JP2000069724A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the assembly property to a teeth part of a molded coil. SOLUTION: In an electric motor which is so arranged as to constitute a stator by engaging a projection 52a2 projecting in circumferential direction provided in a teeth part 52a with a dovetail groove provided in a yoke part, thereby coupling the teeth part 52a where a coil is mounted in advance and the yoke part, the above coil is made a molded coil made in advance into a specified form, and also insulating paper (insulator) 52d of a height roughly equal to the quantity of projection of the projection 52a2 is mounted to the coil mounting section 52a3 of the teeth part 52a before engaging that molded coil 52b from the side of the projection 52a2 of the teeth part 52a, thereby mounting it to the teeth part 52a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor, and more particularly, to a structure of a stator.

[0002]

2. Description of the Related Art As one of electric motors, a tooth portion provided with a coil and a yoke portion are preliminarily mounted by fitting a projecting portion projecting in a circumferential direction provided on a tooth portion into a dovetail groove provided on a yoke portion. Some stators are connected to each other to form a stator. For example, Japanese Unexamined Patent Publication No.
This is disclosed in JP-A-9-215230.

[0003]

In the electric motor disclosed in the above-mentioned publication, since the teeth are provided with a projection projecting in the circumferential direction, the coil is formed in a predetermined shape in advance. When the formed coil is fitted from the protruding portion side of the tooth portion to be mounted on the tooth portion, the formed coil may be unstable with respect to the tooth portion and may be tilted. There is a possibility that the protrusions of the teeth and the teeth engage with each other to impair the assemblability of the formed coil.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and a circumferentially projecting portion provided on a teeth portion is fitted into a dovetail groove provided on a yoke portion. Thus, in the electric motor in which the teeth and the yoke are preliminarily mounted to form a stator, the coil is formed into a formed coil having a predetermined shape, and the formed coil is connected to the teeth. It is characterized in that an insulator having a height substantially equal to the amount of protrusion of the protruding portion is mounted on the coil mounting portion of the tooth portion before fitting from the protruding portion side of the portion and mounting on the tooth portion. . In this case, it is desirable to use a formed coil that is compression-formed into a predetermined shape by a press-type forming jig as the formed coil.

Further, according to the present invention, a stator is formed by connecting the teeth portion and the yoke portion by fitting a circumferentially projecting portion provided on the teeth portion into the dovetail groove provided on the yoke portion. The electric motor according to the above aspect is characterized in that the electric motor has a coil fitted to the teeth portion, and an insulating portion between the coil and the teeth portion having a height substantially equal to the protrusion amount of the protrusion portion.

[0006]

In the electric motor according to the present invention (the invention according to claim 1), when the molded coil is fitted from the projecting portion side of the tooth portion and mounted on the tooth portion, the coil passes through the projecting portion. Since the molded coil to be fitted is guided and fitted by the outer periphery of the insulator, the molded coil is prevented from tilting with respect to the teeth portion, and the molded coil is engaged with the projection of the teeth portion. Is suppressed, and the formed coil can be smoothly and accurately fitted and mounted on the coil mounting portion of the teeth portion.

In the practice of the present invention, when a formed coil which is compression-formed into a predetermined shape by a press-type forming jig is employed as the formed coil (the invention according to claim 2), the space factor of the coil is And the motor characteristics can be improved while the size of the electric motor is reduced.

Further, an electric motor according to the present invention (claim 3)
In the invention according to the invention, when the coil is fitted (fitted and fitted) to a tooth portion having an insulating portion having substantially the same height as the projected amount of the projected portion, the coil fitted through the projected portion is fitted. Since the coil is guided and fitted by the outer periphery of the insulating portion, the coil is prevented from tilting with respect to the tooth portion, and the coil is prevented from engaging with the projecting portion of the tooth portion. It can be fitted smoothly and accurately.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a rack-and-pinion type steering device provided with an electric motor 50 according to the present invention. In this steering device, the steering device extends in the left-right direction of the vehicle and is assembled to a vehicle body (not shown). The input shaft 20 and the steering shaft 3 are attached to the housing 10 to be attached.
0, a ball screw mechanism 40, an electric motor 50, and the like.

