Electromagnetic coupling device

Abstract

To minimize a dead space in a field core to achieve downsizing of the field core in an axial direction or increase the number of turns of an electromagnetic coil.SOLUTION: An electromagnetic coupling device includes: an electromagnetic coil 17; a field core 16 having a hole 33; a terminal block 71 which has a terminal part 43 and is inserted through the hole 33 and supported by the field core 16; and a pair of terminals 44 provided at the terminal part 43. The electromagnetic coupling device includes a pair of first through holes 47 each of which passes through the terminals 44 and penetrates through the terminal board 71. Magnet wires 34 inserted through the first through holes 47 and a pair of lead wires 56, 57 for external connection are soldered to the terminals 44.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic coupling device such as an electromagnetic clutch or electromagnetic brake, and more particularly to a connection structure between a magnet wire of an electromagnetic coil and a lead wire for external connection and a surge voltage absorbing member. [Background technology]

[0002] In conventional electromagnetic coupling devices such as electromagnetic clutches and electromagnetic brakes, a ring-shaped electromagnetic coil is housed in an annular recess in a field core, as described in Patent Document 1, for example. Lead wires for external connection and surge voltage absorbing members are connected to the winding start and end of the electromagnetic coil disclosed in Patent Document 1, respectively. Therefore, as shown in Figure 17, lead wires 4 are wired between the inner bottom surface 2a of the annular recess 2 of the field core 1 and the side surface 3a of the electromagnetic coil 3 housed in the annular recess 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Jikko No. 58-8998 Summary of the Invention [Problem to be solved by the invention]

[0004] As shown in Figure 17, when the lead wire 4 is located between the side surface 3a of the electromagnetic coil 3 and the inner bottom surface 2a of the field core 1, a dead space indicated by the symbol S in Figure 17 is created. This dead space S is a space within the field core 1 where the electromagnetic coil 3 cannot be placed. For this reason, the field core 1 of the conventional electromagnetic coupling device shown in Figure 17 is increased in size in the axial direction (the vertical direction in Figure 17) by the amount of the dead space S, and there is a problem in that the number of turns of the electromagnetic coil 3 is reduced.

[0005] An object of the present invention is to minimize the dead space within the field core, thereby enabling the field core to be made smaller in the axial direction or the number of turns of the electromagnetic coil to be increased. [Means for solving the problem]

[0006] In order to achieve this object, the electromagnetic coupling device of the present invention comprises an electromagnetic coil formed by winding a magnet wire, a field core having a recess for accommodating the electromagnetic coil and a hole formed to penetrate the wall of the recess, a terminal block having a terminal portion protruding outside the field core and passed through the hole and supported by the field core, a pair of terminals provided on the terminal portion, and a pair of through holes that pass through the terminal block through the terminals and communicate between the outside of the field core and the inside of the recess, one of the pair of terminals has soldered to it the winding start end of the magnet wire that is passed through one of the through holes that passes through this terminal and protrudes from the one terminal, and one of a pair of lead wires for external connection, and the other of the pair of terminals has soldered to it the winding end end of the magnet wire that is passed through the other through hole that passes through this terminal and protrudes from the other terminal, and the other of the pair of lead wires for external connection.

[0007] In the electromagnetic coupling device of the present invention, the terminal block has a pair of lead wire holding portions that hold the pair of lead wires for external connection along the pair of terminals, and one of the pair of lead wires may be guided onto the one terminal so as to intersect with the winding start end of the magnet wire, and the other of the pair of lead wires may be guided onto the other terminal so as to intersect with the winding end end of the magnet wire.

[0008] The electromagnetic coupling device of the present invention may further include a surge voltage absorbing member housed inside the terminal block, one end of which is connected to the one terminal and the other end of which is connected to the other terminal.

[0009] In the electromagnetic coupling device of the present invention, the one end and the other end of the surge voltage absorbing member may each be formed by a lead, and another pair of through holes that connect the outside of the field core to the inside of the recess may be drilled at positions adjacent to the pair of through holes in the terminal block and the pair of terminals, and the lead that constitutes the one end and the lead that constitutes the other end of the surge voltage absorbing member may be passed through the other pair of through holes, and the lead that constitutes the one end of the surge voltage absorbing member may protrude from the one terminal so as to sandwich the one lead wire in cooperation with the winding start end of the magnet wire and be soldered to the one terminal together with these, and the lead that constitutes the other end of the surge voltage absorbing member may protrude from the other terminal so as to sandwich the other lead wire in cooperation with the winding end end of the magnet wire and be soldered to the other terminal together with these.

