JPS619155A - Brushless dc motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brushless DC motor having a flat air gap and using a permanent magnet rotor.

An object of the present invention is to simplify this type of conventional brushless DC motor and expand its range of use to devices with high utility value, such as small devices such as tape recorders and record players.

A further object of the present invention is to provide a brushless DC motor that can simplify conventional motors and reduce manufacturing costs.

This problem is solved by a brushless DC motor having the structure described in the claims, that is, 3·n flat plate coils are mounted on a flat printed guide plate, and the axial thickness of the coils is substantially Adhesively arranged to form an air-core stator of equal axial thickness, one side of the printed guide plate is attached to the permanent magnets of the permanent magnet rotor and the other side is attached to a fixed or rotating soft magnetic backing. The problem is solved by a brushless DC motor configured to face the lid plate, each separated by a flat gap.

The invention will now be described in detail with reference to the accompanying drawings, which illustrate suitable embodiments.

The motor 0 shown in FIG. 1 has a bearing tube 11 shown in FIGS. 4 and 5. This bearing tube body 11 is
It is provided with a flange 13 having three threaded holes 12 which serve to weld and fix the bearing tube. During operation, the motor 0 is suspended from the bearing tube 11 (Figs. 1 to 7 show the parts enlarged to about twice the size, and Figs. 8 to 13 show the parts in their original size). ). A U-shaped notch 14 is provided on one surface of the flange 13.

6 and 7 show an insulating intermediate member 15 whose inner recess 16 is slidable on the bearing tube 11 and whose outer diameter corresponds to the outer diameter of the 7 flange 13. The member 15, which is a molded plastic body, is in the form of a ring-shaped tub, the outer wall 17 of which is lower than the inner wall 18. In this case, in the mounting state wA (FIG. 1), a ring-shaped gap 19 is formed on the outside, through which the conductor harness 20 (FIG. 1) is guided laterally.

A radial web 23 divides the ring-shaped tub into three parts, of which parts 24, 26 each have a hole 27, 28 in the bottom, serving to pass the connecting conductor. There is.

8 to 10 show the configuration of flat coils 52, 5S, 54 formed as circular coils, each of which has two coils.
They are wound linearly and connected in series. The flat coils 32, 53, 54 are formed as pasted coils, that is, they are bonded together so that the conductors are stable and rigid in shape.1. i, and therefore it takes a beam of light to support this coil on its inner periphery, and the coil is moved to the motor at 1° g! It is also possible to freely protrude into the gap 35 (FIG. 1). A printed circuit and a Hall generator 37 (in addition to the coil 32) are provided on the lower side (FIG. 8), which are symmetrically glued into this coil board 36.

The current supply to the coil is via five conductors @58.59°40, each of which leads to conductor 58/, 59', 4G' (Fig. 8). There is. Two conductive wires reach into the coil 33 from the conductors 39', 40'. This coil 35 conductor 43.44i
The conductors 45 and 46f reach the inside of the coil 32 from here:
The conductor 5B', 401 is connected to the coil 34 through the conductor 5B', 401. FIG. 14 shows the circuit connections.

A positive voltage is applied to point 59'. Point 38' is connected to the collector of transistor 47, and point 4Q' is connected to the collector of transistor 48. The emitters of transistors 47 and 48 are connected to the negative pole (OV).

The output of the Hall generator 57 is applied to the base of the transistor 47.48. One input of the Hall generator 37 leads to line 49 and the other input passes through a resistor 50 to point 39.
′. A rotational speed control circuit for a motor according to the present invention is described, for example, in Japanese Patent Application Laid-Open No. 50-52516. During operation - the output voltage is controlled by a Hall generator whose output voltage is controlled by the magnetic flux of the rotor 65 - each of the three coils 32-3 alternately ta clockwise or counterclockwise.
4, a momentary interruption occurs between successive electromagnetic drive pulses, during which no electromagnetic drive moment occurs.

As shown in FIGS. 9 and 10, from the Hall generator 57 four leads, li! s4 is protruding outward.

In the center, the guide plate 36 has a triangular opening 55t for alignment and insertion into the bearing tube 11.

11 to 13 show the guide plate 5 attached to the bearing tube body 11.
6t-shown. For this, first, the intermediate member 15 communicates with the guide plate 564C and the conductor wires 58 to 40i holes 28, and the conductor wires 54
It is attached so as to pass through the hole 27. As shown in the twelfth garden.

