JP7275882B2 - Slewing control device for construction machinery - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing control device for a construction machine having an upper swing body capable of swinging with respect to a base.

Patent Document 1 discloses a hydraulic actuator operation structure as a swing control device for construction machinery. The pilot valve in the hydraulic actuator operating structure is provided with a potentiometer for detecting the position of the spool corresponding to the angle of the operating lever. When the operating lever is tilted to pivot the swivel, a signal from the potentiometer regarding the position of the spool is input to a controller. Then, the control device issues an operation signal to the electromagnetic proportional pressure reducing valve so that the larger the tilt angle of the operating lever, the larger the flow rate to the direction switching valve. That is, in the hydraulic actuator operation structure of Patent Document 1, the opening degree of the electromagnetic proportional pressure reducing valve is adjusted according to the amount of operation of the operation lever (tilt angle of the operation lever).

By the way, when the upper revolving body is turned at a work site of an actual construction machine, when the revolving speed of the upper revolving body does not reach the maximum speed corresponding to the operation amount of the revolving operation lever, the upper revolving body Deceleration maneuvers are often initiated to reduce the turning speed.

JP-A-2-261905

However, when the deceleration operation is started before the turning speed reaches the maximum speed corresponding to the operation amount of the turning operation lever, the turning speed at the time when the deceleration operation is started differs for each work. In this case, in the hydraulic actuator operation structure of Patent Document 1, the opening degree of the electromagnetic proportional pressure reducing valve is adjusted according to the operation amount of the operation lever. will vary according to the different turning speeds. This makes it difficult to stop the revolving motion of the upper revolving structure at an appropriate revolving angle and accurately move the attachment to the target position, and requires extra work to correct the position of the attachment.

Further, in Patent Document 1, when the operating lever is operated from near the maximum speed position to the neutral stop position, the spool of the electromagnetic proportional pressure reducing valve is quickly slid to the minimum opening A1. It discloses that This minimum opening A1 is the minimum opening in the range of spool openings that provides the maximum flow rate. That is, the technique disclosed in Patent Document 1 increases the operating speed of the spool near the maximum speed where there is no change in flow rate, and does not solve the above problem.

SUMMARY OF THE INVENTION It is an object of the present invention to determine the timing at which hydraulic braking is applied to a swing motor for each work even when a deceleration operation is started before the swing speed reaches the maximum speed corresponding to the amount of operation of the swing operation lever. To provide a turning control device for a construction machine capable of suppressing variations in the rotation.

The present invention provides a slewing control device for a construction machine having an upper slewing body capable of slewing with respect to a base, comprising a hydraulic pump for discharging hydraulic oil, and the hydraulic oil discharged from the hydraulic pump. a swing motor that operates to swing the upper swing body by receiving a supply of , a swing operation member that receives a swing operation that is an operation for operating the swing motor, and a pilot pressure that corresponds to the amount of operation of the swing operation and a swing control valve interposed between the hydraulic pump and the swing motor, the pilot pressure input from the swing pilot valve to the swing control valve. a turning control valve that opens and closes so as to change the size of the opening on the meter-out side in response to the change, a turning speed detection unit that detects the turning speed of the upper turning body, and the upper turning body turning at the turning speed. The size of the opening on the meter-out side is such that the hydraulic braking action occurs at the braking action pilot pressure for suppressing variations in the timing of the hydraulic braking action in the swing motor for each work when the a pilot pressure calculation unit that calculates a braking action pilot pressure for adjusting the swing speed based on the swing speed; and a pressure reducing valve interposed between the swing pilot valve and the swing control valve, wherein the pilot pressure output from the swing pilot valve is reduced by receiving a pressure reduction command signal. The deceleration operation determination unit determines that the deceleration operation has been received by a decompression valve that can be operated to reduce the pressure to a pilot pressure corresponding to the decompression command signal and input it to the swing control valve, and the deceleration operation of the swing operation member. a pressure reduction signal input unit for inputting the pressure reduction command signal to the pressure reduction valve so as to reduce the pilot pressure output from the swing pilot valve to the brake action pilot pressure when the brake operation is performed.

In this turning control device, when it is determined that the turning operation member has received the deceleration operation (hereinafter sometimes referred to as "deceleration determination time"), the pressure reduction command signal is input to the pressure reducing valve. As a result, the pilot pressure output from the swing pilot valve is reduced to the brake action pilot pressure, and the brake action pilot pressure is input to the swing control valve. As a result, even when the deceleration operation is started before the turning speed reaches the maximum speed corresponding to the amount of operation of the turning operation lever, the timing of causing the hydraulic braking action in the turning motor varies from work to work. can be suppressed. Specifically, it is as follows.

The size of the meter-out side opening of the swing control valve increases or decreases according to the pilot pressure output from the swing pilot valve, and the pilot pressure increases or decreases depending on the amount of operation of the swing operation member. . Therefore, the size of the opening on the meter-out side increases or decreases according to the amount of operation of the turning operation member. Further, the flow rate of the hydraulic oil on the meter-out side increases or decreases according to the turning speed. In order to generate hydraulic braking action in the swing motor, it is necessary to increase the back pressure on the meter-out side. The opening on the meter-out side must be narrowed down to an appropriate size. Specifically, when the turning speed at the time the deceleration operation is started is high (for example, when the turning speed at the time the deceleration operation is started is close to the maximum speed corresponding to the operation amount of the turning operation lever). In addition, the flow rate of hydraulic oil on the meter-out side is also large. In this case, even if the opening on the meter-out side is relatively large, the back pressure on the meter-out side increases, and the hydraulic braking action is likely to occur. On the other hand, when the turning speed at the start of the deceleration operation is small (for example, when the turning speed at the start of the deceleration operation is smaller than the maximum speed corresponding to the operation amount of the turning operation lever, the turning speed and the maximum speed), the flow rate of the hydraulic oil on the meter-out side is also small. In this case, in order to increase the back pressure on the meter-out side and generate the hydraulic braking action, it is necessary to reduce the size of the opening on the meter-out side to a relatively small size.

