JPH11123960A - Power seat for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely prevent a transmission structure from being damaged while ensuring smooth transmission of the driving force of a driving means. SOLUTION: A seat is fitted through a frame on an upper rail moving fore and aft being guided by a lower rail disposed on the floor of a vehicle, and the upper rail is constituted so as to move fore and aft by the rotation of a screw shaft 5 around the axial center formed so as to extend fore and aft and the frame is formed with a driving means for rotating the screw shaft 5 around the shaft center through a driving shaft which is orthogonal to the screw shaft 5 and a transmission structure 6. The transmission structure 6 comprises a worm gear 43 formed concentrically at the front end side of the driving shaft, and a pinion formed concentrically at the front end side of the screw shaft 5 and consisting of a metal bush 7 meshed with the worm gear 43 and a worm wheel 8 made of synthetic resin, and a male screw 52 is fitted at the front end side of the screw shaft 5, and the pinion is screwed to the male screw 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power seat for a motor vehicle which is configured to move back and forth by driving a driving means.

[0002]

2. Description of the Related Art Conventionally, a power seat 1 for an automobile as shown in FIG. 4 is known. The power seat 1 includes a seat bottom 11 fixed via a frame 3 on a slide rail 2 fixed to a floor F of an automobile, and a seat back 12 erected on a rear edge of the seat bottom 11.
And an electric motor 4 attached to the lower portion of the frame 3 and for moving the seat 1 back and forth.

The slide rail 2 has a pair of width-direction lower rails 21 integrally fixed to the floor F, and a pair of width-direction upper rails 22 provided at the upper portion so as to be movable in the front-rear direction while being guided by the lower rails 21. The frame 3 is bridged between the pair of upper rails 22. The seat bottom 11 is fixed to the upper rail 22 and the upper portion of the frame 3 so as to be able to move back and forth while being guided by the lower rail 21 via the upper rail 22.

The upper rail 22 has an inverted U shape in a sectional view.
A screw shaft 500 which is set in a letter shape and is rotatable around its own axis extending in the front-rear direction is mounted therein.
The screw shaft 500 is screwed to a nut member (not shown) fixed in the lower rail 21. By rotating the screw shaft 500 forward and reverse, the upper rail 22 moves forward and backward, and the front and rear of the power seat 1 are moved. The position can be changed.

The electric motor 4 is fixed to the lower portion of the frame 3 by screws or the like. The drive shaft 41 of the electric motor 4 has a so-called double wire 4 comprising an inner wire and a pipe covered with the inner wire in a slidable state.
2 is connected to the screw shaft 500 via a speed change structure 600, and the driving force of the electric motor 4 is controlled via the double wire 42 and the speed change structure 600. It is transmitted to.

FIG. 5 is a cross-sectional view illustrating a conventional transmission structure 600. As shown in FIG. As shown in FIG.
Is a box-shaped casing 501 fixed to the distal end side of the upper rail 22 and a serration 50 on the outer peripheral surface on the distal end side.
3, a pinion 504 having an inner peripheral surface formed with internal teeth 505 meshing with the serrations 502, and a spiral tooth 44 meshing with the pinion 504.
And a worm gear 43 having a worm gear 43.

The pinion 504 has a pair of cylindrical portions 507 at the front and rear ends formed so as to have a smaller diameter than the portion where the external teeth 506 are formed. A support hole 501a into which each of the cylindrical portions 507 is fitted in a sliding contact state is formed, and the pinion 504 is supported by the casing 501 in a state where the front and rear cylindrical portions 507 are fitted into these casings 501. The shaft 500 is supported on the upper rail 22 via the casing 501 so as to be rotatable around its own axis.

A pair of bearing cylinders 508 facing each other are provided on both side walls in the width direction of the casing 501, while the cylindrical portions at both ends of the worm gear 43 are in sliding contact with the bearing cylinders 508. It is inserted. The cylindrical portion inside the worm gear 43 is connected to the inner wire of the double wire 42, whereby the forward and reverse drive rotation of the drive shaft 41 by the drive of the electric motor 4 is performed by the double wire 42, the worm gear 43, and the pinion. The power sheet 1 is transmitted to the screw shaft 500 via the spline shaft 504 and the spline shaft 502, and the rotation of the screw shaft 500 causes the power seat 1 to move back and forth.

