JP2014037190A - Work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide work machine that even in a state in which ratio between rotating speed of an engine and rotating speed of an electric motor varies, can activate a hydraulic pump while keeping energy loss to a minimum.SOLUTION: A hydraulic shovel that is the work machine, comprises: a work device 3 attached to a rotary body 2; an engine 10 mounted on the rotary body 2; a hydraulic pump 11; an electric motor 12 capable of activating the hydraulic pump 11 and being activated as a power generator; and a battery 13 that supplies electricity for activating the electric motor 12 and stores electricity generated when activating the electric motor 12 as a power generator. Further, the hydraulic shovel comprises: an output shaft 14 of the engine 10; a differential gear mechanism 16 provided between an outer shaft 14 of the engine 10 and a rotation shaft 15 of the electric motor 12; a gear 17 provided integrally on the differential gear mechanism 16; a gear 19, engaging with the gear 17, that is provided integrally with an input shaft 18 of the hydraulic pump 11.

Description

  The present invention relates to a work machine such as a hydraulic excavator provided with an electric motor capable of driving a hydraulic pump.

  There exists a thing shown by patent document 1 as this kind of working machine. This prior art is a hybrid construction machine, and includes a vehicle body composed of a traveling body and a revolving body, and a work device attached to the revolving body. In addition, this prior art includes an engine mounted on the revolving structure, and a hydraulic pump that is driven by the engine and discharges pressure oil that drives the traveling structure, the revolving structure, and the work device. Between the output shaft of the engine and the input shaft of the hydraulic pump, gears provided integrally with the output shaft and the input shaft are arranged. In addition, this prior art supplies an electric motor that can drive a generator / motor, that is, a hydraulic pump, and can also be driven as a generator, and supplies electric power to drive the electric motor, and when the electric motor is driven as a generator. A power storage device that stores electric power generated in the battery, that is, a battery is provided. The above-described gears provided integrally with the output shaft of the engine and the input shaft of the hydraulic pump are arranged so as to mesh with the gear provided integrally with the rotation shaft of the electric motor.

  In the conventional technology configured as described above, the hydraulic pump can be driven by the engine and the electric motor by driving the electric motor so as to support the output of the engine.

JP 2011-246955 A

  In the prior art described above, the engine output shaft, the hydraulic pump input shaft, and the electric motor rotation shaft are mechanically connected via a set of gears. Drive the hydraulic pump at the rate of rotation. For this reason, energy loss occurs when the ratio between the engine speed and the electric motor speed changes during operation. For example, even if the hydraulic pump is driven only by the electric motor, the engine must be driven and rotated at the same time. As a result, excessive energy loss is caused. Therefore, in reality, in the above-described prior art, it is impossible to drive the hydraulic pump only by the electric motor.

  The present invention has been made from the above-described prior art, and its purpose is to drive a hydraulic pump while minimizing energy loss even in a situation where the ratio between the engine speed and the electric motor speed changes. An object of the present invention is to provide a working machine that can be made to operate.

In order to achieve this object, the present invention provides a vehicle body, a working device attached to the vehicle body, an engine mounted on the vehicle body, and pressure oil that is driven by the engine to operate the vehicle body and the working device. Occurs when a hydraulic pump to be supplied, an electric motor that can drive the hydraulic pump and that can also be driven as a generator, and power that drives the electric motor are supplied and the electric motor is driven as a generator In a work machine including a power storage device that stores electric power, a differential gear mechanism provided between an output shaft of the engine and a rotating shaft of the electric motor, and the hydraulic pressure unit provided integrally with the differential gear mechanism The present invention configured as described above includes a gear capable of transmitting a rotational force to an input shaft of a pump. Further, the output of the engine can be transmitted to the input shaft of the hydraulic pump via the gear and the hydraulic pump can be driven mainly by driving the engine. At this time, if the engine output alone is insufficient, the rotational force of the electric motor is also transmitted to the input shaft of the hydraulic pump via the rotating shaft of the electric motor, the differential gear mechanism, and the gear, and this electric motor is supported by the engine. Can be used.