[0010] In the electromagnetic coupling device of the present invention, the surge voltage absorbing member may be formed as a surface-mounted component having soldering lands provided at one end and the other end of a package, and may be surface-mounted to the one terminal and the other terminal. [Effects of the Invention]

[0011] According to the present invention, because the lead wires for external connection are connected to the magnet wire outside the field core, there is no need for space within the field core for wiring the lead wires for external connection. This minimizes the dead space that occurs between the field core and the electromagnetic coil, making it possible to reduce the size of the field core in the axial direction or increase the number of windings in the electromagnetic coil. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of an electromagnetic coupling device according to the present invention. [Figure 2] FIG. 2 is a front view of the field core assembly to which lead wires for external connection are connected. [Figure 3]FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] Figure 4 shows the field core. [Figure 5] FIG. 5 is a diagram showing an electromagnetic coil. [Figure 6] FIG. 6 is a cross-sectional view of the terminal block according to the first embodiment. [Figure 7] FIG. 7 is a perspective view of the terminal block. [Figure 8] FIG. 8 is a plan view of the terminal block. [Figure 9] FIG. 9 is a bottom view of the terminal block as seen from the field core side. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 13 is a perspective view of a terminal block according to the second embodiment. [Figure 14] FIG. 14 is a perspective cross-sectional view of a terminal block according to the second embodiment. [Figure 15] FIG. 15 is a perspective view for explaining wiring of the terminal block according to the second embodiment. [Figure 16] FIG. 16 is a perspective view of a terminal block according to the third embodiment. [Figure 17] FIG. 17 is a cross-sectional view showing a part of a conventional field core. DETAILED DESCRIPTION OF THE INVENTION

[0013] (First embodiment) An embodiment of an electromagnetic coupling device according to the present invention will now be described in detail with reference to Figures 1 to 12. In this embodiment, the present invention will be described as being applied to an electromagnetic clutch. The electromagnetic clutch 11 shown in Figure 1 is used to transmit or interrupt power to a rotating shaft 13 of a compressor 12 for a car air conditioner. The electromagnetic clutch 11 includes an annular field core 16 fixed to a front housing 14 of the compressor 12 via a mounting plate 15. An annular electromagnetic coil 17 is housed within the field core 16. The electromagnetic clutch 11 also includes a rotor 19 rotatably supported by a bearing 18 in a cylindrical portion 14a of the front housing 14. The electromagnetic clutch 11 also includes an armature assembly 21 spline-fitted to the tip of the rotating shaft 13 and secured by a bolt 20. The armature assembly 21 includes a hub 23 fixed to the rotating shaft 13 and an armature 25 supported on the hub 23 via a leaf spring 24.

[0014] 2 and 3, the field core 16 is formed in an annular shape and is positioned coaxially with the rotary shaft 13. Furthermore, as shown in FIG. 1, the field core 16 is inserted into an annular groove 19a formed in the rotor 19. The rotor 19 rotates with the field core 16 inserted in the annular groove 19a. A pulley groove 19b is formed on the outer periphery of the rotor 19, and power from, for example, an engine (not shown) is transmitted via a belt (not shown) wound around the pulley groove 19b. A friction surface 19c that faces an armature 25 of the armature assembly 21 is formed on one axial end face of the rotor 19. In the following description, the direction in which the armature 25 is located relative to the rotor 19 will be referred to as "forward of the electromagnetic clutch 11," and the opposite direction will be referred to as "rearward of the electromagnetic clutch 11."

[0015] In this electromagnetic clutch 11, when the electromagnetic coil 17 provided inside the field core 16 is excited, the armature 25 is magnetically attracted to the rotor 19, and the rotation of the rotor 19 is transmitted to the rotating shaft 13 via the armature assembly 21. When the power supply to the electromagnetic coil 17 is cut off, the armature 25 moves away from the rotor 19, and the transmission of power is interrupted.

