JP4979014B2 - Control system for swivel pump in hydraulic excavator - Google Patents

Description

  The present invention belongs to the technical field of a control system for a swing pump in a hydraulic excavator provided with a swing pump independently of a main pump.

Generally, a hydraulic excavator is configured to support an upper swinging body on a lower traveling body in a freely swingable manner, and is configured by mounting a working device including a boom, a stick, a bucket, etc. on the upper swinging body. Some rotary pumps serving as hydraulic supply sources for the swing motor are provided independently from hydraulic actuators for working devices such as boom cylinders and arm cylinders and main pumps serving as hydraulic supply sources for travel motors. By providing the swing pump independently as described above, there is an advantage that the swing operation can be performed without being influenced by the operation of the work device, and this is mainly used in a large hydraulic excavator.
In this, the main pump and the swing pump are driven by the torque supplied from the engine. In this case, it is required to appropriately distribute the supply torque from the engine to the main pump and the swing pump. Therefore, conventionally, there has been known a configuration in which the output of the swing pump is set to a fixed value when the swing is alone, and is gradually increased toward the fixed value with the elapsed time when the boom and the swing are interlocked. (For example, refer to Patent Document 1).
JP 2003-206903 A

  By the way, among the operations performed by the hydraulic excavator, there is an operation that uses the turning force as the pressing force, such as a turning pressing excavation operation (an operation that performs groove excavation while pressing the bucket side surface against the groove side surface with the turning force). When such a work is performed, the swing motor requires almost no oil, so that most of the discharge amount of the swing pump is lost from the relief valve, resulting in wasted energy consumption. In this case, even if the output of the swing pump is gradually increased toward the fixed value with the elapsed time as in Patent Document 1, the relief amount increases as the pump output increases with the elapsed time. There is still a problem that energy is wasted, and there is a problem to be solved by the present invention.

SUMMARY OF THE INVENTION The present invention was created in view of the above circumstances and has been created for the purpose of solving these problems. The invention of claim 1 provides a swivel pump as a hydraulic supply source of a swivel motor for a working device. In a hydraulic excavator provided independently of a main pump serving as a hydraulic pressure supply source for a hydraulic actuator and a travel motor, torque control means for controlling torque supplied from the engine to the swing pump and the main pump, and the hydraulic excavator performs during the work with the provided and work determining means for pivoting the pressing determines the whether the work is used as a force pressing the swirling force, the torque control means, which is determined to be a work pressing turning the work determining means, Rotating torque reduction control is performed to reduce the torque of the slewing pump compared to work involving turning other than turning pressing work. A control system for turning the pump in a hydraulic excavator to symptoms.
According to a second aspect of the present invention, in the control system for the swing pump in the hydraulic excavator according to the first aspect, the torque control means controls to increase or decrease the torque of the swing pump in accordance with the operation amount of the swing operation lever. is there.
According to a third aspect of the present invention, the hydraulic excavator is provided with an engine speed setting operation tool for setting the engine speed when there is no load, and the torque control means is a swirl pump according to a set value of the engine speed setting operation tool. The control system for the swing pump in the hydraulic excavator according to claim 1, wherein the torque is increased or decreased.
The invention according to claim 4 is characterized in that the torque control means has a plurality of turning torque tables in which the torque of the turning pump is set according to the judgment as to whether or not the turning judgment work is performed by the work judging means. It is a control system of the rotation pump in the hydraulic excavator as described in any one of 1 thru | or 3.