Further, a nut 509 having a larger diameter than the spline shaft 502 is screwed to the tip end surface of the spline shaft 502, whereby the spline shaft 502 is connected to the pinion 504.
From the rear.

The pinion 504 is made of synthetic resin, while the worm gear 43 is made of metal. The mesh between the metal worm gear 43 and the synthetic resin pinion 504 causes the worm gear 43 to be lubricated by the synthetic resin. The transmission of the driving force acting on the pinion 504 is smoothly performed.

[0011]

By the way, in the conventional speed change structure 600 as described above, the seat 1 receives a force in the front-rear direction due to the sudden start and stop of the automobile and the vibration during running. When the power is
The power is transmitted to the pinion 504 via the upper rail 22 and the casing 501, whereby the pinion 504 is transmitted.
Presses the front end face of the screw shaft 500 and the nut 509. However, since the pinion 504 is made of a synthetic resin, the pinion 504 is easily broken by the above-mentioned pressing, and has a problem that its service life is shortened.

It is conceivable that the pinion 504 is made of metal in order to solve such inconvenience. However, when the pinion 504 is made of metal, the external teeth 506 of the pinion 504 are made.
And the helical teeth 44 of the worm gear 43 are meshed with each other by metal, which makes it impossible to teach the lubrication performance of one made of synthetic resin, making it difficult to transmit the driving force smoothly. Abnormal noise,
A new problem is raised in which, in extreme cases, the teeth 421, 506 may be damaged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to reliably prevent damage to a transmission structure while ensuring smooth transmission of driving force of a driving unit. It is an object of the present invention to provide a power seat for an automobile having a shift structure for moving a seat.

[0014]

According to the first aspect of the present invention, there is provided a power seat for an automobile, which moves back and forth while being guided by a pair of widthwise lower rails extending in the front and rear direction on the floor of the vehicle. A pair of upper rails in the width direction is provided, a seat is mounted on the upper rail via a frame, and the upper rail moves back and forth by rotation around a shaft center of a screw shaft provided to extend in the front and rear direction. In the power seat for automobiles, the frame is provided with a driving means for rotating the screw shaft around the axis through a drive shaft orthogonal to the screw shaft and a speed change structure, the speed change structure A worm gear formed concentrically on the distal end side of the drive shaft, and a worm gear concentrically formed on the distal end side of the screw shaft; A worm gear, a worm gear, a distal end of the screw shaft and a casing containing the pinion, and a male screw is screwed on the distal end of the screw shaft, and the pinion is screwed to the male screw In this state, the movement in the front-rear direction is restricted by the casing.

According to this power seat for an automobile, the pinion is securely connected to the screw shaft by being screwed to the tip end side of the screw shaft,
When the vehicle suddenly starts or stops suddenly, the force heading back and forth of the screw shaft is reliably transmitted to the pinion, this force is received by the casing via the pinion, and the conventional pinion and screw shaft are spline-coupled. In this case, the force in the front-rear direction of the screw shaft cannot be transmitted evenly to the pinion in the axial direction, as in the case where the pinion is in place. You. Therefore, the failure of the power seat due to the breakage of the pinion is effectively prevented, and the transmission structure can be downsized as compared with the conventional one.

According to a second aspect of the present invention, there is provided a power seat for an automobile according to the first aspect, wherein the pinion includes a metal bush screwed to the male screw and a bush made of a metal. The bushing is made of a synthetic resin gear that is coaxially and corotatably fitted to the outside, and the movement of the bush in the front-rear direction is restricted.

