Motor with reduction mechanism and power seat motor with reduction mechanism

[0031] An embodiment of the present invention will now be described with reference to the drawings.

[0032] Figure 1 is a plan view of a motor with a deceleration mechanism according to an embodiment of the present invention; figure 2 Is a sectional view of the motor; image 3 It is the plan view of the motor after the gearbox of the motor is removed; Figure 4 It is an enlarged cross-sectional view of the main part of the motor; Figure 5 is a schematic diagram of the motor shaft used in the motor when it does not rotate; Figure 6 It is a schematic diagram when the motor shaft used in the motor rotates in the forward direction; Fig. 7 is a schematic diagram when the motor shaft used in the motor rotates in the reverse direction. In addition, a vehicle seat (power seat 1) for explaining a vehicle device having a conventional motor as shown in FIG. 8 is also used here to explain the present invention.

[0033] Figure 1, figure 2 with image 3 As shown, a motor 10 for a power seat with a reduction mechanism (a motor with a reduction mechanism) is provided with an open end side, a substantially cylindrical sleeve (motor box) 11 and a gear with a flange 11b The box 21, in which the flange surrounds the open end 11a of the yoke 11 and is fixed by bolts.

[0034] Such asfigure 2 As shown, a pair of magnets 12 and 12 are fixed on the inner circumferential surface 11c of the sleeve 11 by adhesive or the like. In addition, an armature shaft (motor shaft) 14 consists of a radial bearing 13a fitted in the closed-end cylindrical portion 11d at the other end of the sleeve 11 and a radial bearing 13b fitted near both ends of the shaft hole 22 of the gear box 21. And 13c are rotatably supported.

[0035] The armature shaft 14 has a first worm (worm) 15 and a second worm (worm) 150 located near the front end 14b of the armature shaft, and the thread directions of the two worms are opposite to each other. The first worm 15 and the second worm 150 are used to form a pair of worms. An armature 16 is located at a position opposite to the pair of magnets 12 and 12 of the armature shaft 14. The armature 16 is fixed near the rear end 14b of the armature shaft 14 and has an armature core 16a, which has a coil winding portion 16b with a predetermined number of slots and an armature wound on the coil winding portion 16b of the armature core 16a The coil 16c.

[0036] A commutator 17 is fixed at a position opposite to the boundary between the sleeve 11 of the armature shaft 14 and the gear box 21. The commutator 17 has commutating bars 17a, the number of which is equal to the coil winding portions 16b of the armature core 16a, and each commutating bar 17a is electrically connected to the armature coil 16c.

[0037] The opening end of the shaft hole 22 of the gear box 21 is formed with a large-diameter hole portion 22a, and a pair of brushes 19 and 19 are installed in the large-diameter hole portion 22a at a position opposite to the commutator 17, so that the pair of brushes can be Touch the corresponding reversing bar 17a. Each brush 19 is electrically connected to a motor control circuit (not shown). Switching the on-off of each of the pair of switches of the motor control circuit can generate a current flowing into the armature 16, thereby causing the armature shaft 14 to rotate forward or reverse.

[0038] Such as figure 2 with image 3 As shown, the shaft hole 22 is substantially located in the center of the gear box 21, and a recessed reduction mechanism housing portion 23 is formed to communicate with the shaft hole 22. Cylindrical bosses (thrust bearings for counter gears) 24 and 24' are integrally formed protrudingly at a predetermined position where a pair of worms 15 and 150 on the bottom wall of the reduction mechanism housing portion 23 are clamped In it. Moreover, the annular grooves 25 and 25' are respectively located in the cylindrical protrusions 24 and 24' and at the center thereof. The metal pin-shaped pivots 26 and 26' are pressed into the annular grooves 25 and 25', respectively. The first counter gear (counter gear) 30 is rotatably supported by the pivot shaft 26, and the second counter gear 300 is rotatably supported by the pivot shaft 26'. In addition, such as image 3 As shown, a circular hole 27a is located slightly to the right of the front end of the worm 15 on the bottom wall of the reduction mechanism housing portion 23. A substantially annular rib 27b is formed protrudingly around the circular hole 27a as a whole. The lower end of the cylindrical portion 41 of the output gear 40 is rotatably supported in the substantially annular rib 27b through the radial bearing 28a.

