JP4466291B2 - Eddy current reducer - Google Patents

Description

The present invention relates to an eddy current reduction device, and more particularly to an improvement of an eddy current reduction device of a type in which a magnetic field is applied to a braking disk connected to a rotating shaft of an engine.

  There are several types of eddy current type speed reducers used for auxiliary brakes of large vehicles such as trucks. Focusing on the shape of the braking member connected to the rotating shaft of the engine, it is roughly divided into a type that employs a disc-shaped braking member (disc type) and a type that employs a drum-shaped braking member. Focusing on the configuration that generates magnetism, it is roughly divided into those using permanent magnets, those using electromagnets, and so-called hybrid types using both permanent magnets and electromagnets.

  Japanese Patent Application Laid-Open No. 2003-338825 discloses an eddy current reduction device that improves durability and suppresses deformation by changing the thickness of a disc-shaped braking member between an inner peripheral side and an outer peripheral side.

JP2003-333825A

  In a disk-type eddy current reduction device, the brake disk generates heat and deforms (thermal expansion) during braking, and inelastic strain (plastic strain and creep strain) occurs in the brake disk, resulting in permanent deformation. is there. As a result, fatigue cracks may occur on the surface of the brake disk. When permanent deformation occurs in the brake disk, the distance between the magnet and the disk changes, the brake force cannot be kept constant, and a stable brake force cannot be obtained for a long time. Further, when a fatigue crack occurs on the disk surface, the flow of eddy current generated during braking is interrupted by the crack, and the flow of eddy current deteriorates and the braking force decreases.

The present invention has been made in view of the above situation, and even when used for a long period of time, a stable braking force with small deformation with time of the disk is obtained, and fatigue cracks hardly occur. An object of the present invention is to provide an eddy current type speed reducer with excellent durability.

  In order to achieve the above object, an eddy current reduction device according to a first aspect of the present invention includes a braking disk coupled to a rotating shaft of an engine; and a magnetic field applied to a braking surface of the braking disk during braking. And a plurality of spoke-like support members that support the braking disk with respect to the rotating shaft on a surface opposite to the braking surface of the braking disk. Each of the spoke-like support members extends from the center direction of the braking disk toward the outer circumferential direction, and is inclined with respect to the radial direction of the disk and opposite to the rotation direction during braking of the disk. The

  An eddy current reduction device according to a second aspect of the present invention includes a braking disk coupled to a rotating shaft of an engine; a magnetic field generating unit that applies a magnetic field to a braking surface of the braking disk during braking; A plurality of spoke-like support members that support the braking disk with respect to the rotating shaft are provided on a surface opposite to the braking surface of the disk. Each of the spoke-like support members has a spoke portion that is fixed to the brake disk and a connecting portion that is connected to the outer peripheral portion of the rotating shaft. Further, when the support member is viewed in a cross section perpendicular to the surface of the brake disk and along the longitudinal direction of the spoke-like support member, the center line of the connecting portion is deviated from the center line of the spoke portion.

  An eddy current reduction device according to a third aspect of the present invention is a combination of the first and second aspects described above, a braking disk connected to the rotating shaft of the engine; A magnetic field generating section that applies a magnetic field to the braking surface; and a plurality of spoke-like support members that support the braking disk with respect to the rotating shaft on a surface opposite to the braking surface of the braking disk. Each of the spoke-like support members has a spoke portion that is fixed to the brake disk and a connecting portion that is connected to the outer peripheral portion of the rotating shaft. Each of the spoke-like support members extends from the center direction of the braking disk toward the outer circumferential direction, and is inclined with respect to the radial direction of the disk and opposite to the rotation direction during braking of the disk. Further, when the support member is viewed in a cross section perpendicular to the surface of the braking disk and along the longitudinal direction of the spoke-like support member, the center line of the connecting portion is deviated from the center line of the spoke portion.

  In the present invention, preferably, the angle of the spoke-like support member is set to 30 to 70 degrees toward the opposite side to the rotation direction during braking of the braking disk.

