Load motor for chassis dynamometer device

Abstract

To provide a load motor 1 for chassis dynamo devices that can be installed in a tire house of an automobile, in which outflowing of a liquid coolant from a coolant flow path is prevented without incurring an increase in thickness.SOLUTION: A first annular groove 501 and a second annular groove 502 that are located inward and outward of a first penetration path 301 and a first communication groove in a radial direction R and concentric with a case 2 are engraved in a region that overlaps the outer edge face in an axial direction X of a peripheral wall part 21 at an inner edge face in an axial direction X of an edge wall part 22. A third annular groove 601 and a fourth annular groove 602 that are located inward and outward of a first penetration path 301 and a first communication groove in a radial direction R and concentric with the case 2 are engraved in a region that overlaps the inner edge face in the axial direction X of the peripheral wall part 21 of the case 2 at an outer edge face in an axial direction X of an annular bracket 101. The inside of all of the first annular groove 501, the second annular groove 502, the third annular groove 601, and the fourth annular groove 602 is filled with a sealant, and a coolant flow path meandering the peripheral wall part 21 in circumferential direction is sealed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a load motor for a chassis dynamometer device that is provided in a chassis dynamometer device for testing the performance of automobiles. [Background technology]

[0002] Conventionally, this type of chassis dynamometer device includes a load motor whose rotor shaft is non-rotatably connected to the drive wheels of an automobile, a wheel contact roller rotatably supported on a machine frame, and a compensation motor whose rotor shaft is fixed to the rotary shaft of the wheel contact roller so as to be non-rotatable relative to the wheel contact roller (see, for example, Patent Document 1). In the load motor, an intermediate shaft extending outside the case is connected to the rotor shaft. A flange portion at the tip of the intermediate shaft is fixed to the hub portion of the drive wheels via a spacer and bolts. In a vehicle performance test, the current and frequency flowing through the load motor are controlled to apply an actual load, i.e., a mechanical load. Then, various values, such as vehicle speed signals, longitudinal load changes, torque changes, and center of gravity shifts, detected by a measuring device equipped with a rotary encoder, resolver, pressure sensor, acceleration sensor, etc., are input in real time to a calculation unit in a control system.

[0003] In addition, among chassis dynamometers, there has been developed a type in which the drive wheels are removed from the drive wheel connector of the automobile and the flange portion of the intermediate shaft extending outward from the load motor case is connected to the drive wheel connector, thereby eliminating the wheel contact roller. The load motor of this chassis dynamometer protrudes significantly outward from the vehicle body, just like the load motors provided in the conventional chassis dynamometers.

[0004] In recent years, in an effort to improve driving safety in automobiles, collision avoidance braking systems, leading vehicle start notification systems, traffic sign recognition systems, false start prevention systems, following distance maintenance assistance systems, lane keeping assistance systems, road departure prevention systems, and the like have been developed, and various sensors are installed on the vehicle body. If such automobiles use the above-mentioned load motors that protrude significantly outward from the vehicle body, the sensors may erroneously detect the load motors as obstacles, causing the automobiles to malfunction. In particular, self-driving cars, which are planned for practical use in the future, will be equipped with many more sensors, so there is an urgent need to solve automobile malfunctions due to erroneous detection of load motors.

[0005] In WO 2019 / 053940, the present applicant has proposed a load motor for a chassis dynamometer, the load motor comprising: a case having a peripheral wall, an end wall, and a hollow portion surrounded by the peripheral wall and the end wall; a stator fixed to the inner surface of the peripheral wall of the case; and a rotor housed inside the hollow portion of the case, rotatably disposed radially inward of the stator, and connectable to a drive wheel coupling of a vehicle. In this load motor, the vehicle width direction is defined as the axial direction, the outer side of the vehicle width direction as the axial outward, and the inner side of the vehicle width direction as the axial inward, with the peripheral wall of the case extending in the axial direction and the end wall of the case provided at the axially outer end of the peripheral wall. When installing the load motor for a chassis dynamometer, the case can be inserted axially outward into a wheel well of the vehicle, and the hollow portion of the case can accommodate a brake disc and brake caliper of the vehicle. The rotor also includes a rotor coupling portion connectable to a drive wheel coupling portion of an automobile, a rotor frame extending radially outward at a position axially outward from the brake caliper when the rotor coupling portion is connected to the drive wheel coupling portion, a rotor circumferential wall portion connected to the radially outer end of the rotor frame and extending axially inward from a connection portion with the radially outer end of the rotor frame, and a magnet fixed to the rotor circumferential wall portion. In the load motor for a chassis dynamometer, the brake caliper is inserted into a space radially inward of the rotor circumferential wall portion when the rotor coupling portion is connected to the drive wheel coupling portion.

