JP2004257457A - Electromotive working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily connect a motor to a step-up gear while ensuring high concentricity. <P>SOLUTION: In a power transmission structure which increases the output of a motor 13 as a drive source by a step-up gear 18 and transmits the output to a hydraulic pump 7, an output shaft 15 of the motor is also used for an input shaft of the step-up gear by fitting and connecting the output shaft 15 of the motor to an input shaft hole 22 of the step-up gear 18, the motor 13 is connected to the step-up gear 18 while the self-weight of the step-up gear is supported by the output shaft 15 of the motor, and the rotational reaction force applied to the step-up gear 18 is supported by a reaction force supporting part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric work machine equipped with an electric motor as a drive source.
[0002]
[Prior art]
For example, a hydraulic shovel generally has a configuration in which an engine is mounted as a drive source and each device is driven by the engine.
[0003]
5 and 6 show an upper structure of the engine driven hydraulic excavator. An upper revolving unit 1 is mounted on a lower traveling unit (not shown) so as to be rotatable around a vertical axis, and is provided at a rear portion of the upper revolving unit 1. The engine 3 is installed in the machine room 2. In FIG. 5, reference numeral 4 denotes a cabin.
[0004]
The engine 3 is installed in a horizontally long posture in which the longitudinal direction is the width (left-right) direction of the shovel, and as shown in FIG. 6, one of the output shafts 5, 6 (normally As shown in the figure, a hydraulic pump 7, which is a hydraulic source of a hydraulic actuator such as a hydraulic cylinder, is connected to an output shaft 6 on the right side when viewed from the rear surface.
[0005]
An oil cooler 8 for cooling the working oil, a radiator 9 and a fan 10 for sending these cooling air are arranged on the left side of the engine 3, and the fan drive is connected to the left output shaft 5 via a gear transmission mechanism 11. The fan 10 is driven by the shaft 12.
[0006]
By the way, in the case of a hydraulic excavator used in a place with poor ventilation such as in a tunnel or a building, or in a place where engine noise is a problem, the excavator is driven by a commercial power supply as shown in FIG. There is a case where the electric motor 13 is mounted as a drive source and is remodeled as an electric hydraulic excavator.
[0007]
In this case, output shafts 14 and 15 are provided on the left and right sides of the electric motor 13 as in the case of the engine drive type, and the hydraulic pump 7 is connected to the right output shaft 15 in an interlocked manner.
[0008]
Note that the left output shaft 14 is directly connected to the fan 10. In addition, the radiator 9 for cooling the engine is unnecessary and removed, and the fan 10 sends cooling air only to the oil cooler 8.
[0009]
In this case, the following problem occurs as the drive source is replaced with the electric motor 13 from the engine 3.
[0010]
The engine 3 is usually used at a rotation speed of 2000 rpm or more. However, in the case of the electric motor 13, the output rotation speed of the motor 13 is 1500 rpm in a 50 Hz region and 1800 rpm in a 60 Hz region, for example, in the case of a 4-pole motor. It is much lower than the rotation speed.
[0011]
For this reason, it is necessary to increase the output of the electric motor in order to secure the same working capacity as in the case of the engine driven type.
[0012]
It is conceivable to use an inverter (frequency converter) as this speed increasing means. However, the equipment itself is expensive because the inverter itself is expensive, and a control panel for the inverter and noise countermeasures against harmonics are required. Costly. In addition, adding an inverter and its control panel requires extra space, which is disadvantageous as a speed increasing means.
[0013]
Therefore, it is conceivable to arrange the right output shaft 15 and the pump input shaft 16 coaxially as shown in FIG. 7 and to interpose a speed increasing mechanism (for example, a planetary gear mechanism) 17 therebetween (see Patent Document 1). ).
[0014]
[Patent Document 1]
JP-A-63-137558 [0015]
[Problems to be solved by the invention]
However, when the gearbox 17 is used as described above, the motor output shaft 15 and the gearbox input shaft are used so that vibrations due to misalignment between the motor 13 and the gearbox 17 and breakage of the connecting portion do not occur. (For example, about 0.05).
[0016]
As a measure, as shown in FIG. 7, it is conceivable to use, as the electric motor 13, a motor with a flange in which a flange 15 a is integrally provided on the outer periphery of the output shaft 15. Alternatively, as shown in Patent Document 1, it is conceivable to connect the motor output shaft 15 and the gearbox input shaft via a coupling.
[0017]
However, in this case, by adding the gearbox 17 coaxially with the electric motor 13 and the hydraulic pump 7, the overall length (distance from the right end of the electric motor 13 to the right end of the pump 13) L of the pump drive unit is increased. In addition, due to the addition of the flange 15a (or the coupling), the total length L of the pump driving section is further increased, and may not fit within the width of the machine room 2 as illustrated.
