JP2013208040A - Turning drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turning drive unit capable of cooling an electric motor efficiently with a simple structure.SOLUTION: A turning drive unit 40 for driving the turning body 3 of an excavator includes a vertical electric motor 21 for turning, and a cooling medium circulation device 60 for sucking and discharging the cooling medium by using the torque of the rotating shaft 21A of the vertical electric motor 21 as a power source. The cooling medium circulation device 60 includes a pump having a spiral vane 62 formed coaxially on the rotating shaft 21A of the vertical electric motor 21. The vertical electric motor 21 is cooled with the cooling medium which is sucked or discharged by the cooling medium circulation device 60.

Description

  The present invention relates to a turning drive device that drives a turning mechanism of an excavator.

  In general, a shovel that performs excavation work or the like is provided with a swivel body, and a boom, an arm, and a bucket for performing the excavation work are provided on the swivel body. By rotating the revolving structure, the bucket is moved to an arbitrary position around the shovel. An electric motor may be used as a drive source of a turning drive device for turning the turning body. Driving the turning body with the turning electric motor is called electric turning.

  The output shaft of the turning electric motor is connected to the input shaft of the turning mechanism via a turning transmission. As the electric motor for turning, an electric motor having a high rotational speed is used in order to achieve a small size and high output, and therefore, a planetary gear mechanism having a large reduction ratio is often used as the turning transmission.

  Further, when the electric motor for turning is not driven, the electric motor for turning is in a state where it can freely rotate, so it is necessary to mechanically brake and fix the turning body. For this reason, a brake device (referred to as a mechanical brake) that mechanically brakes the output shaft of the turning transmission is often provided in the vicinity of the turning transmission.

  In the swivel drive device configured as described above, the electric motor serving as a drive source generates heat during driving and needs to be cooled. Accordingly, it has been proposed to connect a gear pump to the rotating shaft of the electric motor and to cool the electric motor by supplying cooling oil discharged from the gear pump to the rotor through an oil passage formed in the rotating shaft (for example, , See Patent Document 1).

JP 2007-20337 A

  In the cooling structure of the electric motor disclosed in Patent Document 1, a gear pump is provided at one end of the rotating shaft of the electric motor, and a through hole is formed in the rotating shaft and the rotor. Therefore, there is a problem that the structure of the electric motor is complicated and the cost of the turning drive device is increased.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a turning drive device that can efficiently cool an electric motor with a simple structure.

  According to an embodiment of the present invention, there is provided a turning drive device for driving a turning body of an excavator, and cooling is performed using a vertical electric motor for turning and a rotational force of a rotating shaft of the vertical electric motor as a power source. A cooling medium circulation device that sucks and discharges the medium, and the cooling medium circulation device includes a pump in which spiral blades are formed on the concentric shaft of the rotating shaft of the vertical electric motor. A featured swivel drive is provided.

  According to the above-described invention, it is possible to provide a turning drive device that can efficiently cool a vertical electric motor with a simple structure.

It is a side view of the shovel in which the turning drive device by one Embodiment of this invention is integrated. It is a block diagram which shows the structure of the drive system of the shovel shown in FIG. It is a block diagram which shows the structure of the turning drive device by one Embodiment of this invention. It is sectional drawing of a turning drive device. It is a figure which shows the flow of the lubricating oil in the turning drive device at the time of low speed rotation. It is a figure which shows the flow of the lubricating oil in the turning drive device at the time of high speed rotation. It is a block diagram which shows the structure of the modification of a turning drive device.

  First, an overall configuration of a shovel incorporating a turning drive device according to an embodiment of the present invention and a configuration of a drive system will be described. FIG. 1 is a side view showing an excavator as an example of an excavator in which a turning drive device according to an embodiment of the present invention is incorporated.

  An upper swing body 3 is mounted on a lower traveling body 1 of the shovel shown in FIG. A boom 4 is attached to the upper swing body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5. The boom 4, the arm 5, and the bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. The upper swing body 3 is provided with a cabin 10 and is mounted with a power source such as an engine.

  The excavator shown in FIG. 1 is an excavator having a power storage device that stores electric power to be supplied to the turning drive device. The present invention can also be applied to an excavator.

  FIG. 2 is a block diagram showing the configuration of the drive system of the shovel shown in FIG. In FIG. 2, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a solid line.