[0006] Generally, motors heat up as the rotor rotates, and chassis dynamometer load motors, like the one described above, require cooling. To address this issue, a serpentine axial coolant flow path is provided around the periphery of the case's peripheral wall, allowing for the flow of liquid coolant, such as water or oil. In this case, measures must be taken to prevent the liquid coolant from leaking outside the coolant flow path. O-rings are typically used to prevent liquid coolant leakage, but installing an O-ring on a chassis dynamometer load motor requires thickening the end wall to accommodate the O-ring. This compromises the chassis dynamometer load motor's thin axial thickness. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-20401 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above, an object of the present invention is to prevent the liquid refrigerant from leaking out of the refrigerant flow path without increasing the thickness of the load motor for a chassis dynamometer proposed above. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a load motor for a chassis dynamometer device that is installed in a chassis dynamometer device that performs performance tests on automobiles, the load motor comprising: a case having a peripheral wall portion, an end wall portion, and a hollow portion surrounded by the peripheral wall portion and the end wall portion; a stator fixed to the inner surface of the peripheral wall portion of the case; and a rotor housed inside the hollow portion of the case, rotatably installed radially inward of the stator, and connectable to a drive wheel connecting portion of the automobile, the vehicle width direction of the automobile being the axial direction, the outer side in the vehicle width direction being the axial outward, and the inner side in the vehicle width direction being the axial inward, with the peripheral wall portion of the case extending in the axial direction and the end wall portions of the case extending in the peripheral The case is provided at the axially outer end of the wall portion, and when the load motor for the chassis dynamometer is installed, the case can be inserted from the axially outer side into the tire housing of the automobile, and the hollow portion of the case can accommodate the brake disc and brake caliper of the automobile. The rotor has a rotor connection portion that can be connected to the driving wheel connection portion of the automobile, a rotor frame that extends radially outward at a position axially outer than the brake caliper when the rotor connection portion is connected to the driving wheel connection portion, and a rotor periphery that is connected to the radially outer end of the rotor frame and extends axially inward from the connection portion with the radially outer end of the rotor frame. a wall portion and a magnet fixed to the rotor peripheral wall portion, and a brake caliper is inserted into a space radially inward of the rotor peripheral wall portion with the rotor connecting portion connected to the drive wheel connecting portion, wherein an annular bracket is provided at the axially inner end of the peripheral wall portion of the case, extending radially inward so as to cover the space between the axially inner end and the axially inner end of the rotor peripheral wall portion, a plurality of through passages penetrating in the axial direction are provided at predetermined intervals in the circumferential direction in the peripheral wall portion of the case, and a plurality of first communication grooves are provided on the axially outer end face of the peripheral wall portion of the case, which communicate every other pair of adjacent through passages as a set, Furthermore, a plurality of second communication grooves are provided on the axially inner end surface of the peripheral wall portion of the case, which connect every other pair of adjacent through passages that are not connected by the first communication grooves, and the first communication grooves and second communication grooves are respectively covered by the end wall portion of the case and the annular bracket, and a refrigerant flow path is formed by the through passages, the first communication grooves and the second communication grooves, which allows liquid refrigerant to flow while meandering circumferentially around the peripheral wall portion of the case, and a first annular groove is provided concentric with the case, at a location where the axially inner end surface of the end wall portion of the case overlaps with the axially outer end surface of the peripheral wall portion of the case, and which is located radially outward from the plurality of through passages and the first communication grooves.A second annular groove is carved concentrically with the case and positioned radially inward from the plurality of through passages and the first communicating groove, and a third annular groove is carved concentrically with the case and positioned radially outward from the plurality of through passages and the first communicating groove, and a fourth annular groove is carved concentrically with the case and positioned radially inward from the plurality of through passages and the first communicating groove at a portion where the axially outer end face of the annular bracket overlaps with the axially inner end face of the peripheral wall portion of the case, and a sealant is filled inside all of the first annular groove, second annular groove, third annular groove and fourth annular groove to seal the refrigerant flow path.

[0010] According to the present invention, a refrigerant flow path is formed in the peripheral wall of the case, snaking in the axial direction around the entire circumference. However, the first and second annular grooves carved into the end wall of the case, and the third and fourth annular grooves carved into the annular bracket are all filled with sealant, so leakage of liquid refrigerant flowing through the refrigerant flow path can be prevented, and this can be achieved without increasing the thickness of the load motor for the chassis dynamometer device.

