JP2014206022A - Revolution braking device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a revolution braking device capable of quickly stopping a revolution body in emergency and highly reliable.SOLUTION: A revolution braking device of a construction machine includes: a brake selector device 54 which supplies a pressure oil to an oil chamber of a brake piston 56 to set a revolution brake 55 to a brake off-state when a revolution operation device 52 is operated, and stops supply of the pressure oil to the oil chamber of the brake piston 56 and returns the pressure oil of the oil chamber of the brake piston 56 to a tank via a throttle 58 to set the revolution brake 55 to a brake on-state when the revolution operation device 52 is not operated; and an emergency stop device 59 which returns the pressure oil of the oil chamber of the brake piston 56 to the tank 44 earlier than the delay time of the throttle 58 to set the revolution brake 55 to a brake on-state when a gate lock lever 90 is switched to an entrance closing position and the pressure of a pilot primary pressure line 201 is lowered.

Description

  The present invention relates to a swing braking device for a construction machine that is provided in a construction machine including a swing body such as a hydraulic excavator and stops and holds the swing body.

  For example, a construction machine such as a hydraulic excavator has an engine that uses gasoline, light oil, or the like as a power source as a power source. The engine drives a hydraulic pump to generate hydraulic pressure, and a hydraulic actuator such as a hydraulic motor or a hydraulic cylinder is driven. To do. Hydraulic actuators are small and light and capable of high output, and are widely used as construction machine actuators.

  Construction machines such as hydraulic excavators have a swivel body. In a hydraulic excavator that drives the swivel body with a hydraulic motor, an oil passage that supplies pressure oil to the hydraulic motor when the swivel lever is returned to the neutral position during the swivel operation. Is closed by the control valve, and the revolving body is decelerated by the relief operation of the relief valve, and then reaches a stop state.

  Such a construction machine such as a hydraulic excavator has a turning brake for stopping and holding the turning body as described in Patent Document 1, for example. This turning brake is configured as a negative brake that is in a brake-off state when oil is supplied to the oil chamber of the brake piston and in a brake-on state when the pressure oil is discharged. In addition, a brake switching valve is provided between the oil chamber of the brake piston, the hydraulic pressure source, and the tank. By switching the brake switching valve according to the operation pilot pressure, the pressure oil in the oil chamber of the brake piston is sucked and discharged. The operation of the turning brake is controlled.

  Patent Document 2 describes a brake device in an excavator that drives a revolving body with an electric motor, and the brake device includes a brake switching valve that is switched and controlled by a control signal of a controller. In addition, a pressure relief circuit is provided in the oil passage connecting the brake switch valve and the oil chamber of the brake piston, and even if the brake switch valve does not switch to the OFF position due to a failure in the controller or other electrical system, the engine can be stopped. The brake brake can be operated by stopping the supply of the brake piston pressure oil and discharging the pressure oil from the brake piston oil chamber via the pressure release circuit.

Japanese Patent Laid-Open No. 10-331208 JP 2010-209637 A

  The swing brake described in Patent Document 1 stops and holds the swing body after the swing body is stopped by the relief operation of the relief valve. Therefore, the swivel body cannot be quickly stopped in an emergency in which the relief valve does not function as a braking means due to a failure of the spool valve stick or the relief valve.

  The same applies to the brake device described in Patent Document 2. In other words, since the pressure relief circuit is configured to exhaust pressure even during normal times, the opening cannot be increased, and if an event occurs in which the brake switching valve does not switch due to failure of the controller, brake switching valve, etc., the engine may be stopped. It is difficult to ensure the desired response speed in an emergency. In addition, since an electric system is used to open and close the brake switching valve, there are many failure factors such as contact failure, short circuit, and disconnection, and thus there is a difficulty in reliability.

  An object of the present invention is to provide a highly reliable turning braking device that can quickly stop a turning body in an emergency.

  (1) In order to achieve the above object, the present invention provides a turning motor for driving a turning body, a turning control device for controlling a rotation direction and a rotation speed of the turning motor by switching operation by a turning operation device, A gate lock lever provided on the seat that opens and closes the entrance / exit leading to the driver's seat, and when the gate lock lever is in the first position (closes the entrance / exit), the pilot pressure source communicates with the pilot primary pressure line. Then, the pilot pressure source pressure is guided to the pilot primary pressure line, the operation pilot pressure can be generated by a plurality of operation devices including the turning operation device, and the gate lock lever (opens the entrance / exit) When switched to the second position, the pilot pressure source and the pilot primary pressure line are shut off and the pilot primary pressure line is turned off. And a gate lock valve for disabling the generation of the operation pilot pressure by the plurality of operation devices, and a brake force applied to the rotation motor when the rotation operation device is not operated. In addition, it is a swing brake that mechanically stops and holds the swing body, and is configured as a negative brake that is in a brake-off state when pressure oil is supplied and in a brake-on state when the pressure oil is returned to the tank. The pilot primary pressure line is communicated with the turning brake when the turning operation device is operated, and the turning brake is braked off by supplying pressure oil from the pilot pressure source to the turning brake, When the turning operation device is not operated, the pilot primary pressure line is disconnected from the turning brake and the turning block is disconnected. A brake switching device for communicating the brake to the tank via a first delay device, returning the pressure oil of the swing brake to the tank via the first delay device, and bringing the swing brake into a brake-on state; and the gate When the lock lever is switched to the second position and the gate lock valve connects the pilot primary pressure line to the tank, the lock lever operates based on a change in the pressure of the pilot primary pressure line, An emergency stop device that returns the tank to the tank earlier than the delay time of the first delay device and sets the turning brake to a brake-on state is provided.

