JP3504959B2 - Small motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized motor used for, for example, audio equipment, precision equipment, electric equipment for automobiles, etc., and more particularly to detecting a motor temperature. The present invention relates to a small motor having a positive temperature coefficient thermistor for controlling overcurrent. 2. Description of the Related Art FIG. 10 is a longitudinal sectional front view of an essential part showing an example of a conventional small motor. In FIG. 10, reference numeral 1 denotes a case, which is formed of a metal material such as soft iron into a bottomed hollow cylindrical shape, and has a permanent magnet 2 formed in an inner peripheral surface, for example, formed in an arc segment shape. The case 1 is configured so that a rotor 5 including an armature 3 and a commutator 4 facing the permanent magnet 2 can be interposed. Next, reference numeral 6 denotes a case cap, which is formed of an insulating material such as a resin material, and is fitted into the opening of the case 1. Reference numeral 7 denotes a brush provided with a sliding contact piece provided at a free end so as to slidably engage with the commutator 4, and is provided on the case cap 6 together with an input terminal 8 electrically connected to the brush 7. . 9,
Reference numerals 10 denote bearings, each of which is fixed to the bottom of the case 1 and the center of the case cap 6, and which constitutes the rotor 5;
12 is rotatably supported. With the above configuration, current is supplied from the input terminal 8 to the armature 3 via the commutator 4 constituting the rotor 5 via the brush 7, thereby being fixed to the inner peripheral surface of the case 1. A rotating force is applied to the armature 3 existing in the magnetic field formed by the permanent magnet 2, and the rotor 5 can be rotated. External devices (not shown) are connected via the output-side shaft 11. Can be driven. The small motor as shown in FIG. 10 has a wide range of applications as described above, and particularly has a motorized mirror,
It is useful for automotive electrical equipment that drives power windows and the like. However, since the small motor has a low output, even if a minor trouble (for example, rusting, dust intrusion, etc.) occurs in the driven part, or when the driven part reaches the driving limit, the small motor is used. An overload condition (extremely impossible to rotate) occurs, and the winding of the armature 3 is overheated,
Undesirable conditions may eventually result in burning. As a countermeasure for overheating to solve the above-mentioned disadvantages, a means for supplying power via a positive temperature coefficient thermistor has been conventionally used. FIG. 11 is a cross-sectional view of a main part showing an example of a case cap of a small motor having a positive temperature coefficient thermistor,
FIG. 12 is a view in the direction of the arrow A in FIG. 11, and the same parts are indicated by the same reference numerals as in FIG. In FIGS. 11 and 12, reference numeral 21 denotes a connecting member, which is integrally provided on the outer end surface of the case cap 6. Connection member 2
1 is formed, for example, in a shape of a hollow square tube with a bottom, and is formed so that a pair of input terminals 8 provided inside the case cap 6 protrude. The input terminals 8 and 8 are formed in parallel and their surfaces are substantially in the same plane. By inserting a connector into the connecting member 21, power can be supplied to the input terminals 8 and 8. It is configured as follows. Reference numeral 22 denotes a positive temperature coefficient thermistor which is formed in a substantially quadrangular plate shape and is configured to be pressed against the surface of one input terminal 8 by a holding member 23 made of a conductive material. The holding member 23 is electrically connected to one brush (not shown) via a conductive member or directly. In this case, the positive temperature coefficient thermistor 22 provided in the case cap 6 has a characteristic that when the temperature exceeds a certain temperature (for example, 100 ° C.), the internal resistance value sharply increases. Therefore, if the overload is continuously applied to the small motor or the temperature of the small motor rises due to the overcurrent flowing when the rotation of the rotor 5 (see FIG. 10) is forcibly locked. Since the internal resistance value of the positive temperature coefficient thermistor 22 is rapidly increased, the current supplied to the small motor is rapidly reduced, and the small motor can be prevented from being overheated. [0008] In the small motor having the above structure, the distance between the pair of input terminals 8 is usually narrowed. There is a problem that the mounting means is complicated. That is, since the surfaces of the pair of input terminals 8 and 8 are substantially on the same plane, when the positive temperature coefficient thermistor 22 relatively moves along the surface of the input terminal 8 to the other input terminal 8 side. May short-circuit the input terminals 8 and 8. For this reason, a means for preventing the movement of the positive temperature coefficient thermistor 22 must be considered, and a complicated means such as providing a stopper or increasing the pressing force by the sandwiching member 23 is required. On the other