JP6119355B2 - Construction machine drive - Google Patents

Description

  The present invention relates to a drive device having a cooling / warming-up system that cools or warms a reduction gear of a swing drive device, for example, in a construction machine such as a hydraulic excavator or a hybrid excavator.

  The background art will be described by taking an excavator turning drive device as an example.

  The excavator is mounted on a crawler-type lower traveling body so that the upper swing body can swing around an axis that is perpendicular to the ground, and a work attachment is attached to the upper swing body.

  In this excavator, a swing drive device that swings the upper swing body is a hydraulic or electric motor as a drive source, and the rotational force of the motor is reduced by a gear reduction mechanism and transmitted to the upper swing body that is a driven part. It consists of a reducer.

  The motor and the speed reducer are provided side by side in the apparatus axis direction in a state where their rotation axes coincide with each other, and are attached to the upper frame in a vertically installed posture with the motor on top.

  The reduction gear is configured by providing a one-to-multi-stage planetary gear type reduction gear unit including a sun gear, a plurality of planetary gears, and a ring gear around a rotation shaft, and the output of the reduction gear is provided on the reduction gear output shaft. It is transmitted to the upper swing body through the pinion provided and the swing gear provided in the lower frame of the lower traveling body.

  Further, as disclosed in Patent Document 1, a brake mechanism (negative parking brake) may be provided in the speed reducer.

  This brake mechanism includes a brake piston, a brake spring, a pressure chamber, and both the rotation side and fixed side brake plates. When the motor (turning) stops, the brake piston is pressed by the spring force of the brake spring to press the brake plates together. Thus, a braking force is applied to the rotation shaft of the speed reducer, and the hydraulic oil from the hydraulic pump is introduced into the pressure chamber during the turning operation, and the brake force is released by pushing the brake piston in the opposite direction.

  The brake mechanism is connected to a hydraulic pump pump and a brake circuit that connects the tank and the pressure chamber. The brake circuit is provided with a brake switching valve that controls supply and discharge of hydraulic oil in conjunction with the operation of the turning lever. .

  On the other hand, lubricating oil is enclosed in the reduction gear housing of the reduction gear, and the lubricating action of the reduction portion is performed.

  Here, during operation, the speed reducer generates heat, and the temperature of the lubricating oil also increases, so a cooling system that cools the speed reducer including the lubricating oil is employed.

  The cooling system also functions as a warm-up system that warms the speed reducer at low temperatures, so that it is actually a cooling / warm-up system.

  As this cooling / warming-up system, as shown in Patent Document 1, a medium passage is provided in a reduction gear casing, and a cooling / warming-up medium such as water or oil is allowed to flow through this medium passage to reduce the speed including lubricating oil. Techniques for cooling / warming up the entire machine from the outer periphery are known.

  In addition, as shown in Patent Document 2, a technique in which a heat exchanger is immersed in lubricating oil and a medium is passed through the heat exchanger is also known.

Japanese Patent No. 4504899 JP2012-112122A

  According to the known technology, the medium always flows while the engine is running, and it continues to operate even when cooling / warming-up of the swing drive is not necessary (when the swing is stopped), resulting in energy loss.

  Further, since a dedicated hydraulic pump, tank and piping for circulating the medium have to be added from scratch, the cost is greatly increased and extra space including piping space is required.

  In order to avoid the above energy loss, the temperature should be controlled so that the medium flows only when necessary, that is, during the turning operation. In this case, a controller for temperature management and a dedicated switching valve are added. As a result, the cost is further increased and the space for additional equipment is increased.

  Accordingly, the present invention provides a drive device for a construction machine that prevents energy loss by operating a cooling / warming-up action only when necessary, can minimize the number of additional equipment, and does not require equipment for temperature management. is there.

As means for solving the above problems, in the present invention, a hydraulic or electric motor as a drive source, a speed reducer that transmits the rotational force of the motor to the driven part at a reduced speed, and a rotating shaft of the speed reducer comprising a brake mechanism for applying braking force, the heat exchanger provided within the reducer for cooling / warming-up of the reduction gear, the brake mechanism, together with the brake piston, the pressing force of the brake piston Both the rotating and fixed brake plates that exert pressure by pressure contact, the brake spring that presses the brake piston in the brake operation direction, and hydraulic oil is introduced when the motor rotates to press the brake piston in the brake release direction Hydraulic oil supply having a pressure chamber for generating a brake release pressure and supplying hydraulic oil for releasing the brake to the pressure chamber of the brake mechanism In the construction machine driving device, the hydraulic oil supply pipe is provided with a brake switching valve that switches supply / stop of hydraulic oil to the pressure chamber according to rotation / stop of the motor. A cooling / warming circuit for cooling / warming the speed reducer is provided by diverting the hydraulic oil supplied to the chamber downstream from the brake switching valve and returning it to the tank via the heat exchanger. A pressure holding valve for holding the pressure chamber at the brake release pressure is provided in the cooling / warming circuit.