[0011] In the present invention, it is preferable that the end wall portion of the case is fastened to the peripheral wall portion of the case at a predetermined interval, a pair of first radial grooves radially connecting the first annular groove and the second annular groove are formed on both circumferential sides of the fastening portion, the annular bracket is fastened to the peripheral wall portion of the case at a predetermined interval, a pair of second radial grooves radially connecting the third annular groove and the fourth annular groove are formed on both circumferential sides of the fastening portion, and all of the first radial grooves and the second radial grooves are filled with a sealant. According to this, the pair of first radial grooves radially connecting the first annular grooves are formed in the end wall portion of the case on both circumferential sides of the fastening portion to the peripheral wall portion of the case, and the pair of second radial grooves radially connecting the second annular grooves are formed in the annular bracket, and all of the first radial grooves and the second radial grooves are filled with a sealant, which is more effective in preventing liquid refrigerant from leaking out of the refrigerant flow paths. [Brief explanation of the drawings]

[0012] [Figure 1]1A is a cross-sectional view of a main part seen from the side, showing one embodiment of a load motor for a chassis dynamometer of the present invention, and FIG. 1B is an enlarged cross-sectional view of a main part of FIG. 1A. [Figure 2] 2 is a partially cutaway front view of the load motor for the chassis dynamometer shown in FIG. 1, viewed from the end wall side. FIG. [Figure 3] 2 is a partially cutaway front view of a main portion of the annular bracket of the load motor for the chassis dynamometer shown in FIG. 1, as viewed from the axial outside. DETAILED DESCRIPTION OF THE INVENTION

[0013] Referring to Figure 1(a), a load motor for a chassis dynamometer (hereinafter simply referred to as load motor) 1 according to one embodiment of the present invention will be described. The load motor 1 is installed in a chassis dynamometer used to test the performance of automobiles, and can be attached to a drive wheel connector c provided at the end of the automobile's axle. The drive wheel connector c varies depending on the structure of the automobile's vehicle suspension, but is a part that includes a brake disc c1, a wheel hub, etc. The load motor 1 comprises a case 2, a stator 3, and a rotor 4.

[0014] In the following description, the radial direction is referred to as R, and the outer and inner sides thereof as o and i, respectively. The width direction of the automobile is referred to as the axial direction X, the outer side in the vehicle width direction as the outer side o of the axial direction X, and the inner side in the vehicle width direction as the inner side i of the axial direction X. The case 2 has a peripheral wall portion 21, an end wall portion 22, and a hollow portion 23 surrounded by the peripheral wall portion 21 and the end wall portion 22. The peripheral wall portion 21 is a cylindrical member extending in the axial direction X. The end wall portion 22 is a circular member provided at the outer end of the peripheral wall portion 21 in the axial direction X. Details of the end wall portion 22 will be described later.

[0015] The stator 3 is fixed to the inner surface of the peripheral wall 21 of the case 2. A coil is wound around the stator 3, allowing it to receive power from a chassis dynamometer. The rotor 4 is housed in a hollow portion 23 of the case 2 and is rotatably provided on the inner side i of the radial direction R of the stator 3. The rotor 4 can be connected to a drive wheel connecting portion c of the automobile.

[0016] When the load motor 1 is installed, the case 2 can be inserted into the wheel housing of the automobile from the outside o in the axial direction X, as described below. During insertion, the brake disc c1 and brake caliper c2 included in the driving wheel connecting portion c of the automobile are inserted into the hollow portion 23.

[0017] A pedestal 801 is provided at the lower end of the peripheral wall 21 of the case 2. The pedestal 801 has a bearing surface 802 which is an arc-shaped curved surface that follows the outer peripheral surface of the peripheral wall 21, and a flat installation surface 803 which is placed on an installation surface on which an automobile is placed during a performance test. Such pedestals 801 are provided at two locations on the peripheral wall 21 of the case 2, one at the outer end and one at the inner end in the axial direction X.

[0018] The rotor 4 includes a rotor coupling portion 41, a rotor frame 42, a rotor peripheral wall portion 43, and a magnet 44. The rotor coupling portion 41 is a portion responsible for coupling to the drive wheel coupling portion c of the vehicle. The rotor 4 is provided with a shaft member 45 that is separate from the rotor frame 42, and the shaft member 45 has the rotor coupling portion 41 on the inner side i in the axial direction X. The rotor frame 42 is coupled to the shaft member 45 at its inner end in the radial direction R. Specifically, the shaft member 45 is a member that extends in the axial direction X, and includes a cylindrical rotor frame fixing portion 45a and a cylindrical rotor frame fixing positioning portion 45b. A thread groove is formed on the outer peripheral surface of the rotor frame fixing portion 45a from its outer end to the middle in the axial direction X. Furthermore, the inner end portion in the axial direction X of the rotor frame fixing portion 45a is bent outward o in the radial direction R, and the outer end portion of the bent portion 45a1 is bent inward i in the axial direction X to form the rotor frame fixing and positioning portion 45b, which extends inward i in the axial direction X. A part of the outer end surface in the axial direction X at the base of the bent portion 45a1 of the rotor frame fixing portion 45a forms a conical surface 45a2 that widens outward o in the radial direction R. A plurality of pins 5 that protrude outward o in the axial direction X are implanted at predetermined intervals on a concentric circle in the rotor frame positioning and fixing portion 45b. The inner end portion in the axial direction X of the rotor frame fixing and positioning portion 45b is bent outward o in the radial direction R, and this bent portion forms the rotor connecting portion 41. A plurality of insertion holes 6 that penetrate in the axial direction X are formed in the rotor connecting portion 41. The through holes 6 allow fasteners such as bolts to be inserted therethrough and are arranged concentrically at predetermined intervals. The through holes 6 can also face one-to-one with a plurality of screw holes (not shown) that penetrate the drive wheel connecting portion c of the brake disc c1 or the like in the vehicle width direction. The shaft member 45 is connected to the drive wheel connecting portion c by inserting fasteners such as bolts through each of the through holes 6 of the rotor connecting portion 41 and screwing them into each of the screw holes in the drive wheel connecting portion c.

