JP7366868B2 - Grid box for electric drive vehicles - Google Patents

Description

The present invention relates to a grid box for electrically driven vehicles.

At mining sites, excavated crushed stone (heavy weight material) is transported by dump trucks. Dump truck drive systems are broadly divided into mechanical and electric. Electric dump trucks are often used in large dump trucks with a maximum load capacity of several hundred tons. An electric dump truck, which is an example of an electrically driven vehicle, drives a travel motor (an electric motor) using electric power generated by rotating a generator using a diesel engine, and rotates wheels connected to the travel motor to travel. On the other hand, power-generating brakes are used when braking or when going down a slope. Dynamic braking is an operation that uses the kinetic energy and potential energy of the vehicle to rotate the travel motor to reduce the speed of the vehicle. The travel motor generates regenerative power by operating the dynamic brake. If this continues, the main circuit voltage of the vehicle will become excessive, so the vehicle must consume the generated regenerative power. In electric dump trucks, this power consumption is done by a grid box.

The grid box is a box-shaped structure that houses a group of electrical resistors (hereinafter referred to as a group of resistors). Grid boxes are often mounted on the deck of a dump truck, on the right side in the direction of travel. When the electric brake is activated, the electric circuit constituted by the electric drive system is connected to the grid box via the chopper. The chopper delivers surplus power to the grid box while repeatedly turning on and off at predetermined timings depending on the voltage status of the circuit, thereby maintaining the circuit voltage within a predetermined range. The resistor group inside the grid box generates heat when energized and consumes surplus power. If left as is, the resistor group will become excessively hot and its integrity will be impaired. The grid box is equipped with an air blower that forcibly blows cooling air onto the heated resistor group to cool it and keep the temperature within an appropriate range.

Prior art related to grid boxes include Patent Document 1 and Patent Document 2.

Patent Document 1 discloses a resistance element made of a metal strip curved in a zigzag shape, and a plurality of insulating elements arranged in a line on upper and lower mounting bolts fixed to a framework, respectively, and holding a plurality of curved portions of the resistance element. A resistor unit is disclosed. Elongated openings are formed in the plurality of curved portions of the metal strip, and protrusions formed on the sides of the insulating elements located across each curved portion are engaged with the openings of each of the curved portions, respectively. The plurality of curved portions of the metal strip are held between the insulating elements using the openings and the protrusions as holding elements. Furthermore, the resistance element portions of the metal strip curved in a zigzag manner, excluding the plurality of curved portions, are each curved in a uniform direction.

Patent Document 2 discloses a plurality of resistors formed from sheet metal having a U-shaped curved portion, and a zigzag resistor in which adjacent resistors at the leg portions of the sheet metal are joined by welding joints, and a zigzag resistor that is vertically separated. A resistor grid is disclosed that includes first and second insulating members arranged and in which a zigzag resistor is supported on the first and second insulating members. As a welded joint that joins the legs of adjacent sheet metal, for example, welding with a tab between the legs, or placing a clip on the tab between the legs and forming a slot between the legs and the clip. and welding. Furthermore, there are various types of support structures for the zigzag resistor with respect to the first and second insulating members. For example, a tag may be welded to a U-shaped curved portion of the zigzag resistor that is part of the current flow path. The tag is inserted into the fitting hole formed in the first insulating member and fixed, and the tab provided between the legs is inserted into the slot formed in the second insulating member and fixed. A zigzag resistor is supported on the first and second insulating members. In addition, a through hole is provided in the U-shaped curved portion of the zigzag resistor, which is a part of the current flow path, and a pin protruding from the first insulating member is inserted into the through hole and fixed. The zigzag resistor is supported by the first and second insulating members by inserting and fixing the tab provided in the second insulating member into the slot formed in the second insulating member.

EP0676774B1 publication US Patent No. 5304978

Dump trucks tend to have larger loading weights and vehicle weights in order to improve transportation efficiency. As the weight of the load and vehicle increases, the kinetic energy and potential energy of the dump truck increase, so the regenerated power during braking increases. Grid boxes need to increase power consumption as vehicles become larger. On the other hand, the grid box mounting area on the deck is limited. Therefore, a significant increase in the size of the grid box is not allowed. From the above, it is necessary to increase the power capacity of the grid box without increasing its size, and to increase the power capacity density.

As one measure to increase the power capacity density of the grid box, a resistor that constitutes a resistor group in the grid box (in Patent Document 1, the resistance element portion between the upper and lower curved parts of the sheet metal strip, in Patent Document 2, , resistors formed from sheet metal) can be arranged more densely. For this purpose, it is preferable to reduce the arrangement pitch of the resistors in the thickness direction and the width direction.

Another measure is to increase the total heat generation amount of the resistor without increasing the size of the resistor. This allows the power capacity density to be increased even with grid boxes of the same size.

In Patent Document 1, the curved part of the metal strip is held between the insulating elements by engaging the protrusion formed in the insulating element with the opening formed in the curved part of the metal strip, and the metal strip is insulated. fixedly supported on the element.

Here, when a power generation brake is applied by the travel motor, a current flows through the resistor, which generates heat and becomes high temperature, causing thermal expansion in the resistor (metal strip). As an example, when 18Cr-8Ni with a linear expansion coefficient α of 16.7 ppm/K is used as the resistor material, when the length L of the resistor is 600 mm and the temperature change ΔT is 600 K, the amount of thermal expansion ΔL is ΔL= α・ΔT・L=exceeds 6mm.

For this reason, in Patent Document 1, in which a metal strip is fixedly supported on an insulating element, the current of the dynamic braking flows through the resistor, and when the resistor thermally expands, the length of the metal strip is increased by buckling (out-of-plane). deformation). At this time, if there is a difference in the amount of buckling (out-of-plane deformation) between adjacent resistors, there is a possibility that they will come into contact and cause a short circuit. For this reason, in Patent Document 1, it is difficult to arrange the resistors at a high density at short pitches in the thickness direction, and the power capacity density of the grid box cannot be increased more than ever.