The intermediate part 15 and the guide plate 36 are placed over the bearing tube 11, with the conductors 38 to 40.54 having a pH of 19 between the rings.
t- projecting laterally outwards through. Intermediate member 15 defines the distance from flange 13 to coils 32-34 (FIG. 1).

A thin insulating plate is passed through the lower side of the bearing tube 11, and a holder 55 is pressed against the bearing tube 11 from below. ~54
The coil is pressed in the direction of the intermediate body 15, thereby completely fixing the coil at its inner periphery. The structural parts configured in this way (FIGS. 11 to 13) are then bonded with epoxy resin to securely and permanently fix the holder 55, coil, guide plate 36, and intermediate member 15-ii to the bearing tube 11. . When the epoxy resin hardens, the two perforated bearings 56 and 57 are press-fitted into the bearing tube 11, and a lubricating oil supply plug 58i is attached between them.

Next, the four wires 38 to 40.54'i are passed through the transverse gap 14 of the flange 13, and the soft magnetic back cover plate 59 is inserted into the center recess 60.
communicates with the flange 11 via the intermediate member 1st,
Therefore, the back cover plate 59 is in contact with the upper side of the coils 52-54.

Next (・, the conductor wires are bundled with an insulating tube (511
figure).

Once the required thickness of the spacing ring 63 is determined, the cap plate 66 is fixed to the shaft 64 via the bushing 62.
Inside the cover plate 66, a six-pole permanent magnet ring 67 having magnetism in the axial direction is aligned and fixedly bonded (the bent type shown in FIG. 4 in JP-A-49-50412). It is also advantageous to use polar geometries). The direction of rotation is indicated by arrow 68 in FIG.

The shaft 64 is inserted into the bearing tube 11 from below.

The magnet 67 first pulls the back cover plate 59 and then attaches it to the cover part 66.
flange 69. Furthermore, a ring 70 is fitted on the upper end of the shaft 64, and this ring 70 serves as a thrust bearing for the suspended rotor and serves as an upper perforated bearing 5.
Touches 6.

To generate the necessary magnetic moment, a dual-function holder 55 serves. The holder 55 is shown in FIG. 2.3 and has the shape of an aX gear in plan view. The reason for this is that the holding body 55f'i has six identical lens-shaped concave portions 75 (corresponding to the number of poles of the rotor) on its circular outer periphery.

Five fixing ribs 77 are formed on the inner periphery 76 and are bent at right angles. Ribs 77 serve to press into bearing tube 11 as shown in FIG.

By cooperating with the magnetic field of the inner circumference of the rotor magnet, the illustrated periphery 74,75 of the holder 55 generates a magnetic moment. This magnetic moment is formed in opposite phase to the direction of the alternating component of the electromagnetic drive moment, and therefore compensates for this alternating component.

Therefore, an effective moment is generated on the shaft 64 during operation, and therefore a vibration component in the generated moment of the motor, i.e.
The alternating moment component is canceled by y.

FIG. 15 shows the motor 10 installed in, for example, a cassette recorder. The flange 13 is an upper holding plate 80
is screwed to.

A KFilA knot screw 82 is screwed into the screw hole of the lower holding plate 81, and an axial bearing 83 made of plastic containing molybdenum disulfide is attached above it. On the axial bearing 85 the spherical lower end 84 of the shaft 64 (FIG. 1)
slides.

The axial clearance of the rotor is set by the adjustment screw 82, and after the setting is made, the screw 82 is bonded. Ring plate 70 (first
Figure) Fi In this case, it does not act as a thrust bearing during operation. As shown in Figure 15, the motor is axially
moments of inertia, thus normally eliminating the need for a special inertial flywheel.

The invention can equally be used in the case of motors with a different number of poles or with a different bearing, for example a ball bearing. The shape of the recess 75 is expediently determined experimentally. FIG. 11 shows the exact positioning of the holder 55 relative to the coil 34. This position defines the relative position of the magnetic moment to the electromagnetic drive moment and thus also indicates the stable rest position of the rotor in the de-energized state.

The holding body 55t'' can also be brought into direct contact with the guide plate 36 instead of via the coils 32-34.

However, contact via the coil is preferred. The reason is that arranging the magnetically active edges 74, 75 of the carrier close to the rotor magnets 67 is highly favorable with respect to the magnetic moment. The object of the present invention also includes the mounting method according to this embodiment.