[0016] 4(A) and 4(B), the field core 16 is formed with an annular groove 31 that extends in the circumferential direction of the field core 16 and opens toward the front of the electromagnetic clutch 11, and a hole 33 that penetrates a bottom wall 32 of the annular groove 31. The electromagnetic coil 17 is housed within the annular groove 31. In this embodiment, the annular groove 31 corresponds to the "recess that houses the electromagnetic coil" of the present invention. 5(A), the electromagnetic coil 17 is formed into a cylindrical shape by winding a magnet wire 34 as a wire. In the electromagnetic coil 17 according to this embodiment, the winding start end 34a and the winding end 34b of the magnet wire 34 are formed at a rear end 17a, which is one end in the axial direction of the cylindrical electromagnetic coil 17, and are formed to extend to the same portion in the circumferential direction. The electromagnetic coil 17 is housed in the annular groove 31 of the field core 16 so that the rear end 17a faces the bottom wall 32 of the annular groove 31 of the field core 16.

[0017] 5(B), a thermal fuse 35 is attached to the other axial end of the electromagnetic coil 17. The thermal fuse 35 is electrically connected to the magnet wire 34 so as to become part of the winding of the electromagnetic coil 17. The outer peripheral surface, inner peripheral surface and both axial end surfaces of the electromagnetic coil 17 are wrapped with insulating cotton tape 36 (see FIG. 5(B)). The annular groove 31 of the field core 16 is filled with insulating casting resin 37 with the electromagnetic coil 17 inserted therein. The casting resin 37 hardens within the annular groove 31, thereby fixing the electromagnetic coil 17 in place within the annular groove 31.

[0018] 4(A), the hole 33 in the field core 16 is formed in an oval shape extending in a tangential direction A of the field core 16 when the field core 16 is viewed from the rear of the electromagnetic clutch 11, and extends in the axial direction of the field core 16, penetrating the bottom wall 32 of the annular groove 31. A terminal block 41 is inserted into this hole 33, as shown in FIGS. 6 and 7, the terminal block 41 includes an inner cylindrical body 42 that fits into the hole 33 of the field core 16, a terminal portion 43 that protrudes rearward (outward from the field core 16) from the field core 16, a pair of terminals 44 provided on the terminal portion 43, and a pair of support pieces 45 that protrude from the terminal portion 43 along the rear surface 16a of the field core 16 (see FIG. 4(A)). The inner cylindrical body 42, the terminal portion 43, and the pair of support pieces 45 are integrally formed from an insulating plastic material.

[0019] As shown in FIG. 9 , the internal cylinder 42 is formed in an elliptical shape that is long in the tangential direction A of the field core 16 (the left-right direction in FIG. 9 ) when viewed from its axial direction. The multiple ellipses drawn concentrically around the internal cylinder 42 in FIG. 9 are lines representing a seal 46 formed on the rear surface (the surface facing the field core 16) of the terminal portion 43 and the support piece 45, as shown in FIG. 10 . The seal 46 serves to seal the gap between the terminal block 41 and the rear surface 16a of the field core 16 and is composed of multiple elliptical ridges 46a and multiple elliptical grooves 46b. These ridges 46a and grooves 46b are arranged alternately. The seal 46 prevents the casting resin 37 injected into the annular groove 31 from leaking out of the field core 16 through the gap between the hole 33 and the internal cylinder 42.

[0020] As shown in FIG. 10 , a pair of first through holes 47 are formed in the internal cylinder body 42. As shown in FIG. 11 , these first through holes 47 penetrate the terminal block 41 via plate-shaped plate portions 48 of the terminals 44. Therefore, when the terminal block 41 is assembled to the field core 16, the first through holes 47 communicate between the outside of the field core 16 and the inside of the annular groove 31. As shown in FIG. 6 , the winding start end 34 a of the magnet wire 34 passes through one first through hole 47 a (the first through hole 47 a on the right side in FIG. 6 ) of the pair of first through holes 47. The winding start end 34 a penetrates one terminal 44 a of the pair of terminals 44 and protrudes outside the terminal block 41, and this protruding portion is soldered to one terminal 44 a with solder 49.

[0021] Furthermore, the winding end 34b of the magnet wire 34 is passed through the other first through hole 47b of the pair of first through holes 47. The winding end 34b passes through the other terminal 44b of the pair of terminals 44 and protrudes outside the terminal block 41, and this protruding portion is soldered to the other terminal 44b with solder 50.