  In this invention comprised in this way, a turning body can be stopped quickly at the time of emergency, and the reliability of a turning braking device can be improved.

  (2) In the above (1), the emergency stop device includes a second delay device that is provided between the swing brake and the tank and has a delay time shorter than that of the first delay device. Is returned to the tank via the second delay device.

  Thereby, the stability of the vehicle body when the revolving body is stopped urgently can be improved.

  (3) In the above (1), the brake switching device includes a brake switching valve disposed in an oil passage connecting the pilot primary pressure line to the swing brake, and the swing brake via the first delay device. A first drain oil passage connected to the tank, the emergency stop device has an emergency stop valve disposed between the brake switching valve, the turning brake and the tank, the brake switching valve, Switching between a first position for communicating the pilot primary pressure line with the turning brake and a second position for blocking communication between the pilot primary pressure line and the turning brake based on the operating pilot pressure from the turning operation device. The emergency stop valve communicates the brake switching valve with the swing brake based on the pressure in the pilot primary pressure line and A third position for blocking communication between the turning brake and the tank; and a fourth position for blocking communication between the brake switching valve and the turning brake and for connecting the turning brake to the tank via the second drain oil passage. And can be switched.

  Thereby, the reliability of the turning braking device can be improved.

  (4) In the above (1), the brake switching device has a brake switching valve disposed in an oil passage connecting the pilot primary pressure line to the turning brake, and the emergency stop device includes the brake switching valve. And an emergency stop valve disposed between the swing brake and the tank, and the brake switching valve communicates the pilot primary pressure line to the swing brake based on an operation pilot pressure from the swing operation device. A first position of the pilot primary pressure line and a second position that cuts off the communication between the pilot primary pressure line and the turning brake, and the emergency stop valve is configured to switch the brake based on the pressure of the pilot primary pressure line. A third position for communicating the valve and the turning brake and for connecting the turning brake to the tank via the first drain oil passage; The communication between the switching valve and the turning brake can be cut off, and the turning brake can be switched to a fourth position where the turning brake is communicated with the tank via the second discharge oil passage. Located in the oil passage.

  Thereby, the reliability of the turning braking device can be improved and the number of parts of the hydraulic piping and the hydraulic device can be reduced.

  (5) In any one of the above (3) and (4), the emergency stop device further includes a second delay device having a delay time shorter than the first delay device, and the second delay device is It arrange | positions at the 2nd discharge | emission oil path.

  Thereby, the stability of the vehicle body when the revolving body is stopped urgently can be improved.

  According to the present invention, it is possible to realize a turning braking device that can quickly stop the turning body in an emergency and has high reliability.

It is a figure which shows the external appearance of the hydraulic shovel which is an example of a construction machine. It is a figure which shows the turning drive system of the construction machine in 1st Embodiment. It is a figure which shows the pressure change of the oil chamber of a brake piston. It is a figure which shows the turning drive system of the construction machine in 2nd Embodiment. It is a figure which shows the turning drive system of the construction machine in 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
~Constitution~
FIG. 1 is a diagram showing a configuration of a hydraulic excavator that is an example of a construction machine on which the turning braking device of the present invention is mounted. In FIG. 1, the hydraulic excavator includes a lower traveling body 10, an upper swing body 20, and an excavator mechanism 30. The lower traveling body 10 includes a pair of crawlers 11 and a crawler frame 12 (only one side is illustrated), a pair of traveling hydraulic motors 13 and 14 (only one side is illustrated) that independently drive and control each crawler, and a speed reduction mechanism thereof (see FIG. (Not shown).

  The upper swing body 20 includes a swing frame 21 on which an engine 22, a hydraulic pump 23 driven by the engine 22, a swing hydraulic motor 24, a speed reducer 25, a control valve 26, and the like are mounted. ing. A turning mechanism (not shown) including a turning ring or the like is provided between the lower traveling body 10 and the upper turning body 20, and the speed reducer 25 decelerates the rotation of the turning hydraulic motor 24 and transmits it to the turning mechanism. The upper turning body 20 is driven to turn relative to the lower traveling body 10 by the driving force of the hydraulic motor 24 for use. The turning hydraulic motor 24 is provided with a turning brake 55 (see FIG. 2).