Further, in Patent Document 1, as a holding element for holding the curved portion of the metal strip to the insulating element, an opening is formed in the curved portion of the metal strip with which a protrusion of the insulating element engages. However, if a through hole is formed in a portion of the resistor through which current flows, the temperature near the through hole becomes locally high when current flows through the resistor, and the magnitude of the current that flows is limited. For this reason, the total amount of heat generated by the resistor decreases, and in this respect as well, Patent Document 1 cannot increase the power capacity density of the grid box.

In Patent Document 2, the zigzag resistor is fixed by inserting a pin or a tag into the first and second insulating members, or by inserting a pin protruding from the first insulating member into a through hole formed in a curved part of a metal strip. The zigzag resistor is fixedly supported by the first and second insulating members. Therefore, in Patent Document 2, as in Patent Document 1, the electric current due to the dynamic braking flows through the resistor, and when the resistor thermally expands, the increase in the length of the metal strip is absorbed by buckling (out-of-plane deformation). Therefore, it is difficult to arrange the resistors at a high density at short pitches in the thickness direction, and it is impossible to increase the power capacity density of the grid box.

In addition, in order to join the legs of adjacent sheet metals, a tab is placed between the legs and a clip is placed over the legs, slots are formed in the legs and the clip and welded, and a zigzag resistor is supported on the first insulating member. Therefore, a through hole is formed in the curved part of the metal strip, and as in Patent Document 1, when current flows through the resistor due to dynamic braking, the temperature near the through hole increases locally, and the flowing current decreases. Due to the limited size, the total heat dissipation of the resistor is reduced and the power capacity density of the grid box cannot be increased.

The object of the present invention is to absorb the increase in length when the resistor thermally expands when a current due to dynamic braking flows through the resistor, and to enable the resistors to be arranged densely at short pitches in the thickness direction. It is an object of the present invention to provide a grid box for an electrically driven vehicle in which the total heat generation amount of the resistor can be increased without increasing the size of the resistor, and the power capacity density of the grid box can be increased.

In order to solve the above-mentioned problems, the present invention is an electric vehicle installed in an electric drive vehicle that converts regenerated electric power generated when an electric motor for driving performs braking into thermal energy, and dissipates the thermal energy to the outside. A grid box for a driving vehicle, comprising a plurality of resistor modules and a blower, each of the plurality of resistor modules being configured by joining a plurality of resistors made of metal plates in a meandering shape, a resistor group formed with a plurality of folded parts at both ends in the length direction of the plurality of resistors; and a plurality of folded parts of the resistor group made of an insulating material, at both ends in the length direction of the plurality of resistors. and a plurality of adapters made of metal plates, the separator having a plurality of through holes formed at predetermined intervals in the thickness direction of the plurality of resistors, and the separator supporting the plurality of resistors. The plurality of folded parts of the body group are respectively inserted into the plurality of through holes of the separator together with the plurality of adapters, and the plurality of adapters each allow deformation in the length direction of the plurality of resistors. and supporting the plurality of folded parts so as to be slidable in the length direction of the plurality of resistors within the plurality of through holes so as to restrain displacement of the plurality of resistors in the thickness direction and width direction. shall be.

As a result, current from the dynamic braking flows through the resistor, and when the resistor expands thermally, the multiple folded parts of the resistor group slide in the length direction of the resistor within the multiple through holes relative to the multiple adapters. Therefore, the resistor does not buckle even when thermally expanded. As a result, a plurality of resistors can be arranged at a high density at short pitches in the thickness direction, and the power capacity density of the grid box can be increased.

Further, since the folded portions of the plurality of resistors are slidably supported by the adapter, there is no need to form through holes in the plurality of resistors. As a result, when current flows through multiple resistors, the temperature near the through hole does not increase locally, and the total heat generation amount of the resistors increases without increasing the size of the multiple resistors. This also allows the power capacity density of the grid box to be increased.

According to the present invention, the current generated by the dynamic braking flows through the resistor, absorbing the increase in length when the resistor thermally expands, and making it possible to arrange the resistors at a high density at short pitches in the thickness direction. , and the total heat generation amount of the resistor can be increased without increasing the size of the resistor. As a result, the power capacity density of the grid box can be increased, and the efficiency and performance of the grid box can be improved.

The above configuration and effects will be made clear by the following description of the embodiments.

1 is an external view of a dump truck as an embodiment equipped with a grid box of the present invention. FIG. 3 is an external perspective view of the grid box of the first embodiment. FIG. 2 is a partially exploded perspective view of the grid box of the first embodiment. FIG. 2 is a perspective view of the resistor module of the first embodiment. FIG. 2 is a perspective view of a resistor group according to the first embodiment. It is a perspective view of the assembly stage of the resistor module of 1st Embodiment. FIG. 2 is a partially cutaway perspective view of the resistor module of the first embodiment. FIG. 2 is a perspective view of the adapter of the first embodiment. FIG. 7 is a partial plan view of the separator of FIG. 6 of the first embodiment viewed from above. FIG. 9A is a sectional view taken along the line BB in FIG. 9A. FIG. 9A is a sectional view taken along line CC in FIG. 9A. FIG. 9A is a sectional view taken along line DD in FIG. 9A. FIG. 2 is a perspective view of a resistor module group according to the first embodiment. FIG. 2 is a cross-sectional perspective view of a resistor module group according to the first embodiment housed in a housing. 12 is a partially enlarged view of the resistor module group shown in FIG. 11. FIG. It is a perspective view of a grid box group of a 1st embodiment. FIG. 3 is a diagram showing an analysis result of heat generation distribution of a resistor in which a through hole is not formed. FIG. 3 is a diagram showing an analysis result of heat generation distribution of a resistor in which arbitrary through holes are formed. FIG. 7 is a diagram showing an analysis result of the temperature of a resistor in which a through hole is not formed. FIG. 7 is a diagram showing an analysis result of the temperature of a resistor in which an arbitrary through hole is formed. FIG. 7 is a partially cutaway perspective view of a resistor module according to a second embodiment. FIG. 7 is a cross-sectional view showing a state in which the folded portion of the resistor and the adapter are inserted into the through hole of the second embodiment. FIG. 7 is a partially cutaway perspective view of a resistor module according to a third embodiment. FIG. 7 is a cross-sectional view showing a folded portion of a resistor and a state in which an adapter is inserted into a through hole of a third embodiment.