  According to the first to third aspects of the present invention, in order to increase the durability of the brake disk, the deformation of the brake disk is not excessively restrained by the support portion, and the generated inelastic strain is reduced. Accordingly, the radial and axial deformations of the disc during braking can be absorbed by the elastic deformation of the spoke-like support portion, and inelastic strain is hardly generated in the brake disc and the support portion. As a result, it is possible to effectively suppress the occurrence of permanent deformation in the brake disk and the reduction of the braking force or the occurrence of fatigue cracks. Furthermore, when the shape of the brake disk is a ring shape for the purpose of reducing the weight of the brake disk, the strength of the disk itself can be increased by providing a spoke-like support portion on the opposite side to the brake surface.

In a fourth aspect of the invention, a braking disk connected to the rotating shaft of the engine;
A magnetic field generator for generating a magnetic field with respect to the braking surface of the braking disk at the time of braking; and a plurality of members that support the braking disk with respect to the outer peripheral portion of the rotating shaft on a surface opposite to the braking surface of the braking disk A position where the support member and the inner peripheral edge of the braking disk intersect with each other; X1; a position where the support member intersects with the outer peripheral edge of the rotation shaft of the engine; and X2; The center of rotation is O; a straight line passing through the position X1 and the center of rotation O of the brake disk is L1; a straight line passing through the position X2 and the center of rotation of the brake disk is L2, and the support member is directed inward at the position X1. L3; a direction extending the support member outward at the position X2; L4; a straight line connecting the position X1 and the position X2; L5; L2 and L4 θ3 and angle between L2 and L5;; .theta.2 the angle formed L1 and the L3 is; corners of θ1 formed by the case of the θ4 the angle between L1 and L5, a structure which satisfies the following expression.
θ1 <θ3 (1)
θ2 <θ4 (2)

The support member is bent so as to satisfy the above conditions, and the inclination angles θ3 and θ4 of the support member are increased, and the coupling portion angles θ1 and θ2 of the support member are decreased, thereby reducing the radial direction and the axial direction of the brake disk. The deformation can be further absorbed by the elastic deformation of the spoke-like support member, and also occurs at the joint portion between the support member and the outer peripheral edge of the rotating shaft of the engine and the joint portion between the support member and the brake disk during braking. Inelastic strain can be reduced.

  Hereinafter, the present invention will be described by taking as an example an eddy current type speed reducer in which a permanent magnet is brought close to and away from a disc-shaped braking member. The technical idea of the present invention can also be applied to an apparatus adopting an electromagnet type or a hybrid type combining an electromagnet and a permanent magnet as a magnetic field generation mechanism.

  FIG. 1 is a cross-sectional view showing the structure of the main part of an eddy current type speed reducer (retarder) according to a first embodiment of the present invention. The eddy current type speed reducer 10 according to the present embodiment includes a braking disk 14 made of a ferromagnetic material connected and fixed to a rotating shaft 12 of an engine, and a braking unit (16, 26) disposed in the vicinity of the braking disk 14. , 28, 30, 32, 34). The brake disk 14 is attached to the rotating shaft 12 by a ring-shaped holding member 18 fixed to the outer periphery of the rotating shaft 12, an annular fixing ring 20 fixed to the flange portion of the holding member 18, and a spoke-like support member 22. It is connected.

  The rotating shaft 12 is connected to a propeller shaft of a large vehicle (truck), for example. The brake disk 14 is formed into a disk shape.

  The braking unit includes a plurality of permanent magnets 16 that generate a magnetic field for braking; a ring-shaped or arc-shaped magnet holding member 26 that holds the permanent magnet 16; and a case that houses the permanent magnet 16 and the magnet holding member 26 30; and an air cylinder 32, a piston rod 28, and a piston 34, which are connected to the magnet holding member 26 and serve as a drive mechanism for moving the permanent magnet 16 toward and away from the brake disk 14.