According to the invention of claim 1, the flow rate of the swing pump is reduced so that the pump output corresponds to the torque reduced by the swing torque reduction control during the swing pressing operation. This can reduce the relief loss when performing the swivel pressing operation that does not require, and can reduce wasteful energy consumption and can greatly contribute to the reduction in fuel consumption.
According to the second aspect of the present invention, torque corresponding to the lever operation amount is supplied to the swing pump, and therefore the pressure oil supply flow rate to the swing motor is reduced based on the operation of the swing operation lever. The pressure oil of the swivel pump can be supplied to the swivel control valve to be controlled without excess or deficiency, thereby contributing to the improvement of circuit stability and operability.
By setting it as invention of Claim 3, the appropriate torque according to the setting value of an engine speed setting operation tool can be supplied to a rotation pump.
According to the invention of claim 4, by using the turning torque table, the torque of the turning pump can be easily obtained depending on whether or not the turning pressing work is performed, and the value of the turning torque table is adjusted. It is possible to easily cope with changes in hydraulic excavator models, mounted engines, characteristics of swivel pumps, and the like.

  Next, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a hydraulic excavator. The hydraulic excavator 1 is attached to a crawler type lower traveling body 2, an upper revolving body 3 that is pivotably supported by the lower traveling body 2, and the upper revolving body 3. The working device 4 is further supported by a boom 5 whose base end portion is supported by the upper swing body 3 so as to be movable up and down, and by a distal end portion of the boom 5 so as to be swingable back and forth. The stick 6 is composed of a bucket 7 attached to the tip of the stick 6 and the like.

  Further, the hydraulic excavator 1 is provided with various hydraulic actuators such as left and right traveling motors 8 and 9, a swing motor 10, a boom cylinder 11, a stick cylinder 12, and a bucket cylinder 13, and the like based on the operation of these hydraulic actuators. Thus, traveling, turning of the upper swing body 3, swinging of the boom 5, the stick 6, and the bucket 7 are performed. The boom cylinder 11, the stick cylinder 12, and the bucket cylinder 13 correspond to a hydraulic actuator for a working device according to the present invention.

  The hydraulic circuit to which the hydraulic actuator is connected will be described with reference to the hydraulic circuit diagram shown in FIG. 2. In FIG. 2, 14 and 15 are main pumps, 16 is a swing pump, 17 is an oil tank, The main pumps 14 and 15 and the swing pump 16 are connected to an engine (not shown) and are driven by torque supplied from the engine.

  The main pumps 14 and 15 are variable displacement hydraulic pumps serving as hydraulic supply sources for the left and right traveling motors 8 and 9, the boom cylinder 11, the stick cylinder 12, and the bucket cylinder 13. The main pump regulators 18 and 19 that control the flow rate of 15 receive a control signal pressure from a main pump control electromagnetic proportional pressure reducing valve 21 controlled by a control device 20 to be described later, and receive main control pumps 14 and 15 from the engine. The pump flow rate is controlled so that the pump output is in accordance with the torque supplied to. Further, the main pump regulators 18 and 19 perform constant horsepower control and load sensing control (or negative control), but these are flow control generally used, and thus description thereof is omitted.

  On the other hand, the swing pump 16 is a variable displacement hydraulic pump serving as a hydraulic pressure supply source of the swing motor 10 and is provided in a state independent of the main pumps 14 and 15. The revolving pump regulator 22 that controls the flow rate controls the pump flow rate so that the pump output corresponds to the torque supplied from the engine to the dedicated pump 16 based on the control signal output from the control device 20. .

  Further, in FIG. 2, reference numerals 23 to 28 are control valves for right and left traveling, turning, boom, stick, and bucket. These control valves 23 to 28 are respectively corresponding operation tools (operation levers). And an operation pedal), the direction and flow rate of oil supply / discharge to and from the left and right traveling motors 8 and 9, the turning motor 10, the boom cylinder 11, the stick cylinder 12 and the bucket cylinder 13 are controlled. .

  Reference numerals 29 and 30 denote swing relief valves. When the pressure in the oil passage connecting the swing control valve 25 and the swing motor 10 becomes equal to or higher than a set pressure, the swing relief valves 29 and 30 The road oil is configured to escape to the oil tank 17.