[0039] In addition, as shown in FIG. 1, the opening at one end of the reduction mechanism housing portion 23 of the gear box 21 is covered by a substantially triangular disk-shaped plastic gear box cover 29 fastened by mechanical bolts 20b. The annular grooves 29a and 29a' are opposed to the corresponding grooves 25 and 25' of the reduction mechanism housing portion 23 of the gear box cover 29, respectively. The upper part of the pivot shaft 26 is pressed into the groove 29a, and the upper part of the armature shaft 26' is pressed into the groove 29'. In addition, a circular hole 29b is formed at a position opposed to the circular hole 27a of the reduction mechanism housing portion 23 of the gear case cover 29. The upper part of the cylindrical portion 41 of the output gear 40 is rotatably supported in the circular hole 29b by a thrust-cum-radial bearing 28b. A pair of worms 15 and 150, a pair of counter gears 30 and 300, and an output gear 40 are installed in the reduction mechanism housing portion 23 of the gear box 22 to form a double reduction mechanism.

[0040] Such as figure 2 ,Figure 5, Figure 6 As shown in FIG. 7, the first counter gear 30 is composed of a large-diameter plastic gear 3 / and a first small-diameter metal gear 35, and the first small-diameter metal gear 35 is concentric with the large-diameter gear 31. The tooth portion 32 meshing with the first worm 15 is formed on the outer circumference of the large-diameter gear 31, and the internal spline 33 is formed on the inner circumference of the large-diameter gear 31. In addition, the teeth 36 meshing with the teeth 42 of the output gear 40 and the external splines 37 meshing with the internal splines 33 of the large-diameter gear 31 are both located on the outer circumference of the first small-diameter gear 35, and are concentric in the axial direction and have different heights. The ground is formed as a whole. In this case, when the large-diameter plastic gear 31 is molded by molding, the large-diameter gear 31 is fixed to the first small-diameter gear 35 by insert molding. Similarly, the second counter gear 300 is composed of a large-diameter plastic gear 310 and a second small-diameter metal gear 350 concentric with the large-diameter gear 310. The tooth portion 320 meshing with the second worm 150 is located on the outer circumference of the large-diameter gear 310, and the internal spline 33 is located on the inner circumference of the large-diameter gear 310. In addition, the tooth portion 360 meshing with the tooth portion 42 of the output gear 40 and the outer spline 37 meshing with the inner spline 33 of the large-diameter gear 310 are located on the outer circumference of the second small-diameter gear 350, and are concentric in the axial direction and have different heights. The ground is formed as a whole. In this case, when the second large-diameter plastic gear 310 is molded by molding, the large-diameter gear 310 is fixed to the second small-diameter gear 350 by insert molding.

[0041] Such as figure 2 ,Figure 5, Figure 6 As shown in FIG. 7, an output shaft 43 is fixed in the cylindrical portion 41 of the output gear 40, and the seat lifter (not shown) of the displacement mechanism 2 of the electric seat 1 protrudes from the gear box 21 of the output shaft 43. When the armature shaft 14 rotates in the forward or reverse direction, the seat lifting device drives a seat 1a to rise or fall. In other words, the output shaft 43 associated with the output gear 40 drives the seat 1a up when the armature shaft 14 rotates in the forward direction, and when the armature shaft 14 rotates in the reverse direction, the drive seat 1a moves down.