[0019] With the rotor coupling portion 41 coupled to the drive wheel coupling portion c, the rotor frame 42 extends outward o in the radial direction R at a position outward in the axial direction X from the brake caliper c2. Specifically, the rotor frame 42 includes a first upright portion 42a extending outward o in the radial direction R, and a second upright portion 42b formed separately from the first upright portion 42a and extending outward o in the radial direction R. An inner end portion 42a1 in the radial direction R of the first upright portion 42a is bent outward o in the axial direction X and has a protruding portion 42a2 protruding inward i in the radial direction R. A plurality of pin holes 7 into which pins 5 can be inserted are formed in an inner portion of the inner end portion 42a1 in the axial direction X. Furthermore, both inner peripheral end surfaces of the inner and outer ends of the protruding portion 42a2 in the axial direction X form conical surfaces that widen outward o in the radial direction R. Meanwhile, an outer end 42a3 in the radial direction R of the first upright portion 42a is bent inward i in the axial direction X to such an extent that it does not come into contact with the brake caliper c2, forming a flange shape. Furthermore, a cylindrical shaft 42d is provided in an intermediate portion between the inner end 42a1 and the outer end 42a3 of the first upright portion 42a, protruding outward o in the axial direction X. The shaft 42d is formed integrally with the first upright portion 42a.

[0020] The first upright portion 42a and the second upright portion 42b are connected to each other via the torque sensor 8. That is, the inner end portion in the radial direction R of the second upright portion 42b has a flange shape similar to the outer end portion 42a3 of the first upright portion 42a, and a plurality of threaded holes penetrating in the axial direction X are formed in each of the outer end portion 42a3 of the first upright portion 42a and the inner end portion of the second upright portion 42b. Therefore, the first upright portion 42a and the second upright portion 42b are connected to each other via the torque sensor 8 by overlapping the inner end faces in the axial direction X of both the inner and outer ends in the radial direction R of the torque sensor 8 with the outer end faces in the axial direction X of the outer end portion 42a3 of the first upright portion 42a and the outer end faces in the axial direction X of the inner ends of the second upright portion 42b, and screwing a bolt 9 into each of the threaded holes from the outside o in the axial direction X of the torque sensor 8.

[0021] The torque sensor 8 is a sensor that measures the torque applied to the shaft, and can be, for example, a non-contact type that detects torque without contact by utilizing the magnetostrictive effect. In this case, a transmitter 8a can be provided in the torque sensor 8 on the side facing the end wall 22. The transmitter 8a can include, for example, a strain gauge, a converter that converts the output signal of the strain gauge into a voltage, and an antenna that transmits the resulting voltage signal. When such a transmitter 8a is provided in the torque sensor 8, a receiver that receives the transmitted signal from the antenna can be provided on the inner end surface of the end wall 22 in the axial direction X, facing the transmitter 8a, and the signal received by the receiver can be input to an evaluation unit, enabling torque analysis, etc.

[0022] The rotor circumferential wall portion 43 is connected to the radially outer end of the second upright portion 42b of the rotor frame 42, and extends inward i in the axial direction X from a connection portion 43a where the second upright portion 42b connects to the radially outer end of the second upright portion 42b. A plurality of magnets 44 are provided at predetermined intervals around the rotor circumferential wall portion 43, and a predetermined gap g is provided between the radially outer end face of each magnet 44 and the radially inner end face of the stator 3. When the outer end of the rotor circumferential wall portion 43 in the axial direction X is bent, the outer end position of this outer end in the radial direction R is set within a range that ensures the gap g. A portion of the outer end of the rotor circumferential wall portion 43 that is closest to the end wall portion 22 protrudes slightly outward o in the radial direction R, and this protrusion can be used for positioning when fixing the magnet 44.

