JP2003014055A - Backlash adjusting device of worm reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strongly support a worm gear shaft in a housing and easily and accurately adjust backlash with a large adjusting width in a backlash adjusting device of a worm reduction gear. SOLUTION: In the backlash adjusting device 41 of the worm reduction gear 40, an automatic self-aligning bearing 92 is mounted to one end on the opposite side of an end of the worm gear shaft 33 connected to at least a motor 30, a bearing hole 45 disposed in the housing 11B so as to support the outer ring 92B of the automatic self-aligning bearing 92 is tilted with respect to the center axis of the worm gear shaft 33, and a bearing position adjusting means 46 (bolt 42) for moving the outer ring 92B of the automatic self-aligning bearing 92 in the axial direction of the bearing hole 45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlash adjusting device for a worm speed reducer suitable for use in an electric power steering device or the like.

[0002]

2. Description of the Related Art In an electric power steering apparatus or the like, as a worm speed reducer for decelerating the rotation of a motor for use, the motor is fixed to a housing, and a worm gear shaft connected to the motor is supported by the housing. A worm wheel that meshes with a worm gear is supported by a housing. In the worm speed reducer, it is necessary to properly adjust the backlash, which is a play between the tooth surfaces when the worm gear and the worm wheel are meshed with each other. That is, if the backlash is too small, the meshing tooth surfaces will compete with each other, and if the backlash is too large, the tooth surfaces will collide with each other during a rapid torque fluctuation, resulting in a hammering sound, abnormal wear of the tooth surfaces, and smooth torque transmission. Spoil.

In the prior art, in order to obtain a proper backlash, the machining accuracy of the worm gear, the worm wheel, the bearing portion of the housing, etc. is made highly precise, and the selective fitting control is performed, resulting in a high cost. Even if the backlash is properly adjusted at the initial stage of assembly, the tooth surfaces of the worm gear and the worm wheel are worn due to long-term use, and the proper backlash cannot be maintained.

Therefore, as a conventional backlash adjusting device, in Japanese Unexamined Patent Publication No. 10-297505 (Prior Art 1), a housing for supporting a worm gear shaft and a housing for supporting a worm wheel are separated from each other, and a mounting interval between both housings is shim. There is one that adjusts by replacing the backlash between the tooth surfaces of the worm gear and the worm wheel.

Further, as another conventional backlash adjusting device, in Japanese Unexamined Patent Publication No. 2000-43739 (Prior Art 2), the bearing of the worm gear shaft can be biased in an arc-shaped recess provided in the housing, and the worm gear shaft is There is one in which biasing means for biasing in the biasing direction is provided to eliminate backlash between the tooth surfaces of the worm gear and the worm wheel.

[0006]

In the prior art 1, not only the housing needs to be attached and detached by using a plurality of bolts for adjusting the backlash and the shim needs to be replaced, but also an appropriate backlash can be obtained. For this reason, it is necessary to think and select a shim having an appropriate thickness, and it is necessary to adjust the mounting position of the housing in both the X direction and the Y direction when the housing is remounted, and the workability of adjusting the backlash is poor.

In the prior art 2, the bearing of the worm gear shaft is supported in an arcuate recess of the housing so that it can be biased.
The support rigidity of the worm gear shaft is low. Further, the bearing of the worm gear shaft can be adjusted in position within the range of the arcuate recess of the housing and only in one direction of the biasing means,
Backlash adjustment range is narrow.

SUMMARY OF THE INVENTION An object of the present invention is to provide a backlash adjusting device for a worm speed reducer, in which a worm gear shaft is firmly supported by a housing, and the backlash is easily adjusted with high accuracy and within a wide adjustment range.

[0009]

According to a first aspect of the present invention, a motor is fixed to a housing, a worm gear shaft connected to the motor is supported by the housing, and a worm wheel that meshes with a worm gear of the worm gear shaft is supported by the housing. In a backlash adjusting device for a worm speed reducer, a self-aligning bearing is mounted on at least one end of a worm gear shaft opposite to an end connected to a motor, and a housing is provided to support an outer ring of the self-aligning bearing. The bearing hole provided is inclined with respect to the central axis of the worm gear shaft in the radial plane of the worm wheel, and the bearing position adjusting means for moving the outer ring of the self-aligning bearing in the axial direction of the bearing hole is provided. It was done.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the bearing position adjusting means comprises a bolt screwed into a bearing hole of the housing, and the bolt has an outer ring of a self-aligning bearing built therein. Is.

