JP2572936Y2 - Hydraulic oil warm-up device in load sensing system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic oil warm-up device for a hydraulic machine to which a load sensing system is applied.
The present invention relates to a hydraulic oil warming-up device in a load sensing system capable of increasing the operating oil temperature in a cold region or the like and improving the working efficiency by simply modifying the conventional technology.

[0002]

2. Description of the Related Art Conventionally, there has been an automatic warm-up method for an engine. However, there has been no automatic warm-up method for hydraulic oil of a hydraulic device driven by the engine. FIG. 5 is a diagram showing a hydraulic circuit in a hydraulic excavator by a conventional load sensing system, wherein 1 is a variable displacement hydraulic pump, 2a is a swing motor driven by the hydraulic pump 1, 2b is a boom cylinder, 3a and 3b. Is an operation valve interposed in the pipeline between the hydraulic pump 1 and the swing motor 2a and the boom cylinder 2b; 4 is a capacity control cylinder of the hydraulic pump 1; 5 is a control pressure of the capacity control cylinder 4; And a load sensing valve 5a for controlling the load sensing valve 5 to supply a control pressure to the displacement control cylinder 4.
5b is a pilot cylinder for urging the load sensing valve 5 to a position b for discharging the control pressure of the displacement control cylinder 4, and the pilot cylinder 5a is an upstream pressure pipe of the operation valves 3a and 3b. On the road, the pilot cylinder 5b is connected to the operation valves 3a, 3
b is connected to the downstream pressure line. Reference numeral 5c denotes a differential pressure setting spring that urges the position b for discharging the control pressure of the displacement control cylinder. Reference numerals 6, 7 denote operation levers of pilot operation valves 6a, 7a for operating the operation valves 3a, 3b. 8a and 8b are pilot cylinders of the operation valve 3a, 9a and 9b are pilot cylinders of the operation valve 3b, and 10a and 10b are for extracting a higher driving pressure among the driving pressures of the swing motor 2a and the boom cylinder 2b. Check valves, 11a and 11b are pressure compensating valves for the swing motor 2a and the boom cylinder 2b, and 13 is the operating valve 3
Reference numerals a and 3b denote upstream safety valves, and reference numeral 14 denotes a tank.

Next, the operation will be described. In order to operate the swing motor 2a or the boom cylinder 2b of the hydraulic excavator, when the operating lever 6 or 7 is operated in a predetermined direction in a predetermined amount while hydraulic oil is being discharged from the variable displacement hydraulic pump 1, the operation is started. The pilot oil pressure from the pilot operation valves 6a and 7a according to the operation amount of the lever 6 or 7 changes the operation valve 3a according to the operation direction of the operation lever 6 or 7.
Or 3b pilot cylinder 8a, 8b or 9
a, 9b, the operation lever 6 or 7
The operation valve 3a or 3b is operated in a predetermined direction by a predetermined amount in accordance with the operation amount of. Therefore, the turning motor 2a or the boom cylinder 2b can be operated according to the operation amount of the operation lever 6 or 7. The higher of the driving pressure of the swing motor 2a or the boom cylinder 2b is taken out by the check valves 10a and 10b, and the pilot cylinder 5b of the load sensing valve 5 and the pressure compensating valves 11a and 11b of the swing motor 2a and the boom cylinder 2b. Control pressure. The load sensing valve 5 is biased to a position a. A pilot cylinder 5a is connected to a discharge port of the hydraulic pump 1. The higher pressure of the driving pressure of the swing motor 2a or the boom cylinder 2b is applied to the load sensing valve 5. The differential pressure between the discharge pressure of the hydraulic pump 1 and the higher one of the driving pressures of the swing motor 2a or the boom cylinder 2b is connected to the pilot cylinder 5b which urges the position b. The discharge amount of the hydraulic pump 1 is controlled so as to be a constant pressure set by the above. Therefore, when the opening degree of the operation valve 3a or 3b is smaller than the discharge amount of the hydraulic pump 1, the operation valve 3
Since the differential pressure between upstream and downstream a or 3b increases, the load sensing valve 5 is urged toward the position a, and the displacement of the hydraulic pump 1 is reduced by the capacity control cylinder 4 so that the opening degree of the operation valve 3a or 3b is reduced. Is controlled by the discharge amount of the hydraulic pump 1 which is
Since relief is not performed from the safety valve 13 except when an overload acts on b, efficient work can be performed.