The input shaft 20 is mounted on the housing 10 so as to be rotatable and immovable in the axial direction. The input shaft 20 has a universal joint, an intermediate shaft,
A torque is transmitted to a steering wheel (all not shown) via a universal joint, a steering main shaft, and the like. The input shaft 20 is engaged with a rack tooth 31 formed on the outer periphery of one side of the steering shaft 30 by a pinion (not shown) formed at an inner end so as to transmit a steering force. 30 is moved in the left-right direction of the vehicle (axial direction of the steering shaft).

The steering shaft 30 is also called a rack bar, and a well-known rack guide 11 (a housing 10) provided with a portion corresponding to the pinion (the rear portion of the portion where the rack teeth 31 are formed) facing the pinion. (Which is assembled) so as to be elastically movable in the radial direction of the steering shaft 30 and the left end cannot be moved in the radial direction of the steering shaft 30 by the end stopper 12 (attached to the housing 10). And is fixed to and supported by the vehicle so as to be movable and non-rotatable in the left-right direction of the vehicle (axial direction of the steering shaft), penetrates the housing 10, and has tie rods 32, 33 and knuckles at both left and right ends. Arm (not shown)
Via a steering wheel (not shown) so that the steering force can be transmitted. The screw shaft 41 of the ball screw mechanism 40 is formed integrally with the steering shaft 30, and a spiral groove is formed on the outer periphery of the screw shaft 41.

The ball screw mechanism 40 includes the steering shaft 30
The rotation of the rotating shaft 51 of the electric motor 50 between the elastic support portion (portion supported by the rack guide 11) and the fixed support portion (portion supported by the end stopper 12) of the steering shaft 30 in the axial direction A rotation displacement conversion means for converting the rotation to a transmission, and provided coaxially with the steering shaft 30, and a screw shaft 41 formed integrally with the steering shaft 30, Motor 50
A nut 42 mounted on the rotating shaft 51 so as to be rotatable around the steering shaft (rotatable with the rotating shaft 51) and immovable in the steering shaft direction, and a thin cylindrical cage between the nut 42 and the screw shaft 41. 43 and rotatably held by the screw shaft 4
It is composed of a number of balls 44 interposed between a spiral groove formed on one outer periphery and a spiral groove formed on the inner periphery of the nut 42.

The electric motor 50 applies an axial steering assisting force to the steering shaft 30 via the ball screw mechanism 40, and is mounted coaxially with the steering shaft 30. It has a cylindrical rotating shaft (output shaft) 51 that is rotatably mounted via the ball bearings 13 and 14 and cannot move in the axial direction, and a stator 52 that also forms a part of the housing 10. The output is controlled by a control device (not shown) based on a signal from a well-known steering torque sensor (not shown), a sensor S for detecting rotation of the rotating shaft 51, and the like.

As shown in FIGS. 1 and 2, the rotary shaft 51 has a stepped cylindrical shaft main body 51a and 16 permanent magnets which are arranged and fixed at equal intervals on the outer periphery of the shaft main body 51a. It is constituted by a magnet 51b. Each permanent magnet 51b
Has a shape that is long in the axial direction, and has an inner peripheral side (S
Poles) are formed in an arc shape convex toward the inner circumference, and the outer circumference side (which is N poles at intervals) is formed in an arc shape centered on the rotation center of the rotating shaft 51. It is formed so that both ends in the circumferential direction are thinner than the central part.

The stator 52 has 18 tooth portions 52a formed by stacking electromagnetic steel plates in the axial direction and forming a block shape.
And a coil 52b attached to each tooth 52a,
A yoke 52c is provided for accommodating the coils 52b and the teeth 52a therein. Each tooth 52a
Has a magnetic pole portion 52a1 extending in the circumferential direction on the inner circumferential side and a projecting portion 52a2 projecting in the circumferential direction on the outer circumferential side, as shown in FIGS.
At the dovetail groove 52c1 provided in the yoke portion 52c to be assembled.
a3 has a protrusion amount L (0.3 to 1.0 mm) of the protrusion 52a2.
The insulating paper 52d (which can be embodied by adopting another insulator) having a height substantially equal to the height of the coil 52b is mounted before the coil 52b is mounted. The yoke portion 52c is made of a magnetic material that functions as a magnetic path forming body and can be used as a structure such as a housing. As its material, for example, an electromagnetic steel sheet or a low carbon steel S10C or S15C steel pipe is used. ing.