[0042] Such as figure 2 with Figure 4 As shown, a cylindrical groove 14c with a circular cross section is formed from the end surface 14f of the rear end 14b of the armature shaft 14 along the axial direction of the armature shaft 14, and a metal spiral compression spring that can be elastically deformed in the axial direction of the armature shaft 14 51 is installed in the cylindrical groove 14c as a spring element, so that one end of the spiral compression spring 51 contacts the bottom 14d of the cylindrical groove 14c, and the plastic cylindrical sliding element 52 is also accommodated in the cylindrical groove 14c. Under the elastic force of the spiral compression spring 51 located between the bottom 14d of the cylindrical groove 14c in the armature shaft 14 and the rear end surface 52a of the rear end of the sliding element 52, the front end 52b of the sliding element 52 moves from the cylindrical groove 14c. The open end 14e extends to the outside and is pressed to contact the bottom 11e of the closed end cylindrical portion 11d of the sleeve 11 (the inner side of the end of the motor box), so that the armature shaft 14 always faces the armature shaft 14 Thrust in the forward direction. The front end 52b of the sliding element 52 is made into a hemispherical shape, and lubricating oil (semi-solid lubricant) 53 is added between the top 52c of the hemispherical front end 52b and the bottom 11e of the closed end cylindrical portion 11d.

[0043] For the electric seat motor 10 with the aforementioned reduction mechanism, since the large-diameter gears 31 and 310 of the pair of counter gears 30 and 300 are located near the front end 14a of the armature shaft 14, the spiral directions are opposite to each other so that the motor shaft The aforementioned pair of worms 15 and 150 that rotate in the forward or reverse direction meshes, causing the first worm 15 to mesh with the first counter gear 30 to generate the thrust load direction of the armature shaft 14 and causing the second worm 150 to reverse the direction of the second. The thrust load directions of the armature shaft 14 generated by the meshing of the rotating gear 301 are opposite to each other and cancel each other. Therefore, it is not necessary to provide thrust bearings that pivotally support the two edge surfaces 14a1 and 14f of the armature shaft 14, so that it is also possible to omit the need to rotatably support the solid first counter gear 30 and the second counter gear 30 with high precision. Thrust bearing of gear 300. Moreover, it is possible to eliminate the play along the thrust direction of the armature shaft 14 of the motor 10 due to the backlash between the teeth of each interlocking part, so that the motor armature shaft 14 can smoothly realize forward and reverse rotations. .

[0044] As shown in FIG. 5, when the armature shaft 14 is not rotating, the front end 52b of the sliding element 52 is compressed by the elastic force generated by the helical compression spring 51 in the cylindrical groove 14c of the armature shaft 14 While contacting the bottom of the closed end cylindrical portion 11d of the sleeve 11 (the inner surface of the end of the motor box) 11e, the elastic force of the spiral compression spring 51 allows the thrust to be in the direction of the arrow F (that is, the direction in which the front end 14a of the armature shaft 14 is oriented ) Always acts toward the armature shaft 14. Thus, the end surface 14f of the rear end 14b of the armature shaft 14 is positioned at the A position, thereby ensuring a predetermined gap between the end surface 14a1 of the front end 14a of the armature shaft 14 and the bottom 13c1 of the radial bearing 13c. In addition, the B position is a position to which the end surface 14f of the rear end 14b of the armature shaft 14 can move when an external force acts in the opposite direction of the F direction and the armature shaft 14 does not rotate. The distance from position A to position B corresponds to the backlash generated between each tooth. Even when the end surface 14a1 of the front end 14a of the armature shaft 14 moves to the B position, the above-mentioned distance is set so that the end surface never contacts the bottom 11e of the closed end cylindrical portion 11d of the sleeve 11.