[0004]

However, in the above load sensing system, the discharge amount of the hydraulic pump 1 increases or decreases in accordance with the opening of the operation valve 3a or 3b, and operates from the safety valve 13 except when an overload is applied. Efficient work can be performed because oil does not relieve,
In a cold region, etc., the temperature of the hydraulic oil is unlikely to rise, so that a malfunction due to a delay in response to the operation may occur, a man-hour for raising the hydraulic oil to a predetermined temperature, and a waiting time until the hydraulic oil reaches the predetermined temperature. It became necessary and reduced work efficiency.

[0005]

Means for Solving the Problems To solve the above problems, the hydraulic oil warming-up device in the load sensing system according to the present invention comprises: (1) a variable displacement hydraulic pump 1 and the variable displacement hydraulic pump 1; Hydraulic actuators 2a,
2b, operating valves 3a, 3b provided in a pipeline between the variable displacement hydraulic pump 1 and the hydraulic actuators 2a, 2b.
A displacement control cylinder 4 for controlling the displacement of the variable displacement hydraulic pump 1, and a position for supplying a control pressure to the displacement control cylinder 4 to move the operation valves 3a, 3b.
And is moved to a position for discharging the control pressure of the displacement control cylinder 4 so that the operation valve 3
a, a differential pressure setting spring 5c at one end.
A pilot cylinder 5a, 5b having a load sensing valve 5, the load sensing system consisting of
In addition , a switching means for switching the pipe line between a communication state and a cutoff state is provided in a pipe line connecting between the pilot cylinders 5a and 5b of the load sensing valve 5. (2) In the above configuration, the switching means for switching the line connecting the two pilot cylinders 5a and 5b of the load sensing valve 5 between a communication state and a cutoff state is a manual type, pilot type or solenoid type switching valve. 1
2, 12a, 12b, 22, 22a, and 22b are installed. (3) Further, in the above configuration, the switching means for switching the pipe line connecting the two pilot cylinders 5a and 5b of the load sensing valve 5 between a communicating state and a disconnected state is provided by an engine water temperature or an engine oil temperature or a working oil temperature signal. And a switching signal for switching the pipe line between the open state and the closed state based on the signal is transmitted to the solenoid type switching valves 12b and 22.
b. (4) In the above configuration, the control device 16
Is configured to output to the solenoid-type switching valves 12b and 22b a switching signal for switching a pipe line connecting the two pilot cylinders 5a and 5b of the load sensing valve 5 between a communication state and a cutoff state after a predetermined warm-up time. Things.

[0006]