[0018]
For this reason, in reality, there is no choice but to directly connect the motor and the gearbox input shaft without a flange or coupling, and as a result, it takes time and skill to assemble the pump drive unit, and furthermore, a high concentricity is secured. It was difficult.
[0019]
The present invention solves the above-mentioned problems, and provides an electric working machine that can easily connect an electric motor and a gearbox while ensuring high concentricity.
[0020]
[Means for Solving the Problems]
The invention according to claim 1 includes a hydraulic pump that is a hydraulic source of a hydraulic actuator, an electric motor as a drive source of the hydraulic pump, and a gearbox that increases the output of the electric motor and transmits the output to the hydraulic pump, A shaft hole is provided at the input portion of the speed increaser, and the output shaft of the motor is fitted and connected to the shaft hole, so that the output shaft of the motor also serves as the input shaft of the speed increaser, and the weight of the speed increaser is reduced. Are connected to the electric motor and the gearbox while being supported by the electric motor output shaft, and a reaction force support portion for supporting a rotational reaction force acting on the gearbox is provided.
[0021]
According to a second aspect of the present invention, in the configuration of the first aspect, in the speed increaser and the hydraulic pump, the speed increaser output shaft also serves as the input shaft of the hydraulic pump, and the pump's own weight is supported by the speed increaser output shaft. They are connected in a state.
[0022]
According to a third aspect of the present invention, in the configuration of the first or second aspect, the output shaft of the electric motor and the input shaft of the hydraulic pump are arranged in a state in which a step is formed in parallel with each other and a step is formed between their shaft centers. This is provided at the step.
[0023]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the output shaft of the electric motor is fitted and connected to the input shaft hole of the gearbox via a taper bush.
[0024]
According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, a vibration isolator for absorbing vibration is provided on the reaction force support portion.
[0025]
According to a sixth aspect of the present invention, in the configuration according to any one of the first to fifth aspects, the electric motor and the hydraulic pump are arranged side by side in the machine width direction.
[0026]
According to the above configuration, the motor output shaft also serves as the gearbox input shaft, and the motor output shaft supports the own weight of the gearbox and connects them together, so that the concentricity between the motor output shaft and the gearbox input shaft is increased. Can be secured.
[0027]
In other words, by simply fitting the motor output shaft into the shaft hole of the input section of the speed increasing gear, the two can be easily connected in a concentric state.
[0028]
Therefore, since no flange or coupling is required, the overall length of the pump driving section can be reduced. As a result, the pump drive unit is made as small as possible while replacing the drive source with an electric motor from an engine and adding a gearbox. This pump drive unit is provided in an engine-driven work machine (especially a small work machine). It can be easily stored in the existing space.
[0029]
In this case, since the rotational reaction force acting on the gearbox is supported by the reaction force support portion, the rotational torque of the electric motor is reliably transmitted to the gearbox.
[0030]
Further, according to the configuration of the second aspect, the hydraulic pump can also be easily connected to the gearbox in a concentric state in which the gearbox output shaft is the pump input shaft.
[0031]
In this case, the motor output shaft supports the weights of both the gearbox and the hydraulic pump.
[0032]
According to the configuration of claim 3, the motor output shaft and the pump input shaft are arranged with a step, and the gearbox is provided so as to fill the step. It is possible to arrange the pump input shaft side portion in the same plane.
[0033]
For this reason, the axial length of the pump drive unit (the length in the machine width direction in claim 6) is smaller than the case where the three members of the motor output shaft, the speed increaser, and the pump input shaft are simply arranged coaxially. ) Can be further reduced.
[0034]
According to the configuration of the fourth aspect, the motor output shaft is fitted and connected to the input shaft hole of the speed increaser via the taper bush, so that the concentricity between the motor output shaft and the input shaft hole is increased, and furthermore, these connection work is performed. Can be further facilitated.
[0035]
According to the configuration of claim 5, since the vibration isolator is provided on the reaction force support portion, transmission of vibration from the electric motor and the gearbox (in addition to the hydraulic pump in claim 3) to the reaction force support portion is suppressed. . Therefore, it is possible to prevent the reaction force support portion from being damaged or deformed due to the vibration.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0037]
In the following embodiments, the same parts as those shown in FIG. 7 are denoted by the same reference numerals, and the description thereof will not be repeated.
[0038]
As shown in FIG. 1, an electric motor 13 as a drive source is provided in the machine room 2 in a horizontally long attitude, and an input shaft 16 of the hydraulic pump 7 is mounted on a right output shaft (hereinafter simply referred to as an electric motor output shaft) 15 by a gear. It is connected via a speed increaser 18 of the type.