Therefore, in the present invention, when the deceleration is determined, the pressure reduction command signal is input to the pressure reducing valve, whereby the pilot pressure output from the swing pilot valve is reduced to the braking action pilot pressure, and the braking action is performed. A configuration is adopted in which a pilot pressure is input to the swing control valve. The brake action pilot pressure is forcibly adjusting the meter-out side opening of the swing control valve to a magnitude corresponding to the swing speed at the time of the deceleration determination so that the hydraulic brake action is quickly generated in the swing motor. It is a pilot pressure for the deceleration determination, and is calculated based on the turning speed at the time of the deceleration determination. Therefore, in the present invention, regardless of the swing speed at the time of the deceleration determination, the size of the opening on the meter-out side of the swing control valve is set to a size that quickly causes the hydraulic braking action in the swing motor. can be adjusted to This is the case where the deceleration operation is started before the turning speed reaches the maximum speed corresponding to the operation amount of the turning operation lever, and the turning speed at the time when the deceleration operation is started differs for each work. Even in such a case, it is possible to suppress variations in the timing at which hydraulic brake action occurs in a swing motor for each work.

The pilot pressure calculation unit is a first map preset in order to suppress variations in the timing of causing the hydraulic brake action in the swing motor for each work, and the map is a map that is calculated based on the swing speed and the swing speed. Using the first map showing the relationship with the size of the opening on the meter-out side of the swing control valve capable of producing the hydraulic braking action in the swing motor when the upper swing structure is swinging, calculating the size of the meter-out side opening, and calculating the braking pilot pressure using a second map showing the relationship between the size of the meter-out side opening and the target secondary pressure in the pressure reducing valve; is preferred.

The swing control device for the construction machine further includes a pilot pressure detection section that detects the pilot pressure output from the swing pilot valve, and the deceleration operation determination section detects the pilot pressure detected by the pilot pressure detection section. is a preset first pilot pressure threshold value that is smaller than the maximum pilot pressure and that is closer to the maximum pilot pressure than 1/2 of the maximum pilot pressure. After becoming equal to or higher than the pilot pressure threshold value , the pilot pressure detected by the pilot pressure detection unit is a preset second pilot pressure threshold value that is smaller than the first pilot pressure threshold value, When the value becomes less than a second pilot pressure threshold value, which is a value closer to the first pilot pressure than 1/2 of the maximum pilot pressure , it may be determined that the turning operation member has received the deceleration operation. preferable.

In this aspect, the timing at which the hydraulic brake is applied in the swing motor, that is, the position of the swing operation lever at which the brake begins to work is uniformly set based on the second pilot pressure threshold. This allows the brake to begin to apply at the same lever position corresponding to the second pilot pressure threshold regardless of the turn speed at which the deceleration maneuver is initiated. This further improves the workability of the turning work. Further, in this aspect, after the turning operation member is operated by an operation amount equal to or greater than the first pilot pressure threshold value, the turning operation member is operated by an operation amount less than the operation amount corresponding to the second pilot pressure threshold value. Only when the control is performed, control is performed to input the reduced braking pilot pressure to the swing control valve. Accordingly, it is possible to more strictly determine whether or not the turning operation member has received the deceleration operation.

As described above, according to the present invention, even when the deceleration operation is started before the swing speed of the upper swing body reaches the maximum speed corresponding to the operation amount of the swing operation lever, the swing motor It is possible to suppress variations in the timing of hydraulic brake action for each work.

1 is a side view showing a construction machine equipped with a swing control device according to an embodiment of the present invention; FIG. It is a figure which shows the hydraulic circuit of the said turning control apparatus. 3 is a block diagram showing the functional configuration of a controller and input/output signals thereof in the turning control device; FIG. 4 is a graph showing changes over time in pilot pressure output from a swing pilot valve of the swing control device and changes over time in swing speed of an upper swing body in the construction machine. and a swing control valve of the swing control device capable of producing a hydraulic braking action in a swing motor of the swing control device when the upper swing body is swinging at the swing speed. It is a map which shows the magnitude|size of the opening by the side of a meter-out, and relationship. 5 is a graph showing the relationship between the size of the meter-out side opening and the target secondary pressure in the pressure reducing valve of the swing control device; 4 is a graph showing the relationship between a target secondary pressure in the pressure reducing valve and a pressure reduction command signal (instruction current) to be input to the pressure reducing valve in order to adjust the secondary pressure in the pressure reducing valve to the target secondary pressure; . 4 is a flow chart showing an arithmetic control operation of a controller in the turning control device;

Preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a construction machine equipped with a swing control device according to this embodiment. This construction machine 100 is a hydraulic excavator, and includes a crawler-type lower traveling body 1 (an example of a base body), and the lower traveling body 1 so as to be able to turn around a turning center axis Z perpendicular to the traveling surface. An upper revolving body 2 mounted thereon and an attachment 3 mounted on the upper revolving body 2 are provided. The attachment 3 includes a boom 4 supported by the upper rotating body 2 so as to be able to rise and fall, an arm 5 rotatably connected to the tip of the boom 4, and a tip of the arm 5 rotatably connected. and a tip attachment 6 . In this embodiment, the tip attachment 6 is a bucket.

The construction machine 100 includes a boom cylinder 7 that operates to raise and lower the boom 4 with respect to the upper swing body 2 and an arm cylinder that operates to rotate the arm 5 with respect to the boom 4 . 8 and a tip attachment cylinder 9 operable to pivotally move the tip attachment 6 relative to the arm 5 .

FIG. 2 is a diagram showing a hydraulic circuit of the swing control device. As shown in FIG. 2, the swing control device includes a hydraulic pump 10, a pilot pump 11, a swing motor 20, a swing operation device 30, a swing control valve 40, a first pressure reducing valve 50A and a second pressure reducing valve 50A. A pressure reducing valve 50B, a first pilot pressure sensor 70A and a second pilot pressure sensor 70B (an example of a pilot pressure detector), a turning speed sensor 80 (an example of a turning speed detector), and a controller 90. .

The hydraulic pump 10 discharges hydraulic oil for operating the swing motor 20 . The pilot pump 11 discharges pilot oil for supplying pilot pressure to the swing control valve 40 . Each of the hydraulic pump 10 and the pilot pump 11 is driven by an engine 12 . Specifically, in the present embodiment, the hydraulic pump 10 is a variable displacement hydraulic pump whose pump displacement is adjustable. The hydraulic pump 10 has an unillustrated regulator. The regulator receives a capacity command signal from the controller 90 and operates to change the pump capacity to a capacity corresponding to the capacity command signal.