According to the above construction, the following operation is performed. When the temperature of the oil that has just started to drive the hydraulic actuator by the hydraulic pump is low, the switching valve installed in the pipeline connecting the two pilot cylinders of the load sensing valve and the switching valve that cuts off the pipeline is set to the communication state. Since there is no differential pressure between the two pilot cylinders of the load sensing valve, the load sensing valve is biased by the differential pressure setting spring to a position for discharging the control pressure of the displacement control cylinder. Accordingly, the capacity of the hydraulic pump is controlled to be maximum, and the amount of hydraulic oil that is relief from the safety valve among the hydraulic oil discharged from the hydraulic pump increases, and the hydraulic oil temperature increases rapidly due to the pressure loss of the hydraulic oil that is relieved. I do. Further, if the operation valve is a center-closed type, it is possible to quickly warm up the hydraulic oil simply by making the operation valve neutral without driving the work machine. When the warm-up of the hydraulic oil is completed, the switching valve installed in the pipeline connecting the two pilot cylinders of the load sensing valve is set to the shut-off state. 3
The working oil does not relieve from the safety valve 13 except when an overload is applied, so that efficient work can be performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIGS. 1 to 4 show an embodiment of a hydraulic oil warm-up device in the load sensing system of the present invention.
1 (a) is diagram showing a hydraulic circuit in the case of applying the present invention to a hydraulic excavator, and FIG. 1 (b) contacting the shuttle valve and the switching valve
Continued the illustration, diagram switched by a pilot pressure switching valve of the P portion in FIG. 2 (a) 1, FIG. 2 (b) sheet
FIG . 3 (a) is an explanatory diagram in which a shuttle valve and a pilot type switching valve are connected , FIG. 3 (a) is a diagram in which switching is performed by a solenoid, and FIG. 3 (b)
Is a description of the connection between the shuttle valve and solenoid type switching valve
FIG . 4A is a diagram in which switching is automatically performed by a controller, and FIG. 4B is a diagram in which a shuttle valve and a solenoid type switching valve are used.
FIG. 1 in (a), 1 is a variable displacement hydraulic pump, a swing motor 2a is driven by the hydraulic pump 1, 2b is also the boom cylinder, 3
Reference numerals a and 3b denote operating valves provided in a pipeline between the hydraulic pump 1, the swing motor 2a and the boom cylinder 2b, 4 denotes a displacement control cylinder of the hydraulic pump 1, and 5 denotes a control pressure of the displacement control cylinder 4. A load sensing valve for supply and discharge, 5a is a pilot cylinder for urging the load sensing valve 5 to a position a for supplying control pressure to the displacement control cylinder 4, and 5b is a pilot cylinder for loading the load sensing valve 5 to the displacement control cylinder. 4 is a pilot cylinder for urging to the position b for discharging the control pressure,
a is connected to an upstream pressure line of the operation valves 3a and 3b, and a pilot cylinder 5b is connected to a downstream pressure line of the operation valves 3a and 3b.

A differential pressure setting spring 5c biases a position b for discharging the control pressure of the displacement control silling.
6, 7 are operating levers of pilot operating valves 6a, 7a for operating the operating valves 3a, 3b, 8a, 8b are pilot cylinders of the operating valve 3a, 9a, 9b are pilot cylinders of the operating valve 3b, 10a , 10b are check valves for taking out the higher one of the driving pressures of the swing motor 2a and the boom cylinder 2b, 11a, 1
1b is a pressure compensating valve for the swing motor 2a and the boom cylinder 2b, 12 is a switching valve for shutting off communication between the pilot cylinders 5a and 5b of the load sensing valve 5, 13 is a safety valve for upstream pressure of the operating valves 3a and 3b, 14 is a tank. Next, FIG. 1B shows another embodiment.
A shuttle valve 10c and a switching valve 22 are arranged in place of the check valves 10a and 10b and the switching valve 12 in FIG. 1A, and the other parts are the same as those in FIG. is there. This will be described with reference to FIG. Shuttle valve 1
Reference numeral 0c is disposed on a conduit connecting the swing motor 2a and the boom cylinder 2b. The shuttle valve 10c is connected to the switching valve 22. The switching valve 22 is connected to the pilot cylinder 5b of the load sensing valve 5. FIG.
In (a), 12a is a pilot type switching valve. FIG. 2B shows another embodiment in which a pilot-type switching valve 22a is arranged in place of the switching valve 22 of FIG. 1B.
Than it is. Shuttle valve 10c is a pilot type switching valve 22
a. The pilot switching valve 22a is connected to the pilot cylinder 5b of the load sensing valve 5. In FIG. 3A, reference numeral 12b denotes a solenoid type switching valve, and reference numeral 15 denotes a switch. FIG. 3B shows another embodiment, in which a solenoid-type switching valve 22b is arranged in place of the switching valve 22 of FIG. 1B. Shuttle valve 1
0c is connected to the solenoid-operated switching valve 22b. This solenoid type switching valve 22b is connected to the pilot cylinder 5b of the load sensing valve 5. In FIG. 4A, 12b is a solenoid type switching valve, 16 is a controller, 17 is a timer, and 18 is a temperature sensor. FIG.
(B) shows another embodiment, in which the switching valve 2 shown in FIG.
2, a solenoid-type switching valve 22b is provided. Shuttle valve 10c is a solenoid type switching valve 22b
Is connected to This solenoid type switching valve 22b is connected to the pilot cylinder 5b of the load sensing valve 5. Reference numeral 16 denotes a controller, 17 denotes a timer, and 18 denotes a temperature sensor.

