JP6935125B2 - Work machine - Google Patents

Description

The present invention relates to a working machine.

A hybrid excavator using an internal combustion engine and an electric motor has been put into practical use. In the hybrid type excavator, electric components such as a buck-boost converter that controls charging and discharging of a power storage device and an inverter that controls an electric motor are used. It is important to take measures against electromagnetic noise generated from electrical components.

A construction machine having a drive unit integrated motor and capable of reducing common mode noise is known (Patent Document 1). In this construction machine, at least one of the motor housing and the drive housing is electrically connected to the frame. The ground wire of the DC power supply is electrically connected only to the drive housing.

Japanese Unexamined Patent Publication No. 2016-53278

The frame of the work machine is painted to prevent rust. When the motor housing or the drive housing is fixed to the painted frame, the impedance at the connection point between the frame and the housing is increased. Therefore, the grounding of the housing becomes insufficient, and the electromagnetic compatibility (EMC) of the drive unit is lowered.

An object of the present invention is to provide a working machine capable of increasing EMC.

According to one aspect of the invention
A ground conductor containing an exposed metal surface with a painted surface and exposed metal on a part of the surface,
With electrical components, including a conductive housing ,
It has a mounting portion and a mounting portion provided on the housing.
The housing is arranged so as to overlap the exposed metal surface, is fixed to the ground conductor at the mounting portion, and the housing is electrically connected to the exposed metal surface. Provided is a working machine that is arranged inside the housing and in a region that does not include the mounting portion in a plan view.

By overlapping the housing and the exposed metal region (exposed metal surface), the housing is connected to the metal body (ground conductor) in the region immediately below the housing. As a result, the grounding of the housing is strengthened, and EMC can be enhanced.

FIG. 1 is a side view of the excavator according to the embodiment. FIG. 2 is a block diagram of an excavator according to an embodiment. FIG. 3A is a plan view of an electric component such as an inverter, a converter, and a power storage device, and FIGS. 3B and 3C are cross-sectional views taken along the alternate long and short dash line 3B-3B and the alternate long and short dash line 3C-3C, respectively. FIG. 4 is a cross-sectional view of an electric component mounted on an excavator according to a comparative example. FIG. 5 is a cross-sectional view of a housing of an electric component mounted on an excavator and a ground conductor according to a modification of the embodiment shown in FIGS. 1 to 3C. FIG. 6A is a plan view of an electric component mounted on an excavator according to another embodiment, and FIG. 6B is a cross-sectional view taken along the alternate long and short dash line 6B-6B of FIG. 6A. 7A is a plan view of the housing of the electrical component mounted on the excavator according to still another embodiment, FIG. 7B is a cross-sectional view taken along the alternate long and short dash line 7B-7B of FIG. 7A, and FIG. 7C is a ground conductor. It is sectional drawing of the state in which the intermediate member is inserted into the through hole of. FIG. 8 is a cross-sectional view of a housing and a ground conductor of an electrical component mounted on an excavator according to still another embodiment.

With reference to FIGS. 1 to 3C, the working machine according to the embodiment will be described by taking a hybrid excavator as an example.

FIG. 1 is a side view of the excavator according to the embodiment. A swivel body 12 is mounted on the lower traveling body 10 so as to be swivelable. The swivel body 12 has a swivel frame 11 that serves as a base for various parts. The swivel frame 11 also functions as a body ground.

The attachment 15 is attached to the swivel body 12. The attachment 15 includes a boom 16 attached to the swivel body 12, an arm 17 attached to the tip of the boom 16, and a bucket 18 attached to the tip of the arm 17. The boom cylinder 21 drives the boom 16 in the undulating direction. The arm cylinder 22 drives the arm 17 with respect to the boom 16 in the opening / closing direction. The bucket cylinder 23 drives the bucket 18 with respect to the arm 17 in the opening / closing direction. As an end attachment, a breaker, a crusher (crusher), a magnet, or the like can be attached instead of the bucket 18.

The cabin 13 and the stairs 14 are arranged on both sides of the position where the attachment 15 of the swivel body 12 is attached. For example, the cabin 13 is located on the left side of the attachment 15, and the stairs 14 are located on the right side of the attachment 15. The operator gets into the cabin 13 and operates the excavator. The stairs 14 are used when an operator or maintenance personnel goes up onto the swivel body 12 during maintenance. A plurality of electrical components are mounted in the space 25 under the stairs 14.