  The case 30 can be formed of a material such as aluminum, aluminum alloy, carbon steel, cast iron, stainless steel, or the like. In the circumferential direction of the annular magnet holding member 26, the permanent magnet 16 is opposed to the surface of the braking disk 14 (braking surface = left side in the figure), and a plurality of permanent magnets having adjacent magnetic pole surfaces arranged in opposite directions. It consists of pieces. Then, the magnet 16 approaches the surface of the braking disk 14 to enter a braking state, and moves away from the braking disk 14 to enter a non-braking state.

  FIG. 1 shows a “pole piece-less” structure in which no pole piece is arranged between the permanent magnet 16 of the case 30 and the braking disk 14. However, in order to prevent a reduction in braking force and during non-braking In order to prevent magnetic leakage, a structure provided with a pole piece made of a soft magnetic material may be employed. In this embodiment, the permanent magnet 16 is used. However, when an electromagnet is used instead of the permanent magnet 16, the braking is switched by turning on / off the current flowing through the coil of the electromagnet. There is no need to be movable with respect to the disk surface.

  FIG. 2 shows a state in which the braking disk 14 is viewed from the side opposite to the braking surface (back surface). A plurality of (for example, eight) spoke-like support members 22 and a large number of radiating fins 24 are formed on the rear surface of the brake disk 14. In the figure, reference numeral 21 denotes a bolt hole, which is used when the fixing ring 20 is fixed to the flange portion of the holding member 18 (not shown). FIG. 3 shows a state in which the support member 22 is viewed in the AA cross section of FIG. 2, that is, a cross section perpendicular to the surface of the brake disk 14 and along the longitudinal direction of the spoke-like support member 22.

  In the brake disk 14, a braking torque is generated by applying a magnetic force from a magnet 16 (not shown) to the rotating brake disk 14. The fins 24 increase the cooling efficiency of the brake disk 14 that generates heat during braking. The fixing ring 20 can be easily fixed with a bolt or the like when the brake disk 14 is fixed to the rotary shaft 12, and has an effect of improving stability at the time of fixing. The spoke-like support member 22 couples (connects) the brake disk 14 and the fixing ring 20 and transmits the braking torque generated on the brake disk 14 to the rotating shaft.

  The rotor (14, 20, 22, 24) can be manufactured by molding each component individually and integrally forming them by welding or the like. Or it can also manufacture integrally by the casting method or the shaving from a steel ingot. The material of the rotor can be, for example, mechanical structural alloy steel or chromium-molybdenum steel. In order to improve the braking force, a layer made of a material having a low electrical resistance such as copper may be provided on the surface of the braking disk 14.

  The spoke-like support member 22 includes a spoke portion 22 b fixed to the back surface of the brake disk 14 and a connecting portion 22 a fixed to the fixing ring 20. As shown in FIG. 3, in this embodiment, when the support member 22 is viewed in a cross section perpendicular to the surface of the brake disk 14 and along the longitudinal direction of the spoke-like support member 22, the connecting portion 22a is connected to the brake disk. 14 is curved toward the opposite side. That is, the center line C1 of the connecting portion 22a is shifted from the center line C2 of the spoke portion 22b.

  By shifting the center line C1 of the connecting portion 22a of the spoke-like support member 22 from the center line C2 of the spoke portion 22b, the positional deviation (difference) between the braking disk 14 and the support portion 22 in the rotation axis direction increases, and the rotation axis direction Thus, the brake disk 14 is supported at a position far away. As a result, the brake disk 14 can be deformed relatively easily in the radial direction as compared with the case of supporting a close position, and inelastic strain generated by restraining thermal expansion during braking is reduced. Further, when the brake disk 14 can be deformed relatively easily, the amount of deformation (warpage) of the brake disk 14 in the direction of the rotation axis is reduced, so that inelastic strain generated in the support member 22 is reduced. As a result, the durability of the support member 22 and the brake disk 14 is improved.