  The shovel mechanism 30 includes a boom 31 that can be raised and lowered rotatably supported by the upper swing body 20, a boom cylinder 32 for driving the boom 31, and an arm 33 that is rotatably supported near the tip of the boom 31. , An arm cylinder 34 for driving the arm 33, a bucket 35 rotatably supported at the tip of the arm 33, and a bucket cylinder 36 for driving the bucket 35. Each actuator (travel hydraulic motors 13 and 14, boom cylinder 32, arm cylinder 34, bucket cylinder 36 and turning hydraulic motor 24) is driven by pressure oil supplied from the hydraulic pump 23, and the drive direction and drive speed are as follows. It is controlled by operating each spool valve in the control valve 26. The upper-part turning body 20 includes a cab 27. A driver seat 28 in the cab 27 has a left and right operation lever device 52 (only one side is shown) and a gate lock lever 90 that opens and closes an entrance / exit 29 leading to the driver seat 28. Is provided. The operation levers of the left and right operation lever devices 52 can be operated in any direction including the cross direction when the operation lever is viewed from above, and when operating the operation lever of the left operation lever device 52 in the front-rear direction, The operation lever device 52 functions as a turning operation device 52 (see FIG. 2).

  FIG. 2 is a diagram showing a turning drive system including the turning braking device 60 according to the embodiment of the present invention. In FIG. 2, the turning drive system controls the flow of pressure oil supplied from the hydraulic pump 23 to the turning hydraulic motor 24 from the hydraulic pump 23, the turning hydraulic motor 24, the speed reducer 25, and the hydraulic pump 23. And a spool valve 43 (a turning control device) for controlling the rotation direction and the rotation speed of the turning hydraulic motor 24. The spool valve 43 is one of the spool valves in the control valve 26 shown in FIG. 1, and is switched by operating the operation lever of the turning operation device 52.

  The spool valve 43 is an open center type flow control valve. When the spool valve 43 is in the neutral position shown in the figure, the hydraulic pump 23 communicates with the tank 44 and the oil discharged from the hydraulic pump 23 is returned to the tank 44. The spool valve 43 is connected to the turning hydraulic motor 24 via the oil passages 102a and 102b. When the spool valve 43 is operated from the neutral position to the A position, the oil discharged from the hydraulic pump 23 is removed from the spool valve 43. The oil is supplied to the turning hydraulic motor 24 through the oil passage 102 a, and the return oil from the turning hydraulic motor 24 is returned to the tank 44 through the oil passage 102 b and the spool valve 43. When the spool valve 43 is operated from the neutral position to the B position, the oil discharged from the hydraulic pump 23 is supplied to the turning hydraulic motor 24 through the spool valve 43 and the oil passage 102b, and is supplied from the turning hydraulic motor 24. The return oil is returned to the tank 44 through the oil passage 102 a and the spool valve 43. Relief valves 48a and 48b and check valves 49a and 49b are provided between the oil passages 102a and 102b. The relief valves 48a and 48b allow oil to escape to the tank 44 when the oil passage 102a or 102b becomes higher than the set pressure when the turning hydraulic motor 24 is operated with the spool valve 43 operated from the neutral position, and the oil passages 102a and 102b. Damage to hydraulic equipment such as the piping and the hydraulic pump 23 is prevented. Further, when the turning hydraulic motor 24 for returning the spool valve 43 to the neutral position is stopped, when the oil passage 102a or 102b on the pressure oil return side (back pressure side) from the turning hydraulic motor 24 becomes higher than the set pressure. Oil is released to the tank 44, and the high pressure in the oil passage 102a or 102b is applied to the turning hydraulic motor 24 as a brake pressure, and the turning hydraulic motor 24 is braked / stopped. The check valves 49a and 49b suck in oil from the tank 44 to prevent cavitation when the pressure in the oil passages 102a and 102b tends to drop below the tank pressure.

  The swing operation device 52 is a hydraulic pilot system that generates an operation pilot pressure corresponding to the operation amount of the operation lever using the pressure of the pilot primary pressure line 201 as a source pressure, and the generated operation pilot pressure is transmitted through the oil passages 202a and 202b. Thus, the spool valve 43 is guided to the pressure receiving portion of the spool valve 43 to switch the spool valve 43. The pilot primary pressure line 201 is connected to the pilot pressure source 50 via the gate lock valve 51. The pilot pressure source 50 includes a pilot pump (not shown) driven by the engine 22 (see FIG. 1) and a pilot relief valve (not shown) that keeps the discharge pressure of the pilot pump constant. The gate lock valve 51 is an electromagnetic valve that is switched by the operation of the gate lock lever 90. When the gate lock valve 51 is in the C position, the pilot pressure source communicates with the pilot primary pressure line to the pilot primary pressure line 201. The pilot pressure source 50 is guided, and the operation pilot pressure can be generated by a plurality of operation devices including the turning operation device 52. When the gate lock valve 51 is in the D position, the pilot pressure source 50 and the pilot primary pressure line The pilot primary pressure line 201 is communicated with the tank 44, and the operation pilot pressure cannot be generated by the plurality of operation devices.