FIG. 2 is a block diagram of an excavator according to an embodiment. The engine 30 and the motor generator 32 are connected to two input shafts of the torque transmission mechanism 31, respectively. The main pump 33 and the pilot pump 34 are connected to the output shaft of the torque transmission mechanism 31. The motor generator 32 can operate as a generator that receives power from the engine 30 to generate electricity and as an assist motor that assists the engine.

The motor generator 32 is connected to the power storage circuit 55 via the inverter 52. The swivel motor 60 is connected to the power storage circuit 55 via the inverter 58. A resolver 62, a mechanical brake 61, and a speed reducer 63 are connected to the rotating shaft of the swivel motor 60. The swivel motor 60 swivels the swivel body 12 (FIG. 1) via the speed reducer 63. The swivel motor 60 can also operate as a regenerative brake that converts the kinetic energy of the swivel body 12 into electrical energy.

The power storage circuit 55 includes a converter 56 and a power storage device 57. The power storage device 57 can charge and discharge electric power. For the power storage device 57, for example, a lithium ion secondary battery, a lithium ion capacitor, an electric double layer capacitor, or the like can be used. The converter 56 is connected to the inverters 52 and 58 via a DC bus, and controls charging and discharging of the power storage device 57. For example, when the power storage device 57 is discharged, the converter 56 boosts the voltage of the power storage device 57 to supply electric power from the power storage device 57 to the DC bus, and when the power storage device 57 is charged, the voltage of the DC bus is stepped down to DC. Power is supplied from the bus to the power storage device 57.

Electrical components such as the inverters 52 and 58, the converter 56, and the power storage device 57 are mounted in the space 25 (FIG. 1) under the stairs 14.

The main pump 33 supplies high-pressure hydraulic oil to the control valve 40. The pilot pump 34 supplies the primary pilot pressure to the operating device 41. The operating device 41 converts the primary side pilot pressure into the secondary side pilot pressure according to the operation of the operator and supplies the pressure sensor 42 to the control valve 40.

The control valve 40 distributes high-pressure hydraulic oil to the boom cylinder 21, arm cylinder 22, bucket cylinder 23, hydraulic motors 24A, and 24B according to the secondary pilot pressure. The hydraulic motors 24A and 24B drive the left and right crawlers of the lower traveling body 10 (FIG. 1).

The pressure sensor 42 converts the secondary pilot pressure into an electric signal, and transmits the converted electric signal to the control device 50. The control device 50 controls the inverters 52 and 58, the converter 56, and the mechanical brake 61 based on the electric signal according to the operation of the operator.

As an example, the control device 50 operates the motor generator 32 as an assist motor when the hydraulic load of the main pump 33 becomes larger than a certain value. Specifically, the control device 50 controls the inverter 52 and the converter 56 to discharge the power storage device 57 and supply electric power to the motor generator 32. When the hydraulic load of the main pump 33 becomes smaller than a certain value, the control device 50 controls the inverter 52 and the converter 56 to operate the motor generator 32 as a generator to charge the power storage device 57.

When the swivel body 12 is swiveled, the control device 50 controls the converter 56 and the inverter 58 to discharge the power storage device 57 and drive the swivel motor 60. When the swivel body 12 is stopped, the control device 50 controls the inverter 58 and the converter 56 to operate the swivel motor 60 as a regenerative brake to charge the power storage device 57.

FIG. 3A is a plan view of electrical components such as the inverters 52 and 58 and the converter 56. 3B and 3C are cross-sectional views taken along the alternate long and short dash line 3B-3B and the alternate long and short dash line 3C-3C, respectively.

The electric component includes a conductive housing 70, and electric circuit components such as power transistors, diodes, and reactors are housed in the housing 70. For the housing 70, for example, an aluminum casting is used. The housing 70 has a substantially rectangular planar shape, and mounting portions 71 are provided at each of the four corners. The housing 70 is fixed to the ground conductor 80 at the mounting portion 71 using a fixture 73 such as a bolt. The ground conductor 80 is a metal body that forms a part of the swivel body 12, is connected to the swivel frame 11 (FIG. 1) by welding or the like, and functions as a conductor for body grounding.

The surface of the metal ground conductor 80 is painted with an insulating paint, and a coating film 81 is formed. A part of the surface of the ground conductor 80 is not painted, and the metal is exposed. The portion where the metal is exposed is referred to as the exposed metal surface 82.