  On the other hand, the control device 20 is configured by using a microcomputer or the like, and as shown in the block diagram of FIG. 3, the operation direction and operation amount of the accelerator dial 31 and the turning operation lever (not shown). A signal from a turning operation detecting means 32 for detecting the operation, a stick operation detecting means 33 for detecting an operation direction and an operation amount of a stick operating lever (not shown), and the like are input, and the main pump is based on these input signals. A control signal is output to the electromagnetic proportional pressure reducing valve 21 for control and the regulator 22 for the swing pump. The control device 20 includes a work determination unit (corresponding to a work determination unit of the present invention) 34 and a torque control unit (described later). (Corresponding to the torque control means of the present invention) 35 is provided.

  Here, the accelerator dial 31 is an operation dial for setting the engine speed when there is no load, and corresponds to the engine speed setting operation tool according to the present invention. A ten-stage accelerator dial value A of “10” is provided. The higher the accelerator dial value A, the higher the engine speed at no load.

  Next, the work determination unit 34 provided in the control device 20 will be described based on the control block diagram shown in FIG. 4. The work determination unit 34 determines the stick operation signal output from the stick operation detection means 33 as a stick operation. It is input to the table 36, and it is determined by the stick operation determination table 36 whether or not the stick operation lever is operated inward (in the direction approaching the upper swing body 3). When the stick operating lever is operated to the in side, an ON signal is output to the AND gate 37, while when the stick operating lever is operated to the out side (a direction away from the upper swing body 3) or is not operated. In this case, an OFF signal is output to the AND gate 37. Further, the work determination unit 34 inputs the turning operation signal output from the turning operation detection means 32 to the turning operation determination table 38 and determines whether or not the turning operation lever has been operated by the turning operation determination table 38. To do. When the turning operation lever is operated, an ON signal is output to the AND gate 37, while when it is not operated, an OFF signal is output to the AND gate 37.

  When the ON signal is input to the AND gate 37 from both the stick operation determination table 36 and the turning operation determination table 38, that is, when the stick-in operation and the turning operation are performed simultaneously. It is determined that a swivel push excavation work (a work of performing a groove excavation while pressing the bucket side surface against the groove side surface with the swivel force), which is one of the swivel push work using the swivel force as the push force, The turning push work ON signal is output. On the other hand, when an OFF signal is input from at least one of the stick operation determination table 36 or the turning operation determination table 38 to the AND gate 37, that is, when the stick-in operation and the turning operation are not performed simultaneously, the turning pressing is performed. It is determined that the work is not performed, and the turning pressing work OFF signal is output.

  On the other hand, as shown in the control block diagram of FIG. 5, the torque control unit 35 is output from a total pump torque TT described later, a turning operation signal input from the turning operation detection means 32, and the work determination unit 34. The turning pressing work ON / OFF signal and the accelerator dial value A output from the accelerator dial 31 are input.

  Here, the total pump torque TT is the total torque that can be supplied from the engine to the main pumps 14 and 15 and the swing pump 16, and corresponds to each dial value A of the accelerator dial 31 by, for example, a torque map (not shown). Is preset. In this case, the total pump torque TT becomes maximum when the accelerator dial value A is the maximum value (in this embodiment, when the accelerator dial value A is “10”), and the total pump torque TT decreases as the accelerator dial value A decreases. However, the maximum value of the total pump torque TT, that is, the maximum value of torque that can be supplied from the engine to the main pumps 14 and 15 and the swing pump 16 is the maximum total pump torque TT-Ma (N M), the total pump torque TT corresponding to each accelerator dial value A is a ratio when the maximum total pump torque TT-Ma (N · m) is 100%. %) And is input to the torque controller 35 as the total pump torque TT (%).

  The torque control unit 35 first outputs the input turning operation signal to the first to fourth turning torque tables 40 to 43. The first to fourth turning torque tables 40 to 43 are tables in which the relationship between the operation amount of the turning operation lever and the turning pump torque TS (%) is set. To 43, the swing pump torque TS (%) corresponding to the lever operation amount is obtained for each accelerator dial value A and for each turn pressing work ON / OFF signal output from the work determination unit 34. The pump torque TS (%) is a ratio (%) of torque supplied from the engine to the swing pump 16 when the maximum total pump torque TT-Ma (N · m) is 100%.