According to a third aspect of the present invention, in addition to the first aspect, the outer ring of the self-aligning bearing is axially slidably mounted in a bearing hole of a housing, and the bearing position adjusting means is a bearing hole of the housing. It is made of a bolt that is screwed onto the outer ring of the self-aligning bearing so that the outer ring can be pushed.

[0012]

According to the invention of claim 1, the following effects are obtained. By the bearing position adjusting means, the outer ring of the self-aligning bearing supporting one end of the worm gear shaft is moved along the inclined bearing hole provided in the housing to displace the central axis of the worm gear shaft, By adjusting the distance between the worm gear shaft and the worm wheel (mounting interval), you can adjust the backlash between the tooth surfaces of the worm gear and the worm wheel.

The outer ring of the self-aligning bearing of the worm gear shaft can support the entire circumference in the bearing hole of the housing,
The worm gear shaft can be firmly supported by the housing.

By simply moving the outer ring of the self-aligning bearing along the bearing hole of the housing by the bearing position adjusting means, the backlash can be adjusted easily and highly accurately, and the backlash can be adjusted within a wide adjustment range.

According to the invention of claim 2, there is the following effect. The self-aligning bearing can be built in the bearing position adjusting means in advance to form a cartridge, and the assembling property can be improved.

According to the invention of claim 3, there is the following action. The outer ring of the self-aligning bearing can be directly supported in the bearing hole of the housing, and the worm gear shaft can be firmly supported by the housing.

[0017]

1 is a partially cutaway front view of an electric power steering apparatus, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is taken along line III-III of FIG. FIG. 4 is a sectional view taken along the line, FIG. 4 is an enlarged view of a main part of FIG. 3, and FIG. 5 is a sectional view showing a modified example of the electric power steering device.

As shown in FIGS. 1 and 2, the electric power steering apparatus 10 includes an aluminum alloy gear housing 1 fixed to a vehicle body frame or the like by a bracket (not shown).
1 (first to third gear housings 11A to 11C). Then, a pinion shaft 14 is connected to a steering shaft 12 to which a steering wheel is coupled via a torsion bar 13, a pinion 15 is provided on the pinion shaft 14, and a rack shaft 16 provided with a rack 16A meshing with the pinion 15 is provided. It is supported on the first gear housing 11A so as to be movable left and right. Steering shaft 12 and pinion shaft 14
A steering torque detection device 17 is provided between them. still,
The steering shaft 12 and the pinion shaft 14 are bearings 12A, 1
It is supported by the gear housing 11 via 4A and 14B.

As shown in FIG. 2, the steering torque detecting device 17 includes two detecting coils 17A surrounding a cylindrical core 17C engaged with the steering shaft 12 and the pinion shaft 14,
17B is provided in the third gear housing 11C. The core 17C includes a vertical groove 17E that engages with the guide pin 17D of the pinion shaft 14 and is movable only in the axial direction, and also includes a spiral groove 17G that engages with the slider pin 17F of the steering shaft 12. As a result, the steering torque applied to the steering wheel is applied to the steering shaft 12, and when the torsion bar 13 elastically deforms, a relative displacement in the rotational direction occurs between the steering shaft 12 and the pinion shaft 14. The rotation direction displacement of the pinion shaft 14 causes the core 17C to be displaced in the axial direction, and the inductance of the detection coils 17A and 17B changes due to the magnetic change around the detection coils 17A and 17B due to the displacement of the core 17C. . That is, when the core 17C moves to the steering shaft 12 side, the inductance of the detection coil 17A closer to the core 17C increases, and the inductance of the detection coil 17B closer to the core 17C decreases. Can be detected.

The rack shaft 1 in the first gear housing 11A
As shown in FIG. 2, a rack guide 19 is built in a cylinder portion 18 provided in a portion facing the pinion 15 with one end of the rack 6 interposed therebetween.
9A) is elastically urged toward the rack shaft 16 by a spring 21 back-supported by a cap 20 attached to the cylinder portion 18, presses the rack 16A of the rack shaft 16 against the pinion 15, and one end of the rack shaft 16 is pushed. Support slidably. The other end of the rack shaft 16 is supported by the bearing 22. In addition, the tie rods 23A, 23 on the left and right are connected to the middle portion of the rack shaft 16 by connecting bolts 22A, 22B.
B is connected.