The revolving motor 20 operates to revolve the upper revolving body 2 by being supplied with the hydraulic oil discharged from the hydraulic pump 10 . Specifically, the swing motor 20 has an output shaft that rotates by being supplied with the hydraulic fluid. The output shaft is connected to the upper revolving body 2 so as to revolve the upper revolving body 2 in both left and right directions. The swing motor 20 has a first port 20A and an opposite second port 20B. When one of these ports 20A and 20B receives the hydraulic oil supply, the output shaft rotates in the direction corresponding to the one port and the hydraulic oil is discharged from the other port.

The swing control valve 40 is interposed between the hydraulic pump 10 and the swing motor 20, and operates to change the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 10 to the swing motor 20. . Specifically, in the present embodiment, the swing control valve 40 is a three-position pilot switching valve. The swing control valve 40 is displaced according to the first swing pilot port 40A, the second swing pilot port 40B, and the pilot pressure of the pilot oil supplied to either one of these swing pilot ports 40A, 40B. A spool, not shown, is possible. The pilot pressure changes according to the operation amount of the turning operation that is the operation for operating the turning motor 20 (the operation amount received by the turning operation lever 31 described later).

The swing control valve 40 is connected to the first port 20A of the swing motor 20 via the first line L11, and is connected to the second port 20B of the swing motor 20 via the second line L12. It is The swing control valve 40 allows the hydraulic oil discharged from the hydraulic pump 10 to flow through the first port 20A and the second port 20B of the swing motor 20 as the spool is displaced according to the pilot pressure. lead alternatively to one side. Thereby, the direction of the hydraulic oil supplied to the turning motor 20 is controlled. Further, the swing control valve 40 has a meter-in side opening size (opening area) and a meter-out side opening size (opening area) of the swing control valve 40 by displacing the spool according to the pilot pressure. area) is changed. The size of the meter-in side opening and the size of the meter-out side opening increase as the pilot pressure input to the turning pilot port increases. Thereby, the flow rate of hydraulic oil supplied to the turning motor 20 is controlled.

More specifically, the spool of the swing control valve 40 is at the neutral position when the pilot pressures supplied to the first and second swing pilot ports 40A and 40B are both zero or very small. be kept. As a result, the center line L1 connected to the discharge port of the hydraulic pump 10 and the swing motor 20 are cut off, and the center line L1 and the tank are connected. On the other hand, when a pilot pressure above a certain level is supplied to either one of the first and second swing pilot ports 40A and 40B, the spool of the swing control valve 40 rotates the pilot in a direction corresponding to the pilot port. It is displaced from the neutral position with a stroke corresponding to the magnitude of the pressure. As a result, the turning supply line L2 branching from the center line L1 is connected to either one of the first line L11 and the second line L12, and the degree of rotation corresponding to the stroke is connected. , the center line L1 is narrowed.

The turning operation device 30 has a turning operation lever 31 (an example of a turning operation member) and a turning pilot valve 32 (remote control valve). The turning operation lever 31 is a member that can be rotated by an operator's turning operation for operating the turning motor 20 . The swivel pilot valve 32 is interposed between the pilot pump 11 and the first and second swivel pilot ports 40A and 40B of the swivel control valve 40, and responds to the operation amount of the swivel operation by the operator. Outputs pilot pressure. Specifically, when the turning operation lever 31 is not operated and the lever position is at the neutral position, the turning pilot valve 32 is designed to reduce the pressure between the pilot pump 11 and the first and second turning pilot ports 40A and 40B. Close the valve to block the gap. On the other hand, when the turning operation is performed and the turning operation lever 31 is rotated from the neutral position, the turning pilot valve 32 is moved in the direction of the turning operation among the first and second turning pilot ports 40A and 40B. is opened so as to supply a pilot pressure corresponding to the manipulated variable of the turning operation to the turning pilot port corresponding to the turning operation.

The first pressure reducing valve 50A is interposed between the swing pilot valve 32 and the first swing pilot port 40A. Upon receiving a pressure reduction command signal, the first pressure reduction valve 50A reduces the pilot pressure output from the swing control valve 32 to a pilot pressure corresponding to the pressure reduction command signal. is configured to be operable to input to the first swivel pilot port 40A at . The second pressure reducing valve 50B is interposed between the swing pilot valve 32 and the second swing pilot port 40B. Upon receiving a pressure reduction command signal, the second pressure reduction valve 50B reduces the pilot pressure output from the swing control valve 32 to a pilot pressure corresponding to the pressure reduction command signal. is configured to be operable to input to the second swivel pilot port 40B at .

Specifically, in the present embodiment, each of the first and second pressure reducing valves 50A and 50B is composed of an electromagnetic valve having a solenoid 50S. In each of the first and second pressure reducing valves 50A and 50B, the pilot pressure input from the swing pilot valve 32 corresponds to a pressure reducing command signal, which is an electrical signal input from the controller 90 to the solenoid 50S. It is configured to be able to reduce the pressure to the pilot pressure. The pilot pressure reduced by the first pressure reducing valve 50A, that is, the secondary pressure of the first pressure reducing valve 50A is input to the first swing pilot port 40A. The pilot pressure reduced by the second pressure reducing valve 50B, that is, the secondary pressure of the second pressure reducing valve 50B is input to the second swing pilot port 40B. In the present embodiment, each of the first and second pressure reducing valves 50A and 50B is composed of an electromagnetic inverse proportional valve, but may be composed of an electromagnetic proportional valve, for example.

Each of the first and second pilot pressure sensors 70A and 70B is composed of a pressure sensor capable of detecting the pilot pressure output from the turning pilot valve 32. As shown in FIG. The first pilot pressure sensor 70A detects the pressure of the pilot oil supplied from the swing pilot valve 32 to the first pressure reducing valve 50A and converts it into a pilot pressure detection signal, which is an electric signal. The second pilot pressure sensor 70B detects the pressure of the pilot oil supplied from the swing pilot valve 32 to the second pressure reducing valve 50B and converts it into a pilot pressure detection signal, which is an electrical signal. These pilot pressure detection signals are input to controller 90 .