  Then, when the accelerator dial value A is low (in the present embodiment, the accelerator dial values “1” to “3”) and the turning pressing work is OFF, it is obtained by the first turning torque table 40. The swing pump torque TS (%) is selected and input to the torque rate limiter 44. When the accelerator dial value A is low and the turning pressing operation is ON, the turning pump torque TS (%) obtained by the second turning torque table 41 is selected and input to the torque rate limiter 44. . Further, when the accelerator dial value A is high (in the present embodiment, the accelerator dial value is “4” to “10”) and the turning pressing work is OFF, it is obtained by the third turning torque table 42. The swing pump torque TS (%) is selected and input to the torque rate limiter 44. Furthermore, when the accelerator dial value A is high and the turning pressing operation is ON, the turning pump torque TS (%) obtained by the fourth turning torque table 43 is selected and input to the torque rate limiter 44. The

Here, in the first to fourth turning torque tables 40 to 43, the turning pump torque TS (%) is 0% when the turning operation lever is not operated, and corresponds to the increase or decrease of the lever operation amount. However, even if the lever operation amount is the same, the swing pump torque TS (%) is set to be different for each of the swing torque tables 40 to 43. That is, as described above, the first and second turning torque tables 40 and 41 are selected when the accelerator dial value A is low, while the third and fourth turning torque tables 42 and 43 have a high accelerator dial value A. The value of the swing pump torque TS (%) of the third and fourth swing torque tables 42 and 43 is the value of the swing pump torque TS (%) of the first and second swing torque tables 40 and 41, respectively. ) Is set larger than the value of. Thus, the swing pump torque TS (%) is controlled to increase or decrease according to the accelerator dial value A. The first and third turning torque tables 40 and 42 are selected when the turning pressing work is OFF, while the second and fourth turning torque tables 41 and 43 are selected when the turning pressing work is ON. The value of the swing pump torque TS (%) of the second and fourth swing torque tables 41 and 43 is set smaller than the value of the swing pump torque TS (%) of the first and third swing torque tables 40 and 42, respectively. Has been. Thereby, when the turning pressing work is ON, the swing pump torque TS (%) is controlled to be smaller than when the turning pressing work is OFF. Thus, when the turning pressing work is being performed, The turning torque reduction control for reducing the turning pump torque TS (%) is performed as compared with the case where the pressing operation is not performed.
In this embodiment, the swing pump torque TS (%) when the lever operation amount in the first, second, third, and fourth swing torque tables 40, 41, 42, and 43 is maximum is 20%. Although these values are set to 10%, 50%, and 40%, these values are examples, and can be appropriately set according to the type of the hydraulic excavator 1, the engine, the characteristics of the swing pump 16, and the like.

  Further, the torque rate limiter 44 limits the rate of change of the inputted swing pump torque TS (%) and outputs it to the multiplier 45 and the subtractor 46.

  The multiplier 45 multiplies the swing pump torque TS (%) output from the torque rate limiter 44 by the maximum total pump torque TT-Ma (N · m), thereby converting the swing pump torque TS into a torque unit (N・ Convert to m). The converted value of the swing pump torque TS (N · m) is converted into a control signal value for the swing pump regulator 22 and output to the swing pump regulator 22.

On the other hand, the subtractor 46 obtains the main pump torque TM (%) supplied from the engine to the main pumps 14 and 15 by subtracting the swing pump torque TS (%) from the total pump torque TT (%). The value of the main pump torque TM (%) is converted into a control signal value for the main pump control electromagnetic proportional pressure reducing valve 21 and output to the main pump control electromagnetic proportional pressure reducing valve 21.
The main pump torque TM (%) is a ratio (%) of torque supplied from the engine to the main pumps 14 and 15 when the maximum total pump torque TT-Ma (N · m) is 100%. expressed.
In this embodiment, the swing pump torque TS is converted into a torque unit (N · m), while the swing pump torque TS is not converted into a torque unit (N · m) while maintaining the ratio (%). However, this corresponds to the software used when the control signal values for the swing pump regulator 22 and the main pump control electromagnetic proportional pressure reducing valve 21 are converted.