  The gate lock lever 90 can be operated between an E position (first position) for closing the entrance / exit and an F position (second position) for opening the entrance / exit, and the operation position is detected by the position sensor 91. When the gate lock lever 90 is operated to the E position, the position sensor 91 outputs an ON signal, and the relay circuit 92 amplifies the ON signal and supplies it to the solenoid of the gate lock valve 51. To position C.

  The turning braking device in the present embodiment is provided in such a turning drive system, and includes a turning brake 55 having a built-in brake piston 56, a brake switching device 61, and an emergency stop device 62. The turning brake 55 applies a braking force to the turning hydraulic motor 24 when the operation lever of the turning operation device 52 is not operated, mechanically stops and holds the turning body 20, and turns when the operation lever of the turning operation device 52 is operated. The brake force of the hydraulic motor 24 is released and the swing body 20 can be turned. When pressure oil is supplied to the oil chamber of the brake piston 56, the brake is turned off, and the pressure oil in the oil chamber of the brake piston 56 is set. Is configured as a negative brake that is turned on when the vehicle is returned to the tank 44.

  The brake switching device 61 communicates the pilot primary pressure line 201 with the oil chamber of the brake piston 56 of the turning brake 55 when the operation lever of the turning operation device 52 is operated, and the pressure oil of the pilot pressure source 50 is connected to the oil chamber of the brake piston 56. To turn the turning brake 55 in a brake-off state, and when the operation lever of the turning operation device 52 is not operated, the communication between the pilot primary pressure line 201 and the oil chamber of the brake piston 56 is cut off and the oil chamber of the brake piston 56 is turned off. This is communicated with the tank 44 via a first delay device 58 (described later), and the pressure oil in the oil chamber of the brake piston is returned to the tank 44 via the first delay device 58 so that the turning brake 55 is braked. is there.

  For this purpose, the brake switching device 61 has a shuttle valve 53 that detects an operating pilot pressure generated by the turning operation device 52 when the operation lever of the turning operation device 52 is operated, and a pilot primary pressure line 201 that is connected to the brake piston 56. The brake switching valve 54 disposed in the oil passage 203 connected to the oil chamber, and the oil passage portion 203c between the brake switching valve 54 and the oil chamber of the brake piston 56, are arranged from the brake switching device 54 to the brake piston 56. A check valve 57 that allows the flow of pressure oil toward the oil chamber and blocks the flow of pressure oil in the reverse direction; and an oil passage 206 (first discharge oil passage) that connects the oil chamber of the brake piston 56 to the tank 44. And a throttle 58 disposed in the oil passage 206.

  The brake switching valve 54 is a hydraulic switching valve that is switched based on the operation pilot pressure of the turning operation device 52 detected by the shuttle valve 53, and communicates the oil passage 203 (the oil passage portion 203a and the oil passage portion 203b). The position G can be switched to the H position where the oil passage 203 (the communication between the oil passage portion 203a and the oil passage portion 203b) is blocked and the oil passage portion 203b is communicated with the tank 44. When the brake switching valve 54 is switched to the G position, the pilot primary pressure line 201 is communicated with the oil chamber of the brake piston 56, and when the brake switching valve 54 is switched to the H position, the pilot primary pressure line 201 is communicated with the oil chamber of the brake piston 56. The oil passage portions 203 b and 203 c on the upstream side of the check valve 57 are connected to the tank 44. In this embodiment, the shuttle valve 53 is shown as means for detecting the turning operation pilot pressure. However, a plurality of operation pressures selected by a plurality of operation devices including the turning operation device 52 are selected. When the shuttle block having the shuttle valve is provided, the turning operation pilot pressure may be detected using the shuttle block.

  Here, when the brake switching valve 54 is switched to the H position and the supply of pressure oil to the oil chamber of the brake piston 56 is stopped, the pressure oil in the oil chamber of the brake piston 56 is discharged to the tank 44 through the oil passage 206. Thus, the pressure in the oil chamber of the brake piston 56 is reduced to the tank pressure. The throttle 58 functions as a first delay device that suppresses a decrease in pressure at that time and gives a time delay, and after the supply of pressure oil to the oil chamber of the brake piston 56 stops, the first delay time T1. The size of the aperture is set so that the turning brake 55 is operated after the elapse of time. Here, the first delay time T1 is set to a time longer than the time until the swing body 20 is stopped by the relief operation of the relief valve 48a or 48b when the operation lever is neutral.