The stator 52 is manufactured through the steps schematically shown in FIGS. 4 to 9. In the coil winding step shown in FIG. 4, the stator 52 resembles the coil mounting portion 52a3 of the teeth 52a. Reel 1 on jig 101
The winding (copper wire having a diameter of about 2.9 mm and having an outer periphery provided with an insulating coating) wound therefrom is wound around the required number of turns, cut off, and removed from the jig 101 as shown in FIG. . The coil 52b shown in FIG. 5 can be obtained by winding the jig 101 around the number of turns corresponding to a plurality of the coils 52b, cutting the jig 101, removing the jig 101 from the jig 101, and cutting the jig 101 for each required number of turns. is there.

In the press forming step shown in FIG. 6, the coil 52b shown in FIG. 5 is set on a press-type forming jig 103 and compression-molded into a predetermined shape. By this compression molding, each wire of the coil 52b is deformed to a non-circular shape so that the gap between the wires is almost eliminated, and the space factor of the coil 52b in the assembled state as shown in FIG. 2 is increased. I have.

In the coil fitting and mounting step shown in FIG. 7, the formed coil 52b compression-formed in the press forming step shown in FIG. 6 is fitted from the side of the projecting portion 52a2 of the tooth portion 52a formed in a block shape. And is attached to the teeth portion 52a. In this case, an insulating paper 52d having a height substantially equal to the amount of protrusion of the protruding portion 52a2 is previously mounted on the coil mounting portion 52a3 of the tooth portion 52a before mounting the coil 52b.

In the process of fitting the coiled tooth portion 52a to the yoke portion 52c shown in FIG.
Is fitted into the dovetail groove 52c1 formed on the inner periphery of the yoke portion 52c by the protruding portion 52a2 and assembled. In addition,
This fitting step is completed by fitting all the teeth portions 52a into the yoke portions 52c and assembling them.

In the molding step shown in FIG. 9, the bottom plate 10 in which the core 104 is integrally provided on the yoke part 52c in which all the teeth parts 52a with coils are assembled and the fitting step is completed.
5 is set using bolts 106, then a liquid resin molding material 107 having electrical insulation is poured from the upper opening, and then the resin molding material 107 is heated and cured, and finally the bottom plate 105 and the core 104 are removed. As a result, all the teeth portions 52a with coils and the yoke portions 52c
Are integrated with an electrically insulating resin to form a stator 5.
2 is produced. At the time of mass production, an injection molding process with good productivity is employed.

In the electric power steering apparatus of the present embodiment configured as described above, the steering force is applied to the input shaft 2.
0 is transmitted directly from the pinion 0 to the portion where the rack teeth 31 of the steering shaft 30 are formed, and the output of the electric motor 50 is controlled by a control device (not shown).
The steering torque is transmitted to the portion of the steering shaft 30 where the screw shaft 41 is formed via the zero (0), and the output of the electric motor 50 (steering assisting force) appropriately assists the steering torque.

By the way, in the electric motor 50 of the present embodiment, as shown in FIG. 7, when the formed coil 52b is fitted from the projecting portion 52a2 side of the tooth portion 52a and mounted on the tooth portion 52a, the projecting portion is formed. Since the molded coil 52b fitted through the 52a2 is guided and fitted by the outer periphery of the insulating paper 52d, the molded coil 52b is prevented from tilting with respect to the tooth portion 52a, and the molded coil 52b is Engagement with the protruding portion 52a2 of the portion 52a is suppressed, and the formed coil 52b can be smoothly and accurately fitted and mounted on the coil mounting portion 52a3 of the teeth portion 52a.

In the present embodiment, as the formed coil fitted and mounted on the teeth 52a, a formed coil 52b compression-formed into a predetermined shape by a press-type forming jig 103 shown in FIG. 6 is employed. Therefore, the space factor of the coils in the stator 52 can be increased, and the motor characteristics can be improved while the size of the electric motor 50 is reduced.