  Further, by projecting and bending the connecting portion 22a of the spoke-like support member 22 to the opposite side to the braking disk 14, the bending portion (22a) has a radial deformation (thermal expansion) of the braking disk 14 during braking. By stretching in the direction, it can be absorbed by elastic deformation. As a result, inelastic strain generated in the support member 22 and the brake disk 14 is reduced, and the durability of the rotor is improved. It should be noted that the direction of bending of the connecting portion 22a can be on the braking disk 14 side, contrary to the example shown in FIG. However, in this case, the linear spoke portion 22b of the support member 22 extends downward as compared with the example of FIG. 5, and the curved position is slightly lowered.

  FIG. 4 is an enlarged view of a part of FIG. 2 and shows the tilt angles of the disk support member and the fins. As shown in FIG. 4, each of the spoke-like support members 22 extends from the center direction of the brake disk 14 (fixing ring 20) toward the outer peripheral direction, but the position where the support member 22 and the inner peripheral edge of the disk 14 intersect each other. Is XS, the support member 22 is disposed at an angle θS with respect to the disk radiation (one-dot chain line) passing through XS and the center O of the disk 14. Each of the fins 24 is disposed at an angle θF with respect to the radial direction of the brake disk 14. That is, when the position where the fin 24 and the inner peripheral edge of the disk 14 intersect is XF, the fin 24 is disposed at an angle θF with respect to the disk radiation (dotted line) passing through the center F of the XF and the disk 14. In addition, the direction of the inclination is that the upper ends (outer peripheral sides) of the spoke-like support members 22 and the fins 24 are directed backward (delayed) with respect to the rotation direction during braking, that is, the rotation direction during braking of the disk. Tilt to the opposite side.

  Thus, when the spoke-like support member 22 is inclined with respect to the rotation direction of the rotor, the radial deformation of the brake disk 14 during braking is absorbed by the support member 22 elastically deforming in the rotation direction of the rotor. It becomes possible. As a result, inelastic strain generated in the support member 22 and the brake disk 14 is reduced, and the durability of the rotor is improved. Further, when the direction of inclination of the spoke-like support members 22 and the fins 24 is directed backward (delayed) with respect to the rotational direction, air (wind) flows smoothly from the inner peripheral side to the outer peripheral side of the rotor, Loss torque during non-braking due to air resistance (windage loss) when rotating is reduced, and it becomes possible to improve the fuel consumption of the vehicle.

  When a magnetic force generated by a magnet 16 (not shown) is applied to the rotating brake disk 14, an eddy current is generated in the brake disk 14, and a braking torque is generated in the brake disk 14 due to the interaction between the eddy current and the magnetic force. This state is a braking state. On the other hand, a state in which no magnetic force is applied to the braking disk 14 and no braking torque is generated is a non-braking state.

  At the time of braking, eddy current is generated and Joule heat is generated at the same time, and the braking disk 14 generates heat. Due to this heat generation, the annular braking disk 14 is thermally expanded and deformed in the direction of increasing the diameter of the ring. The deformation (thermal expansion) of the braking disk 14 is restrained by the support member 22. When the support member 22 constrains deformation in the direction in which the diameter of the brake disk 14 increases (radial direction when viewed in cross section), the brake disk 14 is deformed in the direction of the rotation axis (warps up to the opposite side of the magnet 16). . At this time, if the restraining force by the support member 22 is strong, inelastic strain (plastic strain and creep strain) is likely to occur in the brake disk 14 and the support member 22.

  Thus, when inelastic strain occurs during braking, permanent deformation occurs even after switching to the non-braking state and cooling the braking disk 14. When permanent deformation occurs, the distance between the surface of the brake disk 14 and the magnet 16 changes, so that the braking torque that is generated changes as the magnetic force acting on the brake disk 14 changes. That is, when the restraining force by the support member is excessively strong as in the prior art, the braking force gradually decreases each time the eddy current reduction device is used, and it becomes difficult to obtain a stable braking force for a long period of time. Further, fatigue cracks may occur when inelastic strain is repeatedly applied to the brake disk and the support portion by repeated braking and non-braking.