In comparison with DE 2,352,012, the simple construction of the motor according to the invention and its advantages become clear.

The flat stator main body includes the guide plate 36 (with coils), the coils 52 to 34 (Fig. 1 to 15) themselves, and parts 118, 1.
It can be formed directly by coils 68 to 119 degrees and 169 degrees (factors 16 to 19).

According to FIG. 16, a magnetic cover plate 10 is attached to the rotor shaft 101.
4, a ring-shaped magnet 10 with permanent magnetism in the axial direction.
5 is coaxially fixed to the shaft 131. The cover plate 104 and the magnet 105 together with the boss 102 form a tenth disk 106, which constitutes one structural unit. The boss 1'02 has an insertion hole 107t, the end surface of which indirectly serves as a sliding surface for the bearing tube 109 inserted into the shaft 101 with an axial clearance seat. This construction style is very simple in the axial direction. The bearing tube 109 is made of porous metal and has sliding bearings 11 at both ends thereof.
! 1,114. A seven-lunge plate 116 formed in accordance with the invention is press-fitted into the enlarged central portion 115. A stator plate 118 is fixed to the end face 117 side of the flange plate 116 by adhesive.

It is made to have sufficient rigidity. The square soft magnetic boss 102 is considered for the rotor 105 having four polar axial magnetism, and the radial protrusion 20 of the rectangular soft magnetic boss 102 is considered to be used for the rotor 105 having four polar axial magnetism.
0 is provided (FIG. 20). Two diametrically opposed induction coils are inserted into the stator plate 118 containing the printed circuit, one of which is connected to the first coil.
It is shown in Figure 6.

The second rotor disk 125 consists of a magnetic lid plate, which is between I! 1it- is inserted into the shaft 101, and the magnet 1
Due to the axial tensile force generated by 05, the rotor shaft 10
The fixing plate 127 fitted into the groove portion 126 of No. 1 is contacted. The distance between this groove portion 12.6 and the sliding surface 108 in the axial force direction is the same as the distance shown by the arrows 110 and 120 and the steel plate 123.
Together with the thickness 124, determine the gap width and the upper spacing between rotor and stator, as indicated by the double arrow 129. The end face of the bearing tube body 109 is attached to the fixed plate 127) magnet 1
05 and without this fixing plate.

This results in contact with the upper 108 and lower sliding surfaces.

The bearing tube body leaves a small allowable distance between the sliding surface 108, the steel plates 123 and 124, and the fixed plate 127, or the steel plate 1
It moves in contact with the fixed plate 127 through the interposition of 28 (this is not shown in the figure). The clamp ring 132 prevents the rotor disk 125 from falling off the rotor shaft.

The flange plate 116 has a large thickness in the axial direction for stability reasons. This creates a relatively wide clamping surface or adhesive surface for securely fixing the bearing tube 109 even if the bearing 114 is narrowed in area. Even if this is done, the structural long sound in the axial direction will not become large. The reason for this is that the thick flange plate 116 protrudes into the inside of the ring-shaped magnet 105. This shape is magnetically advantageous. What is the magnitude of the auxiliary magnetic moment?

It is also adjustable by selecting this thickness.

Stator plate 118 includes motor coil 119J-bearing tube body 1
It is thinned in the range between 09 and 09. The reason is coil 11
9 reaches the bearing tube through a gap 199. In this case, the flange plate 116 is fixed to the systator plate 118 by adhesive.

Therefore, it can be fixed to the bearing tube body 109 by press-fitting, by adhesion, or by a combination of press-fitting and adhesion. In FIG. 17, when two or more coils 140 are arranged radially outward within stator plate 139, stator plate 1591! I- Can be fixed to the 7 lunge plate 136 with adhesive or rivets (17th
figure).

Note that in FIG. 17, a rotor shaft 138 is inserted through the bearing tube 137. .

The stator plate is riveted to the seven-lunge plate 136 with two '14 rivets diametrically opposed to each other. The two hollow rivets are located in the intermediate chamber between the motor coils, displaced by two 1806, with only the 10,000 hollow rivet 141 being shown. The structure of the embodiment shown in FIG. 17 is the same as that shown in FIG. 16 except for the above-mentioned points.
are the same. The strength and placement of the hollow rivet do not have an unacceptably negative effect on producing a given magnetic assist moment.