  In the present embodiment configured as described, the flow rates of the main pumps 14 and 15 and the swing pump 16 are controlled based on the control signal from the control device 20 so that the pump output corresponds to the torque supplied from the engine. However, the control device 20 includes a work determination unit 34 that determines whether or not the work performed by the excavator 1 is a turning pressing work that uses the turning force as a pressing force, and the main pump 14 from the engine, 15 and a torque control unit 35 that controls the torque supplied to the swing pump 16, and the torque control unit 35 is determined by the work determination unit 34 that the swing pressing operation is being performed. Therefore, it is possible to reduce the torque (swing pump torque TS) supplied to the swing pump 16 as compared with a case involving a turn other than the turn pressing work. It will perform Mel turning torque reduction control.

  As a result, the swing pump 16 reduces the flow rate so as to obtain a pump output corresponding to the reduced torque during the swing pressing operation, and thus the swing that the hydraulic motor 10 requires almost no oil amount. When the pressing operation is performed, the relief loss from the swing relief valves 29 and 30 can be reduced, so that wasteful energy consumption can be suppressed and the fuel consumption can be greatly reduced.

  Further, since the torque supplied to the swing pump 16 is controlled so as to increase or decrease according to the operation amount of the turning operation lever, the torque corresponding to the lever operation amount is supplied to the swing pump 16. Thus, the pressure oil of the swing pump 16 can be supplied to the swing control valve 25 that controls the supply flow rate to the swing motor 10 based on the operation of the swing operation lever, thereby stabilizing the circuit. It can contribute to improvement of performance and operability.

  Further, the torque supplied to the swing pump 16 is controlled so as to increase / decrease according to the dial value A of the accelerator dial 31 that sets the engine speed when there is no load, and accordingly, according to the accelerator dial value A set by the operator. A suitable torque can be supplied to the rotary pump 16.

  On the other hand, the main pumps 14 and 15 are connected to the dedicated pump 16 from the total torque (total pump torque TT) that can be supplied from the engine set according to the accelerator dial value A to the main pumps 14 and 15 and the dedicated pump 16. Since the torque obtained by reducing the supplied torque (swing pump torque TS) is supplied, the supply torque from the engine can be effectively distributed to the main pumps 14 and 15 and the dedicated pump 16 without waste. It can contribute to the improvement of work efficiency.

  Furthermore, in this, in the torque control unit 35, the relationship between the operation amount of the turning operation lever and the turning pump torque TS is set for each accelerator dial value A and for each working portion turning pressing work ON / OFF signal. The fourth turning torque tables 40 to 43 are provided, and the turning pump torque TS supplied to the turning pump 16 by the first to fourth turning torque tables 40 to 43 can be easily obtained. By adjusting the values of the turning torque tables 40 to 43, even if the model of the hydraulic excavator 1, the engine mounted, the characteristics of the turning pump 16, and the like are changed, these changes can be easily handled. In the present embodiment, the first to fourth four turning torque tables 40 to 43 are set. For example, more detailed turning torque tables can be obtained by finer sorting by the accelerator dial value A. Of course, it can also be provided.

  Moreover, in the first to fourth turning torque tables 40 to 43, the value of the turning pump torque TS is obtained as a ratio to the maximum total pump torque TT-Ma, and the maximum total pump torque TT-Ma is calculated from the engine. Since this is a fixed value set in advance as the maximum value of the torque that can be supplied to the main pumps 14 and 15 and the swing pump 16, the value of the torque supplied to the swing pump 16 is stabilized, so that a stable swing operation is achieved. It can be carried out.

  Further, the value of the swing pump torque TS obtained by the first to fourth swing torque tables 40 to 43 is configured such that the speed of change is limited by the torque rate limiter 44. The torque supplied to the slewing pump 16 does not change suddenly even when the operation is suddenly performed, and thus the problem that the circuit becomes unstable due to a sudden increase or decrease in the discharge flow rate of the slewing pump 16 can be avoided. .