Embodiments of the present invention will be described below with reference to the drawings. The following explanations show specific examples of the contents of the present invention, and the present invention is not limited to these explanations, and various modifications can be made by those skilled in the art within the scope of the technical thinking disclosed in this specification. Changes and modifications are possible. Further, in all the figures for explaining the present invention, parts having the same function are given the same reference numerals, and in the case of repetition, the explanation may be omitted.

<Electric dump truck>
FIG. 1 is an external view of an electric dump truck as an embodiment equipped with a grid box of the present invention.

In FIG. 1, a dump truck 40 is an ultra-large rigid dump truck with a loaded weight of over 200 tons, which is used to transport loads such as ore, crushed stone, or earth and sand at resource extraction sites such as mines.

The front wheels 120 are attached to both sides of the frame in the width direction via trailing arm suspensions (not shown) provided at the front end of the frame, and are configured to be steerable left and right about a king pin. The rear wheels 43 are connected to the drive shaft of the travel motor via a reduction gear, a wheel support, etc. housed in a rear axle provided at the rear end of the frame, and are driven by rotation of the travel motor.

The traveling motor is an electric motor, and one is provided for each of the left and right rear wheels 43, and drives and brakes the left and right rear wheels 43 independently. The pair of travel motors are housed and fixed within the rear axle so that their drive shafts (rotating shafts) are substantially on the same line. Each travel motor is connected to an inverter housed in a control cabinet 42, respectively.

A diesel engine, not shown, is arranged and supported on the frame below the deck 41. The drive shaft (rotating shaft) of the diesel engine is mechanically connected to the drive shafts of the main generator and auxiliary generator. The diesel engine also burns fuel supplied through a fuel supply pipe connected to the fuel tank 170 to rotate the drive shaft.

The generator rotates in response to the rotation of the diesel engine and generates electricity. The generated electric power is converted into appropriate three-phase AC power via a rectifier and an inverter housed in the control cabinet 42, and is supplied to a travel motor connected to the rear wheels 43 via a reduction gear. As a result, when the travel motor rotates, the rear wheels 43 rotate and the vehicle travels. When the electric brake is activated, a part of the main circuit of the electric drive system configured in the control cabinet 42 is switched, and regenerated power generated by the travel motor is supplied to the grid box group 44.

The fuel tank 170 is attached to one side of the frame in the width direction between the front wheels 120 and the rear wheels 43. The fuel tank 170 is connected to the diesel engine via a fuel supply pipe, and supplies stored diesel fuel to the diesel engine.

A hydraulic oil tank not shown in the figure is attached to one side of the frame opposite to the fuel tank 170 in the width direction between the front wheels 120 and the rear wheels 43. The hydraulic oil tank is connected to each hydraulic mechanism via a hydraulic oil supply pipe, and supplies the stored hydraulic oil to the hydraulic mechanism.

The body 200 is a part on which a load such as ore, crushed stone, or sand is loaded. The bottom wall surface of the body 200 is inclined so that the front side is lower than the rear side in the illustrated posture. The body 200 can rotate around a portion connected to the rear end of the frame as a fulcrum by expanding and contracting a hydraulic cylinder attached near the center of the frame. The loaded material is released by extending the cylinder and raising the bottom wall surface of the body 200 so that the front side is higher than the rear side.

The canopy 240 extends from the front edge of the body 200 toward the front of the dump truck 40 and is provided over the entire width direction. The canopy 240 is provided to cover the upper part of the deck 41, and protects the cabin 320, control cabinet 42, grid box group 44, etc. arranged on the deck 41 from the loaded objects.

The deck 41 is a plate-shaped structure parallel to the front-back direction and the width direction of the front part of the dump truck 40. The deck 41 provides a boarding path for the operator to the cabin 320 and a compartment for operating and maintaining the control cabinet 42 and the grid box group 44.

The cabin 320 is provided on the left side of the deck 41. The cabin 320 provides a space for the operator of the dump truck 40 to board and operate the dump truck 40. Inside the cabin 320, various devices such as a seat, a steering wheel, an accelerator pedal, a brake pedal, a shift lever, a body operation section, and an image display section are installed.

The control cabinet 42 is arranged at the center of the deck 41 in the width direction, adjacent to the cabin 320. The control cabinet 42 accommodates power electronic devices such as various inverters and rectifiers inside its casing, and configures circuits for various electric devices.

The grid box group 44 is mounted on the right side of the deck 41 in the direction of travel. The illustrated grid box group 44 is composed of six grid boxes 10 (see FIG. 2, etc.).

<First embodiment>
FIG. 2 is an external perspective view of the grid box according to the first embodiment of the present invention.

The grid box 10 converts regenerative power generated by a driving electric motor (hereinafter referred to as the driving motor) that drives the rear wheels of the dump truck into thermal energy when the electric dump truck brakes, and converts the regenerated electric power into thermal energy. It has the function of dissipating to the outside. In appearance, the grid box 10 includes a blower 11, a duct 12, a current plate 13, a housing 15, and a louver 16. One end of the duct is connected to the blower 11, and the other end is connected to the current plate. The other end of the current plate is connected to the housing 15.

The casing 15 is a rectangular body made of a steel plate, and accommodates a group of resistor modules to be described later and others inside the casing 15.

The blower 11 is an axial blower that rotates an electric motor using electric power generated by an auxiliary generator and rotates an impeller 11A by the electric motor (not shown), and cools in the direction of the rotation axis by rotation of the impeller 11A. Generate wind. Cooling air flows from the blower 11 to the duct 12, the rectifying plate 13, and the housing 15 in this order, and is discharged through the louver 16.