[0045] When the armature shaft 14 is not rotating, when the first worm 15 and the first counter gear 30 are meshed with each other, the lateral tooth side 32a on the side of the tooth portion 32 of the first counter gear 30 contacts the first counter gear 30. When the worm 15, the second worm 150 and the second counter gear 300 are in mesh with each other, the tooth side 320 a on the side of the tooth 320 of the second counter gear 300 contacts the second worm 150. Moreover, when the first small-diameter gear 35 and the output gear 40 mesh with each other, the tooth side 42a on the side of the tooth portion 42 of the output gear 40 contacts the first small-diameter gear 35, and the second small-diameter gear 350 meshes with the output gear 40. In the state, the tooth side 42 b on the other side of the tooth portion 42 of the output gear 40 contacts the second small-diameter gear 350.

[0046] Figure 6 The state when the armature shaft 14 rotates in the forward direction is shown. By rotating the armature shaft 14 in the forward direction, the first counter gear 30, the first small diameter gear 35, the second counter gear 300 and the second small diameter gear 350 rotate counterclockwise as shown by the arrow, and the output shaft 43 is as shown by the arrow. The direction is rotated clockwise, thereby lifting the seat lifting device (not shown) combined with the output shaft 43. Then the armature shaft 14 moves from the non-rotating state of the armature shaft 14 as shown in FIG. 5 against the elastic force of the helical compression spring to Figure 6 As shown on the left side, the end surface 14f of the rear end 14b of the armature shaft 14 is moved to C, which is located between the position A and the position B.

[0047] When the armature shaft 14 rotates in the forward direction, the meshing state of the first worm 15 and the first counter gear 30 is similar to the case where the armature shaft 14 does not rotate as shown in FIG. 5, that is, the first counter gear 30 The tooth side 32 a on the side of the tooth portion 32 contacts the first worm 15. On the other hand, the state in which the second worm 150 and the second counter gear 300 mesh with each other is different from the case where the armature shaft 14 does not rotate as shown in FIG. 5, that is, another tooth 320 of the second counter gear 300 The tooth side 320b on the side contacts the second worm 150. In addition, the state in which the first small-diameter gear 35 and the output gear 40 mesh with each other is similar to the case where the armature shaft 14 does not rotate as shown in FIG. 5, that is, the tooth side 42a on the side of the tooth portion 42 of the output gear 40 contacts the first small-diameter Gear 35. On the other hand, the state in which the second small-diameter gear 350 and the output gear 40 mesh with each other is different from the case where the armature shaft 14 does not rotate as shown in FIG. 5, that is, the tooth side 42a on the side of the tooth 42 of the output gear 40 is in contact. The second small-diameter gear 350.

[0048]FIG. 7 shows the state when the armature shaft 14 rotates in the reverse direction. By rotating the armature shaft 14 in the opposite direction, the first counter gear 30, the first small diameter gear 35, the second counter gear 300 and the second small diameter gear 350 rotate clockwise as shown by the arrow, and the output shaft 43 also rotates in the direction of the arrow. It rotates counterclockwise to drive the seat lifter (not shown) combined with the output shaft 43 to move the seat 1a down. Then the armature shaft 14 moves from the non-rotating state of the armature shaft 14 as shown in FIG. 5 and resists the elastic force of the helical compression spring to the left side as shown in FIG. Figure 6 In the case of forward rotation as shown, the end surface 14f of the rear end 14b of the armature shaft 14 moves to a position C located between the position A and the position B.

[0049] When the armature shaft 14 rotates in the reverse direction, the state where the first worm 15 and the first counter gear 30 mesh with each other is the same as the state where the armature shaft 14 does not rotate as shown in FIG. 5 and Figure 6 The situation when the armature shaft 14 rotates in the forward direction is different, in which the other side of the tooth 32 of the first counter gear 30 is in contact with the first worm 15. On the other hand, the state where the second worm 150 and the second counter gear 300 mesh with each other is similar to the case where the armature shaft 14 does not rotate as shown in FIG. Figure 6 The situation where the armature shaft 14 rotates in the forward direction is different, in which the tooth side 320 b on the other side of the tooth portion 320 of the second counter gear 300 contacts the second worm 150. In addition, the state where the first small-diameter gear 35 and the output gear 40 mesh with each other is different from the case where the armature shaft 14 does not rotate, as well as Figure 6 The illustrated situation where the armature shaft 14 rotates in the forward direction is different, but the tooth side 42 b on the other side of the tooth portion 42 of the output gear 40 contacts the first small-diameter gear 35. On the other hand, the state where the second small-diameter gear 350 and the output gear 40 mesh with each other is similar to the case where the armature shaft 14 does not rotate as shown in FIG. Figure 6 The situation where the armature shaft 14 rotates forward is different, and the tooth side 42b on the other side of the tooth portion 42 of the output gear 40 contacts the second small-diameter gear 350.