In order to make the shape of the rotor appropriate, the inventors conducted a finite element method analysis (hereinafter referred to as FEM analysis) on the relationship between the inelastic strain generated in the support member 22 and the support member shape (rotor shape). evaluated. Table 1 shows the rotor shapes evaluated. As shown in Table 1, the shape of the brake disk 14, the shape and number of fins 24, and the shape of the fixing ring 20 were common to all examples. Further, in the FEM analysis, the material of the rotor is chromium-molybdenum steel (JIS SCM415), the maximum temperature of the braking disk 14 is 650 ° C., the minimum temperature is 100 ° C. The elastic strain range was evaluated. The cross-sectional shape of the fin 24 is a rectangle.

  Table 2 shows the evaluation results of the inelastic strain range generated in the support member 22. In Table 2, the value of the portion where the generated inelastic strain range is maximum is shown. In the table, the support members 22 with the numbers 2, 3, 5 to 9 are such that the connecting portion 22a is curved to the opposite side of the braking disk 14 as shown in FIG. The inelastic strain range generated from 1) is small.

In the example of No. 4, the outer side of the connecting portion 22a of the support member 22 does not protrude (l ₂ = 0), but the inner side is depressed (l ₁ = 3 mm), so the comparative example of No. 1 (l ₁ = l _The inelastic strain range generated from ₂ = 0) is small. The example of number 5 (l ₁ = l ₂ = 3 mm, θ _F = θ _S = 30 °) in which the connecting portion 22a is bent and the support member 22 is inclined, and the example of number 6 (l ₁ = l ₂ = 10 mm, θ _F = θ _S = 45 °) and the example of number 10 (l ₁ = l ₂ = 5 mm, θ _F = θ _S = 70 °) were found to generate very little inelastic strain.

  In general, the greater the inelastic strain range applied, the shorter the fatigue crack initiation life. Therefore, it was confirmed that Nos. 2 to 9 of the inventive examples had a long fatigue crack generation life and superior durability compared to the comparative examples. Furthermore, since the inelastic deformation of the support member 22 is small in the rotor of the present invention example, it has been confirmed that the braking force is hardly lowered even when used for a long time.

  FIG. 6 is a side view (sectional view) showing the shape of the disc support member 122 of the retarder according to the second embodiment of the present invention. Similar to the support member 22 described above, the support member 122 according to the present embodiment includes a spoke portion 122 b fixed to the back surface of the brake disk 14 and a connecting portion 122 a fixed to the fixing ring 20. In the present embodiment, when the support member 122 is viewed in a cross section perpendicular to the surface of the brake disk 14 and along the longitudinal direction of the spoke-like support member 122, the brake disk 14 side of the connecting portion 122a is recessed. However, the side opposite to the braking disk 14 (the right side in the figure) has a shape that does not protrude from the spoke part 122b. In Table 1, this corresponds to the number 4 example.

  FIG. 7 is a plan view showing the structure of the rotor centered on the retarder braking disk 14 according to the third embodiment of the present invention. FIG. 8 is a cross-sectional view (side view) showing the configuration of the brake disk 14, the support member 222, and the fixing ring 20 shown in FIG. 7. FIG. 9 is an enlarged plan view showing the configuration of the main part of the third embodiment. In addition, the same code | symbol is attached | subjected to the component which is the same as or corresponds to each Example mentioned above, and the overlapping description is abbreviate | omitted. Further, the structure and configuration other than the shape of the support member 222, which is a feature of the present embodiment, can be the same as those of the first and second embodiments described above. The fixing ring 20 and the brake disk 14 are arranged with a predetermined gap in the radial direction. The fixing ring 20 is concentric with the brake disk 14 and is connected to the rotating shaft inside the brake disk 14. The fixing ring 20 and the brake disk 14 are connected by a support member 222.