The duct 12 connects the blower 11, the rectifying plate 13, and the housing 15. The current plate 13 adjusts the flow of cooling air generated by the blower 11. The louver 16 adjusts the direction in which the cooling air that has passed through the housing 15 is discharged, and also prevents foreign matter from entering from the outside.

In FIG. 1, the grid box 10 has a blower 11 mounted so as to face the right side of the control cabinet 42 in the direction of movement (that is, the louver 16 (see FIG. 2) is exposed on the right side of the dump truck). .

FIG. 3 is a partially exploded perspective view of the grid box 10 of the first embodiment. The configuration of the grid box 10 will be described in detail using FIG. 3.

The duct 12 is a cylindrical body tapered in the direction of flow of cooling air. The duct 12 has a circular open end connected to the blower 11 and a circular open end connected to the rectifier plate 13 so that the blower 11 having a cylindrical outer shape and the rectifier plate 13 having a rectangular outer shape can be connected. is rectangular.

The current plate 13 is a rectangular frame body, and a lattice is formed inside. The cooling air generated by the rotation of the impeller 11A is accompanied by swirling around the rotation axis of the impeller 11A and has a velocity distribution mainly in the radial direction. Reduce.

In the housing 15, a resistor module group 20G in which a plurality of resistor modules 20 are stacked is arranged. Adjacent resistor modules 20 are electrically and mechanically connected to each other by bus bars 32 . Further, the resistor module group 20G is held by partition plates 14A and 14B welded to side plates 15a and 15a of the housing 15, and is mechanically restrained within the housing 15.

The cooling air generated by the blower 11 flows in order within the housing 15 from the resistor module 20 closest to the blower 11 to the other resistor modules 20 adjacent thereto.

FIG. 4 is a perspective view of the resistor module 20 of the first embodiment.

The resistor module 20 includes a resistor group 21G, separators 24 and 25 that are insulating insulators made of porcelain that support the illustrated upper and lower folded parts 21Fa and 21Fb (see FIG. 5) of the resistor group 21G, and separators 24. , 25, and is comprised of left and right side plates 26A and 26B as shown in the figure, which hold both ends of the separators 24 and 25. The side plates 26A, 26B are made of steel, and are bent in advance into a crank shape so as to cover the end faces and upper and lower surfaces of the ends of the separators 24, 25. Furthermore, slits are formed in the crank-shaped portion at positions corresponding to the notches 24B, 25B (FIG. 6) of the separators 24, 25.

From the left-right direction of the side plates 26A, 26B, the shafts 27A, 27B are fitted into the notches 24B, 25B (FIG. 6) of the separators 24, 25 and the above-mentioned slit processing portions of the side plates 26A, 26B. At both longitudinal ends of each shaft 27A, 27B, a male threaded portion having a diameter smaller than that of the central portion thereof is formed, and the male threaded portions are fastened with nuts 28, 28, respectively. This brings the separators 24 and 25 into a mechanically integrated state. The effective length portion of each shaft 27A, 27B (the length portion of the central portion of shaft 27A, 27B) and the nuts 28, 28 are arranged so that the separator 24, It has the function of maintaining a constant interval of 25.

In FIG. 1, the grid box group 44 consumes regenerated power by the resistor group 21G (see FIG. 5, etc.) of the plurality of built-in resistor modules 20. In addition, the temperature rise caused by the heat generation of the resistor group 21G that occurs at this time is alleviated by the cooling air generated by the blower 11 (see FIG. 2), and the temperature of the resistors 21A and 21B (see FIG. 5, etc.) is maintained within an appropriate range. .

FIG. 5 is a perspective view of the resistor group 21G of the first embodiment.

The resistor group 21G consists of an assembly of resistors 21A and 21B and a terminal 23. The resistor 21A and the resistor 21B are formed by pressing rectangular parallelepiped thin metal plates, and have one end in the length direction of the resistor 21A, which is the upper end in the figure, and the other end, which is the lower end in the figure. Step portions 21SA and 21Sb are formed at the end portions, respectively. Step portions 21SA and 21Sb are also formed at one longitudinal end of the resistor 21B, which is the upper end in the figure, and the other end, which is the lower end in the figure. The step portion 21Sa formed at the upper end portion of the resistor 21A and the step portion 21Sb formed at the lower end portion of the resistor 21A are bent in opposite directions by pressing. The stepped portion 21Sa formed at the upper end portion and the stepped portion 21Sb formed at the lower end portion in the figure are also bent in opposite directions by pressing. Further, the resistors 21A and 21B form a folded part 21Fa on the end side of the upper side in the figure with the step portions 21SA and 21Sa on the upper side in the figure as boundaries, and the folded portions 21Fa on the lower side in the figure with the step portions 21SA and 21Sa on the lower side in the figure as boundaries. A folded portion 21Fb is formed on the side end side, a main body portion (resistance body) 21m of the resistor 21A is formed between the stepped portions 21SA and 21Sb of the resistor 21A, and a folded portion 21Fb is formed between the stepped portions 21SA and 21Sb of the resistor 21B. A main body portion (resistor main body) 21m of the resistor 21B is formed in the resistor 21B.

Both the resistor 21A and the resistor 21B are made of materials having the same shape and the stepped portions 21SA and 21Sb, and these materials are alternately turned upside down to form portions corresponding to the folded portions 21Fa and 21Fb. are faced and abutted, and the abutted portions near the stepped portions 21SA, 21Sb are welded, for example, by spot welding, to form welded portions 21WA, 21Wb, thereby mechanically and electrically integrating the two. By repeating this process for a predetermined number of materials, a predetermined number of resistors 21A and 21B are joined in a meandering manner, forming a resistor group 21G having folded portions 21Fa and 21Fb.