[0050] When the armature shaft 14 rotates in the reverse direction to drive the seat lifting device (not shown) of the displacement mechanism 2, the Figure 6 During the lowering of the seat 1a by turning the output shaft 43 counterclockwise in the direction indicated by the arrow in the middle, such a phenomenon may occur multiple times in a downward movement: for example, when the weight of the passenger sitting on the seat 1a is added to the seat 1a The load acting on the armature shaft 14 changes from a load necessary for operating the seat lifter (a positive load that prevents the armature shaft 14 from rotating in the reverse direction) to a so-called load load, thereby helping The load of the reverse rotation of the armature shaft 14 is greater than the load necessary to operate the seat lifter.

[0051] In this case, the seat lifter is not operated, that is, when the switch for moving down the motor control circuit (not shown) is switched from off to on to pass through the armature shaft as shown in FIG. 5 After 14 is in the non-rotating state, when the seat 1a is moved down by driving the seat lifting device, the armature shaft 14 rotates in the reverse direction, reducing to the positive load state as shown in FIG. 7. When the load acting on the armature shaft 14 changes from a positive load state to a loaded state, the rotating shaft 14 is reduced to a no-load state during the change. When the armature shaft 14 is in a no-load state, the armature shaft 14 moves to the front end 14a under the elastic force of the coil compression spring 51, and the end surface 14f of the rear end 14b of the armature shaft 14 moves from the position C to the position A. Keep in the state shown in Figure 5. In other words, when the first worm 15 and the first counter gear 30 are in mesh with each other, the tooth portion 32 of the first counter gear 30 in contact with the first worm 15 transitions from the other tooth side to the one. Tooth side. During the transition, when the armature shaft 14 moves toward the front end 14a, while the other tooth side 32b is in contact with the first worm 15, the tooth side 32a contacts the first worm 15 to avoid collision of these tooth sides under a large impact force. . Therefore, no noise is generated between the first worm 15 and the tooth portion 32 of the first counter gear 30. When the first small-diameter gear 35 meshes with the output gear 40, although the tooth portion 42 of the output gear 40 in contact with the first small-diameter gear 35 turns from the other tooth side 42b to the one tooth side 42a, There is also no noise generated between the gear 35 and the tooth 42 of the output gear 40. On the other hand, the meshing state of the second worm 150 and the second counter gear 300 and the meshing state of the second small-diameter gear 350 and the output gear 40 remain unchanged, as shown in FIG. 7. That is, the one side 320 a of the tooth 320 of the second counter gear 300 is in contact with the second worm 150, and the other side 42 b of the tooth 42 of the output gear 40 is in contact with the small-diameter gear 350.

[0052] The armature shaft 14 turns from the no-load state to the load state. The load state is similar to the state where the armature shaft 14 is rotating forward, that is, the armature shaft 14 moves toward the rear end 14b, and the end face of the rear end 14b of the armature shaft 14 14f moves from position A to position C and remains at Figure 6 The state shown. The state where the first worm 15 and the first counter gear 30 mesh with each other and the state where the first small-diameter gear 35 and the output gear 40 mesh with each other remain unchanged. One tooth side 32 a of the tooth portion 32 of the first counter gear 30 maintains contact with the first worm 15, and one tooth 42 a of the tooth portion 42 of the output gear 40 maintains contact with the first small-diameter gear 35. On the other hand, with respect to the state where the second worm 150 and the second counter gear 300 are meshed with each other, the tooth portion 320 of the second counter gear 300 in contact with the second worm 150 transitions from the one tooth side 320a to the The other tooth side 320b, while the second small-diameter gear 350 and the output gear 40 mesh with each other, the tooth 42 of the output gear 40 contacting the second small-diameter gear 350 moves from the other tooth side 42b to the one The tooth flank 42a is transformed.

