JP2009179203A - Driving device for seat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a constitution to prevent generation of abnormal noise in a speed reduction mechanism part of a driving device for a seat. <P>SOLUTION: The speed reduction mechanism part 4 of the driving device 1 for the seat is provided with a helical gear 13 engaged with a worm 12 mounted on a rotary shaft of a motor. An inner ring 14B of a ball bearing 14 for rotatably supporting the helical gear 13 is pressed to the axis direction outside by a washer 21. The inner ring 14B presses a rubber washer 25 on a relief part 23 of a bracket 3. When the helical gear 13 is rotated, the inner ring 14B of the ball bearing 14 is rotated, and the rubber washer 25 and the inner ring 14B slide in relation to the bracket 3. The rubber washer 25 therefore acts as the brake of the helical gear 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a seat driving device that slides a seat by driving a motor.

  Some vehicles are equipped with a seat drive device that electrically moves a seat on which an occupant is seated. This type of seat driving device is configured to decelerate the rotation of the motor by a reduction mechanism and to rotate a lead screw that guides the movement of the seat. The speed reduction mechanism has a worm attached to the rotating shaft of the motor, and the worm is meshed with a helical gear fixed to the lead screw. Therefore, when the motor is rotated, the lead screw is rotated via the worm and the helical gear.

Here, when the seat is moved by the seat drive device, a negative load may act on the lead screw due to the occupant's own weight or the like. In this case, the lead screw is rotated more than the number of rotations controlled by the motor, and the rotation of the worm does not coincide with the helical gear connected to the lead screw when attached to the motor. As a result, the helical gear and the worm interfere with each other to generate abnormal noise.
In order to prevent the occurrence of abnormal noise in this manner, in the conventional seat driving device, a metal collar is inserted into the tip of the lead screw, an O-ring is fitted to the outer peripheral surface of the collar, and the O-ring is attached to the bearing. By making sliding contact with the inner peripheral surface, a stable braking force is applied to the lead screw to suppress the mismatch of the rotation of the helical gear and the worm (for example, see Patent Document 1).
JP 2004-114773 A

However, in the conventional sheet driving device, the number of parts is increased by providing the collar. Furthermore, since the lead screw was supported on the bearing through a metal collar, the lead screw became larger in the radial direction and the layout was poor.
The present invention has been made in view of such circumstances, and a main object thereof is to simplify the configuration for preventing the generation of abnormal noise in the speed reduction mechanism portion of the seat driving device.

The invention according to claim 1 of the present invention that solves the above-described problems is a seat drive in which the rotation of the motor is decelerated by the deceleration mechanism and then transmitted to the output shaft, and the vehicle seat is moved by the rotation of the output shaft. The speed reduction mechanism unit includes a gear meshed with a worm attached to a rotating shaft of the motor in a case and connected to the output shaft, and the gear rotates through a bearing on the case. The seat driving device includes a braking member that is freely supported and is pressed against the case by an inner ring of the bearing in contact with the gear.
In the seat drive device, when the output shaft is rotated by an external load, a force that presses the braking member against the case acts on the inner ring of the bearing that supports the gear connected to the output shaft. The braking member functions as a brake that suppresses the rotation of the inner ring of the bearing, and the brake is applied to the rotation of the gear.

The invention according to claim 2 is the seat drive device according to claim 1, further comprising a washer that presses the inner ring of the bearing toward the braking member.
In the seat drive device, the washer generates a force by which the inner ring of the bearing presses the braking member against the case. A stable force can be applied to the braking member.

According to a third aspect of the present invention, in the seat drive device according to the first or second aspect, the brake member is attached to the case so as to prevent the case and the inner ring of the bearing from coming into direct contact with each other. It is accommodated in the provided recessed part, It is characterized by the above-mentioned.
In addition to the effect of the first or second aspect, the seat driving device uses the concave portion formed in the case to house the braking member, so there is no need to separately provide a space for housing the braking member.

According to a fourth aspect of the present invention, in the seat drive device according to any one of the first to third aspects, the output shaft is connected to a mechanism for moving the seat up and down, and the seat is lowered. In some cases, the inner ring, the braking member, and the case are sequentially arranged in a direction in which the output shaft moves.
When the seat is lowered, there may be a negative load that tries to rotate the gear more than the rotation of the motor. At this time, the braking member brakes the rotation of the inner ring of the bearing that supports the gear, so that the gear is prevented from rotating too much.