  Conversely, the rotational force of the electric motor is transmitted to the input shaft of the hydraulic pump via the rotating shaft of the electric motor, the differential gear mechanism, and the gear, and the hydraulic pump can be driven mainly by the driving of the electric motor. . At this time, if the rotational force of the electric motor alone is insufficient, the engine output is also transmitted to the hydraulic pump via the engine output shaft, the differential gear mechanism, and the gear, and this engine is used for assisting the electric motor. Can do.

  That is, the present invention provides a hydraulic pump that minimizes energy loss even when the ratio of the engine speed and the electric motor speed changes due to the differential gear mechanism interposed between the engine and the electric motor. Can be driven.

  Further, the present invention is the above invention, wherein the differential gear mechanism includes a case in which the gear is integrally attached, a pinion shaft disposed in the case and provided integrally with the case, and disposed in the case. A first side gear provided integrally with the output shaft of the engine, a second side gear provided in the case and provided integrally with the rotary shaft of the electric motor, and arranged in the case and rotatable on the pinion shaft. A pinion gear that is mounted and meshes with both the first side gear and the second side gear is provided.

  In the present invention configured as described above, when the hydraulic pump is driven mainly by the engine output, the engine output is output via the engine output shaft, the first side gear of the differential gear mechanism, the pinion gear, and the pinion shaft. The rotation of the shaft is transmitted as the rotation of the case, and the rotation of the gear provided integrally with the case is transmitted as the rotation of the input shaft of the hydraulic pump, so that the hydraulic pump can be driven.

  When the hydraulic pump is driven mainly by the rotational force of the electric motor, the rotation of the rotary shaft of the electric motor is rotated via the rotary shaft of the electric motor, the second side gear of the differential gear mechanism, the pinion gear, and the pinion shaft. Is transmitted as the rotation of the case, and the rotation of the gear provided integrally with the case is transmitted as the rotation of the input shaft of the hydraulic pump, so that the hydraulic pump can be driven.

  Further, the present invention is characterized in that, in the above invention, a brake device for preventing the rotation of the input shaft of the hydraulic pump is provided.

  In the present invention configured as described above, the rotation of the electric motor is rotated via the output shaft of the engine and the differential gear mechanism by driving the engine in a state where the brake device is operated to prevent the rotation of the input shaft of the hydraulic pump. The electric motor can be driven as a generator by rotating the shaft. The electric power generated by the electric motor is stored in the power storage device. The electric power stored in this power storage device is utilized for driving the electric motor when driving the hydraulic pump.

  Further, the present invention is the above-described invention, wherein the generator has a rotating shaft that is provided separately from the electric motor and that rotates according to the rotational force transmitted to the input shaft of the hydraulic pump via the gear. Another electric motor that can be operated and a power storage device that stores electric power generated by the other electric motor are provided.

  According to the present invention configured as described above, when the input shaft of the hydraulic pump transmitted through the differential gear mechanism and the gear is rotated by driving at least one of the engine and the electric motor, the rotating shaft of another electric motor is moved. It rotates and this other electric motor can be driven as a generator. Electric power generated by another electric motor is stored in the power storage device.

  In the present invention, the differential gear mechanism interposed between the engine and the electric motor allows the hydraulic pump to be operated while minimizing energy loss even in a situation where the ratio between the engine speed and the electric motor speed changes. It can be driven. Therefore, the present invention is provided with an engine and an electric motor as a drive source of the hydraulic pump, and can realize the drive of the hydraulic pump only by the electric motor which has been impossible in the past. The present invention can also drive the engine to assist in driving the electric motor.

It is a side view of the hydraulic excavator which comprises 1st Embodiment of the working machine which concerns on this invention. It is a figure which shows the principal part structure of the drive part with which the hydraulic excavator which concerns on 1st Embodiment is equipped. It is the figure which expanded and showed the differential gear mechanism with which the drive part shown in FIG. 2 is equipped. It is a figure explaining an example of operation of a 1st embodiment. It is a figure which shows the principal part structure of the drive part with which 2nd Embodiment of this invention is equipped. It is a figure which shows the principal part structure of the drive part with which 3rd Embodiment of this invention is equipped.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a work machine according to the present invention will be described with reference to the drawings.