[0023] The end wall portion 22 has a first cover 11, which includes an outer cover portion 11a that forms the outer periphery of the end wall portion 22 and an inner cover portion 11b that forms the inner periphery of the end wall portion 22. The outer cover portion 11a and the inner cover portion 11b are connected on the same plane. Referring to FIG. 1(b), an annular protrusion 11a1 that protrudes inward in the axial direction X is provided at the outer end portion of the outer cover portion 11a in the radial direction R. A first annular recessed portion 21a is recessed at the outer end portion of the peripheral wall portion 21 in the axial direction X that faces the annular protrusion 11a1. The attachment position of the outer cover portion 11a to the peripheral wall portion 21 is determined by positioning the annular protrusion 11a1 in the first annular recessed portion 21a. The outer cover portion 11a is fastened to the inner cover portion 11b by threading bolts 12 into bolt screw holes 21a1 formed at the outer end of the peripheral wall portion 21 in the axial direction X through bolt insertion holes 11a2 formed at predetermined intervals in the outer peripheral edge portion. The inner end of the inner cover portion 11b in the radial direction R is bent outward o in the axial direction X to form the body portion 14a of the rotation support portion 14. The body portion 14a is cylindrical, and an inner ring rotation type bearing 15 is attached to the inner surface of the body portion 14a. The cylindrical shaft 42d of the rotor frame 42 protrudes inward i in the radial direction R of the body portion 14a, and the bearing 15 is interposed between the cylindrical shaft 42d and the body portion 14a.

[0024] Furthermore, the rotation support part 14 has a hollow space between the inner end part 42a1 of the rotor frame 42 and the cylindrical shaft 42d, and the rotation sensor 16 is housed in the space 14b. The rotation sensor 16 is composed of a magnetic pickup 16a attached with screws 19 to a first bracket 18 fixed with screws 17 to the outer end face of the body part 14a in the axial direction X, and a sensor gear 16b fitted and fixed to the inner end part 42a1 of the first upright part 42a of the rotor frame 42. The interior of the rotation support part 14, including the rotation sensor 16, is covered and hidden from the outside o in the axial direction X by a second cover 51 attached to the first bracket 18 with screws 20. The second cover 51 is ring-shaped, and a sub-cover 52, which is removed when the nut 10 is removed, is screwed to its center.

[0025] When installing the load motor 1, after connecting the shaft member 45 to the drive wheel connection portion c at the rotor connection portion 41, the pin 5 is inserted into the pin hole 7 with the protrusion 42a2 fitted onto the rotor frame fixing portion 45a, thereby determining the fixing position of the rotor frame 42. In this state, when the nut 10 is screwed inward i from the outer end of the rotor frame fixing portion 45a in the axial direction X, the inner end surface of the protrusion 42a2 in the axial direction comes into close contact with the conical surface 45a2 of the bent portion 45a1 of the rotor frame fixing portion 45a. The outer peripheral surface of the inner end of the nut 10 in the axial direction X is also a conical surface that flares outward o in the axial direction X, so that the inner end surface of the nut 10 in the axial direction X comes into close contact with the outer peripheral end surface of the protrusion 42a2 in the axial direction X, which faces outward o in the axial direction. In this way, the rotor frame 42 is connected to the shaft member 45 at the inner end 42a1, and the rotor 4 becomes rotatable together with the drive wheel connecting portion c.

[0026] When the rotor coupling portion 41 is coupled to the drive wheel coupling portion c, the brake caliper c2 is inserted into the space 23a in the hollow portion 23, on the inner side i in the radial direction R of the peripheral wall portion 21. Therefore, the rotor frame 42 and the brake caliper c2 are not in contact with each other and do not interfere with each other, so there is no need to remove the brake caliper c2 from the vehicle body when installing the load motor 1. Furthermore, the distance in the axial direction X from the rotor coupling portion 41 to the end wall portion 22 of the case 2 can be shortened, and when the rotor coupling portion 41 is coupled to the drive wheel coupling portion c of the vehicle, the protrusion of the rotation support portion 14 of the load motor 1 can be made smaller than the amount by which the wheel protrudes outward from the wheel well when the vehicle's steering wheel is operated to move the wheel left and right, thereby preventing the end wall portion 22 of the case 2 from protruding significantly outward from the wheel well of the vehicle. In this way, the distance in the axial direction X from the rotor connecting portion 41 to the end wall portion 22 is shortened, and the protrusion of the rotation support portion 14 of the load motor 1 is smaller than the amount of protrusion of the vehicle's wheels outward from the wheel well when the vehicle's steering wheel is operated to move the wheels left and right. This prevents various sensors installed in the vehicle from erroneously detecting the load motor 1 as an obstacle, thereby preventing vehicle malfunctions due to sensor erroneous detection and enabling highly reliable vehicle performance testing. Furthermore, since the torque sensor 8 is installed in the rotor frame 42 of the load motor 1, the load motor 1 has a built-in torque sensor 8, and the torque sensor 8 does not protrude outward in the vehicle width direction. This further reduces erroneous detection by various sensors installed in the vehicle. Note that the torque sensor 8 does not necessarily need to be installed in the rotor frame 42, as long as erroneous detection by various sensors installed in the vehicle can be reduced. A measuring device for measuring torque can also be installed separately from the load motor 1.