As shown in FIG. 3, a motor case 31 of the electric motor 30 is fixed to the second gear housing 11B, and a worm gear shaft 33 is connected to a rotary shaft 32 of the electric motor 30 via a connecting body 80. Worm gear shaft 33
Is supported at both ends on the second gear housing 11B by bearings 91, 92 such as ball bearings. A worm gear 37 is integrally provided at an intermediate portion of the worm gear shaft 33, and a worm wheel 38 meshing with the worm gear 37 is fixed to an intermediate portion of the pinion shaft 14. The torque generated by the electric motor 30 is generated by meshing between the worm gear 37 and the worm wheel 38 that form the worm speed reducer 40, and the pinion 1
The steering assist force is applied to the rack shaft 16 through the meshing of the rack 5 and the rack 16A to assist the steering force applied to the steering shaft 12 by the driver.

Here, as shown in FIG. 3, the electric motor 30 has a cylindrical yoke 52 made of a magnetic material such as iron.
A magnet holder 53 made of a cylindrical body 53A made of an insulating resin material that forms magnet housing compartments 53B at a plurality of circumferential positions on the inner circumference of the yoke 52; and a magnet housing compartment 53B of the magnet holder 53. And a magnet 54 which is positioned and held by a magnet holder 53, and a stator 51 which includes a magnet cover 55 (not shown) formed of an ultra-thin plate of a non-magnetic material and press-fitted inside the magnet 54 which is positioned and held by the magnet holder 53. .

The electric motor 30 also has a rotor 56 that is inserted inside the stator 51 and fixed to the rotary shaft 32. The rotor 56 includes an armature core 57 and a commutator 58 provided on the outer circumference of the rotary shaft 32.

Further, the electric motor 30 has a brush 61 which is brought into contact with the commutator 58 of the rotor 56, and a brush holder 62 which positions and holds the brush 61.
Further, the electric motor 30 has a power feeding connector 63 connected to the brush 61, which is positioned and held by the brush holder 62, via a pigtail.

In the electric motor 30, when electric power is supplied from the brush 61 to the amateur core 57 via the commutator 58 of the rotor 56, the magnetic force lines of the amateur core 57 cause the stator 51 to move.
By turning off the magnetic field generated by the magnet 54, the rotor 56 rotates.

In the electric motor 30, the yoke 52 is a cylindrical body having one end open and the other end closed, and the yoke 52 is a motor case 31. The yoke 52 is the housing 11B
One end flange portion 52A fixed to the other end and the other end closing portion 52B
Have.

Next, the rotary shaft 32 of the electric motor 30, the motor case 31 of the worm gear shaft 33, and the housing 11B.
The support structure for the will be described.

(A) Support structure for the worm gear shaft 33 (FIGS. 3 and 4) The worm gear shaft 33 of the electric motor 30 has a worm gear 37 and a worm wheel 38 which form a worm speed reducer 40 as shown in FIGS. It is supported by the housing 11B via a backlash adjusting device 41 that can adjust the backlash.

That is, the worm gear shaft 33 is supported at both ends in the housing 11B by bearings 91 and 92 mounted on both sides of the worm gear 37.

The bearing 91 mounted at the end of the worm gear shaft 33 connected to the motor 30 includes an inner ring 91A and an outer ring 91.
It is composed of a deep groove ball bearing consisting of B and rolling elements 91C,
The inner ring 91A is fitted in the worm gear shaft 33 so as to be relatively movable in the axial direction, and the outer ring 91B is fitted in the housing 1.
It is fixed to the housing 11B by being sandwiched between the step portion 93 of 1B and the stopper ring 94 that is engaged with the housing 11B.

In the housing 11B, the bearing 91
The bearing hole 95 for supporting the outer ring 91B of the
Rotating shaft 3 of motor 30 supported by bearing 71 on B
It is provided so as to be coaxial with the central axis of the worm gear shaft 33 that is in line with 2. The bearing 91 is a bearing 92 described later.
A self-aligning bearing similar to the above may be adopted.