Needless to say, the present invention is not limited to the above embodiment, and in the above embodiment, when the swing pump torque TS (%) is obtained, the operation amount of the swing operation lever and the swing pump torque TS (% The first to fourth turning torque tables 40 to 43 in which the relationship between the turning demand capacity and the turning torque supply ratio TS are used as a table for obtaining the turning pump torque TS (%) in this way. A table in which a relationship with (%) is set can also be used. The required turning capacity in this case is the pump capacity of the turning pump 16 required according to the operation amount of the turning operation lever, and corresponds to the increase or decrease of the operation amount of the turning operation lever by a gain table or the like (not shown). Thus, the turning required capacity DR is also set to increase or decrease.
Further, when determining whether or not the work performed by the hydraulic excavator is the turning pressing work using the turning force as the pressing force, the discharge of the turning pump 16 is performed as in the work determining means of the second embodiment shown in FIG. It can also be configured to make a determination based on the pressure. That is, the work determination means of the second embodiment is provided with a stick operation determination table 36 similar to that of the above-described embodiment, and the pump discharge pressure determination to which the discharge pressure P of the swing pump 16 is input. A table 47 is provided. When it is determined by the pump discharge pressure determination table 47 that the swing pump discharge pressure P is higher than the preset set pressure PS, an ON signal is output to the AND gate 48, and the set pressure is set. If it is determined that it is less than PS, an OFF signal is output. When the ON signal is input from both the stick operation determination table 36 and the pump discharge pressure determination table 47 to the AND gate 48, it is determined that the turning pressing work is being performed, and the turning pressing work ON signal is sent. Output. On the other hand, when an OFF signal is input to the AND gate 48 from at least one of the stick operation determination table 36 or the pump discharge pressure determination table 47, it is determined that the turning pressing work is not being performed, and the turning pressing work OFF signal is determined. Is configured to output. Even if the determination is made based on the discharge pressure of the swing pump 16 as described above, it is possible to accurately determine whether or not the swing pressing operation is being performed.

It is a side view of a hydraulic excavator. It is a hydraulic circuit diagram of a hydraulic excavator. It is a block diagram which shows the input / output of a control apparatus. It is a block diagram which shows the control procedure of a work judgment part. It is a block diagram which shows the control procedure of a torque control part. It is a block diagram which shows the control procedure of the operation | work judgment means in 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rotating motor 14, 15 Main pump 16 Rotating pump 31 Accelerator dial 34 Work determination part 35 Torque control part

Claims (4)

In a hydraulic excavator provided with a swing pump as a hydraulic supply source for a swing motor independently from a hydraulic pump for a work device and a main pump as a hydraulic supply source for a travel motor, the swing pump and the main pump are supplied from the engine. Torque control means for controlling the torque to be applied, and work determination means for judging whether or not the work performed by the hydraulic excavator is a turning pressing work using the turning force as a pressing force. While the to be swiveling pressing operations by determining means is determined, the turning of the hydraulic excavator and performs the turning torque reduction control capable of reducing the torque of the swing pump than working with a turning other than turning the pressing work Pump control system.   2. The control system for a swing pump in a hydraulic excavator according to claim 1, wherein the torque control means controls to increase or decrease the torque of the swing pump in accordance with an operation amount of the swing operation lever.   The hydraulic excavator includes an engine speed setting operation tool for setting the engine speed at no load, and the torque control means controls the increase and decrease of the torque of the swing pump in accordance with the set value of the engine speed setting operation tool. A control system for a swing pump in a hydraulic excavator according to claim 1 or 2.   4. The torque control unit according to claim 1, further comprising: a plurality of swing torque tables in which torques of the swing pump are set depending on whether or not the swing determination operation is performed by the operation determination unit. A control system for a swing pump in the hydraulic excavator described in the item.

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