  When the gate lock lever 90 is switched to the F position (second position) and the gate lock valve 51 is switched to the D position to connect the pilot primary pressure line 201 to the tank 44, the emergency stop device 62 is connected to the pilot primary pressure line. The pressure oil in the oil chamber of the brake piston 56 of the turning brake 55 is returned to the tank 44 earlier than the delay time of the throttle 58 (first delay device) to operate the turning brake. The brake is turned on. For this purpose, the emergency stop device 62 includes oil passage portions 203b and 203c for connecting the brake switching valve 54 to the check valve 57 between the oil chamber of the brake switching valve 54 and the brake piston 56 and the tank 44, and a check. An emergency stop valve 59 connected to an oil passage 207 (second exhaust oil passage) connecting the oil passage portion 203d connecting the valve 57 to the oil chamber of the brake piston 56 to the tank 44 is provided.

  The emergency stop valve 59 is a hydraulic switching valve that is switched based on the pilot primary pressure from the pilot primary pressure line 201, and communicates the oil passage 203 (the oil passage portion 203 b and the oil passage portion 203 c) and the oil passage 207. The J position (third position) that blocks (the communication between the oil passage portion 207a and the oil passage portion 207b), the communication between the oil passage portion 203b and the oil passage portion 203c are cut off, and the oil passage portion 203c communicates with the tank 44. At the same time, it is possible to switch between the K position (fourth position) where the oil passage 207 (the oil passage portion 207a and the oil passage portion 207b) communicates. When the emergency stop valve 59 is switched to the J position, the brake switching valve 54 and the oil chamber of the brake piston 56 are communicated with each other, and the communication between the oil chamber of the brake piston 56 and the tank 44 is shut off. When switched to the position, the communication between the brake switching valve 54 and the oil chamber of the brake piston 56 is cut off, and the oil passage portion 203c that connects the emergency stop valve 59 to the oil chamber of the brake piston 56 is communicated with the tank 44. The oil chamber of the brake piston 56 is communicated with the tank 44 via an oil passage 207 (second discharge oil passage).

  Further, the emergency stop valve 59 is provided with a throttle 63 in an oil passage that communicates the oil passage portion 207a with the tank 44 via the oil passage portion 207b at the K position. When the emergency stop valve 59 is switched to the K position, the supply of pressure oil to the oil chamber of the brake piston 56 is stopped, and the pressure oil in the oil chamber of the brake piston 56 is discharged to the tank 44 via the oil passage 207, and the brake The pressure in the oil chamber of the piston 56 is reduced to the tank pressure. The throttle 63 functions as a second delay device that suppresses a decrease in pressure at that time and gives a time delay, and after the supply of pressure oil to the oil chamber of the brake piston 56 stops, the second delay time T2. The size of the aperture is set so that the turning brake 55 is operated after the elapse of time. Here, the second delay time T2 is a time for reducing the turning speed by the relief operation of the relief valve 48a or 48b to such an extent that the stability of the vehicle body is not impaired at the time of emergency stop of the turning operation. The time is set shorter than the time T1. In the present embodiment, the throttle 63 (second delay device) is disposed inside the emergency stop valve 59 (K position), but any of the oil passage portions 207a and 207b (second exhaust oil passage) is used. You may arrange | position in the location of. In addition, the diaphragm 63 may not be provided when a configuration in which priority is given to a sudden stop.

  FIG. 3 is a diagram showing the relationship between the delay times of the diaphragm 58 (first delay device) and the diaphragm 63 (second delay device). Curve A in the figure shows the oil chamber of the brake piston 56 via the throttle 58 (first delay device) after the operation lever of the turning operation device 52 is returned to the neutral position and the brake switching valve 54 is switched to the H position. The change in pressure in the oil chamber of the brake piston 56 when the pressure oil returns to the tank 44 is shown. Curve B is operated after the gate lock lever 90 is operated to the F position and the emergency stop valve 59 is switched to the K position. A change in pressure in the oil chamber of the brake piston 56 when the pressure oil in the oil chamber of the brake piston 56 returns to the tank 44 via the throttle 62 (second delay device) is shown. P0 in the figure is the pressure in the oil chamber of the brake piston 56 (= pilot primary pressure) when the oil chamber of the brake piston 56 communicates with the pilot primary pressure line 201 and the turning brake 55 is in the brake-off state. P1 in the middle is the pressure of the oil chamber of the brake piston 56 when the oil chamber of the brake piston 56 communicates with the tank 44 and the turning brake 55 is in a brake-on state. In the case of the throttle 58 (first delay device), for example, in the case of the throttle 62 (second delay device), the turning brake 55 is brought into a brake-on state after about 7 to 10 seconds (first delay time T1) has elapsed from the start of pressure release. For example, after about 2 to 3 seconds (second delay time T2) elapses, the turning brake 55 is turned on. Note that Tr in FIG. 3 is a time from when the operating lever of the turning operation device 52 is returned to the neutral position to when the turning body 20 is stopped by the relief operation of the relief valves 48a and 48b, and the second delay time T2. Is set shorter than Tr.