The bearing 92 mounted on the end of the worm gear shaft 33 opposite to the end connected to the motor 30 is the inner ring 9.
2A, an outer ring 92B, and a rolling element 92C, which are self-aligning bearings such as a self-aligning ball bearing (or a self-aligning roller bearing), the inner ring 92A can be relatively moved in the axial direction of the worm gear shaft 33. The outer ring 92B is held in the accommodation hole 43 of the bolt 42 by the stopper ring 44 and built in. At this time, the housing 11B has a bearing hole 45 that is inclined with respect to the central axis of the worm gear shaft 33 within a radial plane of the worm wheel 38 (a plane orthogonal to the central axis of the worm wheel 38), and also has an outer ring 92B of the bearing 92. As described above, the bolt 42 for housing the bearing is installed in the bearing hole 45.
The bolt 42 constitutes the bearing position adjusting means 46 which is screwed to the outer ring 92B and is movable in the axial direction of the bearing hole 45. The center axis of the bearing hole 45 is inclined toward the inside of the housing 11B toward the side closer to the worm wheel 38 than the center axis of the worm gear shaft 33. This allows
Bearing position adjusting means 46 Hexagonal tool hole 42 of barrel 42
When the bolt 42 is screwed inward in the housing 11B by using A, the outer ring 92B of the bearing 92 moves inward in the axial direction of the bearing hole 45, and the bearing 92 and the worm gear shaft 33 move relatively. The worm gear shaft 33
The distance between the shafts of the worm wheel 38 and the worm wheel 38 is reduced, and the backlash between the tooth surfaces of the worm gear 37 and the worm wheel 38 is reduced. On the other hand, bolt 42 to housing 11B
When it is screwed outward in the drawing direction, the outer ring 9 of the bearing 92 is
2B moves outward in the axial direction of the bearing hole 45, widens the axial distance between the worm gear shaft 33 and the worm wheel 38, increases the backlash between the tooth surfaces of the worm gear 37 and the worm wheel 38, and reduces the backlash. You can adjust it in any direction. The screw nut 47 locks the screwing position of the bolt 42.

The worm gear shaft 3 of the electric motor 30
As shown in FIG. 4, 3 is elastically supported with respect to the housing 11B bidirectionally in the axial direction, and when the electric power steering device 10 is driven to reverse, or when a curb of a tire is ridden,
The excessive thrust acting on the worm gear shaft 33 can be absorbed.

That is, the worm gear shaft 33 has an elastic deforming member 97 interposed between the collar-shaped inner ring engaging portion 96 provided on the side of the worm gear 37 with respect to the bearing 91 and the inner ring 91A of the bearing 91, and with respect to the bearing 92. A collar-shaped inner ring engaging portion 98 provided on the worm gear 37 side and an inner ring 92A of the bearing 92.
An elastic deforming tool 99 is interposed between them. Elastic deformer 97
Is composed of an elastic body 97A made of rubber having an annular cross section, and flat disk washers 97B and 97C joined to both side surfaces of the elastic body 97A by seizure. The elastic deformation tool 99 is composed of a compression coil spring 99A. When the worm gear shaft 33 is loaded as described above, the elastic body 97A and the spring 99A are incorporated with a constant amount of precompression (constant shock absorbing performance) and incorporated.
As a result, the worm gear shaft 33 is elastically supported in both axial directions. The elastic body 97A of the elastic deformation tool 97 may be made of a spring, and the spring 99A of the elastic deformation tool 99 may be made of rubber.

(B) Supporting structure for the rotating shaft 32 (FIGS. 3 and 4) As shown in FIGS. 3 and 4, the rotating shaft 32 of the electric motor 30 has one end on the other end of the motor case 31 (yoke 52). It was supported by a bearing 71 provided at the center of the closed portion 52B, and the other end was made unsupported.

Specifically, one end of the rotary shaft 32 is provided with a bearing 71 constituted by an angular ball bearing including an inner ring 71A, an outer ring 71B and a rolling element 71C.
Supported by 1. The other end of the rotary shaft 32 is connected to the one end of the worm gear shaft 33 via the connector 80 as described above. At this time, the two fitting shaft portions 32A, 32A provided at the other end of the rotary shaft 32 at a distance in the axial direction are joined to the fitting hole portion 81 of the connecting body 80 so that they can slide relative to each other without rattling (inlay joint. In addition, the toothed fitting shaft portion 33A provided at one end of the worm gear shaft 33 is connected to the connecting body 80.
It is connected to the toothed fitting hole 82 of the
SB 1603 involute spline large diameter matching),
The rotating shaft 32 and the worm gear shaft 33 are concentrically connected to each other via the connecting body 80.