The folded portions 21Fa and 21Fb are formed at a base end portion 21F1 having the same width as the resistor bodies 21A and 21B (the resistor body 21m and the step portions 21SA and 21Sb), respectively, and on the end side in the length direction from the base end portion 21F1. The proximal end portion 21F1 has left and right shoulder portions 51, 51 formed at the edge portions continuous to the distal end portion 21F2. In other words, the tip portion 21F2 is located closer to the end in the length direction than the shoulders 51, 51. The welded portions 21WA and 21Wb are formed at the base end portion 21F1.

Further, a notch 52 is formed at the edge of the tip portion 21F2, and the notch 52 has a rectangular shape with an open edge when viewed from the side of the tip portion 21F2 and having a bottom edge and left and right side edges. are doing.

Terminals 23 are welded to the folded portions 21Fa on the upper side in the figure of the resistors 21A and 21B located at both ends of the zigzag fold of the resistor group 21G.

An iron chromium aluminum alloy is used as the material for the resistors 21A and 21B. Further, the plate thickness of the resistors 21A and 21B is 1 mm, and the stacking pitch in the central portion is 10 mm. Note that an iron-nickel-chromium alloy may be used as the material for the resistors 21A and 21B. Moreover, its dimensions are not limited to those mentioned above.

FIG. 6 is a perspective view of the resistor module 20 of the first embodiment at an assembly stage.

A plurality of through holes 24A, 25A are formed in the separators 24, 25 at predetermined intervals in the thickness direction of the resistors 21A, 21B, into which the plurality of folded portions 21Fa, 21Fb of the resistor group 21G are inserted. The through holes 24A and 25A each have a rectangular shape when viewed from above in the paper, and the tip portions 21F2 (see FIG. 5) of the folded portions 21Fa and 21Fb of the resistor group 21G are inserted into the through holes 24A and 25A, respectively. has been done. Terminals 23 welded to the resistors 21A and 21B located at both ends of the meandering resistor group 21G pass through the through holes 25A at both ends of the separator 25. The separators 24 and 25 are also formed with the aforementioned notches 24B and 25B at both ends, respectively.

FIG. 7 is a partially cutaway perspective view of the resistor module 20 of the first embodiment, showing the support structure of the folded portions 21Fa of the resistors 21A and 21B within the through hole 25A of the separator 25.

The tip portions 21F2 of the plurality of folded portions 21Fa of the resistor group 21G are respectively inserted into the plurality of through holes 25A of the separator 25 together with the plurality of adapters 53A made of metal plates, and the plurality of adapters 53A are respectively inserted into the plurality of through holes 25A of the separator 25. The folded portion 21Fa and the side walls of the plurality of through holes 25A facing each other in the thickness direction of the resistors 21A and 21B are in contact with each other. Further, the plurality of adapters 53A are arranged in the plurality of through holes 23A so as to allow deformation in the length direction of the resistors 21A, 21B and restrain displacement of the resistors 21A, 21B in the thickness direction and width direction. The plurality of folded portions 21Fa are slidably supported in the longitudinal direction of the plurality of resistors 21A and 21B. The separator 24 side is similarly configured.

Below, the support structure of the folded portion 21Fa within the through hole 25A will be described in detail.

As described above, the folded portion 21Fa of the resistor group 21G has a base end portion 21F1 and a tip portion 21F2 narrower than the base portion 21F1, and a rectangular notch 52 is provided at the edge of the tip portion 21F2. It is formed.

The width of the tip portion 21F2 of the folded portion 21Fa of the resistor group 21G (the dimension of the tip portion 21F2 in the width direction of the resistors 21A, 21B) W21F2 is the width of the through hole 25A formed in the separator 25 (the size of the tip portion 21F2 in the width direction of the resistors 21A, 21B). The size of the through hole 25A in the width direction) is slightly smaller than W25A1 (W21F2<W25A1), and the tip portion 21F2 of the folded portion 21Fa can be inserted into the through hole 25A of the separator 25. Here, "slightly smaller" means that the width W21F2 of the tip portion 21F2 is as close as possible to the width W25A1 of the through hole 25A, and even when the resistors 21A and 21B thermally expand, A dimension that allows the resistors 21A, 21B to move within the through hole 25A without strongly contacting the wall facing the through hole 25A.

The width W21F1 of the base end portion 21F1 of the folded portion 21Fa of the resistor group 21G (the dimension of the base end portion 21F1 in the width direction of the resistors 21A and 21B) W21F1 is the width of the through hole 25A formed in the separator 25 ( The size of the through hole 25A in the width direction of the resistors 21A and 21B is larger than W25A1 (W21F1>W25A1), and the base end portion 21F1 of the folded portion 21Fa cannot be inserted into the through hole 25A of the separator 25. The length of the distal end portion 21F2 of the folded portion 21Fa is set such that when the distal end portion 21F2 is supported by the adapter 53A within the through hole 25A, the length of the resistors 21A and 21B is increased by thermal expansion. The shoulder portion 51 of the separator 21F1 is dimensioned to be a predetermined distance away from the wall surface 25L on the side where the main body portions 21m of the plurality of resistors 21A, 21B of the separator 25 are located.

FIG. 8 is a perspective view of the adapter of the first embodiment. FIG. 9A is a partial plan view of the separator 25 of FIG. 6 of the first embodiment viewed from above. FIG. 9B is a sectional view taken along the line BB in FIG. 9A. FIG. 9C is a sectional view taken along line CC in FIG. 9A. FIG. 9D is a sectional view taken along the line DD in FIG. 9A.

In FIG. 8, each of the adapters 53A has an arch portion 54A and a pair of opposing plate portions 55A continuous to the arch portion 54A, and each of the pair of plate portions 55A has a first plate portion 56A. , has a second plate portion 57A that is narrower than the first plate portion 56A, wider than the arch portion 54A, and continues to the arch portion 54A, and has an end that is continuous to the second plate portion 57A of the first plate portion 56A. Left and right shoulder portions 55A1, 55A1 are formed at the edge portions. Further, the adapter 53A is shaped such that the tip portions of the pair of plate portions 55A contact the folded portions 21Fa (preferably the proximal portions 21F1 of the folded portions 21Fa) of the resistors 21A and 21B. The adapter 53A is formed by pressing the outer shape of a metal plate and then bending it at the arch portion 54A.

