embodiment of the present invention and the first embodiment will be described. When the climbing mode switch 40' is turned on and the remote control valve 49.50 is operated, the pilot pressure derived from the pilot valve 53, 54, 55 or 56 is transferred to the shuttle valve 61, 6.
2.63, it acts on the pressure switch 51 via the oil path 64. The pressure switch 51 switches and energizes the electric circuit 52. Thereby, the maximum flow rate cut solenoid valve 37 is switched from the tank communication oil passage position E to the pilot pressure application oil passage position. The above points are different from the first embodiment. The function of the climbing mode circuit of this second embodiment is similar to that of the first embodiment.

Effects of the Invention When a crawler-type hydraulic excavator with a conventional running circuit goes up the hill, if the hydraulic excavator's distance is fast, the crawler track may slip on the ground and the excavator may not be able to go up the hill.

Therefore, they either lowered the engine speed of the hydraulic excavator or made adjustments in the intermediate range without fully operating the travel lever. However, when the engine speed is lowered, the engine horsepower also decreases, so the climbing horsepower decreases, and when adjusting the left and right travel levers in the intermediate range, the operation positions of the left and right travel levers are kept at the same position. As a result, the hydraulic excavator may not move straight. In addition, a driver who operates the left and right travel levers in the intermediate range becomes fatigued early because he or she must be careful with the driving operations. Not only that, but when the above operation was performed for a long time, the temperature of the hydraulic oil rose due to oil pressure loss, which had an adverse effect on hydraulic equipment and the like.

However, in the climbing mode circuit according to the present invention, a solenoid valve is interposed in the oil path that communicates the hydraulic pump regulator and the pilot pressure hydraulic source, and the climbing mode switch is turned on to switch the travel valve. Then, the pilot pressure acts on the hydraulic pump regulator via the solenoid valve,
Set the discharge flow rate of the hydraulic pump to be lower than the normal discharge flow rate. As a result, the hydraulic excavator can be launched at an optimal speed at which its crawler tracks are unlikely to slip.

Therefore, in the construction machine equipped with the climbing mode circuit according to the present invention, climbing running performance and driving operability during climbing are improved.

[Brief explanation of the drawing]

1 and 2 are climbing mode circuit diagrams of a first embodiment and a second embodiment of the present invention, respectively, FIG. 3 is a side view of a hydraulic excavator, and FIG. 4 is a running circuit diagram of a conventional technology. be. 2.3 Travel motor 9, 9' 11.12 35, 36 39, 52 40, 40'' 49,, 50 10, 10', 47.48 Travel valve Hydraulic pump pilot pump Travel 1. Solenoid valve regulator for 2-speed switching Solenoid valve for maximum flow cut Electric circuit Switch for climbing mode Interlocking switch Remote control valve Pressure switch

Claims (1)

[Claims] (1) In the travel circuit of a hydraulic construction machine equipped with a variable displacement hydraulic pump, the travel motor is rotated by pressure oil supplied from the hydraulic pump, the hydraulic pump regulator and the pilot pressure hydraulic source are communicated. A solenoid valve is interposed in the oil passage, and a switch is provided in the electric circuit, and the solenoid valve is switched in response to a switching operation signal from the travel valve, and pilot pressure can be applied to the regulator.
A climbing mode circuit for construction machinery, characterized in that the circuit is configured to reduce the discharge flow rate of a hydraulic pump.