According to the power seat for an automobile, the force in the front-rear direction of the screw shaft is received by the casing via the metal bush which is hardly damaged, so that the transmission structure is hardly damaged. With
The failure of the power seat due to the breakage of the pinion is more reliably prevented, and the transmission structure can be significantly reduced in size. Further, since the gear made of synthetic resin is meshed with the worm, there is no inconvenience that unpleasant noise is generated when the gear and the worm mesh.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. In the following description, the structure of the seat 1 itself except for the speed change structure is the same as that described above with reference to FIG.

FIG. 1 is a perspective view showing an embodiment of a transmission structure according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. 1 and 4, the XX direction is referred to as the width direction, the YY direction is referred to as the front-rear direction, and particularly the -X direction is leftward, the + X direction is rightward, the -Y direction is forward, and the + Y direction is It is called backward. As shown in these figures, the transmission structure 6 includes a casing 60 fixed to the lower surface of the upper rail 22 with bolts B, a screw shaft 51 on the distal end side of the screw shaft 5 provided in the casing 60, Screw shaft 51
, A worm wheel 8 made of a synthetic resin externally fitted to the bush 7, and a worm gear 42 meshing with the worm wheel 8. The pinion according to the present invention includes the bush 7 and the worm wheel 8.

The casing 60 is formed of a pair of L-shaped plates 61 in the front-rear direction formed by being bent into an L-shape in a side view.
And a pair of side plates 6 in the width direction sandwiched between these L-shaped plates 61.
And 2. The L-shaped plate 61 includes a vertical plate 61a extending in the vertical direction and a horizontal plate 61b extending in the front-rear direction from the upper edge of the vertical plate 61a. The box-shaped casing 60 is formed by being weld-stopped in a state where the side plates 62 are sandwiched between both side edges in the width direction of the pair of vertical plates 61a.

The pair of vertical plates 61a are formed with a pair of fitting holes 63 facing each other in the front-rear direction, and the front and rear portions are formed inside the portions where the fitting holes 63 are formed. A pair of first washers 64 facing each other is provided, and a dual-purpose bearing 65 acting in both the radial direction and the thrust direction is disposed on the facing surface side of each first washer 64.
A pair of second washers 66 in the front-rear direction are arranged inside the bush 5, and the bush 7 is fitted around these own fitting holes 63, the first washers 64, the dual-purpose bearings 65 and the second washers 66 around its own axis. Rotatable casing 6
0 is attached.

A pair of side plates 6 of the casing 60 are provided.
2 is provided with a pair of bearing cylinders 67 projecting so as to extend in the width direction in opposite directions to each other, and a central shaft 45 projecting concentrically from both end faces of the worm gear 43 to these bearing cylinders 67. Is rotatably supported around its own axis in a sliding contact state, whereby the spiral teeth 44 sandwiched between the side plates 62 can rotate around the central axis 45.

The bush 7 has a large-diameter portion 71 formed at the center and a small-diameter portion 72 extending from the large-diameter portion 71 in the front-rear direction and having a smaller diameter than the large-diameter portion 71. Is formed. The pair of small-diameter portions 72 have outer diameters slightly smaller than the inner diameters of the first washer 64, the dual-purpose bearing 65, and the second washer 66 of the vertical plate 61a, so that the second washer 66, the dual-purpose bearing 65 and the first washer 64 can be sequentially fitted to the small diameter portion 72, respectively.

The large-diameter portion 71 has a plurality of serrations 73 extending in the front-rear direction over the entire outer peripheral surface thereof, while the inner peripheral surface of the worm wheel 8 corresponds to the serrations 73. A plurality of internal teeth 81 are provided, and when the internal teeth 81 mesh with the serrations 73, the bush 7 and the worm wheel 8 rotate together.

The inner peripheral surface of the bush 7 has a female screw 7
4 is screwed, while the screw shaft 51 is screwed with a male screw 52 corresponding to the female screw 74.
By screwing the female screw 74 into the bush 7,
Are mounted on the screw shaft 51. Such a bush 7 has a vertical plate 61a of an L-shaped plate 61 having a length dimension.
The screw shaft 51 is dimensioned longer than the bush 7 while the bush 7 is screwed to the screw shaft 51 in the casing 60. The vertical plate 61 in front
It projects slightly outside from the fitting hole 63 of a.