  An engine 11 as a mechanical drive unit and a motor generator 12 as an assist drive unit are respectively connected to two input shafts of a transmission 13. A main pump 14 and a pilot pump 15 are connected to the output shaft of the transmission 13 as hydraulic pumps. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16. An operation device 26 is connected to the pilot pump 15 via a pilot line 25.

  The control valve 17 is a control device that controls a hydraulic system in the hybrid excavator. The hydraulic motors 1A (for right) and 1B (for left), the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 for the lower traveling body 1 are connected to the control valve 17 via a high-pressure hydraulic line.

  The motor generator 12 is connected to a power storage system (power storage device) 120 including a capacitor as a battery via an inverter 18A. The electric storage system 120 is connected to a turning electric motor 21 as an electric work element via an inverter 20. A turning transmission 24 is connected to the rotating shaft 21 </ b> A of the turning electric motor 21. A mechanical brake 23 is connected to one end of the output shaft 24 </ b> A of the turning transmission 24. A cooling lubrication device 60 is connected to the other end of the output shaft 24 </ b> A of the turning transmission 24. The cooling lubricating device 60 is a device that circulates while cooling the lubricating oil in the turning electric motor 21 as will be described later. The turning drive device 40 is configured by the turning electric motor 21, the turning transmission 24, and the cooling lubrication device 60. As will be described later, the turning drive device 40 may include a mechanical brake 23. Here, the turning electric motor 21 corresponds to a turning electric motor for driving the upper turning body 3 to turn, and the mechanical brake 23 corresponds to a brake device that mechanically brakes the upper turning body 3. The output shaft 23A of the mechanical brake 23 (that is, the rotating shaft 24A of the turning transmission 24) is connected to the turning mechanism 2 described above, and the turning mechanism 2 is driven by the rotational force (power) of the output shaft 23A of the mechanical brake 23. The upper turning body 3 turns.

  The operating device 26 includes a lever 26A, a lever 26B, and a pedal 26C. The lever 26A, the lever 26B, and the pedal 26C are connected to the control valve 17 and the pressure sensor 29 via hydraulic lines 27 and 28, respectively. The pressure sensor 29 is connected to a controller 30 that performs drive control of the electric system.

  The controller 30 is a control device as a main control unit that performs drive control of the hybrid excavator. The controller 30 is configured by an arithmetic processing unit including a CPU (Central Processing Unit) and an internal memory, and is realized by the CPU executing a drive control program stored in the internal memory.

  The controller 30 converts the signal supplied from the pressure sensor 29 into a speed command, and performs drive control of the turning electric motor 21. The signal supplied from the pressure sensor 29 corresponds to a signal indicating an operation amount when the operation device 26 is operated to turn the turning mechanism 2.

  The controller 30 performs operation control (switching between electric (assist) operation or power generation operation) of the motor generator 12 and also performs charge / discharge control of the capacitor by drivingly controlling the step-up / down converter of the power storage system 120. Based on the charging state of the capacitor, the operation state of the motor generator 12 (electric (assist) operation or power generation operation), and the operation state of the turning motor 21 (power running operation or regenerative operation), the controller 30 Switching control between the step-up / step-down operation of the step-up / step-down converter is performed, thereby performing charge / discharge control of the capacitor. The controller 30 also controls the amount of charging (charging current or charging power) of the capacitor as will be described later.

  The rotational speed (angular speed ω) of the turning electric motor 21 is detected by a resolver. Further, the angle of the boom 4 (boom angle θB) is detected by a boom angle sensor 7B such as a rotary encoder provided on the support shaft of the boom 4. The controller 30 calculates the estimated turning regenerative power (energy) based on the angular velocity ω of the turning electric motor 21 and calculates the estimated boom regenerative power (energy) based on the boom angle θB. Then, the controller 30 obtains an estimated regeneration target value for the SOC based on the estimated turning regenerative power and the estimated boom regenerative power obtained by the calculation. The controller 30 controls each part of the hybrid excavator so as to bring the SOC of the capacitor 19 close to the calculated expected regeneration target value.