~ Operation ~
The operation of the turning drive system configured as described above will be described.

~~ When turning is not operated ~~
Before the operator operates the operation lever of the turning operation device 52, and when an operation is to be performed, the gate lock lever 90 is in the E position (first position) for closing the entrance / exit. In this state, the gate lock valve is switched to the C position, and the pilot primary pressure line 201 is supplied with the pressure of the pilot pressure source 50 as the pilot primary pressure. Therefore, the emergency stop valve 59 is switched to the J position (second position) by the pilot primary pressure, the oil passage portion 203b and the oil passage portion 203c communicate with each other, and the oil passage portion 207a and the oil passage portion 207b (second discharge oil passage). ) Is blocked. Further, when the operation lever of the turning operation device 52 is in the neutral position, since the turning operation device 52 does not generate the operation pilot pressure, the brake switching valve 54 is in the H position, and the oil passage portion 203a and the oil passage portion. 203 b is blocked and the oil passage portions 203 b and 203 c communicate with the tank 44. For this reason, no pressure oil is supplied to the oil chamber of the brake piston 56, the turning brake 55 is in a brake-on state, and the turning hydraulic motor 24 is stopped and held by the turning brake 55.

~~ During turning operation ~~
When the operator operates the operation lever of the turning operation device 52 from the neutral position, the turning operation device 52 generates an operation pilot pressure, and the brake switching valve 54 is switched to the G position by this operation pilot pressure, and the oil passage portion 203a and the oil The passage portion 203 b is communicated, and the oil chamber of the brake piston 56 is communicated with the pilot primary pressure line 201. For this reason, the pilot primary pressure of the pilot primary pressure line 201 is supplied to the oil chamber of the brake piston 56 via the oil passage 203, the turning brake 55 is brought into a brake-off state, and the turning hydraulic motor 24 can be rotated. Further, the spool valve 43 is switched to the A position or the B position by the operation pilot pressure, the pressure oil of the hydraulic pump 23 is supplied to the turning hydraulic motor 24 through the oil passage 102a or 102b, and the turning hydraulic motor 24 is turned on. Driven by rotation.

~~ When turning at normal time ~~
When the operator returns the operation lever of the turning operation device 52 to the neutral position, the turning operation device 52 stops generating the operation pilot pressure, and the spool valve 43 is switched to the neutral position. As a result, the supply of pressure oil from the hydraulic pump 23 to the turning hydraulic motor 24 is stopped, and the communication with the tank 44 of the oil passage 102a or 102b on the discharge side is also cut off, so that the turning body 20 has a relief valve 48a or 48b. This relief operation decelerates, and after a predetermined time Tr elapses, it reaches a stop state. Further, since the turning operation device 52 stops generating the operation pilot pressure, the brake switching valve 54 is switched to the H position and the communication between the oil chamber of the brake piston 56 and the pilot primary pressure line 201 is cut off. As a result, the supply of pressure oil from the pilot primary pressure line 201 to the oil chamber of the brake piston 56 is stopped, and the pressure oil in the oil chamber of the brake piston 56 is supplied to the oil passage 206 (first exhaust oil passage) and the throttle 58 (first). The pressure in the oil chamber of the brake piston 56 is lowered by being discharged to the tank 44 via the one delay device), and after the first delay time T1 has elapsed, the brake is turned on, and the revolving body 20 is stopped and held. When the brake switching valve 54 is switched to the H position, the oil passage portions 203 b and 203 c are communicated with the tank 44, and the pressure oil in the oil passage portions 203 b and 203 c is discharged to the tank 44. This prevents the pressure oil in the oil passage portions 203 b and 203 c from flowing into the oil passage 206 (first exhaust oil passage) via the check valve 57, and the pressure oil in the oil chamber of the brake piston 56 passes through the throttle 58. It is smoothly discharged into the tank 44, and the brake-on state can be reliably established after the first delay time T1 has elapsed.