  FIG. 1 is a side view of a hydraulic excavator constituting a first embodiment of a work machine according to the present invention, FIG. 2 is a diagram showing a main part configuration of a drive unit provided in the hydraulic excavator according to the first embodiment, and FIG. The figure which expanded and showed the differential gear mechanism with which the drive part shown in FIG. 2 is provided, FIG. 4 is a figure explaining an example of operation | movement of 1st Embodiment.

  As shown in FIG. 1, the work machine according to the first embodiment is a hydraulic excavator. The hydraulic excavator includes a traveling body 1 and a revolving body 2 disposed on the traveling body 1. The traveling body 1 and the revolving body 2 constitute a vehicle body. The working device 3 is attached to the revolving body 2 so as to be rotatable in the vertical direction. The working device 3 includes a boom 4, an arm 5 attached to the tip of the boom 4, a bucket 6 attached to the tip of the arm 5, a boom cylinder 7 that operates the boom 4, and an arm that operates the arm 5. A cylinder 8 and a bucket cylinder 9 for operating the bucket 6 are included.

  Mounted on the revolving structure 2 are an engine 10 shown in FIG. 2 and a hydraulic pump 11 that is driven by the engine 10 and supplies pressure oil that operates the traveling structure 1, the revolving structure 2, and the work device 3. . An electric motor 12 that can drive the hydraulic pump 11 and can also be driven as a generator, and can supply electric power for driving the electric motor 12, and the electric motor 12 as a generator. A power storage device that stores power generated when driven, that is, a battery 13 is mounted.

  As shown in FIG. 2, the work machine according to the first embodiment includes a differential gear mechanism 16 provided between an output shaft 14 of the engine 10 and a rotary shaft 15 of the electric motor 12, and the differential gear mechanism 16. A gear 17 is provided integrally with the gear mechanism 16 and can transmit a rotational force to the input shaft 18 of the hydraulic pump 11. A gear 19 is integrally provided on the input shaft 18 of the hydraulic pump 11, and the gear 19 and the above-described gear 17 are arranged so as to mesh with each other.

  As shown in FIG. 3, the above-described differential gear mechanism 16 includes a case 16 a to which the gear 17 is integrally attached, and a first side gear 16 c that is disposed in the case 16 a and is provided integrally with the output shaft 14 of the engine 10. And have. Further, the differential gear mechanism 16 is disposed in the case 16a and integrally provided on the rotary shaft 15 of the electric motor 12, and the differential gear mechanism 16 is disposed in the case 16a and is rotatably mounted on the pinion shaft 16b. In addition, a pair of pinion gears 16e meshing with both the first side gear 16c and the second side gear 16d is provided.

  In the hydraulic excavator according to the first embodiment configured as described above, the output of the engine 10 is the engine output during heavy excavation work in which the load during excavation work or the like performed by the work device 3 is large, that is, during heavy load work. The rotation of the case 16a is transmitted through the output shaft 14 of 10, the first side gear 16c of the differential gear mechanism 16, the pinion gear 16e, and the pinion shaft 16b. Further, the rotation of the case 16 a is transmitted to the input shaft 18 of the hydraulic pump 11 through a gear 17 provided integrally with the case 16 a and a gear 19 meshing with the gear 17. That is, the hydraulic pump 11 can be driven mainly by driving the engine 10.

  At this time, if only the output of the engine 10 is insufficient, the rotational force of the electric motor 12 is transmitted via the rotary shaft 15 of the electric motor 12, the second side gear 16d of the differential gear mechanism 16, the pinion gear 16e, and the pinion shaft 16b. This is transmitted as the rotation of the case 16a. Further, it is transmitted to the input shaft 16 of the hydraulic pump 11 through a gear 17 provided integrally with the case 16 a and a gear 19 meshing with the gear 17. That is, the electric motor 12 is used to support the engine 10.