[0053] During the change of the armature shaft 14 from the unloaded state to the loaded state, the thrust of the helical compression spring 51 acts on the armature shaft 14 in the direction indicated by the arrow F in FIG. 5. When the tooth portion 320 of the second counter gear 300 in contact with the second worm 150 transitions from the one tooth side 320a to the other tooth side 320b, the helical compression spring 51 that generates thrust in the arrow F direction acts as a damping force. The effect of the gear, thereby avoiding the collision of the other tooth side 320b with the second worm 150 under a large impact force. Moreover, when the tooth portion 42 of the output gear 40 that is in contact with the second small-diameter gear 350 transitions from the other tooth side 42b to the one tooth side 42a, the one tooth side 42a is also prevented from being subjected to a large impact force. Collision with the second small-diameter gear 350. Therefore, the flank of each tooth bite avoids the impact of the large impact force caused by the tooth gap between the teeth of each tooth bite portion, or experiences a greatly reduced impact force, so that each tooth bite No noise is generated between the teeth of the part.

[0054] An example will now be described in which the load acting on the armature shaft 14 transitions from the load state to the positive load state during the downward movement of the seat 1a. When the load changes from the load state to the positive load state, the armature shaft 14 is in a no-load state during this period. In the unloaded state of the armature shaft 14, under the elastic force of the coil compression spring 51, the armature shaft 14 moves toward the front end 14a, and the end surface 14f of the rear end 14b of the armature shaft 14 moves from the C position to the A position and remains In the state shown in Figure 5. That is, the state in which the first worm 15 and the first counter gear 30 mesh with each other and the state in which the first small-diameter gear 35 and the output gear 40 mesh with each other remain unchanged. Then, the one tooth side 32 a of the tooth portion 32 of the first counter gear 30 keeps in contact with the first worm 15, and the one tooth side 42 a of the tooth side 42 of the output gear 40 keeps in contact with the first small-diameter gear 35. On the other hand, when the second worm 150 and the second counter gear 300 are in mesh with each other, the tooth 320 of the second counter gear 300 in contact with the second worm 150 changes from the other tooth side 320b to the one tooth. Side 320a. During the transition operation, when the armature shaft 14 moves toward the front end 14a, the one tooth side 32a comes into contact with the first worm 15 and the other tooth side 32b keeps contact with the first worm, so that these tooth sides avoid Mutual collisions caused by a large impact. Therefore, no noise is generated between the first worm 15 and the tooth portion 32 of the first counter gear 30. In addition, when the second small-diameter gear 350 and the output gear 40 mesh with each other, the tooth portion 42 of the output gear 40 that is in contact with the second small-diameter gear 350 transitions from the one tooth side 42a to the other tooth side 42b. There is also no noise generated between the first small-diameter gear 35 and the teeth 42 of the output gear 40.