[0022] As shown in Figure 10, the terminal portion 43 is composed of a plate-shaped terminal block main body 51 connected to one end of the inner cylinder body 42 (the end located outside the field core 16), and an outer cylinder body 52 that protrudes from this terminal block main body 51 in the axial direction of the field core 16 and behind the electromagnetic clutch 11. A pair of terminals 44 is provided on the terminal block body 51. The pair of terminals 44 is embedded in the terminal block body 51 by insert molding. The pair of terminals 44 according to this embodiment are arranged side by side at a predetermined interval in the tangential direction A described above.

[0023] 8, these terminals 44 are formed by a plate portion 48 that extends along the flat outer surface of the terminal portion 43 inside the external cylinder body 52, and a plurality of protrusions 53 that are bent upright from the plate portion 48 and protrude from the terminal block main body 51 toward the rear of the electromagnetic clutch 11. The plate portion 48 is formed so as to be elongated in a radial direction B of the field core 16 that is perpendicular to a tangential direction A of the field core 16. The terminals 44 are embedded in the terminal portion 43 so that the surface of the plate portion 48 is exposed on the surface of the terminal block main body 51. The protrusions 53 are provided on both ends of the plate portion 48 in the tangential direction A.

[0024] As shown in Figure 8, external cylinder body 52 is formed in the shape of a square cylinder with rounded corners when viewed from the axial direction of field core 16. External cylinder body 52 is formed so that its opening extends in tangential direction A and radial direction B of field core 16. The interior of external cylinder body 52 is eventually filled with and sealed with sealing material 54, as shown in Figure 6. Of the two side walls 52a, 52b extending in the tangential direction A of the outer cylinder body 52, one side wall 52a located radially outside (upper side in Figure 8) of the field core 16 is formed to have a wall thickness thicker than the other side wall 52b, as shown in Figures 7 and 8, and has a pair of grooves 55 formed therein.

[0025] These grooves 55 are for holding a pair of external connection lead wires 56, 57 for supplying power to the electromagnetic coil 17, and penetrate the side wall 52a in the thickness direction (radial direction B) at positions adjacent to a pair of terminals 44 provided on the terminal block body 51. A plurality of lips 58 are formed on the groove walls of these grooves 55 to engage with the coatings 56a, 57a (see FIG. 7) of the lead wires 56, 57 to prevent the lead wires 56, 57 from slipping out. By passing the lead wires 56, 57 through these grooves 55, the lead wires 56, 57 are held in the terminal block 41 with the conductors 56b, 57b exposed at the tips of the lead wires 56, 57 aligned with the terminals 44. In this embodiment, the pair of grooves 55 correspond to the "lead wire holding portion" of the present invention.

[0026] 6, the conductor 56b of one lead wire 56 of the pair of external connection lead wires 56, 57 is led onto one terminal 44 so as to intersect with the winding start end 34a of the magnet wire 34 inserted into one first through-hole 47a, and is soldered to the one terminal 44a together with the winding start end 34a by solder 49. Furthermore, the conductor 57b of the other lead wire 57 is led onto the other terminal 44 so as to intersect with the winding end 34b, and is soldered to the other terminal 44b together with the winding end 34b by solder 50.

[0027] As shown in Fig. 10, a pair of second through holes 61, 61 are drilled in a portion of the terminal block main body 51 that is inside the inner cylinder body 42 and at positions adjacent to the pair of first through holes 47, 47. As shown in Fig. 12, the second through holes 61 penetrate through the plate portion 48 of the terminal 44 and the terminal block main body 51. Therefore, when the terminal block 41 is assembled to the field core 16, the second through holes 61 communicate between the outside of the field core 16 and the inside of the annular groove 31 of the field core 16. In this embodiment, the second through holes 61 correspond to the "another pair of through holes" as defined in the present invention.

[0028] 9 and 10, four protrusions 62 are provided inside the pair of second through holes 61 when the terminal block 41 is viewed from the field core 16 side. These protrusions 62 are disposed on the front surface (the surface facing the field core 16) of the terminal block main body 51 at two locations in the tangential direction A and two locations in the radial direction B. In the space surrounded by these four protrusions 62, a package portion 63a of a diode 63 is inserted, as shown in FIG.