  In addition, the load during excavation work performed by the work device 3 is small during medium load work compared to the heavy load work described above, and the work place is not in an urban area or during normal work when it is not night work. However, the hydraulic pump 11 can be driven mainly by driving the engine 10 as in the above-described heavy load operation by using the engine 10 in the medium speed rotation region. At this time, as described above, when the output of the engine 10 alone is insufficient, the electric motor 12 is driven, and the rotational force of the electric motor 12 can also be used to drive the hydraulic pump 11.

  In addition, the electric motor 12 is driven during a medium-load work as described above and in a work environment in which noise generation is easily restricted, such as work in an urban area or night work. The rotational force of the electric motor 12 is transmitted as the rotation of the case 16a through the rotating shaft 15 of the electric motor 12, the second side gear 16d of the differential gear mechanism 16, the pinion gear 16e, and the pinion shaft 16b. Further, it is transmitted as the rotation of the gear 17 provided integrally with the case 16 a, and is transmitted as the rotational force of the hydraulic pump 11 through the gear 19 that meshes with the gear 17. That is, the hydraulic pump 11 can be driven mainly by driving the electric motor 12. As a result, it is possible to perform work by the work device 3 while suppressing the generation of noise.

  At this time, when the capacity of the battery 13 for driving the electric motor 12 has decreased, the engine 10 can be driven and the hydraulic pump 11 can be driven via the differential gear mechanism 16 and the gears 17 and 19. . That is, the engine 10 is used to support the electric motor 12.

  Further, for example, in the case of light load work where the load is smaller than that in the above-described medium load work as in the case of ground leveling work or fine operation performed by the work device 3, the engine 10 is exemplified as shown in FIG. Is maintained in a stopped state, and the electric motor 12 is driven. As described above, the rotational force of the electric motor 12 is transmitted as the rotation of the case 16a through the rotary shaft 15 of the electric motor 12, the second side gear 16d of the differential gear mechanism 16, the pinion gear 16e, and the pinion shaft 16b. Further, this is transmitted as rotation of the gear 17 provided integrally with the case 16 a, and the input shaft 18 of the hydraulic pump 11 rotates through the gear 19. That is, the hydraulic pump 11 can be driven only by the electric motor 12.

  As described above, according to the hydraulic excavator according to the first embodiment, the rotational speed of the engine 10 and the rotational speed of the electric motor 21 are controlled by the differential gear mechanism 16 interposed between the engine 10 and the electric motor 12. Even in a situation where the ratio changes, the hydraulic pump 11 can be driven while minimizing energy loss. Therefore, as described above, driving of the hydraulic pump 11 by only the electric motor 12 can be realized. Further, according to the first embodiment, the engine 10 can be driven so as to support the driving of the electric motor 12.

  FIG. 5 is a diagram showing a main configuration of a drive unit provided in the second embodiment of the present invention.

  Although not shown in the drawings, the second embodiment having the main configuration of the drive unit shown in FIG. 5 is a hydraulic excavator that is equivalent in appearance to the hydraulic excavator shown in FIG. As shown in FIG. 5, this hydraulic excavator includes a brake device 20 that prevents the input shaft 18 from rotating on the input shaft 18 of the hydraulic pump 11. Other configurations are the same as those of the first embodiment.

  The second embodiment configured as described above can obtain the same effects as the first embodiment, and also drives the engine 10 in a state where the brake device 20 is operated to prevent the input shaft 18 of the hydraulic pump 11 from rotating. As a result, the rotary shaft 15 of the electric motor 12 is rotated via the output shaft 14 of the engine 10, the first side gear 16c, the pinion gear 16e, and the second side gear 16d of the differential gear mechanism 16, and the electric motor 12 is converted into a generator. Can be driven as The electric power generated by the electric motor 12 is stored in the battery 13. The electric power stored in the battery 13 is utilized for driving the electric motor 12 when the hydraulic pump 11 is driven.