The width W56A of the first plate portion 56A of the plate portion 55A of the adapter 53A is larger than the width W25A1 of the through hole 25A formed in the separator 25 (W56A>W25A1), and the width W57A of the second plate portion 57A of the plate portion 55A is , is smaller than the width W25A1 of the through hole 25A (W57A<W25A1). Thereby, the adapter 53A can be inserted into the through hole 25A of the separator 25 in the second plate portion 57A. Further, the shoulder portion 55A1 of the first plate portion 56A of the adapter 53A, in which the second plate portion 57A is inserted into the through hole 25A, is located on the wall surface 25L on the side where the main body portions 21m of the plurality of resistors 21A and 21B of the separator 25 are located. , and restrains the adapter 53A in that position.

The arch portion 54A of the adapter 53A is fitted into the notches 52 of the resistors 21A and 21B. The width W54A1 of the arch portion 54A is set to be slightly smaller than the dimension W52 of the notch 52 in the resistor width direction (W52>W54A1) to prevent an increase in the length of the resistors 21A and 21B due to thermal expansion within the through hole 25A. It has an acceptable size.

Also, the dimension W54A2 of the adapter 53A in the thickness direction of the resistor when the arch portion 54A is viewed from above is the dimension W25A2 of the through hole 25A in the thickness direction of the resistor (the through hole 25A in the thickness direction of the resistors 21A and 21B). (W54A2>W25A2). As a result, the adapter 53A inserted into the through hole 25A has a portion of the outer surface of both side portions (arch portions 54A) contacting the side walls of the through hole 25A facing in the thickness direction of the resistor, and acts as a leaf spring of the arch portion 54A. The adapter 53A is held in the through hole 25A by the elastic force of the adapter 53A. At this time, the adapter 53A contacts the surfaces of the folded portions 21Fa of the resistors 21A and 21B at the tip portions of the pair of plate portions 55A.

The tip portion 21F2 of the folded portion 21Fa of the resistor group 21G is assembled with the adapter 53A from the side where the main body portions 21m of the plurality of resistors 21A and 21B of the separator 25 are located, and is inserted into the through hole 25A. and is supported by adapter 53A. At this time, the arch portion 54A is inserted into the through hole 25A deeper than the bottom edge of the notch 52 and shallower than the end edge of the tip portion 21F2 of the folded portion 21Fa.

The same applies to the separator 24 (see FIG. 6) side.

As described above, the arch portion 54A of the adapter 53A is inserted into the notch 52 with the inner surface of the arch portion 54A floating above the bottom of the notch 52 formed in the folded portion 21Fa, and a part of the outer surface of the arch portion 54A is It is inserted into the through hole 25A so as to contact the side walls facing each other in the thickness direction of the resistors 21A and 21B of the through hole 25A.

Further, a part of the inner surface of the pair of plate portions 55A of the adapter 53A contacts the tip portion 21F2 of the folded portion 21Fa, and a shoulder portion 55A1 is located at the position where the main body portion 21m of the plurality of resistors 21A and 21B of the separator 25 is located. By contacting the outer surface of the wall surface 25L on the side where the adapter 53A is attached and restraining the movement of the adapter 53A, the adapter 53A supports the tip portion 21F2 of the folded portion 21Fa so as to be slidable in the longitudinal direction of the plurality of resistors 21A and 21B.

FIG. 10 is a perspective view of a resistor module group 20G according to the first embodiment.

In the resistor module group 20G, a plurality of resistor modules 20 are stacked in the width direction of the resistor group 21G. Furthermore, the terminals 23 of adjacent resistor modules 20 are electrically connected to each other by bus bars 32 . Each bus bar 32 is a steel plate that is press-formed and then tin-plated. The bus bar 32 and the terminal 23 are both provided with a round hole (not shown), and are connected by passing a bolt through the hole and fastening with a nut. As a result, all the resistors of the resistor module group 20G are electrically connected in series in a so-called single-stroke pattern.

Partition plates 14A and 14B are located in contact with side plates 26A and 26B (see FIG. 4) of the resistor module 20 located at both ends of the stack. The partition plates 14A and 14B are press-formed steel plates. The partition plates 14A, 14B are welded to the side plates 15a, 15a of the housing 15 (see FIGS. 3 and 11), and the resistor module group 20G is held between the partition plates 14A, 14B.

FIG. 11 is a cross-sectional perspective view of the resistor module group 20G of the first embodiment housed in the housing 15. FIG. 12 is a partially enlarged view of the resistor module group 20G shown in FIG. 11.

Each resistor module 20 is mechanically integrated by fastening with screws (not shown) at the portions where the side plates 15a, 15a and the upper and lower plates 15b, 15b (FIG. 4) of the housing 15 come into contact with each other.

The side plates 15a, 15a and the upper and lower plates 15b, 15b of the housing 15 are each made of different plate materials and are separable. Therefore, by temporarily removing the plate material from the required surface and then removing the screws that mechanically restrain each resistor module 20, a specific resistor module 20 can be separated and taken out. This makes it possible to perform repairs and maintenance on a resistor module basis, improving maintainability.

FIG. 13 is a perspective view of the grid box group 44 of the first embodiment.

In a dump truck, if the braking energy of the dump truck is larger than the capacity of a single grid box, a plurality of grid boxes 10 are mounted on one vehicle. In this embodiment, four grid boxes 10 are integrated to be mounted on one vehicle, forming a grid box group 44. Each grid box 10 is mechanically protected by a suspension body 17 and at the same time allows for suspension by a crane. The grid boxes 10 are mechanically fixed relative to each other through a suspension body 17.

FIG. 14A is a diagram showing an analysis result of heat generation distribution of a resistor in which a through hole is not formed. FIG. 14B is a diagram showing an analysis result of heat generation distribution of a resistor in which an arbitrary through hole is formed.