[0029] The diode 63 is for absorbing a surge voltage that occurs when power supply to the electromagnetic coil 17 is cut off. In this embodiment, the diode 63 constitutes what is referred to as a "surge voltage absorbing member" in the present invention. The diode 63 is composed of a cylindrical package portion 63a and leads 63b, 63c extending from both ends of the package portion 63a. In this embodiment, the leads 63b, 63c correspond to what is referred to as "one end and the other end of the surge voltage absorbing member" in the present invention.

[0030] Of the pair of leads 63b, 63c of the diode 63, the one lead 63b located on the right side in Fig. 6 and serving as one end of the diode 63 is inserted into one of the second through-holes 61a of the pair of second through-holes 61. This one lead 63b protrudes from one terminal 44a so as to sandwich the conductor 56b of one lead wire 56 in cooperation with the winding start end 34a of the magnet wire 34, and is soldered together with them to the one terminal 44a. Therefore, the winding start end 34a of the magnet wire 34, the one lead wire 56, and the one lead 63b of the diode 63 are electrically connected to one terminal 44a via the solder 49.

[0031] Of the pair of leads 63b, 63c of the diode 63, the other lead 63c located on the left side in Figure 6 and serving as the other end of the diode 63 is inserted into the other second through-hole 61b of the pair of second through-holes 61. This other lead 63c protrudes from the other terminal 44b so as to sandwich the conductor 57b of the other lead wire 57 in cooperation with the winding end 34b of the magnet wire 34, and is soldered together with them to the other terminal 44b. Therefore, the winding end 34b of the magnet wire 34, the other lead wire 57, and the other lead 63c of the diode 63 are electrically connected to one another via the solder 50 on the other terminal 44b.

[0032] 2, the support piece 45 of the terminal block 41 is formed to fit along the rear surface 16a of the field core 16 and is inserted between a protruding piece 64 provided on the mounting plate 15 and the rear surface 16a. The protruding piece 64 clamps the support piece 45 together with the rear surface 16a.

[0033] To assemble the electromagnetic clutch 11 configured as above, first, the terminal block 41 is attached to the field core 16. At this time, the diode 63 is previously attached inside the inner cylinder 42 of the terminal block 41, and one lead 63b is inserted into one of the second through-holes 61a, and the other lead 63c is inserted into the other second through-hole 61b. When attaching the terminal block 41 to the field core 16, the protruding piece 64 of the mounting plate 15 is plastically deformed to press the support piece 45 against the field core 16.

[0034] Next, the winding start end 34a of the magnet wire 34 of the field core 16 is inserted into one of the first through-holes 47a, and the winding end 34b is inserted into the other of the first through-holes 47b, and the electromagnetic coil 17 is inserted into the annular groove 31 of the field core 16. Then, a casting resin 37 is poured into the annular groove 31, and the casting resin 37 is allowed to harden. Thereafter, lead wires 56 and 57 for external connection are passed through a pair of grooves 55 in the terminal block 41 , and the conductors 56 b and 57 b of these lead wires 56 and 57 are led onto a pair of terminals 44 .

[0035] At this time, the coatings 56a, 57a of the lead wires 56, 57 are passed through and held between the pair of protrusions 53 of the terminals 44, and as shown in Fig. 6, the conductors 56b, 57b of the lead wires 56, 57 are inserted between the winding start end 34a and winding end 34b of the magnet wire 34 and the leads 63b, 63c of the diode 63 on each terminal 44. Then, the conductors 56b, 57b, the winding start end 34a and winding end 34b, and the leads 63b, 63c are soldered to each terminal 44 for each terminal 44. After soldering in this manner, sealing material 54 is injected into the interior of external cylinder body 52 to seal the interior of external cylinder body 52 .

[0036] In this electromagnetic clutch 11, the connection portion between the magnet wire 34 and the lead wires 56, 57 for external connection is provided inside the terminal block 41 and outside the field core 16. This minimizes the dead space that occurs inside the annular groove 31 of the field core 16, making it possible to reduce the size of the field core 16 in the axial direction or increase the number of turns of the electromagnetic coil 17 compared to conventional electromagnetic coupling devices. Furthermore, when connecting the lead wires 56, 57 and the diode 63 to the electromagnetic coil 17, the connections can be made on the terminal block 41, so the number of various connection terminals can be reduced compared to the electromagnetic coils of conventional electromagnetic coupling devices, and the insulation process for the electromagnetic coil 17 can be simplified.