The features of this embodiment are shown in detail in FIG. X1 is a point where the support member 222 and the inner peripheral edge of the braking disk 14 intersect; X2 is a point where the support member 222 and the outer peripheral edge (the outer peripheral edge of the rotation shaft of the engine) intersect; The rotation center is O; a straight line passing through the point X1 and the rotation center O of the braking disk 14 is L1, a straight line passing through the point X2 and the rotation center O of the braking disk 14 is L2, and the direction in which the support member 222 extends inward at the point X1. L3; the direction in which the support member 222 extends outward at the point X2 is L4; the straight line connecting the point X1 and the point X2 is L5; the angle formed by the L2 and L4 is θ1; the angle formed by the L1 and L3 is θ2 The angle formed by L2 and L5 is θ3; and the angle formed by L1 and L5 is θ4, the following expressions (1) and (2) are satisfied.
θ1 <θ3 (1)
θ2 <θ4 (2)

  The support member 222 is bent so as to satisfy the above condition, the inclination angles θ3 and θ4 of the support member 222 are increased, and the angle θ1 of the joint portion X1 of the support member 222 with the brake disk 14 is coupled to the fixing ring 20. By reducing the angle θ2 of the portion X2, the radial and axial deformations of the brake disk 14 can be further absorbed by the elastic deformation of the spoke-like support member 222, and the support member 222 during braking and It is possible to reduce inelastic strain generated in the coupling portion X1 with the brake disk 14 and the coupling portion X2 between the support member 222 and the fixing ring 20.

  FIG. 10 is an explanatory diagram used for comparison with the third embodiment, and shows a planar state in the vicinity of the brake disk of the retarder.

The inventors evaluated the relationship between the inelastic strain generated in the support member 222 and the support member shape by a finite element method analysis (hereinafter referred to as FEM analysis) in order to make the rotor shape appropriate. Table 3 shows the evaluated rotor shapes. Further, the dimensions of the support member shown in FIG. 5 are all the same, and l ₁ = 8 mm, l ₂ = 10 mm, L = −9.2 mm, H = 10 mm, and h = 10 mm for the disks 1 to 7. is there. The support member 222 has a curved shape so as to protrude to the opposite side of the magnet in the axial direction of the rotation shaft. Examples 1 to 3 are disks 14 each having θ1 = θ3 and θ2 = θ4, that is, a linear support member 22 as shown in FIG. On the other hand, in Examples 4 to 7, θ1 <θ3 and θ2 <θ4, and as shown in FIGS. 7 and 9, the support member 222 is curved in a state where the disk is viewed from the front. . In the disks of Examples 1 to 3 and Examples 4 to 7, the brake disk 14, the fixing ring 20, the shape and the number of fins 24, and the thickness and number of the support members (22, 222) are all the same. Only the shape of the member (angles θ1, θ2, θ3, θ4) is different from the angle θF of the fin 24 matched to the angle θ2 of the support member.

  Table 4 shows the evaluation results of the inelastic strain range generated in the support member. Table 4 shows values at locations where the generated inelastic strain range is maximum.

  In Table 4, since the discs of Nos. 4 and 5 employ a support member having a shape satisfying θ1 <θ3 and θ2 <θ4, No. 1 (a linear support member, θ1 and θ2 are Nos. 4 and 4). 5), the inelastic strain range generated in the vicinity of the connecting portion between the support member and the fixing ring and in the vicinity of the connecting portion between the support member and the brake disk is reduced.

  The discs of Nos. 6 and 7 employ a support member having a shape satisfying θ1 <θ3 and θ2 <θ4. Therefore, compared to No. 2 (a linear support member, θ1 and θ2 are the same as those of Nos. 6 and 7). Thus, the inelastic strain range generated in the vicinity of the joint between the support member and the fixing ring and in the vicinity of the joint between the support member and the brake disk is reduced.