According to this configuration, the hydraulic oil for releasing the brake is introduced into the pressure chamber of the brake mechanism during the turning operation, and the hydraulic oil is diverted to the cooling / warming circuit, and the heat exchanger provided in the speed reducer is installed. Since it passes through and returns to the tank, the speed reducer including the lubricating oil can be cooled / warmed up.

  That is, a cooling / warming-up system is configured using a brake mechanism, a hydraulic pump and tank for the brake mechanism, and a switching valve.

  In this case, the hydraulic oil is supplied and circulated only during the turning operation, and is not supplied or circulated when the turning is stopped. In other words, the cooling / warming-up action works only during the turning operation requiring cooling / warming, Other than that, it does not work during operation that does not require cooling / warming-up of the swivel drive device (during idling, traveling, and attachment work without swiveling), thus avoiding wasted energy and saving energy.

  Further, since the pressure in the pressure chamber can be held at the brake release pressure by the pressure holding valve, it is possible to ensure the brake performance originally required for the brake mechanism.

  Furthermore, since there is no need for temperature management, neither temperature management equipment nor control is required, and additional equipment is only a return line connecting the pressure chamber and the tank and a pressure holding valve. It is possible to reduce the number of additional facilities to the minimum necessary, including that they are no longer required, and to suppress an increase in cost and an increase in necessary space.

  In the present invention, it is desirable to provide a throttle that generates the brake release pressure by reducing the flow rate of the hydraulic oil as the pressure holding valve.

  According to this configuration, when the temperature of the hydraulic oil is low, the oil viscosity is high and the passing flow rate (circulation flow rate) is reduced due to the restriction as the pressure holding valve. That is, neither the lubricating oil nor the speed reducer needs to be cooled at a low temperature. Rather, in a situation where it is desirable to warm up, the cooling performance naturally decreases, so that it can be warmed up quickly.

  In this case, it is desirable to provide the throttle on the inlet side of the heat exchanger in the cooling / warming circuit (claim 3).

  In this way, the pressure inside the heat exchanger can be kept at a low pressure while maintaining the pressure in the pressure chamber at the brake release pressure, so that it is not necessary to increase the pressure resistance specification of the heat exchanger more than necessary.

  According to the present invention, the cooling / warming-up action can be performed only when necessary to prevent energy loss, and the additional equipment can be reduced to the minimum, and the equipment for temperature management can be made unnecessary.

It is a circuit block diagram of the said drive device concerning embodiment of this invention. It is a circuit block diagram of the conventional turning drive device.

  The embodiment is applied to an excavator turning drive device.

  FIG. 1 shows an embodiment, and FIG. 2 shows a circuit configuration of each conventional turning drive device.

  First, these common parts will be described.

  Both devices are constituted by a turning motor circuit 2 including a turning hydraulic motor 1 and a speed reducer 3 that decelerates the rotational force of the hydraulic motor 1 and transmits it to an upper turning body (not shown) as a driven part. The

  The turning motor circuit 2 is operated by a turning hydraulic pump (hereinafter referred to as a turning pump) 4, both side pipes 5 and 6 connecting the turning pump 4 and the motor 1, and a remote control valve (not shown) to the motor 1. The control valve 7 controls oil supply / discharge, a pair of relief valves 8 and 9 as brake valves, and a pair of check valves 10 and 11 for preventing cavitation. Reference numeral 12 denotes a return pipe, and 13 denotes an oil cooler provided in the return pipe 12.

  The speed reducer 3 includes one to a plurality of stages of planetary gear type speed reducers (only one stage is shown in the figure) 14 and contains lubricating oil therein.

  The speed reduction unit 14 includes sun, planetary, and ring gears S, P, and R. As is well known, the planetary gear P performs a revolving motion while rotating, and the output of the speed reduction unit 14 is reduced. The shaft 15, the pinion 16, and a revolving gear (not shown) meshing with the shaft 15 are transmitted to an upper frame (upper revolving body) as a driven portion.