[0037] The terminal block 41 according to this embodiment has a pair of grooves 55 (lead wire holding portions) that hold a pair of lead wires 56, 57 for external connection along the pair of terminals 44. One lead wire 56 of the pair of lead wires 56, 57 is led onto one terminal 44a so as to intersect with the winding start end 34a of the magnet wire 34. The other lead wire 57 of the pair of lead wires 56, 57 is led onto the other terminal 44b so as to intersect with the winding end end 34b of the magnet wire 34. When the lead wires 56, 57 for external connection are held in the grooves 55 of the terminal block 41, the conductors 56b, 57b may rise up relative to the terminals 44. If this occurs, it becomes difficult to solder the conductors 56b, 57b to the terminals 44. However, because the conductors 56b, 57b are guided onto the terminals 44 so as to intersect with the magnet wire 34, the conductors 56b, 57b enter the solders 49, 50 that protrude from the terminals 44 along the magnet wire 34, and the conductors 56b, 57b are also soldered. Therefore, by adopting this configuration, soldering can be performed easily and reliably.

[0038] In this embodiment, the electromagnetic clutch 11 includes a diode 63 (surge voltage absorbing member) housed inside the terminal block 41 (inside the inner cylindrical body 42), with one end (lead 63b) connected to one terminal 44a and the other end (lead 63c) connected to the other terminal 44b. Therefore, the electromagnetic clutch 11 according to this embodiment has a structure in which external connection lead wires 56, 57 are connected to a field core assembly consisting of the field core 16, the electromagnetic coil 17, the terminal block 41, and the diode 63. The external connection lead wires 56, 57 can be adapted to the operating environment of the electromagnetic clutch 11. In other words, various lead wire specifications can be accommodated by preparing lead wire assemblies for each specification. In this case, the field core assembly can be made into a common component.

[0039] In this embodiment, a diode 63 is used as the surge voltage absorbing member. A pair of second through holes 61 that communicate between the outside of the field core 16 and the inside of the annular groove 31 are drilled in the terminal block 41 and the pair of terminals 44 at positions adjacent to the pair of first through holes 47. One lead 63b and the other lead 63c of the diode 63 are passed through the pair of second through holes 61. One lead 63b of the diode 63 protrudes from one terminal 44a so as to cooperate with the winding start end 34a of the magnet wire 34 to sandwich the conductor 56b of one lead wire 56, and is soldered to the one terminal 44a together with the winding start end 34a.

[0040] The other end lead 63c of the diode 63 protrudes from the other terminal 44b so as to cooperate with the winding end 34b of the magnet wire 34 to sandwich the conductor 57b of the other lead wire 57, and is soldered to the other terminal 44b together with these. As a result, the conductors 56b and 57b enter the center of the solder that protrudes from the terminal 44 along the magnet wire 34 and the leads 63b and 63c of the diode 63, which further increases the reliability of the soldering and makes the soldering work even easier.

[0041] (Second embodiment) The terminal block can be configured as shown in Figures 13 and 14. In Figures 13 and 14, members that are the same as or equivalent to those described with reference to Figures 1 to 12 are given the same reference numerals, and detailed description thereof will be omitted where appropriate. 13 includes a rectangular cylindrical body 72 and a plate-like terminal body main body 73 provided inside the cylindrical body 72. As shown in FIG. 14, the cylindrical body 72 is formed in a shape that fits into the hole 33 of the field core 16 and has a portion that protrudes outside the field core 16.

[0042] A flange 74, which is larger than the opening width of the hole 33, is provided at the inner end of the cylindrical body 72 located inside the field core 16. The terminal block 71 is fitted into the hole 33 from inside the annular groove 31 with the flange 74 abutting against the inner bottom surface 16b of the field core 16. The terminal block body 73 divides the interior of the cylindrical body 72 into an outer space 75 (see FIG. 13(A)) that opens toward the outside of the field core 16 and an inner space 76 (see FIG. 13(B)) that opens into the field core 16. A pair of terminals 44 are embedded in the terminal block body 73 by insert molding. The surfaces of the terminals 44 are exposed to the outer space 75.