[0027] During vehicle performance testing, the load motor 1 can be connected to a drive wheel connector c to which wheels corresponding to the drive wheels are connected. The drive wheel connector c can be connected to two front wheels if the vehicle is front-wheel drive, two rear wheels if the vehicle is rear-wheel drive, or all four wheels if the vehicle is four-wheel drive. In this case, the vehicle's wheels along with the wheels on which the tires are mounted are removed, and the load motor 1 is inserted into the vehicle's wheel housing from the outside o in the axial direction X. Furthermore, if the drive wheel connector c to be connected to the rotor connector 41 is a wheel hub, multiple bolts are embedded concentrically in the wheel hub at predetermined intervals, protruding outward in the vehicle width direction. Therefore, the bolts embedded in the wheel hub can be used to connect the rotor connector 41 and the drive wheel connector c. In this case, the bolts are inserted into the insertion holes 6 opened in the rotor connector 41 from the inside i in the axial direction X, protruding into the hollow portion 23 of the case 2. Then, a wrench can be used to screw the nut onto the bolt, thereby fastening the rotor connecting portion 41 to the drive wheel connecting portion c.

[0028] In the load motor 1, a second bracket 101 is provided at the axially inner end of the peripheral wall 21 of the case 2 as an annular bracket extending inward i in the radial direction R so as to cover the space between the axially inner end and the inner end of the rotor peripheral wall 43 in the axial direction X. Referring to FIG. 1(c), the second bracket 101 has an annular first flange 101a at its outer peripheral edge offset outward o in the axial direction X. The outer end of the first flange 101a in the radial direction R is capable of contacting the inner end of the peripheral wall 21 of the case 2 in the axial direction X, and the inner end of the first flange 101a in the radial direction R has an annular positioning portion 101b protruding outward o in the axial direction X. The inner end of the peripheral wall 21 of the case 2 in the axial direction X has a second annular recessed portion 21b directly opposite the positioning portion 101b. The mounting position of the second bracket 101 to the case 2 is determined by inserting the positioning portion 101b into the second annular recessed portion 21b. With the second bracket 101 positioned in this manner, bolts 103 are threaded from the outside of the first flange portion 101a in the axial direction X via washers 102 into the outward side o in the axial direction X of the peripheral wall portion 21, thereby fastening the second bracket 101 to the case 2. In order to smoothly thread the bolts 103, bolt insertion holes 101a1 are provided in the first flange portion 101a, and bolt threading holes 21b1 are provided in the inner end of the peripheral wall portion 21 in the axial direction X, both of which are provided at predetermined intervals in the circumferential direction of the peripheral wall portion 21.

[0029] 1(d), the second bracket 101 also has an annular second flange portion 101c at its inner end in the radial direction R, which is offset outward o in the axial direction X. The inner end of the second flange portion 101c in the radial direction R is not in contact with the rotor circumferential wall portion 43, and to enable this non-contact state, a third annular recessed portion 43b1 is provided at the inner end 43b of the rotor circumferential wall portion 43, which is offset inward i in the radial direction R. A dustproof ring 104 made of a material having a lower hardness than the material of the rotor circumferential wall portion 43 is fastened to the second flange portion 101c with screws 105, so that the inner peripheral edge of the dustproof ring 104 is in contact with the outer peripheral surface of the third recessed portion 43b1, which is the outer peripheral surface of the inner end of the rotor circumferential wall portion 43 in the axial direction X. For this reason, as the rotor 4 rotates, the inner peripheral edge of the dustproof ring 104 is scraped away by contact with the outer peripheral surface of the second recessed portion 43b1, i.e., the outer peripheral surface of the inner end in the axial direction X of the rotor circumferential wall portion 43. As a result, a gap large enough to prevent dust from entering is formed between the dustproof ring 104 and the inner end in the axial direction X of the rotor circumferential wall portion 43. This makes it possible to prevent dust generated by brake operation during a performance test from entering the inside of the load motor 1, i.e., the space 23a.