A washer 5 is provided at the front end of the screw shaft 51.
The nut 54 is screwed and fastened via the pin 3, and the washer 53 is in contact with the leading edge of the bush 7. A female screw that meshes with the male screw 52 is also screwed on the inner peripheral surface of the washer 53 so that a double screw is formed by the washer 53 and the nut 54, and the washer 53 and the nut 54 are formed.
And the screw shaft 5 of the bush 7
The state of screwing to 1 is stabilized. The washer 53 and the nut 54 form a structure for preventing the bush 7 from loosening.

A cylindrical stopper 55 is fitted on the front end of the screw shaft 5 in a sliding contact state. The stopper 55 is for preventing further advance when the nut member (not shown) screwed to the screw shaft reaches the frontmost portion of the movable range, and when the nut member reaches the frontmost portion. The front end surface of the stopper 55 is the casing 6
The nut member abuts on the vertical plate 61a to prevent further forward movement of the nut member.

External teeth 82 meshing with the helical teeth 44 of the worm gear 43 are screwed on the outer peripheral surface of the worm wheel 8. Therefore, the worm gear 43 is connected to the central shaft 45.
By rotating forward and backward, this rotation is transmitted to the worm wheel 8 via the external teeth 82, and the forward and reverse rotation of the worm wheel 8 is transmitted to the screw shaft 5 via the bush 7 and the screw shaft 51. , This screw shaft 5
The power seat 1 (FIG. 4) advances and retreats due to the forward and reverse rotation of.

FIG. 3 is a sectional view showing another embodiment of the structure for preventing the bush 7 from loosening. In this loosening prevention structure, a reverse screw 50a concentric with the screw shaft 51 and having a smaller diameter than the screw shaft 51 extends from the distal end surface of the screw shaft 51, and further has the same diameter as the screw shaft 51 concentrically from the distal end surface of the reverse screw 50a. Yes,
And a reverse screw shaft 50 in which a reverse screw 50a is screwed on the outer peripheral surface.
Is extended. A washer 53 'is attached to the reverse screw shaft 50.
The nut 54 ′ of the reverse screw is screwed and fastened via the to abut on the leading edge of the bush 7, thereby stabilizing the screwing state of the bush 7 to the screw shaft 51. By adopting the reverse screw shaft 50, even if the bush 7 rotates in the direction in which the bush 7
Since the bushing 4 'tries to turn in the tightening direction, loosening of the bush 7 is reliably prevented.

As described above in detail, according to the present invention, the pinion for transmitting the rotation of the worm gear 43 around the central axis 45 to the screw shaft 5 in the transmission structure 6 includes a worm wheel 8 made of a synthetic resin, and the worm wheel 8. And a bush 7 meshed with the screw shaft 5.
1 is fixed to the screw shaft 5 by being screwed to the screw shaft 5 of the bush 7 as compared with the conventional case where the pinion 504 (FIG. 5) is attached to the screw shaft 5 by spline connection. The relative movement of the pinion to the screw shaft 5 is reliably prevented, and the mounting state of the pinion on the screw shaft 5 is stabilized.

In addition, a force in the front-rear direction is applied to the power seat 1 due to sudden start and stop of the vehicle, vibrations during running, etc., so that a large force in the front-rear direction acts on the screw shaft 5. Since the bush 7 integral with the screw shaft 5 is made of metal, and the front and rear edges of the large-diameter portion 71 are sandwiched between the pair of second washers 66, the bush 7 is applied to the screw shaft 5. The large force is received by the large-diameter portion 71 abutted on the second washer 66. Since the large-diameter portion 71 is not made of a synthetic resin like the conventional pinion 504, the disadvantage that the pinion is broken is surely ensured. Is prevented.

The worm wheel 8 meshing with the metal worm gear 43 is made of a synthetic resin, and the synthetic resin generally has lubricating performance. Is smoothly transmitted to the worm wheel 8 having the above-mentioned structure, and inconveniences such as generation of abnormal noise are reliably prevented.