Each part of the excavator such as the ground conductor 80 is processed at a parts factory different from the assembly factory where the electric component is attached to the ground conductor 80, and is transported to the assembly factory. The entire surface of the ground conductor 80 is painted in order to prevent the ground conductor 80 from rusting during the period from the processing of the ground conductor 80 to the time when the ground conductor 80 is transported to the assembly factory and the electrical components are attached. The exposed metal surface 82 is preferably formed by painting the entire surface of the ground conductor 80 at a parts factory and then peeling off a part of the coating film 81 at an assembly factory.

When painting the ground conductor 80, the exposed metal surface 82 may be covered with a mask member such as an adhesive form so that the exposed metal surface 82 is not painted. In this case, the mask member may be peeled off before the electrical component is attached to the ground conductor 80 at the assembly plant.

The exposed metal surface 82 is composed of, for example, two elongated rectangular regions arranged in parallel. The housing 70 is arranged at a position overlapping the exposed metal surface 82. For example, in a plan view, the exposed metal surface 82 is arranged inside the housing 70.

A conductive intermediate member 90 is arranged between the exposed metal surface 82 and the bottom surface of the housing 70. The housing 70 is pressed against the intermediate member 90 by the force fixing the housing 70 to the ground conductor 80, and the housing 70 and the intermediate member 90 come into surface contact with each other. The intermediate member 90 electrically connects the housing 70 and the ground conductor 80. As the intermediate member 90, for example, a conductive member such as a single-sided adhesive copper foil tape or a conductive rubber pad can be used.

When a single-sided adhesive copper foil tape is used as the intermediate member 90, the adhesive surface may be attached to the exposed metal surface 82 of the ground conductor 80. When a conductive rubber pad is used as the intermediate member 90, the intermediate member 90 can be held between the housing 70 and the ground conductor 80 by applying a compressive force to the intermediate member 90 by the fixture 73.

Next, the excellent effects of the examples shown in FIGS. 1 to 3C will be described with reference to the comparative examples shown in FIG.

FIG. 4 is a cross-sectional view of an electric component mounted on an excavator according to a comparative example. In this comparative example, the exposed metal surface 82 and the housing 70 of the electrical component do not overlap. The housing 70 is connected to the exposed metal surface 82 via a ground cable 75. One end of the ground cable 75 is connected to the housing 70 by a fixture 73 for fixing the housing 70, and the other end is connected to the exposed metal surface 82 by a fixture 76 such as a bolt. There is.

In the comparative example shown in FIG. 4, the housing 70 and the ground conductor 80 are connected via the ground cable 75. On the other hand, in the embodiment shown in FIGS. 3A to 3C, the bottom surface of the housing 70 is electrically connected to the ground conductor 80 directly below via the intermediate member 90. As described above, in the embodiment, the housing 70 and the intermediate member 90, and the intermediate member 90 and the ground conductor 80 are in surface contact with each other. Further, the current path connecting the housing 70 and the ground conductor 80 is shortened. Therefore, as compared with the comparative example, the housing 70 can be connected to the ground conductor 80 with low impedance. As a result, the grounding of the housing 70 can be strengthened. By strengthening the earth, electromagnetic compatibility (EMC) can be enhanced.

Further, in the comparative example shown in FIG. 4, the area for attaching the housing 70 and the exposed metal surface 82 for attaching the ground cable 75 must be separately secured in the ground conductor 80. On the other hand, in the examples shown in FIGS. 3A to 3C, it is not necessary to secure the exposed metal surface 82 separately from the area where the housing 70 is attached. Therefore, it is possible to save space.

Further, in the comparative example shown in FIG. 4, it is necessary to attach / detach the ground cable 75 every time the housing 70 is removed from the ground conductor 80. Since it is necessary to deform the ground cable 75 when the ground cable 75 is attached or detached, the removal of the housing 70 may cause disconnection of the earth cable 75 or poor continuity. On the other hand, since the ground cable is not used in the examples shown in FIGS. 3A to 3C, it is possible to suppress the occurrence of ground failure due to disconnection, poor continuity, or the like.

Further, in the examples shown in FIGS. 3A to 3C, the fixture 76 (FIG. 4) for attaching the ground cable 75 to the ground conductor 80 is unnecessary. Therefore, the man-hours for attaching the housing 70 to the ground conductor 80 can be reduced.