  According to the present invention, when the seat is moved, the worm and the gear are prevented from interfering with each other, and no abnormal noise due to the gear interference is generated. Since there is no need to provide a collar as in the prior art, the number of parts can be reduced. Since there is no need to arrange a large number of parts in the radial direction, the apparatus can be downsized and the degree of freedom in layout can be increased.

The best mode for carrying out the invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the seat drive device 1 is connected to a speed reduction mechanism section 4 including a bracket 2 and 3 that are attached to a seat (not shown) on which an occupant is seated, and the speed reduction mechanism section 4. When the motor 5 is rotated, the lead screw 6 that is the output shaft is rotated. The lead screw 6 is connected to a link (not shown) that moves the seat up and down.

As the motor 5, a brush motor configured to be able to rotate forward and reverse is used. The motor 5 is controlled by a control device (not shown) so that, for example, the motor 5 rotates forward when the sheet is raised and rotates backward when the sheet is lowered.
In the motor 5, the bracket 5 </ b> A is fixed to the case main body 7 of the speed reduction mechanism unit 4 with a bolt or the like. The rotation shaft of the motor 5 passes through the bracket 5 </ b> A and is inserted into the speed reduction mechanism 4, and is rotatably supported by the case body 7. Further, as shown in FIG. 2, a worm 12 is attached to the rotating shaft 11 of the motor 5.

The speed reduction mechanism unit 4 includes a case 8 in which both end portions of the case body 7 are closed by two brackets 2 and 3. The brackets 2 and 3 are attachment portions 2A and 2B used when the end portions are bent and attached to the seat frame.
In the case 8, a worm 12 and a helical gear 13 engaged with the worm 12 are accommodated. The helical gear 13 is disposed orthogonal to the rotating shaft 11 of the motor 5. The helical gear 13 is a gear portion 13B in which a part of the cylindrical portion 13A bulges outward in the radial direction, and the bulging portion is formed on the outer periphery with teeth that mesh with the worm 12. The gear portion 13B is provided at a substantially central portion in the axial direction of the helical gear 13, and both end portions of the cylindrical portion 12A sandwiching the gear portion 13B are rotatably supported by ball bearings 14. In the ball bearing 14, the outer ring 14A is press-fitted and fixed to the case 8, and the cylindrical part 12A is supported by the inner ring 14B. Furthermore, a lead screw 6 is screwed inside the cylindrical portion 12A.

  The lead screw 6 passes through the speed reduction mechanism unit 4 in a direction orthogonal to the rotation shaft 11 of the motor 5. More specifically, the lead screw 6 is inserted into the case main body 7 through a hole formed in the bracket 2, and passes out of the case 8 through a hole formed in the bracket 3 through the inside hole of the case 7 and the helical gear 13. Has been pulled out. Stoppers 15 and 16 are provided at both ends of the lead screw 6 outside the case 8, and the lead screw 6 can be reciprocated until one of the stoppers 15 and 16 contacts the case 8. it can. Further, a connecting portion 17 connected to a link for raising and lowering a sheet (not shown) extends from the end portion on the one stopper 16 side.

Here, a washer 21 is inserted between each inner ring 14 </ b> B of the two ball bearings 14 and the gear portion 13 </ b> B of the helical gear 13. The washer 21 is in surface contact with a surface orthogonal to the axis of the gear portion 13B. Further, the ball bearing 14 is in contact with only the inner ring 14B, and presses the inner ring 14B to the opposite side, that is, the brackets 2 and 3 side.
In each bracket 2, 3, the peripheral edge portion of the hole through which the lead screw 6 passes is bent outward in the axial direction to form relief portions 22 and 23 that are concave portions. The escape portions 22 and 23 are shaped so that the inner ring 14B does not directly contact the brackets 2 and 3 when the inner ring 14B is biased toward the brackets 2 and 3 by the washer 21.

  As shown in FIGS. 2 and 3, a rubber washer 25 serving as a braking member is disposed in the escape portion 23 on the connecting portion 17 side of the lead screw 6 among the escape portions 22 and 23. The rubber washer 25 is brought into surface contact with each of the inner ring 14B and the bracket 3 in a state where the rubber washer 25 is compressed with a preset compression amount.