Therefore, the rotary shaft 32 and the worm gear shaft 33 of the electric motor 30 are concentrically coupled to each other, and as a result, the end of the rotary shaft 32 on the side connected to the worm gear shaft 33 does not have a bearing in the motor case 31. An unsupported structure is used, and both ends of the worm gear shaft 33 are provided with the bearings 91, 9
Two points are supported on the housing 11B via the rotary shaft 32
Only one end of the motor case 31 by the bearing 71 described above.
It was decided to support one point.

Further, the inner periphery of the fitting hole portion 81 of the connection body 80 and both fitting shaft portions 32A of the rotary shaft 32 of the electric motor 30,
A torque limiter 83 was interposed between the outer circumferences that were sandwiched between 32A and formed in a recessed shape. The torque limiter 83 is a connector 80.
Of the electric power steering device 10 which is normally used in the electric power steering device 10 and includes an elastic ring such as a spring resin that is press-fitted between the inner periphery of the rotating shaft 32 and the outer periphery of the rotating shaft 32 and elastically supported in the radial direction. Torque less than torque),
By the elastic force of the elastic ring, the connecting body 80 and the rotating shaft 32 continue to be connected without slipping, while the electric motor 30 when the stroke of the rack shaft 16 is suddenly stopped due to the tire riding on a curb during steering. With respect to the impact torque (torque above the limit torque) in which the inertia torque of the electric spring exceeds the elastic force of the elastic ring, the rotating shaft 32 is slipped with respect to the connecting body 80, and the torque of the electric motor 30 of the connecting body 80 is changed. It functions so that it is not transmitted to the side.

In supporting the rotating shaft 32 by the bearing 71, the electric motor 30 press-fits the rotating shaft 32 into the inner ring 71A and fits the outer ring 71B into the motor case 31 (or presses the outer ring 71B into the motor case 31). Then, the rotary shaft 32 is fitted in the inner ring 71A with a clearance), and as a result, the occurrence of backlash that may occur in the axial direction of the rotary shaft 32 is prevented as follows. That is, in the state where the step portion 80A provided between the fitting hole portion 81 and the toothed fitting hole portion 82 of the connector 80 is abutted against the end surface of the rotating shaft 32 in the axial direction, the rotating shaft 32 is rotated against the anti-worm gear shaft. Disc spring (or O-ring) that pushes in the direction of 33
The annular elastic body 85 consisting of is provided near the side of the connection body 80.
Specifically, the elastic body 85 includes the end surface of the connection body 80 and the bearing 9.
The first inner ring 91 </ b> A (or the collar-shaped step portion of the worm gear shaft 33) is interposed between the inner ring 91 </ b> A and the end surface.

According to this embodiment, there are the following effects. Outer ring 92B of self-aligning bearing 92 supporting one end of worm gear shaft 33 by bearing position adjusting means 46.
By moving the bearing 92 and the worm gear shaft 33 relative to each other along an inclined bearing hole 45 provided in the housing 11B, so that the central axis of the worm gear shaft 33 is the bearing 91 at the other end of the worm gear shaft 33. The center distance (mounting interval) between the worm gear shaft 33 and the worm wheel 38 can be changed by swinging the worm gear 38 as a fulcrum to adjust the backlash between the tooth surfaces of the worm gear 37 and the worm wheel 38.

Self-aligning bearing 92 of worm gear shaft 33
The outer ring 92B can be evenly supported in the bearing hole 45 of the housing 11B over the entire circumference without a gap, and the worm gear shaft 33 can be firmly supported by the housing 11B.

By simply moving the outer ring 92B of the self-aligning bearing 92 by the bearing position adjusting means 46 along the bearing hole 45 of the housing 11B, the backlash can be adjusted easily and highly accurately, and the self-aligning bearing 92 can be easily adjusted. By moving the outer ring 92B in one direction, the axial distance between the worm gear shaft 33 and the worm wheel 38 can be narrowed, and by moving the outer ring 92B in the other direction, the axial distance between the worm gear shaft 33 and the worm wheel 38 can be widened, resulting in backlash. Can be adjusted bidirectionally with a wide adjustment width.