[0043] A pair of first through holes 47 and a pair of second through holes 61 are opened in these terminals 44. These first and second through holes 47, 61 are formed to penetrate the terminals 44 and the terminal block main body 73, respectively. A winding start end 34a and a winding end 34b of the magnet wire 34 are passed through the first through-hole 47. One lead 63b and the other lead 63c of a diode 63 serving as a surge voltage absorbing member housed in an inner space 76 within the cylindrical body 72 are passed through the second through-hole 61.

[0044] A pair of through holes 77 for holding a pair of lead wires 56, 57 for external connection are formed at the outer end of the cylindrical body 72 that protrudes outside the field core 16. As shown in FIG. 14 , these through holes 77 are formed in a portion of the cylindrical body 72 that is radially outward of the field core 16 and that is adjacent to a pair of terminals 44, penetrating the field core 16 in the radial direction B. By passing the lead wires 56, 57 through these through holes 77, as shown in FIG. 15 , the conductors 56b, 57b of the lead wires 56, 57 cross the magnet wire 34 and the leads 63b, 63c of the diode 63 that protrude above the terminal 44, and the conductors 56b, 57b are inserted between the magnet wire 34 and the leads 63b, 63c. The magnet wire 34, the leads 63b, 63c, and the conductors 56b, 57b are soldered to the terminal 44 with solders 49, 50. Although not shown, the inside of the outer end of the cylindrical body 72, i.e., the outer space 75, is filled with the sealing material 54 and sealed after the soldering is completed.

[0045] The terminal block 71 according to this embodiment is inserted into the hole 33 from within the annular groove 31 of the field core 16 and assembled to the field core 16. A diode 63 is assembled in advance to this terminal block 71. Then, after the magnet wire 34 is passed through the first through-hole 47 and the electromagnetic coil 17 is housed in the annular groove 31, the annular groove 31 is filled with casting resin 37. When this casting resin 37 hardens, the terminal block 71 is fixed to the field core 16.

[0046] In this embodiment as well, the connection portion between the magnet wire 34 and the lead wires 56, 57 for external connection is provided inside the terminal block 71, outside the field core 16. This minimizes the dead space that occurs inside the annular groove 31 of the field core 16, making it possible to reduce the size of the field core 16 in the axial direction or increase the number of turns of the electromagnetic coil 17 compared to conventional electromagnetic coupling devices.

[0047] (Third embodiment) The terminal block can be configured as shown in Fig. 16. In Fig. 16, the same or equivalent members as those described in Figs. 1 to 12 (first embodiment) are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate. 16, a terminal block 81 has a diode 82 as a surge voltage absorbing member surface-mounted on a pair of terminals 44. The diode 82 according to this embodiment is a surface-mounted component including a rectangular pillar-shaped package 82a and soldering lands 82b and 82c provided on one end and the other end of the package 82a, respectively.

[0048] The diode 82 is surface-mounted on the terminals 44a and 44b of the terminal block 81 via solder (not shown), with the lands 82b and 82c overlapping the terminals 44a and 44b, respectively. When this embodiment is adopted, the terminal block 81 is not provided with the second through-hole 61 when the above-described embodiment is adopted. As shown in this embodiment, by adopting a configuration in which the surge voltage absorbing member (diode 82) is surface-mounted on the terminal block 81, the wiring work for the surge voltage absorbing member is simplified compared to when a surge voltage absorbing member with leads is used, thereby improving the productivity of the electromagnetic coupling device.

[0049] Although the above-described embodiments show examples in which the present invention is applied to an electromagnetic clutch, the present invention is not limited to such a case and can be applied to other electromagnetic coupling devices such as an electromagnetic brake. [Explanation of symbols]

[0050] 11...electromagnetic clutch (electromagnetic coupling device), 16...field core, 17...electromagnetic coil, 31...annular groove (recess), 33...hole, 34...magnet wire, 34a...winding start end, 34b...winding end, 41, 71, 63b, 63c...lead, 43...terminal portion, 44...terminal, 49, 50...solder, 47...first through hole, 55...groove, 56, 57...lead wire for external connection, 61...second through hole, 63, 82...diode (surge voltage absorbing member), 77...through hole (lead wire holding portion), 81...terminal block, 82a...package, 82b, 82c...soldering lands.