  As described above, it was confirmed that even if θ1 and θ2 are the same, the generated inelastic strain range can be reduced in the disk employing the support member that satisfies the conditions of θ1 <θ3 and θ2 <θ4.

  Further, comparing No. 3 and No. 6 in which θ3 and θ4 are equal, the inelastic strain range in which No. 6 in which θ1 and θ2 are smaller is smaller. In the example of No. 6, this is because the angle α (= 90 ° −θ1) formed by the support member 222 and the fixing ring 20 shown in FIG. 7 and the angle β (= 90 ° − formed by the support member 222 and the brake disk 14). θ2) is an angle α (= 90 ° −θ1) formed by the support member 22 and the fixing ring 20 shown in FIG. 10 in the example of number 3, and an angle β (= 90 ° −θ2) formed by the support member 22 and the brake disk 14. This is considered to be because the concentration of strain at the joint between the support members 222 and 22 and the fixed dering 20 and the brake disk 14 is small.

  In general, the fatigue crack generation life becomes shorter as the inelastic strain range to be applied is larger. Therefore, it can be seen that Nos. 4 to 7 in this example have a longer fatigue crack generation life than Nos. 1 to 3 and are excellent in durability. Furthermore, since the inelastic deformation of the support member (222) is small in the rotor of this example, it has been confirmed that the braking force is hardly lowered even when used for a long time.

  As described above, in the present embodiment, in the joint portion between the support member 222 and the fixing ring 20, the straight line connecting the joint portion between the support member 222 and the fixing ring 20 and the joint portion between the support member 222 and the brake disk 14 rotates. The angle θ1 between the support member 222 and the fixing ring 20 is smaller than the angle θ3 between the support member 222 and the fixing ring 20, and the angle θ1 between the support member 222 and the brake disk 14 is supported at the connection portion between the support member 222 and the brake disk 14. The support member 222 rotates at the joint portion between the support member 222 and the brake disk 14 than the angle θ4 formed by the straight line connecting the joint portion between the member 222 and the fixing ring 20 and the joint portion between the support member 222 and the brake disk 14 with respect to the rotation direction. The angle θ2 formed with the direction is reduced. Therefore, the support member 222 is sufficiently inclined with respect to the rotation direction, and at the same time, the angles α and β formed by the support member 222 and the fixing ring 20 and the support member 222 and the brake disk 14 are prevented from becoming excessively small. Therefore, it is possible to improve the durability of the rotor.

  In the present embodiment, θ1 and θ2 are preferably 0 ° to 60 °. If the angle is larger than 60 °, the angles α and β shown in FIG. 7 become small even if the support member is curved so as to satisfy the conditions of θ1 <θ3 and θ2 <θ4. It becomes difficult to sufficiently suppress the concentration of strain on the joint portion.

  Further, θ3 and θ4 are desirably 30 ° to 100 °. If the angle is smaller than 30 °, even if the support member is bent so as to satisfy the conditions of θ1 <θ3 and θ2 <θ4, the amount of the curve becomes small, so that the deformation of the brake disk can be sufficiently absorbed by the support member. Disappear. As a result, inelastic strain generated in the brake disk and the support member may not be sufficiently suppressed. On the other hand, when θ3 and θ4 are larger than 100 °, the length of the support member between the fixing ring and the braking disk becomes excessively long, so that the rigidity of the support member is insufficient, and the vibration when the disk is rotated is generated. May become excessively large. More preferably, θ3 is 60 ° or more, and θ4 is 50 ° or more.

As mentioned above, although the Example (embodiment, embodiment) of this invention was described, this invention is not limited to these Examples at all, It changes in the category of the technical idea shown by the claim. It is possible. In the example described above, the connecting portion 22a and the spoke portion 22b of the spoke-like support member 22 have a continuous shape, but a structure in which the connecting portion 22a and the spoke portion 22b are separated can also be adopted. Further, the cross-sectional shapes of the support member 22 and the fins 24 are not limited to a rectangle, and other shapes can be adopted. Further, in the above-described example, the fins 24 are linear ones that are continuous from the inner peripheral side to the outer peripheral side of the brake disk 14, but may be curved or divided in the middle. May be.