The turning speed sensor 80 is configured by a sensor capable of detecting the rotational speed of the turning motor 20 as the turning speed. The turning speed sensor 80 detects the turning speed and converts it into a turning speed detection signal, which is an electric signal. The turning speed detection signal is input to the controller 90 . Specifically, the turning speed sensor 80 detects the magnitude and turning direction of the detected turning speed of the upper turning body 2 and converts it into the turning speed detection signal. The turning speed detection signal is input to the controller 90 . As the turning speed sensor 80, for example, a sensor such as a gyro sensor, an encoder, or a resolver can be used, but it is not limited to these.

The swing control device includes a relief valve line L21, a pair of relief valves 61A and 61B provided on the relief valve line L21, a check valve line L22, and a pair of check valves 62A provided on the check valve line L22. , 62B, a connection line L23, and a make-up line L24. Each of the relief valve line L21 and the check valve line L22 bypasses the swing motor 20 and connects the first line L11 and the second line L12 to each other. The connection line L23 connects an intermediate portion between the pair of relief valves 61A and 61B in the relief valve line L21 and an intermediate portion between the pair of check valves 62A and 62B in the check valve line L22. do. The intermediate portion of the check valve line L22 is connected to the tank via a make-up line L24. The make-up line L24 may be provided with a back pressure valve (not shown). Of the pair of check valves 62A and 62B, one check valve 62A is arranged in a direction to prevent the inflow of hydraulic oil from the first line L11, and the other check valve 62B is arranged in the second line L11. It is arranged in a direction to block the inflow of hydraulic oil from L12.

In the swing control device, as the pilot pressure supplied to the first or second swing pilot port 40A or 40B becomes smaller, the swing control valve 40 has a meter-out side opening. It operates so that the size of (opening area) becomes smaller. Therefore, when the pilot pressure supplied to the swing pilot port decreases during the swing operation of the upper swing body 2, the pressure in the line on the meter-out side of the first line L12 and the second line L12 (back pressure) increases. As a result, a hydraulic brake action is generated in the swing motor 20 to reduce the swing speed of the upper swing structure 2, so that the swing speed of the upper swing structure 2 is gradually reduced. During deceleration of the swing, the pair of relief valves 61A and 61B are caused by the inertial force of the upper swing body 2 to cause the first line L11 and the second line L12 to move toward the meter-out side. Protect the hydraulic circuit by preventing overpressure in the lines. Further, during deceleration of the swing, the pair of check valves 62A and 62B exceeds the rotational speed corresponding to the amount of hydraulic oil supplied from the hydraulic pump 10 due to the inertial force of the upper swing body 2. To prevent cavitation caused by rotation of the turning motor 20 at the number of revolutions.

FIG. 3 is a block diagram showing the functional configuration of the controller 90 in the turning control device and its input/output signals. The controller 90 is composed of a computer having a CPU, a ROM storing various control programs, and a RAM used as a work area for the CPU. The controller 90 includes a deceleration operation determination section 91, a pilot pressure calculation section 92, and a pressure reduction signal input section 93 as functions.

The deceleration operation determination unit 91 performs a deceleration operation, which is an operation for decreasing the revolving speed of the upper revolving body 2, to the revolving operation lever 31 based on the pilot pressure detected by the pilot pressure sensors 70A and 70B. is received or not.

The pilot pressure calculation unit 92 calculates a braking action pilot pressure for causing a hydraulic brake action in the swing motor 20 when the upper swing structure 2 is swinging at the swing speed detected by the swing speed sensor 80 . to calculate The brake action pilot pressure is a pilot pressure for adjusting the size of the meter-out side opening of the swing control valve 40 so that the hydraulic brake action occurs.

The decompression signal input section 93 reduces the pilot pressure output from the turning pilot valve 32 to the braking action pilot pressure when the deceleration operation determination section 91 determines that the turning operation lever 31 has received the deceleration operation. A decompression command signal for reducing the pressure to 0 is input to the solenoid 50S of the decompression valve corresponding to the direction in which the swing operation lever 31 is tilted, out of the pair of decompression valves 50A and 50B.

The operation of the turning control device according to the present embodiment and the operation of the turning control device according to the comparative example will be described below.

FIG. 4 is a graph showing changes over time in the pilot pressure (turning Pi pressure) output from the turning pilot valve 32 and changes over time in the turning speed of the upper turning body 2 . The pilot pressure in FIG. 4 is the pilot pressure detected by the pilot pressure sensor corresponding to the turning operation direction among the first and second pilot pressure sensors 70A and 70B. In FIG. 4, the solid line indicates the change in turning speed with time in the turning control device according to the present embodiment, and the broken line shows the change with time in turning speed in the turning control device according to the comparative example.

As shown in FIG. 4, at time t0, the turning operation by the operator is started from the state where the turning operation lever 31 is arranged at the neutral position. In the turning operation, the turning operation lever 31 is tilted in the turning operation direction corresponding to either the right turning direction or the left turning direction. When the turning operation is started, the amount of operation received by the turning operation lever 31, that is, the tilting angle of the turning operation lever 31, gradually increases continuously from time t0 to time t2. The tilting operation of the turning operation lever 31 stops at the time t2, and the operation amount of the turning operation lever 31 is held at the operation amount LM from the time t2 to the time t3. In the specific example shown in FIG. 4, the operation amount LM in the time period from the time t2 to the time t3 is the maximum tilt position corresponding to the maximum tilt position at which the turning operation lever 31 can tilt in the direction of the turning operation. This is the operation amount LM (so-called full lever). Then, at time t3, a return operation, which is an operation of the turning operation lever 31, is started so that the turning operation lever 31 approaches the neutral position side from the maximum tilt position. When the return operation is started, the operation amount of the turning operation gradually decreases continuously from time t3 to time t7, and becomes zero at time t7.

As shown in FIG. 4, the turning pilot valve 32 outputs a pilot pressure corresponding to the amount of operation of the turning operation between time t0 and time t7. Specifically, the pilot pressure output from the swing pilot valve 32 increases with the increase in the manipulated variable from time t0, reaches pilot pressure PM at time t2, and reaches pilot pressure PM at time t2. The pilot pressure PM is maintained until the time t3. The pilot pressure output from the swivel pilot valve 32 decreases as the operation amount decreases from time t3, and becomes zero or a minimum value at time t7. In the specific example shown in FIG. 4, the pilot pressure PM from the time t2 to the time t3 is the maximum pilot pressure PM corresponding to the maximum manipulated variable LM.