  In the work by the hybrid excavator having the above-described configuration, the turning electric motor 21 is driven by the electric power supplied via the inverter 20 in order to drive the upper turning body 3 to turn. The rotational force of the output shaft 21 </ b> A of the turning electric motor 21 is transmitted to the output shaft 23 </ b> A of the mechanical brake 23 via the turning transmission 24 and the mechanical brake 23. The output shaft 23A of the mechanical brake 23 corresponds to the output shaft of the turning drive device 40.

  FIG. 3 is a block diagram showing a configuration of the turning drive device 40 according to the embodiment of the present invention. As described above, the turning drive device 40 includes the turning electric motor 21 that is an electric motor as a drive source. The turning electric motor 21 is a vertical electric motor that is arranged so that the rotation shaft extends in the direction of gravity. A helical planetary reduction gear is connected to the output shaft side of the turning electric motor 21 as the turning transmission 24. A disc brake as a mechanical brake 23 is provided on the rotating shaft 24A of the turning transmission 24 (helical planetary speed reducer). A rotating shaft 24A of the turning transmission 24 (helical planetary speed reducer) corresponds to the output shaft 23A of the mechanical brake 23 and serves as the output shaft 40A of the turning drive device 40.

  FIG. 4 is a cross-sectional view of the turning drive device 40. In the present embodiment, the sun gear 42 of the helical planetary reduction gear constituting the turning transmission 24 is fixed to the output shaft 21 </ b> A of the turning electric motor 21. The sun gear 42 is engaged with a plurality of planetary gears 44. Each of the planetary gears 44 is rotatably supported by a carrier 46 provided with an output shaft 24A of a turning transmission 24 (helical planetary speed reducer). Each planetary gear 44 meshes with an internal gear formed on the inner surface of the gear case 50.

  The gear case 50 in which the internal gear is formed is fixed to the end plate 21a of the turning electric motor 21 and cannot rotate by itself. On the other hand, the carrier 46 provided with the output shaft 24A is rotatably supported via a bearing with respect to the end case 52 fixed to the gear case 50.

  In the helical planetary speed reducer configured as described above, when the output shaft 21A of the turning electric motor 21 rotates and the sun gear 42 rotates, the planetary gear 44 rotates (spins). The planetary gear 44 meshes with an internal gear formed on the inner surface of the gear case 50, and the gear case 50 formed with the internal gear attempts to rotate by the rotational force of the planetary gear 44. However, since the gear case 50 is fixed to the end plate 21a of the turning electric motor 21, it cannot be rotated. As a result, the carrier 46 that is rotatably supported by itself while supporting the planetary gear 44 rotates. Due to the planetary gear action as described above, the rotation of the output shaft 21A of the turning electric motor 21 is decelerated and output to the rotating shaft 24A (output shaft) extending from the carrier 46.

  The mechanical brake 23 is a device that applies a brake by suppressing the rotational force of the rotating shaft 24A of the turning transmission 24, and may be provided separately from the turning transmission 24, but is provided in the turning transmission 24. You may comprise so that it may be. For example, the mechanical brake 23 is configured by a disc brake, the brake disc is attached to a gear case 50 as a fixed portion and an output shaft 24A of the turning transmission 24, and a brake pad provided on the gear case 50 as a fixed portion is used as a brake disc. You may comprise so that a braking force may be generated by pressing. In this case, an axially movable piston is provided in the gear case 50, and the brake pad is pressed against the disc brake by the piston to apply a braking force to the rotating shaft 24A.

  With the configuration described above, the mechanical brake 23 can be incorporated into the gear case 50 of the turning transmission 24, and the structure of the turning drive device 40 can be simplified. However, the mechanical brake 23 may be provided separately from the turning transmission 24, and in the present embodiment, the mechanical brake 23 is described as being not incorporated in the turning transmission 24.

  In order to lubricate the gear parts of the helical planetary reduction gear that constitutes the turning transmission 24, the sealed space formed inside the gear case 50 of the turning transmission 24 is filled with lubricating oil. The lubricating oil in the turning transmission 24 also has a function of cooling the meshing part of the gear while lubricating the gear parts. In the present embodiment, the lubricating oil of the turning transmission 24 is used as a cooling medium for cooling the turning electric motor 21.