[0030] 1(a), 1(b), 1(c), 2 and 3, a plurality of through passages 301 penetrating in the axial direction X are provided at predetermined intervals in the circumferential direction in the peripheral wall portion 21 of the case 2, and first communication grooves 302 that connect every other pair of adjacent through passages 301 as a set are provided in the outer end face in the axial direction X of the peripheral wall portion 21. Furthermore, second communication grooves (not shown) similar to the first communication grooves 301 are provided in the inner end face in the axial direction X of the peripheral wall portion 21 that connect every other pair of adjacent through passages 301 that are not connected by the first communication grooves 302 as a set. The first communicating groove 302 and the second communicating groove are covered by the end wall portion 22 and the second bracket 101 of the case 2, respectively. The through passage 301, the first communicating groove 302, and the second communicating groove form a refrigerant flow path through which a liquid refrigerant, such as water or oil, can flow while meandering in the circumferential direction around the peripheral wall portion 21 of the case 2. This refrigerant flow path is connected to an inlet port 401 and an outlet port 402 connected to the bottom of the outer cover portion 11a of the end wall portion 22. When an inlet pipe (not shown) is connected to the inlet port 401 and an outlet pipe (not shown) is connected to the outlet port 402, respectively, the liquid refrigerant flows through the refrigerant flow path via the inlet port 401 and flows out from the outlet port 402. By circulating the liquid refrigerant through the refrigerant flow path, the load motor 1 can be cooled during automobile performance testing, and the temperature rise associated with the rotation of the rotor 4 can be suppressed.

[0031] Further, the end wall portion 22 of the case 2 is provided with a first annular groove 501 concentric with the case 2 and positioned outward o in the radial direction R from the plurality of through passages 301 and the plurality of first communicating grooves 302, and a second annular groove 502 concentric with the case 2 and positioned inward i in the radial direction R from the plurality of through passages 301 and the plurality of first communicating grooves 302, at a location where the end wall portion 22's outer end face in the radial direction R overlaps with the outer end of the peripheral wall portion 21's axial direction X. Further, the second bracket 101 is provided with a third annular groove 601 concentric with the case 2 and positioned outward o in the radial direction R from the plurality of through passages 301 and the plurality of first communicating grooves 302, and a fourth annular groove 602 concentric with the case 2 and positioned inward i in the radial direction R from the plurality of through passages 301 and the plurality of first communicating grooves 302, at a location where the end wall portion 22's outer end face in the radial direction R overlaps with the inner end face of the peripheral wall portion 21's axial direction X.

[0032] In the load motor 1, the first annular groove 501, the second annular groove 502, the third annular groove 601, and the fourth annular groove 602 are all filled with a sealant 901 to seal the refrigerant flow path. Therefore, in the load motor 1, the refrigerant flow path is formed in the peripheral wall portion 21 of the case 2, snaking in the axial direction X around its entire circumference. However, because the first annular groove 501, the second annular groove 502, the third annular groove 601, and the fourth annular groove 602 are all filled with the sealant 901, leakage of the liquid refrigerant flowing through the refrigerant flow path can be prevented without an O-ring, and this can be achieved without increasing the thickness of the load motor 1. If an O-ring were provided, the end wall portion 22 and the second bracket 101 would have to be thickened by about 7 mm to form a recess for attaching the O-ring, resulting in a total thickness increase of 14 mm. However, because sealing can be achieved without an O-ring, such an increase in thickness can be avoided in the load motor 1.

[0033] 2 and 3, in the load motor 1, the end wall portion 22 of the case 2 and the second bracket 101 are respectively provided with a pair of first radial grooves 701 connecting the first annular groove 501 and the second annular groove 502 in the radial direction R on both circumferential sides of the bolt insertion hole 101a1, i.e., a fastening portion with the peripheral wall portion 21 of the case 2, and a pair of second radial grooves 702 connecting the third annular groove 601 and the fourth annular groove 602 in the radial direction R on both circumferential sides of the fastening portion with the peripheral wall portion 21 of the case 2. As with the first annular groove 501, the second annular groove 502, the third annular groove 601, and the fourth annular groove 602, a sealant 901 is filled inside all of the first radial grooves 701 and the second radial grooves 702. Filling the first radial grooves 701 and the second radial grooves 702 with the sealant 901 is effective in preventing the liquid refrigerant from leaking out of the refrigerant flow path.

[0034] The cross-sectional shapes of the first annular groove 501, the second annular groove 502, the third annular groove 601, the fourth annular groove 602, the first radial groove 701, and the second radial groove 702 are not particularly limited. An appropriate shape capable of holding the sealant 901 can be selected from various shapes such as semicircular, rectangular, and trapezoidal. The type of sealant 901 to be filled is also not particularly limited, as long as it has high sealing properties. For example, a silicone-based liquid gasket can be used.