The resistor 21C in FIG. 14A has a plurality of welded portions 22C near both ends (upper and lower ends). It is electrically connected in series with another adjacent resistor through the welded portion 22C. In this analysis, one of the resistors was extracted and the Joule heat distribution was determined when a predetermined potential was applied between the upper and lower welded parts 22C and a current was passed. From this, it can be seen that almost no current flows at the ends of the welded portion 22C, and the heat generation density is approximately 0, and that the heat generation density at the center of the resistor is approximately equal. The total heat generation amount (work amount) of the resistor 21C, which was obtained by integrating the heat generation density by the resistor volume, was 742W.

Regarding the resistor 21D in FIG. 14B, the Joule heat generation distribution was similarly determined when a predetermined potential was applied between the upper and lower welded parts 22C and a current was passed. In FIG. 14B, it can be seen that the non-uniformity of the heat generation density at the center of the resistor is higher than in FIG. 14A, and especially in the vicinity of the left and right sides of the through hole 21E, the heat generation density is significantly high. Even though a resistor 21D made of the same material as the resistor 21C in FIG. 14A was used and a potential difference was applied in the same way, the calculated total heat generation amount (work amount) of the resistor 21D was 723 W, and the analysis shown in FIG. 14A It was small compared to the result.

FIG. 15A is a diagram showing an analysis result of the temperature of a resistor in which a through hole is not formed. FIG. 15B is a diagram showing an analysis result of the temperature of a resistor in which an arbitrary through hole is formed.

The temperature rise on the surface of the resistor 21C was analyzed when heat was radiated by applying an airflow assumed to be blown from the blower 11 (FIG. 2) from left to right in the paper under the heat generation conditions of FIG. 14A. A uniform maximum temperature increase region was generated on the right side of the paper (downstream side of the airflow) in the center of the resistor 21C. The temperature rise was 438K.

The temperature rise was similarly analyzed for the resistor 21D in FIG. 15B. In response to the heat generation distribution trend of FIG. 14B, a tendency of uneven temperature rise was shown compared to FIG. 15A. Local temperature increases were observed on the left and right sides of the paper surface of the through hole 21E, and the maximum temperature increase was 485 K in this area, which was higher than in the analysis of FIG. 15A.

From the above studies, it can be seen that when a through hole is provided in the portion of the resistor through which current flows, the total heat generation amount (work amount) of the resistor decreases and the temperature rise increases. Both of these reduce the power capacity density of the grid box, reducing its efficiency and performance as a grid box.

In this embodiment, since through holes are not formed in the resistors 21A, 21B, when current flows through the resistors 21A, 21B, the temperature does not locally increase, and the size of the resistors 21A, 21B The total amount of heat generated (work amount) of the resistors 21A and 21B can be increased without increasing the amount of heat, and the efficiency and performance of the grid box are improved.

According to this embodiment, the following effects can be obtained.

1. In this embodiment, the resistors 21A, 21B can relatively slide in the length direction of the resistors 21A, 21B on the contact surfaces with the adapter 53A, so that the current generated by the dynamic braking is applied to the resistors 21A, 21B. When the temperature of the resistors 21A, 21B increases due to the flow, the resistors 21A, 21B can freely expand thermally, and the resistors 21A, 21B do not buckle. As a result, the resistors 21A and 21B can be arranged at high density at short pitches in the thickness direction, increasing the power capacity density of the grid box 10 and improving the efficiency and performance of the grid box.

2. Since the folded portions 21Fa of the resistors 21A, 21B are slidably supported by the adapter 53A, there is no need to form through holes or slits in the resistors 21A, 21B. As a result, when current flows through the resistors 21A, 21B, there is no problem that the temperature near the through hole becomes locally high. The total calorific value of the bodies 21A and 21B can be increased, and the efficiency and performance of the grid box can be improved. Moreover, the maximum temperature of the resistors 21A, 21B is kept low, and the soundness of the resistors 21A, 21B is maintained.

3. Since the resistors 21A and 21B are restrained by the leaf spring properties of the arch portion 54A of the adapter 53A, no deformation or displacement occurs within the through holes 24A and 25A. Also in the width direction of the resistors 21A, 21B, the relative displacement or deformation of the resistors 21A, 21B is restrained by the contact between the adapter 53A and the notch 52, and the contact between the adapter 53A and the through holes 24A, 25A, so that the resistance Displacement and deformation of the bodies 21A, 21B in the width direction can be suppressed.

<Second embodiment>
FIG. 16 is a partially cutaway perspective view of the resistor module of the second embodiment, similar to FIG. It is a diagram. FIG. 17 is a sectional view similar to FIG. 9B, showing a state in which the folded portions 21Fa of the resistors 21A and 21B and the adapter 53B of the second embodiment are inserted into the through hole 25A.

In this embodiment, each of the plurality of adapters 53B has an arch portion 54B, and a pair of opposing plate portions 55B connected to the arch portion 54A, and the entire surface of the pair of plate portions 55B covers the resistor 21A, It is formed into a shape that makes surface contact with the folded portion 21Fa of 21B. The other configuration of the adapter 53B is the same as the adapter 53A of the first embodiment.

In this embodiment, the entire surfaces of the pair of plate portions 55B of the adapter 53B are in surface contact with the folded portions 21Fa of the resistors 21A and 21B. Thereby, the displacement of the resistors 21A and 21B in the thickness direction (left and right direction in the drawing) can be suppressed even more strongly than in the first embodiment. As a result, the distance between adjacent resistors 21A and 21B is always maintained evenly. Therefore, the airflow from the blower 11 that flows between the resistors 21A and 21B is evenly distributed, resulting in a uniform cooling effect, thereby improving the temperature uniformity between the resistors 21A and 21B. In addition, since the spacing between adjacent resistors 21A and 21B is always equal, contact between resistors 21A and 21B can be more reliably prevented, and resistors 21A and 21B can be arranged densely at shorter pitches in the thickness direction. The power capacity density of the grid box 10 can be increased.