  The gear case 50 is fixed to the end plate 21a of the turning electric motor 21, and the tip of the rotating shaft 21A extending outward from the end plate 21a protrudes into a sealed space filled with lubricating oil in the gear case 50. Yes. By attaching the sun gear 42 to the tip of the rotating shaft 21A, the sun gear 42 is disposed in a sealed space filled with lubricating oil.

  The turning transmission 24 is attached to the lower end side (end plate 21 a side) of the turning electric motor 21. The turning electric motor 21 is a high-speed vertical electric motor, and end plates 21a and 21b are attached to both sides of a cylindrical motor casing 21c. Inside the motor casing 21c, a rotating shaft 21A is housed in a rotor 21d and a stator 21e extending through the center thereof. The rotating shaft 21A is rotatably supported by bearings provided on the end plates 21a and 21b.

  The upper end of the turning electric motor 21 opposite to the rotating shaft 21A extends outward from the end plate 21b, and a cyclone blade 62 is formed at this end. The outer periphery of the cyclone blade 62 is covered with a pump case 64 to form a cyclone pump. This cyclone pump constitutes the cooling medium circulation device 60 as described later.

  The turning drive device 40 according to the present embodiment is arranged so that the rotating shaft 21A of the turning electric motor 21 is vertical. That is, when the turning drive device 40 is incorporated into the shovel, the turning transmission 24 is positioned below the turning electric motor 21, and the cooling medium circulation device 60 is positioned above the turning electric motor 21.

  Here, the rotating shaft 21A of the turning electric motor 21 is a hollow shaft, and the lubricating oil circulation hole 21a extends through the rotating shaft 21A in the axial direction. The lower end of the lubricating oil circulation hole 21a is open to a sealed space in the gear case 50 of the turning transmission 24 at a portion where the sun gear 42 is attached to the rotating shaft 21A. Therefore, the lubricating oil filled in the sealed space in the gear case 50 of the turning transmission 24 can flow into the lubricating oil circulation hole 21a. On the other hand, the upper end of the lubricating oil circulation hole 21 a opens into the internal space of the pump case 64.

  The pump case 64 includes a cylindrical cylinder 64a and end plates 64b and 64c at both ends thereof. A vent mechanism 66 is provided on the upper end plate 64b. When the pressure in the internal space of the pump case 64 increases, the air in the internal space can be discharged to the outside through the vent mechanism 66.

  In the present embodiment, a lubricating oil suction / discharge port 68 is provided on the lower side surface of the pump case 64. A lubricating oil intake / discharge port 54 is also provided on the side surface of the gear case 50 of the turning transmission 24. The lubricating oil suction / discharge port 68 of the pump case 64 and the lubricating oil suction / discharge port 54 of the gear case 50 are connected by a lubricating oil distribution pipe 70. The lubricating oil distribution pipe 70 is configured so that lubricating oil flows therein, and an oil cooler 72 is provided as a cooling device in the middle thereof. The oil cooler 72 is configured by, for example, a pipe having a heat radiating fin on the outer periphery, and cools the lubricating oil by releasing heat of the lubricating oil flowing through the inside to the surroundings.

  The oil cooler 72 is not limited to the above-described piping with heat radiation fins, and various known cooling devices can be used. For example, a water jacket may be provided in the middle of the lubricating oil distribution pipe 70 to configure the water-cooled oil cooler 72. Here, when the turning electric motor 21 is driven and the rotating shaft 21A rotates, the cyclone blade 62 also rotates simultaneously. When the cyclone blade 62 rotates, the hydraulic oil moves up and down along the cyclone blade 62. Thereby, the cooling medium circulation device 60 functions as a pump.

  Moreover, although the example which formed the cyclone blade | wing 62 in the outer periphery of the rotating shaft 21A was shown in the said Example, you may form the cyclone blade | wing 62 in the inner periphery of the rotating shaft 21A.

  Next, the flow of the lubricating oil in the turning drive device 40 having the above-described configuration will be described.

  First, the flow of lubricating oil when the turning electric motor 21 rotates at a low speed will be described with reference to FIG. FIG. 5 is a diagram illustrating the flow of the lubricating oil in the turning drive device 40, and the turning drive device 40 is schematically illustrated. FIG. 5A shows the flow of the lubricating oil when the turning electric motor 21 is rotating at the low speed and the forward direction, and FIG. 5B shows the flow of the lubricating oil when the turning electric motor 21 is rotating at the low speed and the reverse rotation. .