Next, a modified example of the above embodiment will be described with reference to FIG.
FIG. 5 is a cross-sectional view of a housing 70 of an electric component mounted on an excavator and a ground conductor 80 according to a modified example. In the modified example shown in FIG. 5, the intermediate member 90 is adhered to the exposed metal surface 82 with a conductive adhesive, and is arranged so as to extend over the coating film 81 around the exposed metal surface 82. The bottom surface of the housing 70 is in close contact with the intermediate member 90 arranged on the coating film 81.

In this modification, even when the coating film 81 is thicker than the intermediate member 90, the housing 70 and the intermediate member 90 can be brought into close contact with each other, and the electrical conduction between the two can be stably ensured.

Next, other examples will be described with reference to FIGS. 6A and 6B. Hereinafter, the description of the configuration common to the examples shown in FIGS. 1 to 3C will be omitted.

FIG. 6A is a plan view of the electrical component mounted on the excavator according to the present embodiment, and FIG. 6B is a cross-sectional view taken along the alternate long and short dash line 6B-6B of FIG. 6A. In the embodiments shown in FIGS. 3A to 3C, an aluminum casting is used as the housing 70, and the mounting portion 71 is integrally formed with the main body of the housing 70. On the other hand, in this embodiment, the L-shaped mounting portion 71 is welded to the main body of the housing 70. The housing 70 is composed of the main body and the mounting portion 71. The bottom surface of the main body of the housing 70 is arranged at a position higher than the bottom surface of the mounting portion 71.

Further, in this embodiment, the exposed metal surface 82 is composed of one elongated region. The exposed metal surface 82 is arranged substantially in the center in the width direction of the housing 70 in a plan view, and has a long planar shape in the longitudinal direction of the housing 70.

An intermediate member 90 is arranged between the exposed metal surface 82 and the housing 70. Elastic members 91 are arranged on both sides of the intermediate member 90. The elastic member 91 is sandwiched between the bottom surface of the housing 70 and the coating film 81 of the ground conductor 80, and is compressed in the height direction.

If the intermediate member 90 is arranged only in the center in the width direction, the posture of the housing 70 becomes unstable as compared with the configuration in which the intermediate member 90 is arranged at two places in the width direction. However, in this embodiment, the elastic member 91 The posture of the housing 70 can be stabilized by arranging the housing 70. Further, in this example as well, the same effect as in the examples shown in FIGS. 1 to 3C can be obtained.

Next, still another embodiment will be described with reference to FIGS. 7A-7C. Hereinafter, the description of the configuration common to the examples shown in FIGS. 1 to 3C will be omitted.

FIG. 7A is a plan view of the housing 70 of the electrical component mounted on the excavator according to the present embodiment. FIG. 7B is a cross-sectional view taken along the alternate long and short dash line 7B-7B of FIG. 7A. A through hole (slit) 84 having an elongated planar shape is formed in the ground conductor 80 directly below the housing 70. A coating film 81 is formed on both sides of the ground conductor 80, and the ground conductor 80 is exposed on the inner surface of the through hole 84. The through hole 84 can be formed by painting the entire surface of the ground conductor 80 and then drilling a hole.

The side surface of the through hole 84 corresponds to the exposed metal surface 82 shown in FIGS. 3A to 3C. An intermediate member 90 having conductivity and elasticity is inserted in the through hole 84. The intermediate member 90 is brought into close contact with the side surface of the through hole 84 by its restoring force and is electrically connected to the ground conductor 80. As the intermediate member 90, for example, a conductive silicone resin can be used.

FIG. 7C is a cross-sectional view showing a state in which the intermediate member 90 is inserted into the through hole 84 of the ground conductor 80. The intermediate member 90 includes a body portion 90A and heads 90B above and below the body portion 90A. The body 90A is inserted into the through hole 84. The head 90B protrudes from the surface of the coating film 81 to prevent the intermediate member 90 from falling out of the through hole 84.

As shown in FIG. 7B, when the housing 70 is fixed to the ground conductor 80, the housing 70 crushes the upper head 90B of the intermediate member 90. As a result, the bottom surface of the housing 70 is brought into close contact with the upper surface of the intermediate member 90, and the housing 70 is electrically connected to the intermediate member 90. Also in this example, the same effect as that of the examples shown in FIGS. 1 to 3C can be obtained.

Next, still another embodiment will be described with reference to FIG. Hereinafter, the description of the configuration common to the examples shown in FIGS. 1 to 3C will be omitted.

FIG. 8 is a cross-sectional view of the housing 70 and the ground conductor 80 of the electrical component mounted on the excavator according to the present embodiment. Hereinafter, the description of the configuration common to the examples shown in FIGS. 1 to 3C will be omitted.