hand, depending on the specifications of the small motor, the positive characteristic thermistor 22 having a relatively large size may be required. However, in the configuration shown in FIG. There is a problem that the degree of freedom in selecting the dimensions of the characteristic thermistor 22 is reduced. Therefore, there is also a problem that an appropriate PTC thermistor 22 cannot be interposed, and the use of a small motor may be limited. SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems existing in the prior art, to prevent a short circuit between input terminals, and to provide a small motor having a high degree of freedom in selecting a positive temperature coefficient thermistor. . In order to achieve the above object, the present invention relates to a case having a hollow cylindrical shape having a bottom and made of a metal material and having a permanent magnet fixed to an inner peripheral surface thereof. A rotor comprising an armature and a commutator opposed to the permanent magnet, a brush fitted into the opening of the case and slidably engaged with the commutator, and a brush directly or other conductively connected to the brush. A case cap provided with an input terminal electrically connected via a member, and rotatably supporting the rotor via bearings provided on the bottom of the case and the case cap. in small motor comprising, arranged so that parallel and their surface an input terminal of a pair existing in approximately the same plane, the projection portion is provided on the surface of one of the input terminals, Li Kui strip leg such conductive material Part tip
The part is formed into a plurality of fork-shaped divided pieces and
Part of these split pieces bend and protrude from the surface of the leg
Technical means is employed in which a positive temperature coefficient thermistor is pressed and held on the protrusion of the one input terminal via the holding portion of the holding member formed on the holding portion. According to the above configuration, even if a positive temperature coefficient thermistor disposed in a narrow portion only comes into contact with only one of the input terminals and is slightly larger in size, it is mounted. There is no contact with the other input terminal. FIGS. 1 and 2 are a plan view and a bottom view, respectively, showing a case cap according to an embodiment of the present invention. FIG. 3 is a partial cross-sectional side view taken along the line CC in FIG. 1, and FIG. 10A is a partial sectional view, FIG. 10A is a sectional view taken along line DD in FIG. 1, FIG. 10B is a sectional view taken along line EE in FIG.
12 to 12 are denoted by the same reference numerals. In FIGS. 1 to 4, the case cap 6 is formed in a substantially cup shape by an insulating material such as a resin material, and has a hollow cylindrical connecting member 41 protruding from the outer end surface. Reference numerals 81 and 82 denote a pair of input terminals, which are formed as described later, and have a cross-sectional profile provided on the case cap 6 inserted and fixed in a T-shaped through hole 42. The free ends of the input terminals 81 and 82 are
It is provided so as to protrude into the connection member 41. Reference numeral 43 denotes a connection terminal, which is formed in a substantially L-shape, is provided on the case cap 6 via an attachment member 44, and is formed so that the connection end protrudes from the outer end surface of the case cap 6. A brush 7 formed in a substantially L shape and having a sliding contact piece 45 at a free end is connected to the connection terminal 43 inside the case cap 6. One connection terminal 4
3 and the input terminal 81 are electrically connected via the conductive member 46, and a capacitor 47 is electrically connected between the connection terminals 43 via the lead wire 60. Reference numeral 48 denotes a clamping member, which is formed in a substantially U-shape by a conductive material as described later, and has one leg in contact with the connection terminal 43 inside the case cap 6 and the other leg connected to the input terminal. The positive temperature coefficient thermistor 49 having a substantially quadrangular shape is provided so as to sandwich the same in cooperation with the terminal 82. With the above configuration, the case cap 6 is fitted into the opening of the case 1 as shown in FIG. 10, and the locking claws (not shown) provided in the opening of the case 1 are attached to the case cap 6. By folding it into the provided locking portion 50, the case 1
And the case cap 6 can be assembled integrally. The capacitor 4 connected between the connection terminals 43, 43
Numeral 7 is for reducing electric noise generated from the small motor. Next, the configuration of the input terminals 81 and 82 will be described. FIGS. 5 and 6 are explanatory diagrams showing the input terminals 81 and 82 in FIGS. 1, 2 and 4, respectively, wherein (a) is a cross section, (b) is a left side surface, and FIG. 5 (c) is a bottom surface. Is shown. First, in FIG. 5, the input terminal 81 is formed in a substantially L-shaped cross section with a conductive material, so that a stopper portion 51 is provided at a lower end portion. Next, a cut-and-raised tongue piece 52 is provided at the intermediate portion, and a cut-and-raised protrusion 53 is provided at the stopper portion 51. On the other hand, the input terminal 82 in FIG.
