JP2010209637A - Brake device of electric turning type working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To convert a negative brake to a brake-on state promptly and securely even if there occurs such a situation that a brake selector valve is not switched from a brake-off position to a brake-on position due to a failure or the like of a control means. <P>SOLUTION: The brake device is constituted by providing the brake selector valve 19 to a brake line 18 connecting a hydraulic pump 11 and a tank T and the brake cylinder 16 of the negative brake 15, and the brake selector valve switches the brake-off position (i) and the brake-on position (ii). A pressure relief circuit 24 which brings about a brake-on state by releasing the hydraulic pressure of the negative brake 15 to the tank T is connected to the brake line 18. A throttle 25 and a flow regulating valve 26 are provided at the pressure relief circuit 24, and the opening of the flow regulating valve varies in accordance with a pressure difference between the front and the rear of the throttle 25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a brake device that brakes a turning body with a negative brake in an electric turning work machine such as an excavator that drives the turning body to turn with an electric motor.

  An explanation will be given using an excavator as an example.

  As shown in FIG. 3, the excavator has an upper swing body 2 mounted on a crawler-type lower traveling body 1 so as to be rotatable around a vertical axis O. The upper swing body 2 has a boom 3, an arm 4, and a bucket 5. The excavation attachment A including the cylinders 6, 7, and 8 for the boom, arm, and bucket is mounted.

  In this excavator, an electric turning method using an electric motor as a turning drive source is known.

  In this electric turning method, unlike the hydraulic turning method in which the turning body is driven by a hydraulic motor, a brake device is required because the electric motor itself has no stop holding force.

  On the other hand, a negative brake is used as a turning brake device, that is, a brake is turned off when a hydraulic pressure is applied, and a mechanical brake that brakes the upper turning body 2 by a spring force when the hydraulic pressure is released (hereinafter referred to as a negative brake). Is known.

  And the technique which employ | adopted the negative brake in the electric turning system is also well-known as shown in patent document 1. FIG.

  This known technique will be described with reference to FIG.

  In this known technique, the engine 9 drives the main pump 10 and the brake pump 11 as a brake hydraulic pressure source, and the main pump 10 drives the hydraulic actuators including the hydraulic cylinders 6 to 8 of the excavation attachment A, A hydraulic / electric combined system is used in which a generator (not shown) is connected in parallel with the main pump 10 and the swing motor 12 is driven using the generator and a battery as a power source.

  The swing motor 12 is driven by a command current from the inverter 14 based on a command from the controller 13.

  The swing motor 12 is provided with a negative brake 15, and the rotational force of the swing motor 12 is transmitted to the upper swing body 2 via the speed reduction mechanism in a state where the negative brake 15 is turned off (brake release). Turns.

  The negative brake 15 is urged in the extending direction of the cylinder 16 with the brake cylinder (hydraulic cylinder) 16 being contracted to be in a brake-off state when the hydraulic pressure is applied, and with the hydraulic pressure removed from the brake cylinder 16. And a brake spring 17 that exhibits braking force.

  As a means for controlling the negative brake 15, an electromagnetic brake switching valve 19 is provided on the brake line 18 connecting the brake pump 11 and the tank T and the brake cylinder 16.

  The brake switching valve 19 is switched between the brake-off position A and the brake-on position B by a command signal input from the controller 13 to the electromagnetic operation unit 19a via the signal line 20, and is braked at the illustrated brake-off position A. The hydraulic pressure from the pump 11 is sent to the brake cylinder 16 and the brake is turned off, and the hydraulic pressure in the cylinder 16 is released to the tank T at the brake on position B and the brake is turned on.

  Reference numeral 21 denotes a turning lever as a turning operation means. The operation of the turning lever 21 is converted into a hydraulic signal (pilot pressure) by the pilot valve 22 and further converted into an electric signal by the pressure sensors 23 and 23 and input to the controller 13. .

  Thus, when the lever is operated, the brake switching valve 19 is switched to the brake-off position A, the negative brake 15 is turned off, and the turning operation is performed. On the other hand, when the lever is not operated (neutral), the brake switching valve 19 is moved to the brake-on position. The negative brake 15 is turned on and the upper swing body 2 is stopped and held.

  As another technique related to a turning brake device using a negative brake, as shown in Patent Document 2, in a brake circuit using a hydraulic turning type and a manual brake switching valve, a brake cylinder and a tank are provided. A technique is known in which a throttle is provided in the tank line to be connected, and when the brake switching valve is erroneously operated during turning, the oil release from the brake cylinder is delayed by the throttle to alleviate the shock of switching to brake on.

JP 2004-36303 A Japanese Utility Model Publication No. 3-46554

  However, according to the known technique of Patent Document 1, if the brake switching valve 19 is not switched from the brake-off position A to the brake-on position B due to a failure of the controller 13 or disconnection of the signal line 20, the brake function is lost. Is called.