<Third embodiment>
FIG. 18 is a partially cutaway perspective view of the resistor module of the third embodiment, similar to FIG. It is a diagram. FIG. 19 is a sectional view similar to FIG. 9B, showing a state in which the folded portions 21FaC of the resistors 21A and 21B and the adapter 53C of the third embodiment are inserted into the through hole 25A.

In this embodiment, each of the folded portions 21FaC of the resistor group 21G has a base end portion 21F1 and a tip portion 21F2C, and the tip portion 21F2 is inserted into the through hole 25A on both sides of the folded portion 21FaC. A pair of bent parts 58, 58 with spring properties are provided which protrude from the surface and extend in the width direction of the folded part 21FaC. The pair of bent portions 58, 58 are formed by bending the materials of the resistors 21A, 21B into a V-shaped cross section by pressing, respectively. The other configuration of the adapter 53C is the same as the adapter 53A of the first embodiment.

In each of the plurality of adapters 53C, the inner surfaces of the pair of plate parts 55A, 55A contact the pair of bent parts 58, 58, and the outer surfaces of the pair of plate parts 55A, 55A contact the resistor 21A of the through hole 25A. , 21B are inserted into the through hole 25A so as to contact the side walls facing in the thickness direction. In addition, the dimensions of the arch portion 54C of the adapter 53C are determined so that the entire surface of the plate portion 55A contacts the side walls facing in the thickness direction of the resistors 21A and 21B of the through hole 25A.

As a result, the bent portion 55 has a spring property and can be expanded and contracted, so that it can slide in the relatively resistive direction while contacting the adapter 53C with a constant frictional force. Therefore, even if there is some error in the size of the through hole 25A, no backlash (vibration) will occur. As a result, the spacing between adjacent resistors is always maintained evenly, and as in the second embodiment, the resistors 21A and 21B can be arranged densely at a shorter pitch in the thickness direction. Power capacity density can be increased.

10: Grid box 11: Air blower 20: Resistor module 20G: Resistor module group 21A, 21B: Resistor 21G: Resistor group 21SA, 21Sb: Step portion 21Fa, 21Fb, 21FaC: Folded portion 21m: Main body of resistor (Resistor body)
21F1: Base end portion 21F2, 21F2C: Tip portion 21WA, 21Wb: Welded portion 23: Terminals 24, 25: Separators 24A, 25A: Through hole 32: Bus bar 44: Grid box group 51: Shoulder portion 52: Notches 53A, 53B, 53C: Adapters 54A, 54B, 54C: Arch portion 55A: Plate portion 56A: First plate portion 57A: Second plate portion 55A1: Shoulder portion 58: Bending portion

Claims (5)

A grid box for an electric drive vehicle mounted on an electric drive vehicle that converts regenerated power generated when a traveling electric motor performs braking into thermal energy and dissipates the thermal energy to the outside,
Equipped with multiple resistor modules and a blower,
Each of the plurality of resistor modules includes:
A resistor group configured by joining a plurality of resistors made of metal plate materials in a meandering shape, and having a plurality of folded parts formed at both longitudinal ends of the plurality of resistors;
a separator made of an insulating material and supporting the plurality of folded portions of the resistor group at both longitudinal ends of the plurality of resistors;
Equipped with multiple adapters made of metal plates,
The separator has a plurality of through holes formed at predetermined intervals in the thickness direction of the plurality of resistors,
The plurality of folded parts of the resistor group are respectively inserted into the plurality of through holes of the separator together with the plurality of adapters,
Each of the plurality of adapters is arranged in the plurality of through-holes so as to allow deformation of the plurality of resistors in the length direction and restrain displacement of the plurality of resistors in the thickness direction and width direction. A grid box for an electrically driven vehicle, characterized in that a plurality of folded portions are slidably supported in the longitudinal direction of the plurality of resistors. The grid box for an electrically driven vehicle according to claim 1,
Each of the plurality of folded portions of the resistor group has a notch formed at its tip,
Each of the plurality of adapters has an arch part and a pair of opposing plate parts connected to the arch part, and the pair of plate parts has a first plate part and a width wider than the first plate part. a second plate portion that is narrow and wider than the arch portion and is continuous with the arch portion, and a shoulder portion is formed at an edge portion of the first plate portion that is continuous with the second plate portion;
The arch portions of the plurality of adapters are inserted into the notches with the inner surfaces of the arch portions floating above the bottoms of the notches of the plurality of folded portions, and a portion of the outer surface of the arch portions is inserted into the notches of the plurality of folded portions. inserted into the plurality of through holes so as to contact the side walls of the holes facing in the thickness direction of the plurality of resistors;
The pair of plate portions of the plurality of adapters have respective inner surfaces in contact with the tip portions of the plurality of folded portions, and the shoulder portions form a wall surface of the separator on the side where the main body portions of the plurality of resistors are located. The plurality of adapters support the tip portions of the plurality of folded portions so as to be slidable in the length direction of the plurality of resistors by contacting the plurality of adapters and restraining the movement of the plurality of adapters. Grid box for electric drive vehicles. The grid box for an electrically driven vehicle according to claim 2,
A grid box for an electrically driven vehicle, wherein the plurality of adapters are formed in a shape such that tip portions of the pair of plate portions contact the plurality of folded portions, respectively. The grid box for an electrically driven vehicle according to claim 2,
The grid box for an electrically driven vehicle, wherein the plurality of adapters are formed in such a shape that the entire surfaces of the pair of plate portions are in contact with the tip portions of the plurality of folded portions, respectively. The grid box for an electrically driven vehicle according to claim 2,
Each of the tip portions of the plurality of folded portions has a pair of bent portions that protrude from both sides of the plurality of folded portions and have spring properties;
In the plurality of adapters, the inner surfaces of the pair of plate portions contact the pair of bent portions, and the outer surfaces of the pair of plate portions contact the plurality of through holes in the thickness direction of the plurality of resistors. A grid box for an electrically driven vehicle, characterized in that the grid box is inserted into the plurality of through holes so as to be in contact with a side wall facing the.

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