As shown in FIG. 4, the turning speed of the upper turning body 2, that is, the turning speed detected by the turning speed sensor 80, gradually increases from the time t0 when the turning operation is started. The maximum speed VM has not been reached at time t2 when the operation amount of the turning operation reaches the maximum operation amount LM. In the specific example shown in FIG. 4, the return operation is started before the turning speed reaches the maximum speed VM, and the turning speed gradually decreases due to the hydraulic brake action without reaching the maximum speed VM. do. In the present embodiment shown by the solid line in FIG. 4, the turning speed becomes zero at time t8, and in the comparative example shown by the broken line in FIG. zero at the time. The reason why the time required to stop the turning motion is different between the present embodiment and the comparative example will be described.

At time t3 when the return operation is started, the amount of operation of the turning operation lever 31 is the maximum amount of operation LM, and the pilot pressure output by the turning pilot valve 32 is the maximum pilot pressure PM. The size of the opening on the meter-out side of the turning control valve 40 is the maximum opening area. On the other hand, at the time t3, the turning speed is lower than the maximum speed VM. Therefore, at time t3, the flow rate of hydraulic oil discharged from the swing motor 20 and flowing through the meter-out side line L11 or L12 is a relatively small flow rate corresponding to the swing speed at time t3. Become. Therefore, at the time t3 when the return operation is started, the back pressure on the meter-out side does not rise sufficiently, so that the hydraulic brake action that reduces the swing speed of the upper structure 2 does not substantially occur. . Therefore, as shown in FIG. 4, the turning speed of the upper turning body 2 increases due to inertia even after the time t3.

Specifically, in the comparative example, the turning speed further increases from time t3 to time t6 to reach speed Ve, and the flow rate of hydraulic oil flowing through line L11 or L12 on the meter-out side increases. The amount of operation of the turning control lever 31 decreases continuously from time t3 to time t6, and the size of the opening on the meter-out side also decreases continuously. Then, in the comparative example, at time t6, the back pressure on the meter-out side rises to such an extent that the hydraulic braking action occurs. After time t6, the turning speed slightly increases due to inertia, but then begins to decrease and becomes zero at time t9.

In this comparative example, the time period T2 from the time t3 to the time t6 is a dead zone in which the hydraulic brake action does not substantially occur even though the return operation has started. In this comparative example, the time t6 at which the hydraulic brake action begins to occur varies according to the turning speed at the time t3 at which the return operation is started. fluctuate. That is, the point of time t6 (brake point) is a value that varies each time the returning operation is performed. This makes it difficult to accurately stop the attachment 3 at the target position. As a result, extra work is required to correct the position of the attachment.

On the other hand, in the present embodiment, when the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation at time t5, the decompression signal input unit 93 outputs the decompression command signal. Input to the corresponding pressure reducing valve 50A or 50B. As a result, the pilot pressure output from the swing pilot valve 32 is reduced to the brake action pilot pressure by the pressure reducing valve 50A or 50B, and the brake action pilot pressure is input to the swing control valve 40 . As a result, the size of the opening on the meter-out side of the turning control valve 40 is adjusted to a size corresponding to the braking pilot pressure, so that when the upper turning body 2 is turning at the turning speed, Hydraulic braking action can be generated in the turning motor 20 at the same time. Specifically, it is as follows.

In the present embodiment, a first pilot pressure threshold value Pi1 and a second pilot pressure threshold value Pi2 for determining the deceleration operation are set in advance, and these threshold values Pi1 and Pi2 are stored in the memory of the controller 90. ing.

The first pilot pressure threshold value Pi1 is set to determine whether the operation amount of the turning operation is the maximum operation amount LM or an operation amount close to the maximum operation amount LM. is the threshold. Therefore, as shown in FIG. 4, the first pilot pressure threshold value Pi1 is set to the maximum pilot pressure PM corresponding to the maximum manipulated variable LM or a value close to the maximum pilot pressure PM. Specifically, in the present embodiment, the first pilot pressure threshold value Pi1 is a value smaller than the maximum pilot pressure PM, and more than half the maximum pilot pressure PM. It is set to a value close to the pressure PM.

The second pilot pressure threshold Pi2 is set when the operation amount of the turning operation is reduced from the maximum operation amount LM, that is, when the turning operation lever 31 moves from the maximum tilted position toward the neutral position. This is a threshold value set to determine that Therefore, as shown in FIG. 4, the second pilot pressure threshold Pi2 is set to a value smaller than the first pilot pressure threshold Pi1. Specifically, in the present embodiment, the second pilot pressure threshold Pi2 is set to a value closer to the first pilot pressure threshold Pi1 than half the maximum pilot pressure PM.

After the pilot pressure detected by the pilot pressure sensor 70A or 70B becomes equal to or higher than the first pilot pressure threshold value Pi1, the deceleration operation determination unit 91 determines that the pilot pressure detected by the pilot pressure sensor is reduced to the above When the pressure becomes less than the second pilot pressure threshold value Pi2, it is determined that the turning operation lever 31 has received the deceleration operation. In the specific example shown in FIG. 4, the pilot pressure detected by the pilot pressure sensor 70A or 70B becomes equal to or higher than the first pilot pressure threshold Pi1 at time t1, and reaches the second pilot pressure threshold Pi1 at time t5. It becomes less than pressure threshold Pi2. Therefore, the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation at the time t5.

When it is determined that the turning operation lever 31 has received the deceleration operation, the pilot pressure calculating section 92 calculates the braking pilot pressure (target secondary pressure) based on the turning speed. The calculation of the brake application pilot pressure is performed based on maps shown in FIGS. 5 and 6, for example.

FIG. 5 shows the swing speed of the upper swing body 2 and the swing control valve 40 capable of producing the hydraulic braking action in the swing motor 20 when the upper swing body 2 is swinging at the swing speed. is an example of a map showing the relationship between the size of the opening on the meter-out side (rotating MO opening area) in . FIG. 6 is a graph showing the relationship between the size of the opening on the meter-out side (swing MO opening area) and the target secondary pressure in the pressure reducing valve (inverse proportional valve) of the swing control device. The maps shown in the graphs of FIGS. 5 and 6 are preset and stored in the memory of the controller 90 respectively.

Hereinafter, the time when the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation may be referred to as "deceleration determination time". The turning speed detected by is sometimes referred to as "turning speed at the time of deceleration determination".