Next, FIG. 1 (a), FIG. 2 (a), FIG.
(A), the work movement is described by the configuration of Figure 4 (a). The hydraulic excavator is turned by a hydraulic pump 1 into a swing motor 2a.
Alternatively, when the oil temperature has just started to drive the boom cylinder 2b and the oil temperature is low, the switching valve 12 installed in the pipe connecting the pilot cylinders 5a and 5b of the load sensing valve 5 is set to the b position to set the communication state. Since the pressure difference between the pilot cylinders 5a and 5b of the load sensing well 5 disappears, the load sensing valve 5 is set to the position b by the differential pressure setting spring 5c.
Is drained to the tank 14. Accordingly, the hydraulic pump 1 is controlled so as to increase in capacity, and the amount of hydraulic oil relieved from the safety valve 13 out of the hydraulic oil discharged from the hydraulic pump 1 increases, and the operation valves 3a and 3b are made center-closed. If the operating valve is neutralized without driving the work machine, all the hydraulic oil discharged from the hydraulic pump 1 is relieved by the safety valve 13, and the warm-up of the hydraulic oil can be quickly achieved by the pressure loss. it can. When the warming-up of the hydraulic oil is completed, the switching valve 12 installed in the conduit connecting between the two pilot cylinders 5a and 5b of the load sensing well 5 is set to the shut-off state at the position a, and the hydraulic pressure is increased as in the conventional case. The discharge amount of the pump 1 increases or decreases in accordance with the opening degree of the operation valve 3a or 3b, and hydraulic oil is not relieved from the safety valve 13 except when an overload is applied, so that efficient work can be performed. Switching valve 1 in FIG.
2 is a pilot type switching valve 12a shown in FIG.
Is replaced with a solenoid type switching valve 12b shown in FIG.
As shown in FIG.
Temperature sensor for water temperature, engine oil temperature or hydraulic oil temperature signal
Output from the controller 18 to the controller 16
The solenoid-operated switching valve 12b is operated to be in the cut-off state at the position a.
After completion of the warm-up operation of the engine,
After time, the solenoid-operated directional control valve 12b is connected to the position b.
It may be activated to a state. Next, FIG. 1 of another embodiment.
(B), FIG. 2 (b), FIG. 3 (b), FIG. 4 (b)
The operation according to this will be described. 1 (a) and 2
(A), FIGS. 3 (a) and 4 (a) have the same basic circuit.
Only the differences will be described. Figure 1 switching valve 2 2 (b)
When the communication state is established at the position b, the load sensing valve 5
Pressure difference between the pilot cylinders 5a and 5b
The load sensing valve 5 is set to b by the differential pressure setting spring 5c.
To control the position, the control pressure of the capacity control cylinder 4 is
Drain to 14. This reduces the capacity of the hydraulic pump 1
Controlled to increase. The same operation as in FIG.
The description is omitted. The switching valve 22 is set to the a position to shut off.
When turned off, the swing motor 2a and the boom cylinder 2b
Of the drive pressures of
Through the a position of the switching valve 22 through the load sensing valve
5 acts on the pilot cylinder 5b,
The discharge pressure of the pressure pump is the pilot of the load sensing valve 5.
The load sensing valve 5 is controlled by acting on the cylinder 5a.
Control of the discharge amount of the hydraulic pump 1
You. FIG. 2B shows the switching valve 22 shown in FIG.
This is a lot-type switching valve 22a. The operation is shown in FIG.
It is the same as (b) and the description is omitted. FIG. 3B is a diagram.
The switching valve 22 shown in FIG. 1 (b) is replaced with a solenoid type switching valve 22b.
It was made. The operation is the same as in FIG.
Is omitted. FIG. 4B shows the switching valve 22 shown in FIG.
Is changed to a solenoid type switching valve 22b, and the engine water temperature,
The engine oil temperature or hydraulic oil temperature signal is
Controller 16 to output solenoid type
The switching valve 22b is operated in the shut-off state at the position a,
After the warm-up operation of the
Operates the solenoid-type switching valve 22b in the communication state at the position b.
May be. The operation of the solenoid type switching valve 22b is shown in FIG.
It is the same as (b) and the description is omitted.