  When the turning electric motor 21 rotates at a low speed in the forward rotation direction, as shown in FIG. 5 (a), the cyclone pump constituting the cooling medium circulating device 60 rotates forward, and as shown by arrow A in FIG. The lubricating oil in the machine 24 goes upward through the lubricating oil circulation hole 21a of the rotating shaft 21A. At this time, since the rotation of the cyclone pump rotating together with the rotating shaft 21A of the turning electric motor 21 is low speed, the hydraulic oil cannot reach the upper end of the lubricating oil circulation hole 21a, and is in the middle of the lubricating oil circulation hole 21a. To rise. The lubricating oil rising in the lubricating oil circulation hole 21a is lubricating oil supplied from the oil cooler 72 to the turning transmission 24 as indicated by an arrow B1 in the drawing, and is low-temperature lubricating oil. Therefore, the rotating shaft 21A and the surrounding rotor 21d are cooled by the flow of low-temperature lubricating oil.

  When the turning electric motor 21 is rotated forward at a low speed and then reversely rotated at a low speed, the cyclone pump constituting the cooling medium circulation device 60 is rotated reversely as shown in FIG. 5B, as indicated by an arrow C1 in the figure. The lubricating oil in the turning transmission 24 goes upward through the lubricating oil distribution pipe 70 (oil cooler 72). At this time, since the rotation of the cyclone pump that rotates together with the rotating shaft 21 </ b> A of the turning electric motor 21 is low speed, the lubricating oil cannot reach the upper end of the lubricating oil distribution pipe 70, and is in the middle of the lubricating oil distribution pipe 70. To rise. The lubricating oil rising in the lubricating oil circulation pipe 70 is the lubricating oil that has returned to the turning transmission 24 from the lubricating oil circulation hole 21a of the rotating shaft 21A of the turning electric motor 21 as indicated by an arrow D1 in the drawing, and has a high temperature. Lubricating oil. Therefore, the lubricating oil rising in the lubricating oil circulation pipe 70 is cooled by passing through the oil cooler 72.

  As described above, during the normal rotation of the turning electric motor 21, the lubricating oil cooled to the low temperature by the oil cooler 72 is supplied to the turning transmission 24. Then, the low temperature lubricating oil flows upward through the lubricating oil circulation hole 21a of the rotating shaft 21A, and the rotating shaft 21A is cooled. When the turning electric motor 21 rotates in the reverse direction, the lubricating oil that has become hot due to absorption of heat in the rotating shaft 21 </ b> A is returned to the turning transmission 24. The high-temperature lubricating oil returned to the turning transmission 24 flows into the lubricating oil distribution pipe 70 and rises in the lubricating oil distribution pipe 70. At this time, the lubricating oil flowing in the lubricating oil distribution pipe 70 is cooled by the oil cooler 72 and becomes low-temperature lubricating oil.

  Each time the upper revolving unit 3 of the excavator repeats a right turn and a left turn during operation, the above-described reciprocating flow of the lubricating oil occurs. Therefore, each time the turning electric motor 21 rotates forward, the rotating shaft 21A of the turning electric motor 21 and the surrounding rotor 21d are cooled by the lubricating oil.

  Next, the flow of lubricating oil when the turning electric motor 21 rotates at high speed will be described with reference to FIG. FIG. 6 is a view showing the flow of the lubricating oil in the turning drive device 40, and the turning drive device 40 is schematically shown. FIG. 6A shows the flow of the lubricating oil when the turning electric motor 21 is rotating forward at high speed, and FIG. 6B shows the flow of the lubricating oil when the turning electric motor 21 is rotating backward at a high speed. .

  When the turning electric motor 21 rotates at a high speed in the forward rotation direction, as shown in FIG. 6A, the cyclone pump constituting the cooling medium circulation device 60 rotates at a high speed at a high speed. Lubricating oil in the transmission 24 passes through the lubricating oil circulation hole 21a of the rotating shaft 21A toward the upper end of the lubricating oil circulation hole 21a. At this time, the air heated in the rotating shaft 21A prior to the lubricating oil fills the pump case 64 and is discharged from the vent mechanism 66 to the outside. The air discharged from the vent mechanism 66 is air that has absorbed the heat of the rotating shaft 21A and the rotor 21d, and primary cooling is performed by discharging the heated air.