As shown in FIG. 5, when the turning speed at the time of the deceleration determination is, for example, speed Va, the size of the opening on the meter-out side that can cause the hydraulic braking action at the turning speed Va is the opening area. Ka or less opening area. Further, when the turning speed at the time of the deceleration determination is, for example, a speed Vb that is lower than the speed Va, the size of the opening on the meter-out side that can cause the hydraulic braking action at the turning speed Vb is The opening area is equal to or smaller than the opening area Kb, which is smaller than the opening area Ka.

That is, when the turning speed at the time of the deceleration determination is relatively large, the hydraulic braking action is generated at a lever position where the operation amount of the turning operation lever 31 (tilting angle of the turning operation lever 31) is relatively large. A brake is applied to the swing motion of the upper swing body 2 . On the other hand, when the turning speed at the time of the deceleration determination is small, the turning operation lever 31 is returned to a lever position where the amount of operation of the turning operation lever 31 is small in order to generate the hydraulic brake action. The opening area of the side openings needs to be reduced.

In the present embodiment, at the time t3 when the return operation is started, the back pressure on the meter-out side does not rise sufficiently, so that a hydraulic braking action to reduce the swing speed of the upper swing body 2 occurs. do not have. Therefore, as shown in FIG. 4, the turning speed of the upper turning body 2 increases due to inertia even after the time t3. Also, at time t5, which is the deceleration determination time, the back pressure on the meter-out side has not yet risen sufficiently, so that no hydraulic braking action to reduce the swing speed of the upper structure 2 occurs.

However, in the present embodiment, when the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation at the time t5, the pilot pressure calculation unit 92 determines the turning operation at that time. The braking pilot pressure is calculated based on the speed. Specifically, when the turning speed at the time of the deceleration determination is, for example, speed Va, the pilot pressure calculation unit 92 calculates the size of the opening on the meter-out side corresponding to the speed Va based on the map shown in FIG. The opening area Ka, which is the height of the opening, is calculated. Next, the pilot pressure calculation section 92 calculates the target secondary pressure Pa of the pressure reducing valve corresponding to the opening area Ka, that is, the brake application pilot pressure Pa, based on the map shown in FIG.

FIG. 7 shows the relationship between the target secondary pressure in the pressure reducing valve and the pressure reduction command signal (instruction current) to be input to the pressure reducing valve in order to adjust the secondary pressure in the pressure reducing valve to the target secondary pressure. It is a graph showing. When the braking pilot pressure Pa is calculated, the pressure reduction signal input unit 93 reduces the pilot pressure output from the swing pilot valve 32 to the braking pilot pressure Pa based on the map shown in FIG. A pressure reduction command signal Ca, which is a current value such that the pressure reduction valves 50A and 50B, is calculated, and the pressure reduction command signal is input to the solenoid 50S of the corresponding pressure reduction valve of the pair of pressure reduction valves 50A and 50B.

When the turning speed at the time of the deceleration determination is the speed Vb, the pilot pressure calculation unit 92 determines the size of the opening on the meter-out side corresponding to the speed Vb based on the map shown in FIG. A certain opening area Kb is calculated, and the braking action pilot pressure Pb corresponding to the opening area Kb is calculated based on the map shown in FIG. A signal Cb is calculated, and the pressure reduction command signal Cb is input to the solenoid 50S of the pressure reducing valve.

As a result, the pilot pressure output from the swing pilot valve 32 is reduced to the brake action pilot pressure Pa (or Pb) in the pressure reducing valve 50A or 50B, and the brake action pilot pressure Pa (or Pb) is reduced to the swing pressure. Input to the control valve 40 . As a result, the size of the opening on the meter-out side of the swing control valve 40 is adjusted to a size corresponding to the brake application pilot pressure Pa (or Pb), so that the upper swing body 2 can reach the swing speed Va. (or Vb), a hydraulic braking action can be produced in the swing motor 20. This makes it possible to quickly generate the hydraulic brake action in the swing motor 20 regardless of the magnitude of the swing speed at the time of the deceleration determination. As a result, it is possible to suppress variations in the time required for the brake to start working in the deceleration operation regardless of the magnitude of the turning speed at the time of the deceleration determination. This makes it possible to realize a stable turning deceleration operation and a turning stopping operation, and to improve the workability of the turning work.

In this embodiment, the time period T1 from the time t3 to the time t5 is a dead zone in which the hydraulic brake action does not substantially occur even though the return operation has started. In this embodiment, the time t5 at which the hydraulic braking action begins to occur does not vary according to the turning speed at the time t3 at which the return operation is initiated, but is preset by the second pilot. It is determined based on the pressure threshold value Pi2. Therefore, the size of the time period T1 does not vary according to the turning speed at time t3 when the return operation is started, and is determined based on the preset second pilot pressure threshold value Pi2. This suppresses the brake point (at time t5) from fluctuating as in the comparative example.

Next, specific operations performed by the controller 90 in the turning control device according to this embodiment will be described with reference to the flowchart of FIG.

FIG. 8 is a flow chart showing the arithmetic control operation of the controller 90 in the turning control device according to the present embodiment. First, the deceleration operation determination unit 91 of the controller 90 determines whether or not the turning operation lever 31 has received the deceleration operation. Determination of the deceleration operation by the deceleration operation determination unit 91 is performed based on the processing shown in steps S1 to S9 in FIG. 8, for example. Specifically, it is as follows.

The deceleration operation determination unit 91 acquires the pilot pressure (turning Pi pressure) detected by the pilot pressure sensors 70A and 70B (step S1). Next, the deceleration operation determination unit 91 determines that the pilot pressure detected by one of the pilot pressure sensors 70A and 70B corresponding to the direction of the turning operation is equal to or higher than the first pilot pressure threshold value Pi1. It is determined whether or not (step S2). As shown in FIG. 4, when the pilot pressure becomes greater than or equal to the first pilot pressure threshold value Pi1 at the time t1, the deceleration operation determination unit 91 detects the pilot pressure detected by the pilot pressure sensor 70A or 70B. is greater than or equal to the first pilot pressure threshold value Pi1 (YES in step S2), the full lever flag is set to ON, and the brake flag is set to OFF (step S3).

Next, the deceleration operation determination unit 91 determines whether or not the brake flag is OFF (step S4). Since the setting of the brake flag remains OFF immediately after the brake flag is set to OFF in step S3, the deceleration operation determination unit 91 determines that the brake flag is OFF. (YES in step S4).