The bearing position adjusting means 46 is the housing 1
The bolt 42 is screwed into the bearing hole 45 of 1B, and the outer ring 92B of the self-aligning bearing 92 is built in the bolt 42. Therefore, the self-aligning bearing 92 can be built in the bearing position adjusting means 46 in advance to form a cartridge, and the assemblability can be improved.

FIG. 5 shows a modification of the backlash adjusting device 41 shown in FIGS. 3 and 4. In the backlash adjusting device 100 of this modified example, the outer ring 92B of the self-aligning bearing 92 is directly loaded in the sliding portion 101A of the inclined bearing hole 101 corresponding to the above-mentioned bearing hole 45 of the housing 11B so as to be slidable in the axial direction. , Bearing position adjusting means 102 barrel 1
03 (hexagonal tool hole 103A) is screwed into the threaded portion 101B of the bearing hole 101 of the housing 11B, and the outer ring 92B of the self-aligning bearing 92 can be moved in the axial direction of the bearing hole 101 by the bolt 103. 104 is a lock nut. The outer ring 92B of the self-aligning bearing 92 is pressed against the end surface of the bolt 103 by the spring 99A of the elastic deforming tool 99 provided on the worm gear shaft 33 while the bolt 10 is being pressed.
3 pushes the housing 11B inward to move the bearing hole 101 inward in the axial direction to reduce backlash, and the bolt 103 pulls the housing 11B outward to screw the bearing hole 101. The backlash can be increased by moving it to the outside in the axial direction, and the backlash can be adjusted in both directions.

According to the backlash adjusting device 100,
The outer ring 92B of the self-aligning bearing 92 can be directly supported in the bearing hole 101 of the housing 11B, and the worm gear shaft 33 can be firmly supported by the housing 11B.

In the embodiment of the present invention, the bearing 92
The case where the bearing 92 moves in the axial direction of the tilted bearing hole 45 and the worm gear shaft 33 relatively moves has been described in detail. The bearing 92 (the bearing 92 moves in the axial direction of the tilted bearing hole 45) and the worm gear shaft. When 33 does not move relatively, the bearing 91 side may be moved relatively.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the connecting structure between the rotary shaft of the electric motor and the worm gear shaft may be a general free coupling structure. The present invention is not limited to the embodiment, and any modification of the design within the scope of the present invention is included in the present invention.

[0048]

As described above, according to the present invention, in the backlash adjusting device of the worm speed reducer, the worm gear shaft is firmly supported by the housing, and the backlash can be adjusted easily and accurately with a wide adjustment range. You can

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an electric power steering device.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is an enlarged view of a main part of FIG.

FIG. 5 is a cross-sectional view showing a modified example of the electric power steering device.

[Explanation of symbols]

11 housing 30 electric motor 32 rotation axis 33 Worm gear shaft 37 Worm Gear 38 Worm Wheel 40 Worm reducer 41,100 Backlash adjuster 42, 103 bolt 45, 101 Bearing hole 46, 102 Bearing position adjusting means 92 Self-aligning bearing 92B outer ring

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Claims (3)

[Claims] 1. A backlash adjusting device for a worm speed reducer, comprising: a motor fixed to a housing; a worm gear shaft connected to the motor supported on the housing; and a worm wheel meshing with a worm gear of the worm gear shaft supported on the housing. A self-aligning bearing is mounted on at least one end of the shaft opposite to the end connected to the motor, and a bearing hole provided in the housing so as to support the outer ring of the self-aligning bearing is provided in a radial plane of the worm wheel. A backlash adjusting device for a worm speed reducer, which has a bearing position adjusting means that is inclined with respect to the central axis of the worm gear shaft and that allows the outer ring of the self-aligning bearing to move in the axial direction of the bearing hole. . 2. The backlash adjusting device for a worm speed reducer according to claim 1, wherein the bearing position adjusting means comprises a bolt screwed into a bearing hole of the housing, and the outer ring of the self-aligning bearing is built in the bolt. . 3. An outer ring of the self-aligning bearing is axially slidably mounted in a bearing hole of a housing, and the bearing position adjusting means is screwed into the bearing hole of the housing.
The backlash adjusting device for a worm speed reducer according to claim 1, wherein the backlash adjusting device comprises a bolt capable of pushing the outer ring of the self-aligning bearing.