  A negative brake mechanism 17 for stopping and holding the upper swing body is provided in the speed reducer 3.

  The brake mechanism 17 includes a brake spring 18, a brake piston 19 that is pressed downward by the brake spring 18, a pressure chamber 20 into which hydraulic oil is introduced during a turning operation, and a vertical position below the brake piston 19. It consists of both the rotating shaft side and fixed side brake plates 21 and 22 arranged, and hydraulic oil is introduced into the pressure chamber 20 during the turning operation, and a brake release pressure is established. As a result, the brake piston 19 rises and the brake is released.

  On the other hand, when the turning is stopped, the brake release pressure is released to the tank T, and the brake plates 19 and 22 are pressed against each other by the pressing force of the brake piston 19 by the spring force of the brake spring 18 to exert the braking force. Thus, the upper swing body is stopped and held.

  Further, a hydraulic brake circuit is provided for introducing hydraulic oil into the pressure chamber 20 during the turning operation.

  This hydraulic brake circuit includes a hydraulic pump 24 for releasing a brake driven by the engine 23 together with the swing pump 4, a hydraulic oil supply line 25 connecting the hydraulic pump 24 and the tank T and the pressure chamber 20, and this operation. It is constituted by a brake switching valve 26 provided in the oil supply pipe 25.

  The brake switching valve 26 is configured as an electromagnetic switching valve that switches between a hydraulic oil supply position A and a tank position B in response to a signal from a controller (not shown) based on the operation / non-operation of the swing operation lever, and operates when the swing operation is performed. It is set at the oil supply position (a) and at the tank position (b) when turning is stopped.

  At the hydraulic oil supply position a, the hydraulic oil discharged from the hydraulic pump 24 is supplied to the pressure chamber 20, and when the brake release pressure is raised, the brake piston 19 rises and the brake is released. At the tank position B, the pressure chamber 20 The hydraulic oil is discharged into the tank T, the brake piston 19 is lowered by the spring force, and the brake is activated.

  Further, a heat exchanger 27 for cooling / warming up the reduction gear 3 including the lubricating oil is provided in the reduction gear 3.

  The heat exchanger 27 may be incorporated in the casing of the speed reducer 3 as an independent flat box or spiral tube, or may be configured by providing a medium passage in a part of the peripheral wall of the speed reducer casing.

  Here, in the conventional apparatus shown in FIG. 2 (for example, known techniques described in Patent Documents 1 and 2), a cooling / warming circuit that circulates a medium such as water or oil in a path passing through the heat exchanger 27 by a dedicated pump. Are configured independently, and the medium is always passed through the heat exchanger 27 during engine operation.

  For this reason, as described above, since there is no need for cooling / warming-up of the turning drive device (when turning is stopped), it continues to operate, causing problems such as energy loss.

  On the other hand, in the embodiment apparatus shown in FIG. 1, a cooling / warming circuit 28 that diverts the hydraulic oil supplied to the pressure chamber 20 of the brake mechanism 17 during the turning operation and returns the hydraulic oil to the tank via the heat exchanger 27 is provided. Provided.

  That is, a cooling / warming-up hydraulic oil introduction pipe 29 is branched and connected downstream of the brake switching valve 26 in the hydraulic oil supply pipe 25 constituting the hydraulic brake circuit, and the hydraulic oil introduction pipe 29 is heated. In addition to being connected to the inlet of the exchanger 27, the outlet of the heat exchanger 27 is connected to the return line 12 (tank T) of the motor circuit 2 by a tank line 30.

  In addition, a throttle (synonymous with a throttle valve) 31 as a pressure holding valve is provided in the hydraulic oil introduction conduit 29 (on the inlet side of the heat exchanger 27 in the cooling / warming circuit 28), and the flow rate of the hydraulic oil is reduced by this throttle 31. The pressure chamber 20 is configured to be held at the brake release pressure by being throttled.

  According to this configuration, the hydraulic oil for releasing the brake is introduced into the pressure chamber 20 of the brake mechanism 17 during the turning operation, and the hydraulic oil is diverted to the cooling / warming circuit 28 and passes through the heat exchanger 27. By returning to the tank T, the speed reducer 3 including the lubricating oil is cooled or warmed up.

  That is, when the temperature of the lubricating oil and the speed reducer 3 is higher than the temperature of the hydraulic oil, such as during a turning operation (particularly during a turning operation with a high load), the cooling function works, so The warm-up function works in situations where the temperature of the lubricating oil or the speed reducer 3 is lower than the hydraulic oil temperature as in the case of time.