FIG. 1 is a cross-sectional view showing the structure of the main part of a retarder according to a first embodiment of the present invention, showing a braking state. FIG. 2 is a plan view showing the structure of the rotor around the braking disk of the retarder shown in FIG. FIG. 3 is a cross-sectional view taken along the line AA of FIG. FIG. 4 is an enlarged view of a part of FIG. 2 and shows the tilt angles of the disk support member and the fins. FIG. 5 is a diagram corresponding to FIG. 3 and is an explanatory diagram showing the shape of the disk support member. FIG. 6 is a side (sectional) view showing the shape of the disc support member of the retarder according to the second embodiment of the present invention. FIG. 7 is a plan view showing the structure of a rotor centering on a retarder braking disk according to a third embodiment of the present invention. FIG. 8 is a cross-sectional view (side view) showing the configuration of the brake disk, support member, and fixing ring shown in FIG. FIG. 9 is an enlarged plan view showing the configuration of the main part of the third embodiment. FIG. 10 is an explanatory diagram used for comparison with the third embodiment, and shows a planar state in the vicinity of the brake disk of the retarder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Eddy current type speed reducer 12 Rotating shaft 14 Brake disk 16 Permanent magnet 20 Fixed ring 22,122,222 Spoke-like support member 22a, 122a, 222a Connecting part 22b, 222b Spoke part 24 Radiation fin

Claims (4)

A brake disc connected to the rotating shaft of the engine;
A magnetic field generator for applying a magnetic field to the braking surface of the braking disk during braking;
A plurality of spoke-like support members that support the braking disk with respect to the rotating shaft on a surface opposite to the braking surface of the braking disk;
Each of the spoke-like support members has a spoke part fixed to the brake disc and a connection part connected to the outer peripheral part of the rotating shaft,
When the support member is viewed in a cross section perpendicular to the surface of the brake disk and along the longitudinal direction of the spoke-like support member, the connecting portion is curved toward the opposite side of the brake surface of the brake disk, and Protrudes outside the spokes ,
Each of the spoke-like support members extends from the center direction of the braking disk toward the outer circumferential direction, and is inclined with respect to the radial direction of the disk and is inclined to the opposite side to the rotation direction during braking of the disk,
X1 is a position where the spoke-shaped support member and the inner peripheral edge of the brake disk intersect; X2 is a position where the support member and the outer peripheral edge of the rotation shaft of the engine intersect; O is the rotation center of the brake disk; L1 is a straight line passing through the position X1 and the rotation center O of the braking disk; L2 is a straight line passing through the position X2 and the rotation center O of the braking disk; L3 is a direction in which the support member extends inward at the position X1; A direction in which the support member extends outward at the position X2 is L4; a straight line connecting the position X1 and the position X2 is L5; an angle formed by L2 and L4 is θ1; an angle formed by L1 and L3 is θ2 An angle formed by L2 and L5 is θ3; and an angle formed by L1 and L5 is θ4, an eddy current reduction device satisfying the following expression:
θ1 <θ3 (1)
θ2 <θ4 (2)   2. The eddy current reduction device according to claim 1, wherein the angles [theta] 1 and [theta] 2 are 0 to 60 [deg.], And the angles [theta] 3 and [theta] 4 are 30 to 100 [deg.].   The eddy current reduction device according to claim 2, wherein the angle θ3 is 60 ° or more and θ4 is 50 ° or more.   A plurality of fins formed on a surface opposite to the braking surface of the braking disk;
  Each of the fins extends from the center direction of the braking disk toward the outer peripheral direction, and is disposed to be inclined with respect to the radial direction of the disk opposite to the rotation direction during braking of the disk. The eddy current type reduction device according to any one of claims 1 to 3.

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