In this embodiment, the exposed metal surface 82 is arranged directly below the mounting portion 71 of the housing 70. Also in this embodiment, the housing 70 including the mounting portion 71 and the exposed metal surface 82 overlap each other. An insulating anti-vibration member 92 is sandwiched between the mounting portion 71 and the exposed metal surface 82. The in-plane spread of the anti-vibration member 92 is larger than that of the exposed metal surface 82, and the exposed metal surface 82 is arranged inside the anti-vibration member 92 in a plan view. As the anti-vibration member 92, for example, anti-vibration rubber can be used.

The intermediate member 90 is electrically connected to the housing 70 by inserting a part of the plate-shaped intermediate member 90 between the vibration isolator member 92 and the mounting portion 71. The intermediate member 90 is electrically connected to the ground conductor 80 by inserting the other part of the intermediate member 90 between the anti-vibration member 92 and the exposed metal surface 82. The fixture 73 penetrates the mounting portion 71, the intermediate member 90, the vibration isolator member 92, and the ground conductor 80, and fixes the housing 70 to the ground conductor 80.

Also in this embodiment, the housing 70 is electrically connected to the ground conductor 80 via the intermediate member 90, and the same effect as that of the embodiment shown in FIGS. 1 to 3C can be obtained. Further, in this embodiment, the entire surface of the exposed metal surface 82 is covered with the anti-vibration member 92. Therefore, the effect that rust on the exposed metal surface 82 can be suppressed can be obtained.

FIG. 8 shows an example in which the fixture 73 penetrates the mounting portion 71, the intermediate member 90, the vibration isolator member 92, and the ground conductor 80, but it is not always necessary to penetrate the intermediate member 90 and the vibration isolator member 92. .. The intermediate member 90 and the anti-vibration member 92 may be arranged at a position deviating from the position of the fixture 73.

It goes without saying that each of the above embodiments is exemplary and the configurations shown in different examples can be partially replaced or combined. Similar effects and effects due to the same configuration of a plurality of examples will not be mentioned sequentially for each example. Furthermore, the present invention is not limited to the above-mentioned examples. For example, it will be obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

10 Lower traveling body 11 Swivel frame 12 Swivel body 13 Cabin 14 Stairs 15 Attachment 16 Boom 17 Arm 18 Bucket 21 Boom cylinder 22 Arm cylinder 23 Bucket cylinder 24A, 24B Hydraulic motor 25 Space for accommodating electrical components 30 Engine 31 Torque transmission mechanism 32 Electric generator 33 Main pump 34 Pilot pump 40 Control valve 41 Operating device 42 Pressure sensor 50 Control device 52 Inverter 55 Power storage circuit 56 Converter 57 Power storage device 58 Inverter 60 Swivel motor 61 Mechanical brake 62 Resolver 63 Reducer 70 Electrical component housing Body 71 Mounting part 73 Fixture 75 Earth cable 76 Fixture 80 Ground conductor 81 Paint film 82 Metal exposed surface 84 Through hole 90 Intermediate member 90A Body 90B Head 91 Elastic member 92 Anti-vibration member

Claims (4)

A ground conductor containing an exposed metal surface with a painted surface and exposed metal on a part of the surface,
With electrical components, including a conductive housing ,
It has a mounting portion and a mounting portion provided on the housing.
The housing is arranged so as to overlap the exposed metal surface, is fixed to the ground conductor at the mounting portion, and the housing is electrically connected to the exposed metal surface. A work machine arranged inside the housing and in an area not including the mounting portion in a plan view. Further, it has an intermediate member that electrically connects the housing to the exposed metal surface.
The work machine according to claim 1 , wherein the intermediate member is arranged between the exposed metal surface and the bottom surface of the housing, and electrically connects the housing and the ground conductor. Further, it has an intermediate member that electrically connects the housing to the exposed metal surface.
The work machine according to claim 1 or 2 , wherein the housing is electrically connected by being pressed against the intermediate member by a force fixing the housing to the ground conductor and making surface contact with the intermediate member. Further, it has an intermediate member that electrically connects the housing to the exposed metal surface.
A vibration-proof member is arranged between the housing and the exposed metal surface, a part of the intermediate member is arranged between the vibration-proof member and the housing, and the other part is the vibration-proof member. The work machine according to any one of claims 1 to 3 , which is arranged between the metal and the exposed metal surface.

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