In the electric power steering apparatus according to the present embodiment, the yoke 52c of the electric motor 50 can be used as a part of the housing 10 of the electric power steering apparatus. The power steering device can be configured simply and compactly, and the preload torque (load) of the steering can be generated by using the eddy current loss (iron loss amount) in the yoke portion 52c, so that the vehicle can run properly. Performance (prevention of wobble due to moderate handle weight).

In this embodiment, since the yoke portion 52c of the electric motor 50 is formed of a steel pipe, the amount of expensive electromagnetic steel sheets used can be reduced, and the yoke portion 52c can be formed at a low cost. The power steering device can be manufactured at low cost. Also, the steering shaft 3
Reference numeral 0 denotes a rack bar that is coaxially disposed and penetrates the rotation shaft 51 of the electric motor 50, so that the electric motor 50 can be compactly disposed around the rack bar, that is, the steering shaft 30, so that the diameter can be reduced. In addition, the size of the electric power steering device can be reduced.

In the above-described embodiment, the present invention is applied to the electric motor 50 employed in the electric power steering device. However, the present invention projects in the dovetail groove provided in the yoke portion in the circumferential direction provided in the teeth portion. The present invention can be applied to various electric motors in which a stator is formed by connecting a tooth portion and a yoke portion in which a coil is mounted in advance by fitting a protruding portion, and is limited to the above embodiment. is not.

[Brief description of the drawings]

FIG. 1 is an overall view showing an embodiment of an electric power steering device according to the present invention.

FIG. 2 is a sectional view showing a configuration of a rotating shaft and a stator of the electric motor shown in FIG.

FIG. 3 is a diagram illustrating a relationship between a protrusion of a tooth portion and insulating paper.

FIG. 4 is a view schematically showing a coil winding step in a stator manufacturing step.

FIG. 5 is a perspective view of a coil manufactured in the coil winding step of FIG. 4;

FIG. 6 is a diagram schematically showing a press forming step in a stator manufacturing step.

FIG. 7 is a view schematically showing a coil fitting / attaching step in a stator manufacturing step.

FIG. 8 is a view schematically showing a step of fitting a tooth part with a coil to a yoke part in a step of manufacturing a stator.

FIG. 9 is a view schematically showing a molding step in a stator manufacturing step.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Housing, 11 ... Rack guide, 12 ... End stopper, 13, 14 ... Ball bearing, 20 ... Input shaft, 3
0: steering shaft, 40: ball screw mechanism, 41: screw shaft, 42: nut, 43: cage, 44: ball, 50
... Electric motor, 51 ... Rotating shaft, 51a ... Shaft main body, 51b
... permanent magnet, 52 ... stator, 52a ... teeth part, 5
2a1 magnetic pole portion, 52a2 projecting portion, 52a3 coil mounting portion, 52b coil, 52c yoke portion, 52c1
... Dovetail groove, 52d ... Insulating paper, 103 ... Press-type forming jig.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) SS10 SS19 SS24 SS44 TT04 TT05 TT26 5H621 GA01 GA02 HH01 JK02 JK05 JK17

Claims (3)

[Claims] 1. A circumferentially protruding portion provided on a teeth portion is fitted into a dovetail groove provided on a yoke portion.
In an electric motor in which a stator and a yoke are connected to each other with a coil mounted thereon in advance to form a stator, the coil is formed into a formed coil having a predetermined shape, and the formed coil is protruded from the teeth. An electric motor, wherein an insulator having a height substantially equal to the amount of protrusion of the protruding portion is mounted on a coil mounting portion of the tooth portion before being fitted to the teeth portion and mounted on the teeth portion. 2. The electric motor according to claim 1, wherein the formed coil is a formed coil that is compression-molded into a predetermined shape by a press-type forming jig. 3. By fitting a circumferentially projecting portion provided on the teeth portion into a dovetail groove provided on the yoke portion,
In an electric motor in which a teeth portion and a yoke portion are connected to form a stator, a coil fitted to the teeth portion and a height between the coil and the teeth portion substantially equal to a projection amount of the projection portion. An electric motor having an insulating portion.