Next, the deceleration operation determination unit 91 determines whether or not the setting of the full lever flag has been switched from ON to OFF (step S5). Immediately after the full lever flag is set to ON in step S3, the setting of the full lever flag is maintained to be ON. to OFF (NO in step S5). In this case, the pressure reduction signal input unit 93 does not input the pressure reduction command signal to the pressure reducing valve (step S6). Specifically, in the present embodiment, each of the pressure reducing valves 50A and 50B is composed of an electromagnetic inverse proportional valve. A command signal (for example, a signal corresponding to a minimum current value) is input to the pressure reducing valve so that the pressure reducing valve corresponding to does not reduce the pilot pressure output from the swing pilot valve 32 (step S6).

Next, the deceleration operation determination unit 91 acquires again the pilot pressures detected by the pilot pressure sensors 70A and 70B (step S1), It is determined again whether or not the pilot pressure detected by the corresponding pilot pressure sensor is equal to or higher than the first pilot pressure threshold value Pi1 (step S2). The deceleration operation determination unit 91 determines that the pilot pressure is not equal to or greater than the first pilot pressure threshold value Pi1 at time t4 (NO in step S2). Further, the deceleration operation determination unit 91 determines that the pilot pressure is less than the second pilot pressure threshold value Pi2 at the time t5 (YES in step S7), and sets the full lever flag to OFF. (step S8).

Next, the deceleration operation determination unit 91 determines again whether or not the brake flag is OFF (step S4). When the setting of the brake flag is maintained OFF in step S3, the deceleration operation determination unit 91 determines that the brake flag is OFF (YES in step S4).

Next, the deceleration operation determination unit 91 determines whether or not the setting of the full lever flag has been switched from ON to OFF (step S5). In the present embodiment, at time t5, the deceleration operation determination unit 91 determines that the setting of the full lever flag has been switched from ON to OFF (YES in step S5). In this case, the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation, and sets the brake flag to ON (step S9).

Next, the pilot pressure calculation unit 92 calculates the braking pilot pressure based on the turning speed at the time of the deceleration determination. The calculation of the brake application pilot pressure by the pilot pressure calculator 92 is performed based on the processing shown in steps S10 to S12 of FIG. 8, for example. First, the pilot pressure calculation unit 92 acquires the turning speed at the time of the deceleration determination from the turning speed sensor 80 (step S10). Next, the pilot pressure calculation unit 92 calculates the size (opening area) of the opening on the meter-out side (MO opening) that can cause the hydraulic braking action at the turning speed at the time of the deceleration determination, for example. 5 (step S11). Next, the pilot pressure calculator 92 calculates a braking pilot pressure (target Pi pressure) corresponding to the opening area based on, for example, a map shown in FIG. 6 (step S12).

Next, the decompression signal input unit 93 calculates a decompression command signal based on, for example, a map shown in FIG. 7, and inputs the decompression command signal to the solenoid 50S of the decompression valve 50A or 50B (reverse proportional valve). (Step S13). As a result, the pilot pressure output from the swing pilot valve 32 is reduced to the brake action pilot pressure by the pressure reducing valve 50A or 50B, and the brake action pilot pressure is input to the swing control valve 40 . As a result, the size of the meter-out side opening of the swing control valve 40 is adjusted to a size corresponding to the braking pilot pressure. Braking action can be produced.

Although the processing after step S13 in FIG. 8 is performed is not particularly limited, the following aspects can be exemplified. The deceleration operation determination unit 91 acquires again the pilot pressures detected by the pilot pressure sensors 70A and 70B (step S1), and the pilot pressures detected by the pilot pressure sensors reach the first pilot pressure threshold value Pi1. It is determined again whether or not the above is satisfied (step S2). The deceleration operation determination unit 91 determines that the pilot pressure is not equal to or greater than the first pilot pressure threshold value Pi1 at a point after the time t5 (NO in step S2), and the pilot pressure is reduced to the second threshold value Pi1. It is determined that the pilot pressure is less than the pilot pressure threshold value Pi2 (YES in step S7), and the setting of the full lever flag remains OFF (step S8).

Next, the deceleration operation determination unit 91 determines again whether or not the brake flag is OFF (step S4). Since the setting of the brake flag is maintained ON after time t5, the deceleration operation determination unit 91 determines that the brake flag is not OFF (NO in step S4).

Next, the pilot pressure calculation unit 92 calculates the brake application pilot pressure based on the turning speed at a point after the time t5. The calculation of the brake application pilot pressure by the pilot pressure calculator 92 is performed based on the processing shown in steps S10 to S12 of FIG. 8, for example. As a result, even after the time t5, the pilot pressure output from the turning pilot valve 32 is reduced to the braking pilot pressure by the pressure reducing valve 50A or 50B, and the braking pilot pressure is reduced to the turning pressure. Input to the control valve 40 . As a result, the size of the opening on the meter-out side of the swing control valve 40 is adjusted to a size corresponding to the braking pilot pressure. Hydraulic braking action can be continuously produced at 20 .

The present invention is not limited to the embodiments described above. The present invention can include, for example, the following aspects.

(A) Processing after Deceleration Determination In the above-described embodiment, the decompression signal input unit 93 outputs the decompression command signal to the decompression valve 50A or 50B at time t5 shown in FIG. The signal is input to the solenoid 50S (step S13), and after the time t5, the processes of steps S1 to S13 in FIG. 8 are repeated, but the present invention is not limited to this. In the present invention, as the processing after time t5, processing different from the processing of steps S1 to S13 in FIG. 8 may be adopted. Specifically, after the pressure reduction signal input unit 93 inputs the pressure reduction command signal to the solenoid 50S of the pressure reduction valve at the time t5 (during the deceleration determination) shown in FIG. , a map having characteristics such that the target secondary pressure of the pressure reducing valve gradually decreases is set, and a command signal calculated based on the map is input to the solenoid 50S of the pressure reducing valve. good. The map connects, for example, the braking pilot pressure Pa (or Pb) at time t5 (during deceleration determination) and the pilot pressure Pc, which is smaller than the braking pilot pressure Pa, with a straight line or a curved line. may be generated by The pilot pressure Pc may be, for example, a pilot pressure that causes the spool of the swing control valve 40 to be placed in a neutral position, or a pilot pressure when the opening on the meter-out side of the swing control valve 40 starts to open. It may be pilot pressure.