[0039]
The motor output shaft 15 and the pump input shaft 16 are arranged parallel to each other and vertically displaced so that a step a is formed between their axes. A speed-increasing gear 18 is provided so as to be buried.
[0040]
As shown in FIG. 2, the speed increaser 18 includes input, intermediate, and output spur gears 19, 20, and 21 arranged in the same plane (vertical plane). An output spur gear 21 is attached to the pump input shaft 16.
[0041]
With this configuration, the rotational force of the electric motor 13 is increased by the speed increaser 18 and transmitted to the hydraulic pump 7, so that by setting the speed increase ratio to an appropriate value, the pump rotation speed equivalent to that of the engine type can be obtained. As a result, the working capacity of the machine body can be utilized.
[0042]
In this case, by providing the step a, the respective spur gears 19, 20, and 21 can be arranged in the same vertical plane as described above, so that the axial length L1 of the pump drive unit (see FIG. 1) L1 is greatly reduced from the drive unit length L in the case where the motor output shaft 15, the gearbox 17, and the pump input shaft 16 are simply arranged coaxially as shown in FIG. Can be miniaturized.
[0043]
FIG. 3 shows a detailed structure of a connecting portion between the motor output shaft 15 and the gearbox 18.
[0044]
The motor output shaft 15 is coupled to the input spur gear 19 while being fitted in an input shaft hole 22 provided in the input spur gear 19 of the speed increasing gear 18, and the coupling portion performs the transmitting action of the rotational force. , The weight of the entire gearbox 18 is supported.
[0045]
That is, the motor 13 and the gearbox 18 are connected in such a manner that the motor output shaft 15 also serves as the gearbox input shaft, and the weight of the gearbox is supported by the motor output shaft 15.
[0046]
As described above, since the motor output shaft 15 and the gearbox input shaft are the same shaft, their concentricity is automatically secured, and the motor output shaft 15 is fitted into the input shaft hole 22 of the gearbox 18. The two can be easily connected in a concentric manner.
[0047]
Accordingly, there is no need to interpose a flange or a coupling between the two, and the overall length L1 of the pump driving unit can be further reduced.
[0048]
For this reason, the drive source is replaced with the electric motor 13 from the engine 3 shown in FIGS. 5 and 6, and the pump drive unit is miniaturized as much as possible while adding the speed increasing device 18. This pump drive unit is engine-driven work machine. (Especially small work machines) can be easily stored in the existing space.
[0049]
Further, a taper bush 23 is fitted into a tip end of the input shaft hole 22 of the speed increaser 18, and a tip end of the motor output shaft 15 is fitted and connected to the input shaft hole 22 via the taper bush 23.
[0050]
The concentricity between the motor output shaft 15 and the input shaft hole 22 can be increased by the tapered bush 23, and the connecting operation thereof can be further facilitated.
[0051]
Further, as shown in FIG. 4, a bracket 25 protrudes from a lower portion of the casing 24 of the speed increaser 18, and the bracket 25 is provided on a fixed portion of the machine room 2 via a vibration isolator (for example, rubber) 26. The bracket 27 is fixed to the reaction force support bracket 27.
[0052]
Thereby, a reaction force support portion 28 is formed, and the rotation reaction force acting on the speed increaser 18 in the direction of the arrow in FIG. 4 by the rotation of the motor 13 is supported by the reaction force support portion 28, so that the motor torque is reduced. Is reliably transmitted.
[0053]
Further, vibration is absorbed by the vibration isolator 26 provided on the reaction force support portion 28, and transmission of vibration from the electric motor 13 and the speed increasing device 18 to the reaction force support portion 28 is suppressed. Therefore, it is possible to prevent the reaction force support portion 28 from being damaged or deformed due to the vibration.
[0054]
On the other hand, as in the case of the electric motor 13 and the gearbox 18, the gearbox 18 and the hydraulic pump 7 use the pump input shaft 16 as the gearbox output shaft as shown in FIG. The gears are connected while being supported by a speed output shaft (pump input shaft) 16.
[0055]
Accordingly, in this embodiment, the motor output shaft 15 supports the own weights of both the gearbox 18 and the hydraulic pump 7, and the rotational reaction force of the hydraulic pump 7 is also supported by the reaction force support portion 28 shown in FIG.
[0056]
In this way, the gearbox 18 and the hydraulic pump 7 can also be easily connected concentrically.
[0057]
By the way, according to the present invention, a flange or a coupling is not required between the motor output shaft 15 and the gearbox 18, and the overall length L1 of the pump drive unit can be reduced. Alternatively, the motor output shaft 15, the speed increaser 18 and the pump input shaft 16 may be arranged coaxially.