[0055] The armature shaft 14 transforms from a no-load state to a positive load state, where the positive load state is similar to the state where the armature shaft 14 rotates in the opposite direction, that is, the armature shaft 14 moves toward the rear end 14b, and the rear end 14b of the armature shaft 14 The end surface 14f of the A is moved from the position A to the position C and remains in the state shown in FIG. 7. The meshing state of the second worm 150 with the second counter gear 300 and the meshing state of the second small-diameter gear 350 and the output gear 40 remain unchanged. The one tooth side 320a of the tooth portion 320 of the second counter gear 300 is the same. The second worm 150 is kept in contact, and the other tooth side 42b of the tooth portion 42 of the output gear 40 is kept in contact with the second small-diameter gear 350. On the other hand, with regard to the state in which the first worm 15 and the first counter gear 30 are meshed with each other, the tooth portion 32 of the first counter gear 30 in contact with the first worm 15 transitions from the one tooth side 32a to the other One tooth side 32b, and regarding the state where the first small-diameter gear 35 and the output gear 40 mesh with each other, the tooth portion 42 of the output gear 40 that is in contact with the first small-diameter gear 35 transitions from the one tooth side 42a to the other Tooth side 42b.

[0056] When the armature shaft 14 changes from a no-load state to a positive load state, under the action of the elastic force of the helical compression spring 51, the thrust force is applied to the armature shaft 14 in the direction indicated by the arrow F in FIG. 5. When the tooth portion 32 of the first counter gear 30 in contact with the first worm 15 transitions from the one tooth side 32a to the other tooth side 32b, the helical compression spring 51 that generates thrust in the direction of the arrow F acts as a damping force. The effect of the actuator prevents the other tooth side 32b from colliding with the second worm 15 under a large impact force. Moreover, when the tooth portion 42 of the output gear 40 that is in contact with the first small-diameter gear 35 transitions from the one tooth side 42a to the other tooth side 42b, it is also avoided that the other tooth side 42b is in the same direction under a large impact force. The collision of the first small-diameter gear 35. Therefore, the flank of each tooth bite avoids the impact of the large impact force caused by the tooth gap between the teeth of each tooth bite portion, or experiences a greatly reduced impact force, so that each tooth bite No noise is generated between the teeth of the part.

[0057] As described above, the front end 52b of the sliding element 52 is pressed by the elastic force of the spiral compression spring 51 installed at the cylindrical groove 14c of the armature shaft 14 and contacts the bottom 11b of the sleeve 11, and is pressed against the bottom 11b of the sleeve 11 Under the action of the elastic force, a thrust along the direction of the front end 14a of the armature shaft 14 is always generated. Therefore, even if multiple load loads occur during one operation of the seat lifting device lowering the seat 1a, the tooth side of each tooth part can avoid the impact of the large impact force caused by the backlash. The backlash occurs in the same Between the teeth of the large-diameter gears 31 and 310 of a pair of counter gears 30 and 300 meshing with the worm 15 and 150, and each of the output gears 40 meshing with the small-diameter gears 35 and 350 of the same pair of counter gears 30 and 300 Between the teeth of a tooth bite, or in other words, will experience a greatly relaxed impact force to ensure that even in the double reduction mechanism, the inter-tooth noise that occurs between the teeth of each tooth bite can be It is eliminated by a simple motor.

[0058] Since the spiral compression spring 51 and the sliding element 52 are installed in the cylindrical groove 14c in the rear end 14b of the armature shaft 14, the spiral compression spring 51 and the sliding element 52 basically do not protrude outward, so the entire electric seat is used The size of the motor is reduced. In addition, since there is lubricating oil between the top 52c of the hemispherical front end 52b of the sliding element 52 and the bottom 11e of the sleeve 11, the coil compression spring 51 and the sliding element 52 together with the armature shaft 14 can be realized with a simple structure. Rotate smoothly, so that the helical compression spring 51 and the sliding element 52 are installed in the cylindrical groove 14c at the rear end 14b of the armature shaft 14, and a smooth impact force is applied to the armature shaft in the direction of the front end 14a of the armature shaft 14. 14 on.

[0059]Although according to the embodiment of the present invention, the above-mentioned motor with a deceleration mechanism is described as a motor for a power seat with a deceleration mechanism applied to an electric vehicle, it goes without saying that the above embodiment can also be applied to any belt Among other motors with a reduction mechanism, such as wiper motors and power window motors.