~~ In case of emergency turning stop ~~
When the operator urgently stops the turning operation, the operator returns the operation lever of the turning operation device 52 to the neutral position and operates the gate lock lever 90 to the F position (second position). When the gate lock lever 90 is operated to the F position, the gate lock valve 51 is switched to the D position, and the pilot primary pressure line 201 communicates with the tank 44. As a result, the pressure in the pilot primary pressure line 201 is reduced to the pressure in the tank 44, the emergency stop valve 59 is switched to the K position, and the communication between the oil chamber of the brake piston 56 and the pilot primary pressure line 201 is shut off. The oil passage portion 207a and the oil passage portion 207b (second discharged oil passage) are communicated with each other through a throttle 63 (second delay device). As a result, the supply of pressure oil from the pilot primary pressure line 201 to the oil chamber of the brake piston 56 is stopped, and the pressure oil in the oil chamber of the brake piston 56 passes through the oil passage portion 207a, the restrictor 63, and the oil passage portion 207b. By discharging to the tank 44, the pressure in the oil chamber of the brake piston 56 decreases, and after the second delay time T2 has elapsed, the brake is turned on, and the revolving structure 20 is held stopped. Here, the second delay time T2 is set shorter than the first delay time T1 and shorter than the stop time Tr due to the relief operation of the relief valves 48a and 48b. As a result, the turning operation can be quickly stopped in an emergency. When the emergency stop valve 59 is switched to the K position, the oil passage portion 203 c is communicated with the tank 44, and the pressure oil in the oil passage portion 203 c is discharged to the tank 44. This prevents the pressure oil of 203c from flowing into the oil passage 207 (second discharge oil passage) via the check valve 57, and the pressure oil in the oil chamber of the brake piston 56 smoothly flows into the tank 44 via the throttle 63. It is discharged, and the brake-on state can be reliably established after the second delay time T2 has elapsed.

~effect~
According to the turning braking device of the present embodiment, the following effects can be obtained.

  (1) By operating the gate lock lever 90 and switching the emergency stop valve 59, the hydraulic oil is quickly discharged from the oil chamber of the brake piston 56, and the turning brake 55 is operated, and the turning body 20 is stopped emergencyly. Can do.

(2) By making the emergency stop valve 59 a hydraulic switching valve that is switched by the pilot primary pressure, the cause of failure can be reduced and the reliability of the swing braking device can be improved.
<Second Embodiment>
FIG. 4 is a diagram showing a turning drive system including a turning braking device according to the second embodiment of the present invention. The difference between the turning brake device in the present embodiment and the turning brake device in the first embodiment (see FIG. 2) is that the inside of the emergency stop valve 59 is replaced with the first discharged oil passage 206 (see FIG. 2). The first exhaust oil passage 208 is provided at (J position), and the throttle 64 disposed in the first exhaust oil passage 208 instead of the first delay device 58 (see FIG. 2) disposed in the first exhaust oil passage 206. (First delay device).

Also in the turning braking device in the present embodiment, the same effect as in the first embodiment can be obtained. Furthermore, by providing the first drain oil passage 208 and the first delay device 64 inside the emergency stop valve 59 (J position), the number of parts of the hydraulic piping and the hydraulic device can be reduced.
<Third Embodiment>
FIG. 5 is a diagram showing a turning drive system including a turning braking device according to the third embodiment of the present invention. The turning drive system in the present embodiment is an electric type, and includes a generator 72 driven by an engine (not shown), an inverter 71, a turning electric motor 70, pressure sensors 75a and 75b, a controller 74, and a battery 73. And. The configuration of the turning braking device is the same as that of the first embodiment.

  The electric power generated by the generator 72 is supplied to the turning electric motor 70 via the inverter 71 and drives the turning electric motor 70. The pressure sensors 75a and 75b are provided in the pilot secondary pressure lines 202a and 202b, respectively, convert the two pilot secondary pressures supplied from the turning operation device 52 into electric signals and output them to the controller 74. The controller 74 inputs electric signals from the pressure sensors 75a and 75b, performs predetermined calculation processing, outputs the electric signals after the calculation processing to the inverter 71 as control signals, and rotates the rotation direction and rotation speed of the electric motor 70 for turning. To control. The battery 73 is connected to the generator 72 and the turning electric motor 70 via the inverter 71, and stores the surplus power of the generator 72 and the regenerative power generated during braking of the turning body 20 via the inverter 71. . The electric power stored in the battery 73 is used for drive assist of the turning electric motor 70 or other electric system. Note that the inverter 71, the controller 74, and the pressure sensors 75a and 75b (portions surrounded by a one-dot chain line in FIG. 5) constitute the turning control device in the present embodiment.

~effect~
Also in the turning braking device in the present embodiment, the same effect as in the first embodiment can be obtained. In addition, when the turning braking device in the present embodiment is replaced with the turning braking device in the second embodiment (see FIG. 4), the same effect as in the second embodiment can be obtained.

DESCRIPTION OF SYMBOLS 10 Lower traveling body 11 Crawler 12 Crawler frame 13, 14 Traveling hydraulic motor 20 Upper turning body 21 Turning frame 22 Engine 23 Hydraulic pump 24 Turning hydraulic motor 25 Reducer 26 Control valve 27 Driver's cab 28 Driver's seat 29 Entrance / exit 31 Boom 32 Boom cylinder 33 Arm 34 Arm cylinder 35 Bucket 36 Bucket cylinder 43 Spool valve (turning control device)
44 Tank 48a, 48b Relief valve 49a, 49b Check valve 50 Pilot pressure source 51 Gate lock valve 52 Swing operation device 53 Shuttle valve 54 Brake switching valve 55 Swing brake 56 Brake piston 58 Restriction (first delay device)
59 Emergency stop valve 60 Swing braking device 61 Brake switching device 62 Emergency stop device 63 Aperture (second delay device)
64 stop (first delay device)
70 Electric motor for turning 71 Inverter 72 Generator 73 Battery 74 Controller 75a, 75b Pressure sensor 90 Gate lock lever 91 Position sensor 92 Relay circuit 102a, 102b Oil passage 201 Pilot primary pressure line 202a, 202b Pilot secondary pressure line 203-205 Oil passage 206 Oil passage (first exhaust oil passage)
207 Oil passage (second exhaust oil passage)
208 oil passage (first exhaust oil passage)