Next, the operation of the sheet drive device 1 will be described.
When raising the seat, the motor 5 is rotated forward. A helical gear 13 meshed with a worm 12 attached to the rotary shaft 11 is rotated in the forward direction. The lead screw 6 is rotated by the helical gear 13, and the connecting portion 17 drives the link. The lead screw 6 is moved in the left direction in FIG. A seat frame (not shown) is lifted with respect to the rail on the vehicle body side, and the seat fixed to the seat frame rises.
When the seat is lowered, the motor 5 is rotated in the reverse direction. The helical gear 13 meshed with the worm 12 is rotated in the direction opposite to that when it is raised. The lead screw 6 is reversely rotated by the helical gear 13, and the connecting portion 17 drives the link. The lead screw 6 is moved rightward in FIG. The seat frame is lowered toward the rail, and the seat fixed to the seat frame is lowered.

  When the helical gear 13 rotates, the inner ring 14B of the ball bearing 14 and the rubber washer 25 slide against the inner surface of the escape portion 23 of the bracket 3, so that the helical gear 13 acts as a brake against the rotation of the helical gear 13. When the seat is lowered, a load is applied by the seat and the occupant, so that a negative load that further rotates the lead screw 6 and the helical gear 13 is applied rather than the rotation by the motor 5. At this time, the rubber washer 25 acts as a brake, thereby preventing the helical gear 13 from being turned too much. As a result, interference between the helical gear 13 and the worm 12 is prevented, and no abnormal noise is generated.

  Since the rubber washer 25 is not inserted into the escape portion 22 on the opposite side, almost no braking force is generated when the lead screw 6 is moved from the center toward the relief portion 22. Since this direction is a direction in which the seat is lifted, a negative load does not act, and the helical gear 13 is not rotated too much by an external load. For this reason, stable operation is possible even without a braking force.

  According to this embodiment, since the inner ring 14B of the ball bearing 14 presses the rubber washer 25 toward the bracket 3 in the axial direction, rattling in the thrust direction is prevented and braking force is stably applied. Can be generated. Since a cylindrical collar is not required as in the prior art, an increase in the number of parts can be suppressed. Since the braking force is generated in the axial direction, the size in the radial direction can be reduced as compared with the conventional configuration in which the braking force is applied in the radial direction. Further, since the helical gear 13 is directly received by the ball bearing 14, it is not necessary to provide a space for supporting the lead screw with the bearing in the case as in the prior art, and the shaft length can be shortened.

Further, the pressure applied by the washer 21 to the inner ring 14B of the ball bearing 14 is relieved by the rubber washer 25, so that excessive stress is not applied to the ball bearing 14. Since the rubber washer 25 is arranged so as to be pressed against the bracket 3 by the inner ring 14B and generate a braking force when the seat is lowered, it is possible to prevent the generation of abnormal noise when the seat is lowered.
Since the rubber washer 25 is accommodated by using the relief portion 23 that is recessed so that the inner ring 14B of the ball bearing 14 does not directly interfere with the bracket 3, a space for arranging the O-ring is secured as in the conventional case. The apparatus can be reduced in size compared to the case.

Note that the present invention can be widely applied without being limited to the above-described embodiment.
For example, instead of raising and lowering the seat, a seat driving device that slides the seat back and forth may be used.
The braking member may be a ring-shaped member such as an O-ring. The braking member may be inserted into both relief portions 22 and 2. A worm gear can be used instead of the helical gear 13.

1 is an external view of a sheet drive device according to an embodiment of the present invention. It is sectional drawing which shows the structure of a deceleration mechanism part. It is an enlarged view for demonstrating arrangement | positioning of a helical gear, a washer, a ball bearing, a rubber washer, and a bracket.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seat drive device 4 Deceleration mechanism part 5 Motor 6 Lead screw (output shaft)
8 Case 12 Worm 13 Helical gear 14 Ball bearing 14A Outer ring 14B Inner ring 21 Washer 22, 23 Escape part 25 Rubber washer (braking member)

Claims (4)

A seat drive device that transmits the rotation of the motor to the output shaft after decelerating the rotation of the motor, and moves the vehicle seat by the rotation of the output shaft,
The speed reduction mechanism has a case to which the motor is attached, and the case is meshed with a worm formed on the rotating shaft of the motor and a gear connected to the output shaft is freely rotatable via a bearing. And a braking member provided between the side surface of the inner ring of the bearing that contacts the gear and the case.   The seat drive device according to claim 1, further comprising a washer that presses the inner ring of the bearing toward the braking member.   The seat driving device according to claim 1, wherein the braking member is housed in a recess formed between the case and the inner ring of the bearing.   The output shaft is connected to a mechanism for raising and lowering the seat, and the inner ring, the braking member, and the case are arranged in order in a direction in which the output shaft moves when the seat is lowered. The sheet drive device according to any one of claims 1 to 3.

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