  In this case, when the engine 9 is stopped, the supply of pressure oil from the brake pump 11 to the brake cylinder 16 is stopped, and the oil in the cylinder 16 escapes to the tank T due to leakage from the brake switching valve 19 and the like as time elapses. The brake turns on, but the upper swing body 2 cannot be stopped and held until then.

  Note that when the known technique disclosed in Patent Document 2 is diverted to the electric swing type, even if a situation occurs in which the brake switching valve 19 is not switched to the brake-on position B, the oil in the brake cylinder 16 passes through the throttle. Since the tank T comes off, the brake turns on.

  However, since the flow rate through the throttle (the time required until the brake is turned on) depends on the viscosity of the oil, it takes time until the brake is turned on at a low temperature where the viscosity of the oil becomes high, and the necessary stop / hold function cannot be obtained. There is a fear.

  Therefore, the present invention can quickly and reliably switch the negative brake to the brake-on state even when the brake switching valve does not switch to the brake-off position or the brake-on position due to a failure of the control means. The present invention provides a brake device for a swivel work machine.

  According to the first aspect of the present invention, an upper swing body that is swiveled by a swing motor is mounted on a lower traveling body, and the upper swing body is braked by a negative brake that is braked off when hydraulic pressure is applied. The brake switching valve is provided in the brake line connecting the hydraulic pump and the tank and the negative brake. The brake switching valve is controlled by the control means so as to turn off the negative brake when the turning operation is performed. In a brake device for an electric swivel work machine configured to switch between a brake-on position where the negative brake is in a brake-on state when not operated, the hydraulic pressure of the negative brake is drained into the tank at the brake line. A pressure release circuit is connected to turn off the brake. The road, in which a stop, a flow rate adjusting valve opening degree is changed in a direction in which the opening degree large in difference 圧大 according to differential pressure across the diaphragm is provided.

  According to a second aspect of the present invention, in the configuration of the first aspect, as the control means, an electric motor controller that controls the turning electric motor via an inverter according to a turning operation and a non-operation, and a turning operation and a non-operation And a switching valve controller for switching the brake switching valve between the brake-off and brake-on positions.

  According to the present invention, in the configuration in which the brake switching valve is provided in the brake line connecting the hydraulic pump and the tank and the negative brake (hereinafter referred to as negative brake in accordance with the description of the background art), the hydraulic pressure of the negative brake is applied to the brake line. A pressure release circuit that connects the tank to the brake and puts it in a brake-on state is connected. The pressure release circuit is provided with a throttle and a flow rate adjustment valve that changes its opening according to the differential pressure before and after the throttle. When a situation occurs in which the brake switching valve does not switch from the brake-off position to the brake-on position due to a malfunction or the like, the hydraulic pressure of the negative brake is released to the tank via the pressure release circuit.

  As a result, the negative brake automatically switches to the brake-on state, so that the upper-part turning body can be stopped and held.

  In addition, a flow control valve is provided that automatically changes the opening according to the differential pressure before and after the throttle, so if the oil viscosity is high at low temperatures, the differential pressure before and after the throttle increases and the flow control valve opens. Increases and the amount of oil drained into the tank increases. That is, the time until the negative brake is activated is constant regardless of the viscosity of the oil.

  Thereby, a reliable fail-safe function is obtained, and the upper-part turning body can be reliably stopped and held.

  Further, according to the invention of claim 2, as the control means, an electric motor controller for controlling the electric motor and a switching valve controller for controlling the brake switching valve are provided, and the control system is divided into two systems of the brake system and the electric motor system. The motor system remains alive even when the brake system fails, and the brake system remains alive even when the motor system fails.

  For this reason, in a situation where the brake system is not switched on due to a failure in the brake system, the motor is controlled to be stopped by the motor control (for example, “in-situ holding control”) until the negative brake is turned on by the pressure release circuit. The turning motion itself can be ensured.

  On the other hand, even when the electric motor system fails, it is possible to ensure the stop holding action by the negative brake.

It is a circuit block diagram which shows 1st Embodiment of this invention. It is a circuit block diagram which shows 2nd Embodiment of this invention. It is a schematic side view of the shovel which is an example to which the present invention is applied. It is a conventional circuit block diagram.

  In the following embodiment, the same parts as those in FIG. 4 are denoted by the same reference numerals, and redundant description thereof is omitted.

1st Embodiment (refer FIG. 1)
In the first embodiment, the hydraulic pressure of the brake cylinder 16 is set downstream of the brake switching valve 19 (negative brake 15 side) in the brake line 18 connecting the hydraulic pump 11 and the tank T and the brake cylinder 16 of the negative brake 15. A pressure release circuit 24 is connected to the tank T.

  The pressure release circuit 24 is provided with a throttle 25 and a flow rate adjustment valve 26 in series.