  Thus, a cooling / warming-up system using the brake mechanism 17, the hydraulic pump 24, the tank T, and the brake switching valve 26 for that purpose is configured.

  In this case, the hydraulic oil is supplied and circulated only during the turning operation by the switching operation of the brake switching valve 26, and is not supplied or circulated when the turning is stopped. In other words, the cooling / warming-up action is It works only during turning operations that require cooling, and does not work during other operations that do not require cooling / warming-up of the turning drive (when idling, running, or attachment work without turning). Avoid wasting money and save energy.

  Further, since the pressure in the pressure chamber 20 can be maintained at the brake release pressure by the throttle 31, the brake performance originally required for the brake mechanism 17 can be ensured.

  Furthermore, since there is no need for temperature management, neither equipment for temperature management nor control is required, and additional equipment is only a branched hydraulic oil introduction line 29, tank line 30, and throttle 31, so that a dedicated pump In addition, additional equipment including the need for a tank can be reduced to the minimum necessary, and an increase in cost and an increase in necessary space can be suppressed.

  In this case, since the throttle 31 is used as a pressure holding valve, when the temperature of the hydraulic oil is low (viscosity is high), the passage flow rate (circulation flow rate) decreases. That is, neither the lubricating oil nor the speed reducer 3 needs to be cooled at a low temperature. Rather, in a situation where it is desirable to warm up, the cooling performance naturally decreases, so that it can be warmed up quickly.

  In addition, since the throttle 31 is provided on the inlet side of the heat exchanger 27 in the cooling / warming-up circuit 28, the inside of the heat exchanger 27 is kept at a low pressure while maintaining the pressure in the pressure chamber 20 at the brake release pressure. Therefore, it is not necessary to make the pressure resistance specification of the heat exchanger 27 higher than necessary.

Other embodiments
(1) The pressure holding valve may basically be a valve that can secure the brake release pressure in the pressure chamber 20, and is not limited to the throttle 31 mentioned in the above embodiment, but other pressure such as a relief valve (safety valve). A control valve may be used.

  (2) The present invention is not limited to the shovel drive device for excavators, and is widely applied to other swing-type construction machine swivel drive devices and drive devices with a brake mechanism other than the swivel drive device that require a cooling / warming function. Can be applied.

DESCRIPTION OF SYMBOLS 1 Hydraulic motor for rotation 3 Reduction gear 4 Hydraulic pump for rotation 17 Brake mechanism 18 Brake spring 19 Brake piston 20 Pressure chamber 21, 22 Brake plate 24 Hydraulic pump for brake release 25 Hydraulic oil supply line 26 Brake switching valve 27 Heat exchanger 28 Cooling / warming circuit 29 Hydraulic oil introduction line 30 Tank line 31 Throttle as pressure holding valve T Tank

Claims (3)

A hydraulic or electric motor as a driving source, a reduction gear that transmits by reducing the rotational force of the motor to the driven parts, and the brake mechanism for applying a braking force to the rotation shaft of the reduction gear, in the speed reducer Provided with a heat exchanger that cools / warms the speed reducer , and the brake mechanism includes a brake piston and a rotating side and a fixed side that press against each other by a pressing force of the brake piston to exert a braking force. Both brake plates, a brake spring that presses the brake piston in the brake operating direction, a pressure chamber that generates a brake release pressure that introduces hydraulic oil when the motor rotates and presses the brake piston in the brake release direction, and , A hydraulic oil supply line for supplying hydraulic oil for releasing the brake to the pressure chamber of the brake mechanism is provided, and the motor is connected to the hydraulic oil supply line. In a construction machine drive device provided with a brake switching valve that switches supply / stop of hydraulic oil to / from the pressure chamber according to rotation / stop, hydraulic fluid supplied to the pressure chamber is downstream of the brake switching valve. Is provided with a cooling / warming circuit that cools / warms the speed reducer by returning to the tank via the heat exchanger, and the pressure chamber is set to the brake release pressure in the cooling / warming circuit. A construction machine drive device comprising a pressure holding valve for holding.   2. The drive device for a construction machine according to claim 1, wherein the pressure holding valve is provided with a throttle that generates the brake release pressure by reducing the flow rate of hydraulic oil. The drive device for a construction machine according to claim 2, wherein the throttle is provided on an inlet side of the heat exchanger in the cooling / warming-up circuit.

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