Claims

1. an electromagnetic coil formed by winding a magnet wire; a field core having a recess for accommodating the electromagnetic coil and a hole formed through a wall of the recess; a terminal block having a terminal portion protruding outside the field core and passed through the hole and supported by the field core; a pair of terminals provided in the terminal portion; a pair of through holes that pass through the terminal block and communicate with the outside of the field core and the inside of the recess; a surge voltage absorbing member housed inside the terminal block, one end of which is connected to one of the pair of terminals and the other end of which is connected to the other of the pair of terminals; a winding start end of the magnet wire that is passed through one of the through holes penetrating the one terminal and protrudes from the one terminal, and one of a pair of lead wires for external connection is soldered to the one terminal; The other terminal is soldered to a winding end of the magnet wire that is passed through the other through hole that penetrates the other terminal and protrudes from the other terminal, and to the other lead wire of the pair of lead wires for external connection, The terminal block is an inner cylindrical body that fits into the hole of the field core; an outer cylindrical body located rearward of the inner cylindrical body along the axial direction of the field core and protruding outward from the field core; a plate-shaped terminal block main body connected to one end of the inner cylindrical body so as to separate the inner cylindrical body from the outer cylindrical body; The surge voltage absorbing member is housed inside the inner cylindrical body, The pair of terminals are provided on the plate-shaped terminal block main body located inside the outer cylindrical body when viewed from the rear, An electromagnetic coupling device characterized in that the winding start and end ends of the magnet wire, the pair of lead wires, and one end and the other end of the surge voltage absorbing member are soldered to the terminals inside the outer cylindrical body.

2. 2. The electromagnetic coupling device according to claim 1, the terminal block has a pair of lead wire holding portions that hold the pair of lead wires for external connection along the pair of terminals, one of the pair of lead wires is guided onto the one terminal so as to cross the winding start end of the magnet wire; An electromagnetic coupling device, characterized in that the other of the pair of lead wires is led onto the other terminal so as to intersect with the winding end of the magnet wire.

3. 3. The electromagnetic coupling device according to claim 2, the one end and the other end of the surge voltage absorbing member are each formed by a lead, another pair of through holes communicating with the outside of the field core and the inside of the recess are drilled at positions adjacent to the pair of through holes in the terminal block and the pair of terminals, a lead serving as the one end and a lead serving as the other end of the surge voltage absorbing member are passed through the other pair of through holes; a lead serving as the one end of the surge voltage absorbing member protrudes from the one terminal so as to sandwich the one lead wire in cooperation with the winding start end of the magnet wire, and is soldered to the one terminal together with the lead and the winding start end of the magnet wire; An electromagnetic coupling device characterized in that the lead at the other end of the surge voltage absorption member protrudes from the other terminal so as to cooperate with the winding end of the magnet wire to sandwich the other lead wire, and is soldered to the other terminal together with these.

4. An electromagnetic coil formed by winding magnet wire; a field core having a recess for accommodating the electromagnetic coil and a hole formed through a wall of the recess; a terminal block having a terminal portion protruding outside the field core and passed through the hole and supported by the field core; a pair of terminals provided in the terminal portion; a pair of through holes that pass through the terminal block through the terminal and communicate with the outside of the field core and the inside of the recess, One of the pair of terminals has a winding start end of the magnet wire that is passed through one of the through holes penetrating the terminal and protrudes from the one terminal, and one of a pair of lead wires for external connection is soldered to the one terminal, the other terminal of the pair of terminals is soldered to the winding end of the magnet wire that is passed through the other through hole that penetrates the other terminal and protrudes from the other terminal, and to the other lead wire of the pair of lead wires for external connection; the terminal block has a pair of lead wire holding portions that hold the pair of lead wires for external connection along the pair of terminals, one of the pair of lead wires is guided onto the one terminal so as to cross the winding start end of the magnet wire; the other lead wire of the pair of lead wires is guided onto the other terminal so as to cross the winding end of the magnet wire, The electromagnetic coupling device further comprises a surge voltage absorbing member housed inside the terminal block, one end of which is connected to the one terminal and the other end of which is connected to the other terminal.

5. 5. The electromagnetic coupling device according to claim 4, The surge voltage absorbing member is formed as a surface-mounted component having soldering lands at one end and the other end of a package, and is surface-mounted to the one terminal and the other terminal.

Images