  The flow rate adjusting valve 26 automatically changes its opening degree in a direction in which the opening degree increases with a large differential pressure in accordance with the differential pressure before and after the throttle 25 (P1-P2). The passage flow rate changes according to

  Further, in the conventional apparatus shown in FIG. 4, the swing motor 12 and the brake switching valve 19 are controlled by a single controller 13, whereas in the first embodiment, when the swing lever 21 is operated as a control means. An electric motor controller 27 that controls the turning electric motor 12 via the inverter 14 in response to non-operation (neutral), and a brake switching valve 19 in both brake-off and brake-on positions depending on whether the lever is operated or not. A brake controller 28 for switching between a and b is provided.

  According to this configuration, the brake switching valve 19 does not switch from the brake-off position B to the brake-on position B due to a failure of the brake controller 28 or a disconnection of the signal line 20 even though the turning lever 21 is neutral. In this case, if the engine 9 (brake pump 11) is stopped, the hydraulic pressure of the brake cylinder 16 is discharged to the tank T via the pressure release circuit 24.

  Thereby, since the negative brake 15 automatically switches to a brake-on state, the upper-part turning body 2 can be stopped and held.

  In addition, since the opening degree of the flow rate adjusting valve 26 automatically changes according to the differential pressure before and after the throttle 25, if the oil viscosity is high at low temperatures, the differential pressure before and after the throttle increases, and the flow rate adjusting valve 26 The opening degree increases, and the passage flow rate (the amount of oil withdrawn to the tank T) increases. That is, the time until the negative brake 15 is activated is constant regardless of the viscosity of the oil.

  Thereby, a reliable fail-safe function is obtained and the upper-part turning body 2 can be reliably stopped and held.

  In addition, since the control system is divided into two systems, that is, the motor system by the motor controller 27 and the brake system by the brake controller 28, the motor system is alive even when the brake system fails, and the brake system is alive even when the motor system fails. Become.

  Therefore, in a situation where the negative brake 15 is not switched on due to a failure of the brake system, the motor control by the motor system (for example, “in-situ holding control” is performed until the negative brake 15 is turned on by the pressure release circuit 24. ") Makes it possible to stop and hold, and to ensure the turning motion itself.

  On the other hand, even when the motor system is out of order, it is possible to ensure the stop holding action by the negative brake 15.

Second embodiment (see FIG. 2)
Only differences from the first embodiment will be described.

  In the second embodiment, the same pressure release circuit 24 as that in the first embodiment is connected to the brake line 18 on the upstream side (pump 11 side) of the brake switching valve 19. Has been.

  Even with this configuration, even if the brake switching valve 19 does not switch from the brake-off position A to the brake-on position B, the hydraulic pressure of the brake cylinder 16 is switched when the engine 9 (brake pump 11) is stopped. Since the tank T is extracted by the pressure release circuit 24 via the valve 19, the fail-safe function can be achieved as in the first embodiment.

  The control system is divided into an electric motor system by the electric motor controller 27 and a brake system by the brake controller 28, and the operation and effect by this are the same as in the first embodiment.

  In both the first and second embodiments, the throttle 25 of the pressure relief circuit 24 has an opening degree at which a sufficient pressure is generated in the brake cylinder 16 to overcome the brake spring 17 and make the brake off state during the turning operation. Set to

Other Embodiments (1) In both the above embodiments, a means for detecting that an abnormality such as a failure has occurred in both the motor system and the brake system, and an alarm is issued when the abnormality is detected, or the engine 9 is forced You may make it stop.

  (2) When the engine 9 is forcibly stopped when an abnormality occurs as described above, or when the engine 9 is stopped during normal operation, the brake is switched before the engine is stopped as a dual fail-safe function with the pressure relief circuit 24. The valve 19 may be configured to be switched to the brake-on position a.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving body 9 Engine 11 Brake pump 12 Turning electric motor 14 Inverter 15 Negative brake 16 Brake cylinder 17 Brake spring 18 Brake line 19 Brake switching valve 21 Swing lever 22 Pilot valve 23 Pressure sensor 24 Depressurization circuit 25 Restriction 26 Flow control valve 27 Electric motor controller 28 Brake controller

Claims (2)

  An upper swing body that is swiveled by a swing motor is mounted on the lower traveling body, and the upper swing body is braked by a negative brake that is braked off when hydraulic pressure is applied. A brake switching valve is provided in the brake line connecting to the negative brake, and the brake switching valve controls the brake off position where the negative brake is in a brake-off state when the turning operation is performed, and the negative brake is braked when the turning is not operated. In the brake device for an electric swing work machine configured to be switched between a brake-on position to be turned on, a pressure release to release the hydraulic pressure of the negative brake to the tank to the brake line in the brake line A circuit is connected. Electric slewing type working machine braking device, wherein a flow regulating valve which is opening in a direction in which the opening degree large in difference 圧大 changes provided in accordance with the differential pressure across the diaphragm.   As the control means, an electric motor controller that controls the turning electric motor via an inverter according to turning operation and non-operating operation, and the brake switching valve to brake off and brake on according to turning operation and non-operating operation. 2. The brake device for an electric swing work machine according to claim 1, further comprising a switching valve controller that switches between both positions.

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