  When the cyclone pump continues to rotate normally at high speed, the lubricating oil which has flowed through the lubricating oil circulation hole 21a of the rotating shaft 21A and absorbed heat and becomes a high temperature, as indicated by an arrow A2, from the upper end of the lubricating oil circulation hole 21a. It flows out, flows in the pump case 64 as shown by an arrow A3, and flows into the lubricating oil distribution pipe 70. The high-temperature lubricating oil that has flowed into the lubricating oil distribution pipe 70 flows to the oil cooler 72 as indicated by an arrow A4. The high-temperature lubricating oil is cooled when flowing through the oil cooler 72 as shown by an arrow B <b> 1, becomes low-temperature lubricating oil, and returns to the turning transmission 24.

  While the turning electric motor 21 rotates at a high speed in the normal rotation direction, the rotating shaft 21A and the rotor 21d are cooled while the lubricating oil circulates as described above. Unlike the low-speed rotation, the rotating shaft 21A and the rotor 21d can be continuously cooled by circulating the lubricating oil even if the flow of the lubricating oil is not switched.

  On the other hand, when the turning electric motor 21 reversely rotates at a high speed, as shown in FIG. 6B, the cyclone pump constituting the cooling medium circulating device 60 rotates reversely, and as shown by an arrow C1 in the drawing, the rotating transmission The lubricating oil in 24 goes upward through the lubricating oil distribution pipe 70 (oil cooler 72). At this time, the lubricating oil rising in the lubricating oil distribution pipe 70 is cooled by the oil cooler 72 and flows into the pump case 64 as low-temperature lubricating oil as indicated by an arrow C2 in the figure. At this time, the heated air staying in the pump case 64 is discharged from the vent mechanism 66, and secondary cooling is performed.

  Thereafter, the low-temperature cooling water accumulated in the pump case 64 flows into the lubricating oil circulation hole 21a from the upper end of the rotating shaft 21A as indicated by an arrow D1, and flows downward in the lubricating oil circulation hole 21a by gravity. While the lubricating oil flows down in the lubricating oil circulation hole 21a, the lubricating oil absorbs heat from the inner wall surface of the lubricating oil circulation hole 21a and flows into the turning transmission 24 as indicated by an arrow D2. The lubricating oil flowing into the turning transmission 24 cools the gear portion in the turning transmission 24 and then becomes high-temperature lubricating oil, and again passes through the lubricating oil distribution pipe 70 (oil cooler 72) as shown by an arrow C1. Head upward.

  As described above, the rotating shaft 21A and the rotor 21d are cooled while the lubricating oil circulates as described above even while the turning electric motor 21 rotates at high speed in the reverse rotation direction. Unlike the low-speed rotation, the rotating shaft 21A and the rotor 21d can be continuously cooled by circulating the lubricating oil even if the flow of the lubricating oil is not switched.

  As described above, when the turning electric motor 21 rotates at a low speed, the turning electric motor 21 is cooled from the inside when rotating in one direction (in the example shown in FIG. 5, the normal rotation direction), and the opposite direction (shown in FIG. 5). When rotating in the reverse direction in the example, the lubricating oil flows into the oil cooler 72 to be cooled, and heat is released from the oil cooler 72. When the turning electric motor 21 rotates at a low speed, the amount of heat generated by the turning electric motor 21 is small, and the amount of heat generated at the gear portion of the turning transmission 24 is also small. Therefore, when the turning electric motor 21 rotates at a low speed, a large cooling capacity is not required. Therefore, cooling is performed with the lubricating oil when rotating in one direction, and the heat of the lubricating oil is released to the outside when rotating in the opposite direction. Thus, the turning electric motor 21 and the turning transmission 24 can be sufficiently cooled.

  On the other hand, when the turning electric motor 21 rotates at a low speed, the lubricating oil circulates and the turning electric motor 21 and the turning transmission 24 are always cooled when rotating in one direction (in the forward rotation direction in the example shown in FIG. 6). Even when rotating in the direction (reverse rotation direction in the example shown in FIG. 6), the lubricating oil circulates and the turning electric motor 21 and the turning transmission 24 are always cooled. When the turning electric motor 21 rotates at a high speed, the amount of heat generated by the turning electric motor 21 is large, and the amount of heat generated at the gear portion of the turning transmission 24 is also large. Accordingly, when the turning electric motor 21 rotates at a high speed, a large cooling capacity is required. Therefore, cooling is always performed with lubricating oil that is always circulated in any of the forward and reverse rotation directions, and the turning electric motor 21 and the turning speed change are sufficiently performed. The machine 24 can be cooled.