  FIG. 6 is a diagram showing a main configuration of a drive unit provided in the third embodiment of the present invention.

  Although the third embodiment having the main configuration of the drive unit shown in FIG. 6 is not shown, for example, it is a hydraulic excavator that is equivalent in appearance to the hydraulic excavator shown in FIG. As shown in FIG. 6, the hydraulic excavator has a rotating shaft 22 that rotates according to the rotational force transmitted to the input shaft 18 of the hydraulic pump 11, and another electric motor 21 that can operate as a generator. A power storage device that stores electric power generated by the other electric motor 21, that is, a battery 24 is provided. A rotating shaft 22 of another electric motor 21 is provided integrally with a gear 23 that meshes with a gear 19 provided integrally with the input shaft 18 of the hydraulic pump 11. Other configurations are the same as those of the first embodiment.

  In the third embodiment configured as described above, the same effects as the first embodiment can be obtained, and at least one of the engine 10 and the electric motor 12 is driven via the differential gear mechanism 16 and the gears 17 and 19. As the input shaft 18 of the hydraulic pump 11 is transmitted, the rotating shaft 22 of another electric motor 21 rotates, and this other electric motor 21 can be driven as a generator. The electric power generated by the other electric motor 21 is stored in the power storage device, that is, the battery 24.

  The drive unit of the work machine according to the present invention basically connects the engine 10 and the electric motor 12 via the differential gear mechanism 16, and connects the differential gear mechanism 16 and the hydraulic pump 10 to the gears 17 and 19. Therefore, it is also suitable for a mini excavator that is a small machine that is easily limited by the installation space of the engine 10, the electric motor 12, and the hydraulic pump 11.

  In addition, since the hydraulic pump 11 can be driven only by driving the electric motor 12 or the electric motor 12 as a main body, the work apparatus 3 can perform work, so that it is required to reduce noise as in the work in town. Can easily cope with the working environment. From this point of view, the present invention is also suitable for a mini excavator, which is a small machine that can be easily used in a town.

1 Running body (car body)
2 Revolving body (car body)
3 Working device 10 Engine 11 Hydraulic pump 13 Battery (power storage device)
14 output shaft 15 rotation shaft 16 differential gear mechanism 16a case 16b pinion shaft 16c first side gear 16d second side gear 16e pinion gear 17 gear 18 input shaft 19 gear 20 brake device 21 another electric motor 22 input shaft 23 gear 24 battery (storage battery) apparatus)

Claims (4)

A vehicle body, a work device attached to the vehicle body, an engine mounted on the vehicle body, a hydraulic pump that is driven by the engine and supplies pressure oil that operates the vehicle body and the work device, and can drive the hydraulic pump In a work machine comprising an electric motor that can be driven as a generator, and a power storage device that supplies electric power for driving the electric motor and stores electric power generated when the electric motor is driven as a generator. ,
A differential gear mechanism provided between an output shaft of the engine and a rotating shaft of the electric motor;
A work machine comprising: a gear provided integrally with the differential gear mechanism and capable of transmitting a rotational force to an input shaft of the hydraulic pump. The work machine according to claim 1,
The differential gear mechanism includes a case in which the gear is integrally attached, a pinion shaft disposed in the case and provided integrally with the case, and provided in the case and provided integrally with the output shaft of the engine. A first side gear, a second side gear disposed in the case and provided integrally with a rotating shaft of the electric motor, a first side gear disposed in the case and rotatably mounted on the pinion shaft. And a pinion gear meshing with both of the second side gears. The work machine according to claim 1 or 2,
A work machine comprising a brake device for preventing rotation of the input shaft of the hydraulic pump. The work machine according to claim 1 or 2,
Another electric motor provided separately from the electric motor, having a rotating shaft that rotates according to a rotational force transmitted to the input shaft of the hydraulic pump via the gear, and operable as a generator;
A work machine comprising a power storage device that stores electric power generated by the other electric motor.

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