[0010]

[Effect of the Invention] As described above in detail, the following effects can be obtained by the present invention. (1) Between the two pilot cylinders of the load sensing valve
A simple modification that only requires the installation of a switching valve that switches between the communication state and the cutoff state is sufficient, so that the conventional technology can be modified at low cost. (2) If the operation valve of the working machine is a center closed type,
Since the warm-up of the working oil can be achieved in a short time without operating the working machine with the operating valve in neutral, the working efficiency can be greatly improved.

[Brief description of the drawings]

1 (a) is a diagram showing a hydraulic circuit in the case of applying the present invention to the hydraulic excavator. (B) is the same as the shuttle valve
It is explanatory drawing which connected the valve replacement.

FIG. 2A is a diagram in which a switching valve at a portion P in FIG. 1 is switched by a pilot oil pressure. (B) Same, Shut
FIG. 4 is an explanatory diagram in which a valve and a pilot type switching valve are connected.

FIG. 3A is a diagram in which a switching valve at a portion P in FIG. 1 is switched by a solenoid. (B) is the shuttle valve
FIG. 3 is an explanatory diagram in which a solenoid-operated switching valve is connected.

FIG. 4 (a) is a diagram in which a switching valve of a portion P in FIG. 1 is automatically switched by a controller.
(B) is an explanatory view of the same connection of the shuttle valve and the solenoid-type switching valve .

FIG. 5 is a diagram showing a conventional technique.

[Explanation of symbols]

1: Variable displacement hydraulic pump, 2a: Swing motor, 2b ...
Boom cylinder, 3a, 3b operating valve, 4 capacity control cylinder, 5 load sensing valve, 5a, 5b pilot cylinder, 5c differential pressure setting spring, 6, 7 operating lever, 6a, 7a bi-lot operating valve , 8a, 8b ... pilot cylinder, 9a, 9b ... pilot cylinder, 1
0a. 10b: check valve, 10c: shuttle valve, 11
a, 11b: pressure compensating valve, 12 , 22 : switching valve, 12
a , 22a : pilot type switching valve, 12b , 22b : solenoid type switching valve, 13: safety valve, 14: tank, 15
... Switch, 16 ... Controller, 17 ... Timer, 18
... Temperature sensor.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02F 9/22 F15B 11/00 F15B 11/05 F15B 21/04

Claims (4)

(57) [Scope of request for utility model registration] 1. A variable displacement hydraulic pump, a hydraulic actuator driven by the variable displacement hydraulic pump, an operation valve interposed in a pipe between the variable displacement hydraulic pump and the hydraulic actuator, A displacement control cylinder for controlling the displacement of the displacement type hydraulic pump; and a position for supplying control pressure to the displacement control cylinder, which is connected to an upstream side of the operation valve, and discharges the control pressure of the displacement control cylinder. It is moved to the position to be connected to the downstream side of the operating valve, whereas a pilot Schilling having a differential pressure setting spring to the end, the load sensing valve, in <br/> load sensing system consisting of the load sensing valve A switching means for switching the pipeline between a communicating state and a cutoff state is provided in a pipeline connecting between the two pilot cylinders. Hydraulic oil warm-up device in the load sensing system. 2. The hydraulic oil warm-up device for a load sensing system according to claim 1, wherein the switching means for switching a pipe connecting the two pilot cylinders of the load sensing valve between a communication state and a cutoff state is a manual type or a switching type. The hydraulic oil warm-up device in the load sensing system according to claim 1, wherein a pilot-type or solenoid-type switching valve is provided. 3. The hydraulic oil warm-up device in the load sensing system according to claim 1, wherein the switching means for switching a pipe line connecting the two pilot cylinders of the load sensing valve between a communication state and a cutoff state includes an engine water temperature or an engine water temperature. A control device for obtaining an engine oil temperature or hydraulic oil temperature signal and outputting a switching signal for switching the pipe line between a communication state and a cutoff state to a solenoid-type switching valve based on the signal. Hydraulic oil warm-up device in sensing system. 4. The hydraulic oil warm-up device in the load sensing system according to claim 3, wherein the control device includes:
After a predetermined warm-up time, a switching signal for switching a pipe line connecting the two pilot cylinders of the load sensing valve between a communication state and a cutoff state is output to a solenoid-type switching valve. Machine equipment.