Therefore, depending on the case, it may be necessary to use the same number of glue bets as the number of poles. In the low evening of two poles, 180 as mentioned above.
It is advantageous to use two rivets which are displaced by .degree. Figure 20 uses a four-pole rotor with four rivets) 141'ii. In the second embodiment shown in FIG. 18, the 10th disk 150 represents the 20th sunset plate 151. The two rotor plates of H each form one structural element. The sun-sunset plate 150 consists of a magnetic cover plate 152, which has a central recess 153, into which a boss 154 formed as a belt roll is inserted. The boss 154 has an insertion hole 156, the end surface of which serves as a support surface 157 for a bearing tube 158 inserted into the rotor shaft 155 with an axial gap support gold ingot. The bearing tube has two ball bearings 159 and 160 at both ends.
't''!, and the rotor shaft 155 rotates therein. Ball bearings 159, 160, F.

The inner rings 141, 162 are axially spaced between Pi! j′t
'' is supported on the rotor shaft 155, and the outer ring 165.
164 are supported on both sides of the inner tube 165 of the bearing tube body 158. A rigid stator plate 168 is fixed to an end surface 167 of the flange plate 166 on the rotor disk 150 side. Two 7'C motor coils 169 and 170 are inserted into the stator plate 168 and are diametrically opposed to each other. The stator plate consists of two cases 1 made of iron plates.
The outer edges 174, 175 of 72, 175 are riveted together. Two rivets distributed around the circumference No. 18
As shown in the figure.

2 cases 172.17! S is two 4-sunset boards 15
Form a metal case for the rotor consisting of 0.151,
The boss 154 projects from the case through a central hole 178. The electrical circuit elements for the rectifier circuit are the stator plate 168
may be identified. In the illustrated embodiment, the circuit elements 180, 181 protrude from the housing and are fixed to the edge 182 of the stator plate and also within the housing, where 9! The raw material is not displayed. Another magnetic iron 183 is fixed to the case 173 by means of fixing means (not shown) and can be adjusted by means of an adjusting screw 184 screwed into the case, so that the overall magnetic auxiliary moment t-m can be adjusted. The second lower rotor disk 151 has a single structure consisting of a magnetic cover plate 185. A metal boss 187 is formed in the central recess 186, and a ring-shaped permanent magnet is formed in the cover plate 185 in the axial direction. 1
88 is fixed.

The boss 187 moves in contact with the inner ring 162 of the ball bearing 159 with two steel plates 190 and 191Q interposed therebetween.
It touches the inner ring 161 of the ball bearing 159 with a 54 mm steel plate 193 interposed therebetween, and moves on its movement surface 157. In this way both bosses 154. t87 is inner ring 161
Via ゜162, ball bearings 159, 160, inner tube 16
5. Supported via a bearing tube 158t. It is particularly advantageous if the bearing tube is a smooth cylindrical sleeve.

Other than this, the ball bearing 159°160 is the bearing tube 1511
Provided on the turning part of. This support takes place without gaps. The reason for this is that the rotor discs of both swords are attracted to each other up to the stopper by the magnetic force of the magnet 18B. The spacing of the two rotor discs 150, 151 is given very precisely by the axial position of the two ball bearings as well as the thickness of the plates 190, 191, 193, the dimensions of which can be maintained very easily and precisely even in mass production. Ru. Both rotor discs 150,1
The gap width 194 between 51 is defined by the curvature of the rotor discs 150, 151 that defines this gap 194 and the axial spacing between the planes of motion of 1.87 to the boss 154; As shown in Figure 16, since it can be held accurately, the gap width can be kept within the allowable value.

Adjustment of the stator plate 168 within the air gap is also simple. This is because the axial position of the seven flange plates 166 on the bearing tube 158 can be adjusted.

Spacing between rotor disk 151 and stator plate 168.

For example, the distance 194 is the thickness t of the plates 190 and 191,
Change is the key to change. For example, if the distance 15Ji between J and Q, which is necessary to prevent contact between parts of the rotor, is increased, the output of the motor will generally decrease.

The boss 154 is formed as a fully ruptured roll, and its driven surface is 1
It is displayed as 98. The insertion hole 156 extends to the height of the subject 198, so that lateral forces can be better gripped. This has already been explained in detail with respect to FIG.