[0058]
In this case, the speed-increasing gear 18 may adopt a coaxial arrangement (for example, a planetary gear mechanism).
[0059]
In addition, the present invention can be applied not only to a hydraulic excavator but also to a deep hole excavator, a crusher, and the like that are configured using a hydraulic excavator as a base.
[0060]
【The invention's effect】
As described above, according to the present invention, the motor output shaft also serves as the gearbox input shaft, supports the own weight of the gearbox with the motor output shaft, and supports the rotational reaction force acting on the gearbox as a reaction force. Since both are connected in a state where they are supported by the unit, the two can be easily connected in a concentric state only by fitting the output shaft of the motor into the shaft hole of the input unit of the gearbox.
[0061]
Therefore, since no flange or coupling is required, the overall length of the pump driving section can be reduced. As a result, the drive source is replaced with an electric motor from an engine, and the pump drive unit is miniaturized as much as possible while adding a gearbox. This pump drive unit is provided in an engine-driven work machine (particularly a small work machine). It can be easily stored in the existing space.
[0062]
According to the second aspect of the present invention, the hydraulic pump can be easily connected to the gearbox in a concentric state in which the gearbox output shaft is the pump input shaft.
[0063]
According to the third aspect of the present invention, the motor output shaft and the pump input shaft are arranged with a step, and the speed increaser is provided to fill the step. The axial length of the pump drive unit (the length in the machine width direction in claim 6) can be further reduced as compared with the case where the operators are simply arranged coaxially.
[0064]
According to the invention of claim 4, the motor output shaft is fitted and connected to the input shaft hole of the speed increaser via the taper bush, so that the concentricity between the motor output shaft and the input shaft hole is increased, and furthermore, these connecting operations are performed. This can be further facilitated.
[0065]
According to the fifth aspect of the present invention, since the vibration isolator is provided on the reaction force support portion, transmission of vibration from the electric motor and the gearbox (in the third embodiment, a hydraulic pump) to the reaction force support portion is suppressed, and the reaction by the vibration is suppressed. Damage and deformation of the force support can be prevented.
[Brief description of the drawings]
FIG. 1 is a rear view showing an arrangement of an electric motor, a hydraulic pump, and the like in a working machine according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the speed increaser according to the embodiment.
FIG. 3 is a diagram showing a part of FIG. 2 in a further enlarged manner.
FIG. 4 is a front view showing a structure of a reaction force support portion in the embodiment.
FIG. 5 is a schematic plan view showing an upper structure of the engine-driven work machine.
FIG. 6 is a rear view showing an arrangement of an electric motor, a hydraulic pump, and the like in the work machine.
FIG. 7 is a diagram corresponding to FIG. 6 when an electric motor is mounted instead of an engine as a drive source.
[Explanation of symbols]
Reference Signs List 13 Motor 15 as drive source Motor output shaft 16 also used as gearbox input shaft 16 Pump input shaft 18 also used as gearbox output shaft Gearbox 22 Gearbox input shaft hole 23 Taper bush 28 Reaction force support 25 Bracket 27 Constituting Reaction Force Support Section Same Reaction Force Support Bracket 26 Vibration Isolator

Claims (6)

A hydraulic pump that is a hydraulic source of the hydraulic actuator, an electric motor as a drive source of the hydraulic pump, and a gearbox that increases the output of the electric motor and transmits the output to the hydraulic pump. A shaft hole is provided in the shaft, and the output shaft of the motor is fitted and connected to the shaft hole, so that the motor output shaft also serves as the gearbox input shaft, and the own weight of the gearbox is supported by the motor output shaft. An electric work machine, wherein the electric motor and the speed increaser are connected in the extended state, and a reaction force support portion for supporting a rotational reaction force acting on the speed increaser is provided. 2. The electric work machine according to claim 1, wherein the gearbox and the hydraulic pump are connected in a state where the gearbox output shaft also serves as the input shaft of the hydraulic pump, and the pump's own weight is supported by the gearbox output shaft. An electric work machine characterized by being performed. The output shaft of the electric motor and the input shaft of the hydraulic pump are arranged in parallel and in a state where a step is formed between their axes, and a speed-increasing gear is provided at the step. 2. The electric work machine according to 2. The electric work machine according to any one of claims 1 to 3, wherein an output shaft of the electric motor is fitted and connected to an input shaft hole of the speed increaser via a taper bush. The electric work machine according to any one of claims 1 to 4, wherein a vibration isolator that absorbs vibration is provided on the reaction force support portion. The electric work machine according to any one of claims 1 to 5, wherein the electric motor and the hydraulic pump are arranged side by side in the machine width direction.

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