In the same manner as the input terminal 81 shown in FIG.
Is provided with a cut-and-raised tongue piece 52 in the middle. Numeral 54 denotes a projection, which is provided between the stopper 51 and the cut and raised tongue piece 52 so as to protrude toward the cut and raised tongue piece 52. In order to form the input terminals 81 and 82 as described above, it is preferable to use press forming means. FIGS. 7A and 7B are explanatory views showing the holding member 48 in FIGS. 2 and 4, wherein FIG. 7A shows a side view and FIG. 7B shows a front view. FIGS. 8 and 9 are respectively a view in the direction of arrow F in FIG. 7A and a view in the direction of arrow G in FIG. 7B. 7 to 9, the holding member 48 is made of a conductive elastic metal material and has substantially U-shaped portions having legs 55a and 55b.
Form in the shape of a letter. The angle between the legs 55a and 55b is set to, for example, 120 ° in FIG. The distal end of the leg 55a is formed in a fork shape, for example, into three divided pieces, and a cut-and-raised tongue piece portion 57 is provided at the central divided piece 56, and the divided pieces 58 on both sides are formed with the cut and raised tongue piece A holding portion is formed on the protruding side of the piece portion 57 so as to be bent and protruded. Reference numeral 59 denotes a hole, which is provided at the distal end of the other leg 55b, for improving the locking action of the holding member 48 with the case cap 6 (see FIGS. 1 to 4) described later. The manner in which the input terminals 81 and 82 and the holding member 48 are mounted on the case cap 6 with the above configuration will be described. First, the input terminals 81 and 82 are connected to the inside of the case cap 6 in FIG.
Insert into 2. In this case, since the through-hole 42 has a T-shaped cross-sectional profile as shown in FIG. 1, the cut-and-raised tongue piece 5 is formed in the middle as shown in FIGS.
It is extremely easy to insert the input terminals 81 and 82 having the protrusions 2 into the through holes 42. Next, after the input terminals 81 and 82 are inserted until their stoppers 51 abut against the end face of the case cap 6, the cut and raised tongue piece 52 is bent substantially at right angles to the surfaces of the input terminals 81 and 82. As a result, the input terminals 81, 8
2 is fixed to the case cap 6. Therefore, input terminal 8
Therefore, the pull-out resistance in the longitudinal direction of the first and the second 82 can be ensured. Note that a processing jig can be used to bend the cut-and-raised tongue piece 52. However, since the processing direction in this case is the longitudinal direction of the input terminals 81 and 82, the connection member 41 is present in the vicinity. However, no interference occurs during processing. After fixing the input terminals 81 and 82, FIG.
By plastically deforming the cut-and-raised protruding portion 53 upward as shown in FIG.
And the conductive member 46 are electrically connected. Next, the clamping member 4
2 is inserted into a predetermined position of the case cap 6 together with the connection terminal 43 and the brush 7 as shown in FIG.
To be fixed. Thereby, the above members are surely connected not only mechanically but also electrically. On the other hand, the leg portion 55a of the sandwiching member 48 shown in FIGS. 7 to 9 is opposed to the input terminal 82 through a slight gap as shown in FIGS. 2 and 4 (b). The positive characteristic thermistor 49 can be easily inserted, and by the insertion of the positive characteristic thermistor 49, the split piece 58 and the cut-up tongue piece which are in the refracted state and the inclined state in the free shape as shown in FIGS. All 57 are elastically deformed to a horizontal state. Therefore, the positive characteristic thermistor 49 is connected to the input terminal 8.
It can be reliably held between the second projection 54 and the second projection 54. On the other hand, even if an external force in the pull-out direction acts on the PTC thermistor 49 from this state, the cut-and-raised tongue piece 57 acts to bite into the electrode of the PTC thermistor 49, so that the withdrawal strength can be increased, and the reliability can be increased. The performance is improved. In this case, the positive temperature coefficient thermistor 49 is
As shown in (b), the input terminal 82 is
, But not with the other input terminals 81 as shown in FIG. Therefore, there is no possibility of causing a short circuit between the input terminals 81 and 82. After assembling as described above, a capacitor 47 is connected to the protruding end of the connection terminal 43 as shown in FIGS.