  As described above, according to the present embodiment, the cooling capacity varies depending on the rotation speed of the turning electric motor 21, so that the coolant flow rate is controlled based on the rotation speed of the turning electric motor 21. It is not necessary to control the capacity, and the cooling capacity can be automatically controlled with a simple configuration.

  In the above-described embodiment, the rotation of the turning electric motor 21 is decelerated by one turning transmission 24 (helical planetary reduction gear). However, when the electric motor having a high rotation speed is used as the turning electric motor 21. Further, it is possible to reduce the speed to a desired number of rotations by making the turning transmission multistage. FIG. 7 is a block diagram showing the configuration of the turning drive device when the turning transmission is multistage.

  The turning drive device 100 shown in FIG. 7 is configured by adding a planetary speed reducer 80 as a second-stage turning transmission to the turning drive device 40 shown in FIG. A planetary gear reducer 80 serving as a second-stage turning transmission can be configured by further attaching a sun gear to a rotating shaft 24A serving as an output shaft of the turning transmission 24 and disposing a planetary gear around the sun gear.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 1A, 1B Hydraulic motor 2 Turning mechanism 3 Upper turning body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 7A Hydraulic piping 7B Boom angle sensor 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 12 Motor generator 13 Transmission 14 Main pump 15 Pilot pump 16 High pressure hydraulic line 17 Control valve 18, 18A, 18B, 20 Inverter 19 Capacitor
21 Electric motor for turning 21A Output shaft 21a, 21b End plate 21c
21d rotor 21e stator 22 resolver 23 mechanical brake 24 turning transmission 25 pilot line 26 operating device 26A, 26B lever 26C pedal 26D button switch 27 hydraulic line 28 hydraulic line 29 pressure sensor 30 controller 40, 100 turning drive device 42 sun gear 44 planetary Gear 46 Carrier 50 Gear case 52 End case 54 Lubricating oil inlet / outlet port 60 Cooling medium circulating device 62 Cyclone blade 64 Pump case 64a Cylinder 64b, 64c End plate 66 Vent mechanism 70 Lubricating oil distribution pipe 72 Oil cooler 80 Planetary reducer (2 Stage transmission)
120 Power storage system

Claims (7)

A turning drive device for driving a turning body of an excavator,
A vertical electric motor for turning;
A cooling medium circulating device that sucks and discharges the cooling medium using the rotational force of the rotating shaft of the vertical electric motor as a power source;
The cooling medium circulating apparatus includes a pump having a spiral blade formed on a concentric shaft of the rotating shaft of the vertical electric motor. The swivel drive device according to claim 1,
The vertical electric motor has a through-hole extending in the axial direction of the rotating shaft passing through a rotor, and the turning drive device in which the cooling medium flows in the through-hole. The swivel drive device according to claim 2,
The rotating shaft of the cooling medium circulation device has a through hole extending in the axial direction,
The rotating shaft of the cooling medium circulation device is configured to rotate together with the rotating shaft of the vertical electric motor,
The turning drive device in which the through hole of the rotating shaft of the cooling medium circulating device communicates with the through hole of the rotating shaft of the vertical electric motor. The swivel drive device according to claim 3,
The cooling medium circulation device is a turning drive device that is a pump that generates a negative pressure on a concentric shaft by rotation of the rotating shaft. It is a turning drive device as described in any one of Claims 1 thru | or 4, Comprising:
The cooling medium circulating device is disposed on the upper side of the vertical electric motor, and a swivel drive device in which a reduction gear is disposed on the lower side of the vertical electric motor. The swivel drive device according to claim 5,
A turning drive device in which a circulation path of the cooling medium circulation device is connected to the reduction gear, and the cooling medium is lubricating oil of the reduction gear. The swivel drive device according to claim 6,
A swivel drive device having a heat exchanger connected between the pump and the speed reducer.

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