Claims (5)

A turning motor for driving the turning body;
A turning control device that is controlled by a turning operation device to control a rotation direction and a rotation speed of the turning motor;
A gate lock lever provided at the driver's seat to open and close the entrance to the driver's seat;
When the gate lock lever is in the first position (closing the entrance / exit), the pilot pressure source communicates with the pilot primary pressure line to guide the pilot pressure source pressure to the pilot primary pressure line, and the turning The operation pilot pressure can be generated by a plurality of operation devices including the operation device, and when the gate lock lever is switched to the second position (opening the entrance / exit), the pilot pressure source and the pilot primary pressure line A swing brake device for a construction machine, comprising: a gate lock valve that makes the pilot primary pressure line communicate with a tank and disables the generation of the operation pilot pressure by the plurality of operation devices;
A turning brake that mechanically stops and holds the turning body by applying a braking force to the turning motor when the turning operation device is not operated. When pressure oil is supplied, the brake is turned off and the pressure oil is applied to the tank. A turning brake configured as a negative brake that is braked on when returned,
When the turning operation device is operated, the pilot primary pressure line is communicated with the turning brake, pressure oil from the pilot pressure source is supplied to the turning brake to turn the turning brake into a brake-off state, and the turning operation device is turned off. During operation, the pilot primary pressure line and the turning brake are disconnected from each other, the turning brake is connected to the tank via the first delay device, and the pressure oil of the turning brake is supplied to the tank via the first delay device. A brake switching device for returning and turning the turning brake to a brake-on state;
When the gate lock lever is switched to the second position and the gate lock valve connects the pilot primary pressure line to the tank, the gate lock lever operates based on a change in the pressure of the pilot primary pressure line, and the pressure of the swing brake An emergency stop device for returning oil to the tank earlier than the delay time of the first delay device and setting the swing brake to a brake-on state. In the turning brake device for the construction machine according to claim 1,
The emergency stop device includes a second delay device that is provided between the swing brake and the tank and has a delay time shorter than that of the first delay device, and supplies the pressure oil of the swing brake to the second delay device. A turning brake device for a construction machine, characterized by being returned to the tank via In the turning brake device for the construction machine according to claim 1,
The brake switching device includes a brake switching valve disposed in an oil passage that connects the pilot primary pressure line to the turning brake, and a first discharge oil passage that connects the turning brake to a tank via the first delay device. And
The emergency stop device has an emergency stop valve disposed between the brake switching valve, the turning brake and the tank,
The brake switching valve shuts off the communication between the pilot primary pressure line and the swing brake, based on the operation pilot pressure from the swing operation device, and the first position for communicating the pilot primary pressure line with the swing brake. Switch to the second position,
The emergency stop valve has a third position for communicating the brake switching valve and the turning brake and blocking the communication between the turning brake and the tank based on the pressure of the pilot primary pressure line, and the brake switching valve. And a swing brake device for a construction machine, wherein the swing brake can be switched to a fourth position where the swing brake is communicated with a tank via a second drain oil passage. In the turning brake device for the construction machine according to claim 1,
The brake switching device has a brake switching valve disposed in an oil passage connecting the pilot primary pressure line to the turning brake,
The emergency stop device has an emergency stop valve disposed between the brake switching valve, the turning brake and the tank,
The brake switching valve shuts off the communication between the pilot primary pressure line and the swing brake, based on the operation pilot pressure from the swing operation device, and the first position for communicating the pilot primary pressure line with the swing brake. Switch to the second position,
The emergency stop valve is configured to cause the brake switching valve and the swing brake to communicate with each other based on the pressure of the pilot primary pressure line, and to communicate the swing brake with the tank via the first discharge oil passage; , The communication between the brake switching valve and the turning brake can be cut off, and the turning brake can be switched to a fourth position where the turning brake is communicated with the tank via the second discharge oil passage.
The turning brake device for a construction machine, wherein the first delay device is disposed in the first discharge oil passage. In the turning braking device of the construction machine according to claim 3 or 4,
The emergency stop device further includes a second delay device having a shorter delay time than the first delay device,
The turning brake device for a construction machine, wherein the second delay device is arranged in the second oil discharge passage.

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