, For example, by soldering. In this case, the end of the conductive member 46 is also soldered to the connection terminal 43 together with the lead wire 60, so that electrical connection is ensured. In this embodiment, a hollow cylindrical connecting member 41 is protruded from the outer end face of the case cap 6, and input terminals 81 and 82 are present in the connecting member 41.
Has been described that is electrically connected to the input terminals 81 and 82 via other conductive members. However, in the present invention, the input terminal 8 and the brush 7 are directly connected as shown in FIG. Naturally, the present invention can also be applied to a small motor having the configuration. Since the present invention has the above-described configuration and operation, the following effects can be obtained. (1) Even if the surfaces of a pair of input terminals are arranged in substantially the same plane, the positive temperature coefficient thermistor contacts only one of the input terminals, and the other Since they face each other with an interval therebetween, a short circuit between input terminals can be completely prevented. (2) Even if the distance between the input terminals is small, the shape and size of the PTC thermistor can be freely selected, and the degree of freedom in the selection is large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a case cap according to an embodiment of the present invention. FIG. 2 is a bottom view showing a case cap according to the embodiment of the present invention. FIG. 3 is a cross-sectional side view taken along a line CC in FIG. 1; 4A and 4B are cross-sectional views of main parts showing a case cap according to the embodiment of the present invention, wherein FIG. 4A is a cross-sectional view taken along line DD in FIG. 1 and FIG. 5A and 5B are explanatory diagrams showing an input terminal 81 in FIGS. 1, 2 and 4, wherein FIG. 5A is a cross section, FIG.
(C) shows the bottom surface. FIGS. 6A and 6B are explanatory diagrams showing an input terminal 82 in FIGS. 1, 2 and 4, wherein FIG. 6A is a cross-sectional view, and FIG. 7A and 7B are explanatory views showing the sandwiching member 48 in FIGS. 2 and 4, wherein FIG. 7A is a side view and FIG. 7B is a front view. FIG. 8 is a view in the direction of arrow F in FIG. 7 (a). FIG. 9 is a view in the direction of arrow G in FIG. 7 (b). FIG. 10 is a vertical sectional front view of a main part showing an example of a conventional small motor. FIG. 11 is a sectional view of a main part showing an example of a case cap of a small motor provided with a positive temperature coefficient thermistor. 12 is a view in the direction of arrow A in FIG. [Explanation of References] 6 Case cap 48 Nipping member 49 Positive temperature coefficient thermistor 54 Protrusion 81, 82 Input terminal

Continuation of front page (72) Inventor Ryoichi Someya 280 Ryugoji Temple, Motono-mura, Inba-gun, Chiba Prefecture Mabuchi Motor Co., Ltd. Technical Center (JP, U) JP-A-59-176350 (JP, U) Patent 3421421 (JP, B2) Patent 2708694 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 11/00 H02K 5/00-5/26 H02K 23/00-23/68

Claims (1)

(1) A case (1) formed of a metal material into a hollow cylinder with a bottom and having a permanent magnet (2) fixed to an inner peripheral surface thereof; Armature (3) facing 2)
A rotor (5) composed of a brush and a commutator (4); a brush (7) fitted into the opening of the case (1) and slidably engaged with the commutator (4); 7) and a case cap (6) provided with input terminals (81) and (82) electrically connected directly or via another conductive member (46). ) And a bearing (9) provided on the case cap (6),
In a small motor in which the rotor (5) is rotatably supported via (10), a pair of input terminals (81) and (82) are in parallel and their surfaces are substantially in the same plane. provided as protrusions on the surface of the one input terminal (82) to (54) is provided, Li Kui strip leg such a conductive material the leading end of (55a) Four
Formed into a plurality of divided pieces (58)
Of the split piece (58) of the leg (55a)
A holding member (4) formed on a holding portion protruding from the surface.
8) A small-sized motor characterized in that a positive temperature coefficient thermistor (49) is pressed and held on said projection (54) of said one input terminal (82) via said holding portion.