[0033]

According to the power seat for an automobile according to the first aspect of the present invention, the transmission structure is provided concentrically with the worm gear formed concentrically on the distal end side of the drive shaft and on the distal end side of the screw shaft. And a pinion that meshes with the worm gear, and a worm gear, a distal end side of the screw shaft and a casing that houses the pinion. However, since the pinion is regulated by the casing moving in the front-rear direction, the pinion is securely connected to the screw shaft, and when the vehicle suddenly starts or stops suddenly, the force traveling in the front-rear direction of the screw shaft is surely fixed. This force is received by the casing via the pinion, and the conventional pinion and screw shaft are splined. In this case, the force that goes in the front-rear direction of the screw shaft cannot be evenly transmitted to the pinion in the axial direction, as in the case where the pinion is used. Can be eliminated. Therefore, it is possible to effectively prevent the failure of the power seat due to the breakage of the pinion, and to reduce the size of the transmission structure as compared with the conventional one.

According to the power seat for an automobile according to the second aspect of the present invention, the pinion is made of a metal bush that is screwed to the male screw, and the synthetic resin is fitted around the bush concentrically and corotatably. Since the casing is restricted from moving in the front-rear direction of the bush, in particular, the force in the front-rear direction of the screw shaft is received by the casing via a metal bush that is difficult to be damaged, The transmission structure can be made more difficult to be damaged, and the failure of the power seat due to the breakage of the pinion can be prevented more reliably. In addition, the transmission structure can be significantly reduced in size. Also,
Since the synthetic resin gear is meshed with the worm, it is possible to reliably prevent unpleasant noise generated when the gear and the worm mesh with each other.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a transmission structure according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view showing another embodiment of a bush loosening prevention structure.

FIG. 4 is a perspective view showing one embodiment of a power seat.

FIG. 5 is a cross-sectional view illustrating a conventional transmission structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Kneading injection molding apparatus 11 Seat bottom 12 Seat back 2 Slide rail 21 Lower rail 22 Upper rail 3 Frame 4 Electric motor 41 Drive shaft 42 Double wire 43 Worm gear 44 Helical tooth 45 Center axis 5 Screw axis 5a Connection axis 50 Reverse screw axis 50a Reverse screw 51 Screw shaft 52 Male screw 53 Washer 54 Nut 55 Stopper 6 Transmission structure 61 L-shaped plate 61a Vertical plate 61b Horizontal plate 62 Side plate 63 Fitting hole 64 First washer 65 Dual bearing 66 Second washer 67 Bearing cylinder 677 Bush 71 Large diameter part 72 Small diameter part 73 Serration 74 Female screw 8 Worm wheel 81 Internal teeth 82 External teeth B Bolt F Floor

Claims (2)

[Claims] 1. A pair of widthwise upper rails which are moved forward and backward while being guided by a pair of widthwise lower rails disposed on a floor of a vehicle so as to extend in the front and rear direction are provided. The seat is attached,
The upper rail is configured to move back and forth by rotation about an axis of a screw shaft provided to extend in the front-rear direction, and the frame is provided with a drive shaft orthogonal to the screw shaft and a transmission structure. In a power seat for automobiles provided with driving means for rotating a screw shaft around an axis, the transmission structure includes a worm gear formed concentrically on the distal end side of the drive shaft, and a distal end side of the screw shaft. It is provided concentrically, and comprises a pinion that meshes with the worm gear, a worm gear, a distal end side of the screw shaft and a casing that houses the pinion, and a male screw is screwed on the distal end side of the screw shaft, The pinion is restricted from moving in the front-rear direction by the casing while being screwed to the male screw. Power seat for a motor vehicle, wherein the Rukoto. 2. The pinion comprises a metal bush screwed onto the male screw, and a synthetic resin gear coaxially and corotatably fitted on the bush, in the front-rear direction of the bush. The power seat according to claim 1, wherein movement of the vehicle is restricted.