This problem becomes less of a problem when ball bearings are provided. In the embodiment shown in Figure 18.19, case 172.
The case formed by 73 can also be used for the embodiment of FIG. 16.

Figure 19, which is an enlarged view of Figure 18, shows the ball bearing system 165.1.
There are particular economic advantages in improving the invention with 64 in conjunction with that of FIG. If the bearing seat requires turning inside the bearing tube or is suitable for the purpose,
The bearing tube 158 can be manufactured very economically from hexagonal steel integrally with the flange plate 166 as an automatic rotating part.
In this case, turning can be carried out simultaneously.

Machine steel is magnetically soft enough to have an effective reluctance moment. FIG. 21 is of course based on a six-pole rotor.

On the other hand, when using an arbitrary sliding bearing as shown in FIG.
This is advantageous as it allows the size to be reduced (particularly in cases where the shaft diameter is 6 yen). In this case, sinterable mold materials (members 116, 118
), it can be economically applied to the whole body in one piece, and the reason is that there is not much difference in price between this bridge member having the edge portion 116t and the tubular shape. This configuration is advantageous for mass-produced products, where the combination of small dimensions and minimum magnetic moment of resistance is sufficient. In this case, the number of machining processes that produce chips is 4.

Sintered materials are not substantially magnetically optically soft to strong reluctance moments. If the flange plate 116 is thick in the axial direction, this can be compensated for, but only to a certain extent.

FIG. 20 shows a cross section taken along the 151st arrow V-V. When the number of poles of the rotor matches the number of protrusions 200, there should be a minimum magnetic cross section between the protrusions 200. A spatial rivet displacement structure of 45'' is selected for the position shown (4-pole rotor).

The dotted edges 202 of the recesses 203 between the protrusions 201 in FIG. 21 can also be modified for adjusting a predetermined reluctance moment. This also applies to the protrusion 201. Projection 20
1 can be bent as a plate, for example by different dimensions. or,
The flange portion can also be produced from steel plate at an advantageous cost as a pressed and drawn member.

The present invention should not be understood as being limited to the embodiments shown here.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the brushless DC motor according to the present invention, and is a plan view of the second soft magnetic holder, and FIG. 3 shows the cross-sectional line 1-1 in FIG. The figure is a plan view of the combination of the bearing tube body and the flange, and shows the cross-sectional line V-V in FIG. The figure shows the cross-sectional line ■--■ in FIG. 6, FIG. 8 is a plan view of a guide plate equipped with three flat coils, and FIG. 9 shows the cross-sectional line ■-X in FIG. . Fig. 10 is a plan view of the guide plate in Figs. 8 and 9; Fig. 11 is a plan view of the guide plate bonded to the bearing tube;
The figure shows the cross-sectional line of FIG. 11, FIG. 13 is a plan view of the guide plate attached to the bearing tube, and FIG.
The entire driving circuit of the motor shown in the figure is shown, Figure 15 shows the motor shown in Figure 1 installed, Figure 16 shows the motor of the second embodiment of the present invention, and Figure 17 shows the flange plate. 18 shows the fourth embodiment, and FIG. 19 is an enlarged view of the bearing tube shown in FIG. 18. Yes, Figure 20 is the first
The cross-sectional line V-V in FIG. 6 is shown, and FIG. 21 shows the arrow WM in FIG. 18. 10...Brushless DC motor tower 35...Flat gap 55...Soft magnetic element, holder 65...Rotor 15...Intermediate body 11.109...Bearing tube body 116...Flange plate

Claims (3)

[Claims] (1) In a brushless DC motor that has a flat air gap and uses a permanent magnet rotor, 3·n flat coils (32, 33, 34) are placed on a flat printed guide plate (36). Adhesively arranged to define an air-core stator of axial thickness substantially equal to the axial thickness of the coils, one side of said printed guide plate (36) is connected to the permanent magnets of said permanent magnet rotor, and the other side is connected to the permanent magnets of said permanent magnet rotor. A brushless DC motor is characterized in that it faces a fixed or rotating back cover plate (59) made of soft magnetic material, separated by a flat gap. (2) In the brushless DC motor according to claim 1, the flat coils (32, 33, 34) are bonded coils in which each strand has a fixed shape and is formed as a rigid integral piece. A brushless DC motor. (3) In the brushless DC motor according to claim 1 or 2, each of the three flat coils (32, 33, 34) has a Hall generator (
37) is provided with a brushless DC motor.