At time t5 shown in FIG. 4 (during the deceleration determination), after the pressure reduction signal input unit 93 inputs the pressure reduction command signal to the solenoid 50S of the pressure reduction valve, the pilot pressure is reduced by the pressure reduction valve. If the hydraulic brake action is generated even if it is not performed, the pressure reduction signal input unit 93 outputs a command signal to reduce the pilot pressure output from the swing pilot valve after the time t5. It is not necessary to input to the pressure reducing valve.

(B) Deceleration Operation Determination In the above-described embodiment, the deceleration operation determination unit 91 determines the deceleration operation through the processing of steps S1 to S9 shown in FIG. 8, but the present invention is not limited to this. . In the present invention, the first pilot pressure threshold value may be omitted in determining the deceleration operation, and the deceleration operation determination may be performed based only on the second pilot pressure threshold value. That is, when the pilot pressure detected by the pilot pressure detection unit becomes less than a preset pilot pressure threshold value (threshold value corresponding to the second pilot pressure threshold value), the deceleration operation determination unit determines the It may be determined that the turning operation member has received the deceleration operation.

(C) Manipulation amount when determining deceleration In the above-described embodiment, the first pilot pressure threshold value Pi1 is set to a value that can determine whether or not the operation amount of the turning operation is the maximum operation amount. However, the present invention is not limited to this. In the present invention, for example, the first pilot pressure threshold is set to a value that can determine whether or not the operation amount of the turning operation is smaller than the maximum operation amount (for example, a so-called half lever). may have been

(D) Types of Construction Machinery In the above embodiments, the construction machine is a hydraulic excavator, but the construction machine on which the swing control device of the present invention is mounted is not limited to a hydraulic excavator, and can be a swing-type crane or the like. Other construction machines may be used. Also, the tip attachment is not limited to a bucket, and may be other tip attachments such as grapples, crushers, breakers, and forks.

(E) Substrate In the above-described embodiment, the undercarriage 1 is used as a substrate, but the substrate is not limited to the one that can run like the undercarriage 1, and is installed at a specific location to provide an upper part. It may be a base that supports the revolving body 2 .

REFERENCE SIGNS LIST 1 lower running body 2 upper swing body 10 hydraulic pump 20 swing motor 30 swing operation device 31 swing operation lever (an example of a swing operation member)
32 swivel pilot valve 40 swivel control valve 50A first pressure reducing valve 50B second pressure reducing valve 70A, 70B pilot pressure sensor (an example of a pilot pressure detection unit)
80 Turning speed sensor (an example of turning speed detection unit)
90 controller 91 deceleration operation determination unit 92 pilot pressure calculation unit 93 pressure reduction signal input unit 100 construction machine Ca, Cb pressure reduction command signal Ka, Kb size (opening area) of opening on meter-out side of swing control valve
LM maximum operation amount (an example of operation amount of turning operation member)
PM Maximum pilot pressure Pa, Pb Brake action pilot pressure (secondary pressure of pressure reducing valve)
Pi1 First pilot pressure threshold Pi2 Second pilot pressure threshold Va, Vb, VM Turning speed

Claims (3)

A swing control device for a construction machine comprising an upper swing body capable of swinging with respect to a base body,
a hydraulic pump that discharges hydraulic oil;
a swing motor that receives the supply of the hydraulic oil discharged from the hydraulic pump and operates to swing the upper swing structure;
a turning operation device having a turning operation member that receives a turning operation, which is an operation for operating the turning motor, and a turning pilot valve that outputs a pilot pressure corresponding to the amount of operation of the turning operation;
A swing control valve interposed between the hydraulic pump and the swing motor, wherein the size of an opening on the meter-out side is changed according to the pilot pressure input from the swing pilot valve to the swing control valve. a swing control valve that opens and closes at
a turning speed detection unit that detects the turning speed of the upper turning body;
A brake application pilot pressure for suppressing variations in the timing of hydraulic brake application in the swing motor for each operation when the upper swing structure is swinging at the swing speed, and the hydraulic brake is applied. a pilot pressure calculation unit that calculates a braking action pilot pressure for adjusting the size of the opening on the meter-out side based on the turning speed;
a deceleration operation determination unit that determines whether or not the turning operation member has received a deceleration operation, which is an operation for decreasing the turning speed;
A pressure reducing valve interposed between the swing pilot valve and the swing control valve, wherein the pilot pressure output from the swing pilot valve corresponds to the pressure reducing command signal by receiving a pressure reducing command signal. a pressure reducing valve operable to reduce the pressure to a pilot pressure and input it to the swing control valve;
When the deceleration operation determination unit determines that the turning operation member has received the deceleration operation, the decompression command signal for reducing the pilot pressure output from the turning pilot valve to the braking pilot pressure is provided. A swing control device for a construction machine, comprising: a decompression signal input unit for inputting to a decompression valve. A turning control device for a construction machine according to claim 1,
The pilot pressure calculation unit is a first map preset in order to suppress variations in the timing of causing the hydraulic brake action in the swing motor for each work, and the map is a map that is calculated based on the swing speed and the swing speed. Using the first map showing the relationship with the size of the opening on the meter-out side of the swing control valve capable of producing the hydraulic braking action in the swing motor when the upper swing structure is swinging, calculating the size of the meter-out side opening, and calculating the brake application pilot pressure using a second map showing the relationship between the size of the meter-out side opening and the target secondary pressure in the pressure reducing valve; Slewing control device for construction machinery. The turning control device for construction machinery according to claim 1 or 2 ,
further comprising a pilot pressure detection unit that detects the pilot pressure output from the swivel pilot valve,
The deceleration operation determination unit determines that the pilot pressure detected by the pilot pressure detection unit is a preset first pilot pressure threshold value that is lower than the maximum pilot pressure, and the maximum pilot pressure After becoming equal to or higher than the first pilot pressure threshold value, which is a value closer to the maximum pilot pressure than 1/2 of the value , the pilot pressure detected by the pilot pressure detection unit is set in advance to the second pilot is less than the first pilot pressure threshold and is closer to the first pilot pressure than half the maximum pilot pressure. A turning control device for a construction machine, which determines that the turning operation member has received the deceleration operation when the turning operation member has received the deceleration operation.

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