[0035] Although one embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited thereto. The details of the rotor rotation support structure, the configuration and structure of the drive wheel coupling portion, the end wall structure, and the annular bracket structure, etc., can be varied in the present invention, including those that are conventionally known. [Explanation of symbols]

[0036] 1...load motor for chassis dynamometer, 2...case, 21...circumferential wall portion, 22...end wall portion, 23...hollow portion, 23a...space radially inner of rotor peripheral wall portion 43, 3...stator, 4...rotor, 41...rotor coupling portion, 42...rotor frame, 43...rotor peripheral wall portion, 43a...connection portion at radially outer end of rotor frame 42, 44...magnet, 101...second bracket (annular bracket), 301...through passage, 302...first communicating groove, 501...first annular groove, 502...second annular groove, 601...third annular groove, 602...fourth annular groove, 701...first radial groove, 702...second radial groove, 901...sealant, c...drive wheel coupling portion, c1...brake disc, c2...brake caliper, X...axial direction, R...radial direction, o...outside, i...inside.

Claims

1. A load motor for a chassis dynamometer device provided in a chassis dynamometer device for performing performance tests on automobiles, The rotor is provided with a case having a peripheral wall, an end wall, and a hollow portion surrounded by the peripheral wall and the end wall, a stator fixed to the inner surface of the peripheral wall of the case, and a rotor housed inside the hollow portion of the case, rotatably disposed radially inward of the stator, and connectable to a drive wheel connecting portion of an automobile, The width direction of the automobile is defined as the axial direction, the outer side of the width direction is defined as the axial outward direction, and the inner side of the width direction is defined as the axial inward direction, with the peripheral wall portion of the case extending in the axial direction and the end wall portion of the case being provided at the outer end of the axial direction of the peripheral wall portion, the case can be inserted into the tire house of the automobile from the outer axial direction when installing the load motor for the chassis dynamo device, and the brake disc and brake caliper of the automobile can be inserted into the hollow portion of the case, The rotor comprises a rotor connecting portion connectable to a drive wheel connecting portion of an automobile, a rotor frame extending radially outward at a position axially outward from the brake caliper when the rotor connecting portion is connected to the drive wheel connecting portion, a rotor circumferential wall portion connected to the radially outer end of the rotor frame and extending axially inward from a connection portion with the radially outer end of the rotor frame, and a magnet fixed to the rotor circumferential wall portion, and when the rotor connecting portion is connected to the drive wheel connecting portion, a brake caliper is inserted into a space radially inward of the rotor circumferential wall portion, an annular bracket is provided at an axially inner end of the peripheral wall portion of the case, the annular bracket extending radially inward so as to cover a space between the axially inner end of the peripheral wall portion of the case and the axially inner end of the rotor peripheral wall portion; A plurality of through passages penetrating in the axial direction are provided at predetermined intervals in the circumferential direction in the peripheral wall portion of the case, a plurality of first communication grooves are provided in the axial outer end face of the peripheral wall portion of the case, which connect every other pair of adjacent through passages as a set, and a plurality of second communication grooves are provided in the axial inner end face of the peripheral wall portion of the case, which connect every other pair of adjacent through passages that are not connected by the first communication grooves as a set, the first communication groove and the second communication groove are covered by the end wall portion of the case and the annular bracket, respectively, and the through passage, the first communication groove, and the second communication groove form a refrigerant flow path that allows the liquid refrigerant to flow while meandering circumferentially around the peripheral wall portion of the case; a first annular groove concentric with the case and positioned radially outward from the plurality of through passages and the first communicating grooves, and a second annular groove concentric with the case and positioned radially inward from the plurality of through passages and the first communicating grooves, engraved at a position where the axially inner end surface of the end wall portion of the case overlaps with the axially outer end surface of the peripheral wall portion of the case; a third annular groove concentric with the case and positioned radially outward from the plurality of through-passages and the first communicating groove, and a fourth annular groove concentric with the case and positioned radially inward from the plurality of through-passages and the first communicating groove, are engraved at a portion where the axially outer end surface of the annular bracket overlaps with the axially inner end surface of the peripheral wall portion of the case; A load motor for a chassis dynamometer, characterized in that the first annular groove, the second annular groove, the third annular groove and the fourth annular groove are all filled with a sealant to seal the refrigerant flow path.

2. 2. A load motor for a chassis dynamometer as claimed in claim 1, wherein the end wall portion of the case is fastened to the peripheral wall portion of the case at a predetermined interval, a pair of first radial grooves are formed on both circumferential sides of the fastening portion to radially connect the first annular groove and the second annular groove, the annular bracket is fastened to the peripheral wall portion of the case at a predetermined interval, a pair of second radial grooves are formed on both circumferential sides of the fastening portion to radially connect the third annular groove and the fourth annular groove, and a sealant is filled inside all of the first radial grooves and the second radial grooves.

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