JP2009222185A - Method of manufacturing parallel shaft gear mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive manufacturing method of a parallel shaft gear mechanism. <P>SOLUTION: This reduction gear 24 as the parallel shaft gear mechanism has first and second shafts 31 and 32 mutually arranged in parallel, a driving gear 26 arranged to be co-rotatable with the first shaft 31, a first intermediate gear 27A arranged to be co-rotatable with the second shaft 32 and meshing with the driving gear 26, and self-lockable first and second nuts 42 and 46 threadedly engaged with its screw parts 83 and 93 for fixing inner rings 75 and 85 of bearings 40 and 44 to the first and second shafts 31 and 32. This manufacturing method is provided for fastening and fixing the first and second nuts 42 and 46 to the screw parts 83 and 93 of the corresponding first and second shafts 31 and 32 in a state of meshing the driving gear 26 and the first intermediate gear 27A and of regulating rotation of the first shaft 31 by a second holding tool 132. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a parallel shaft gear mechanism.

The parallel shaft gear mechanism is used in, for example, an electric power steering device. The parallel shaft gear mechanism has a pair of gears that mesh with each other and a pair of support shafts that respectively support the pair of gears. The pair of support shafts are rotatably supported by bearings. Further, the inner ring of the bearing is fixed to the support shaft.
Further, in Patent Document 1, in order to fix the ball screw nut to the inner periphery of the hollow support shaft of the electric power steering apparatus, an annular male screw member is screwed to the female screw formed on the inner periphery of the support shaft. It is described. In order to screw-fit the male screw member to the support shaft, the support shaft is prevented from rotating.
JP 2000-95123 A

  In order to fix the inner ring of the bearing to the support shaft of the parallel shaft gear mechanism, it is conceivable that a nut having a locking function, a so-called self-lock nut, is screwed to the male screw formed on the outer periphery of the support shaft. Yes. In order to screw-fit the self-locking nut, it is necessary to prevent the support shaft from rotating using a jig. Moreover, when attaching a self-lock nut to a some spindle, the jig | tool for rotation prevention is required for each of a some spindle. For example, it is necessary to form a portion that engages with the jig on each of the plurality of support shafts. Moreover, the operation | work which attaches / detaches a jig | tool to a spindle is required for each of a some spindle. Therefore, the manufacturing cost is high.

  Therefore, an object of the present invention is to provide a method for manufacturing a parallel shaft gear mechanism that is inexpensive to manufacture.

  In the manufacturing method of the parallel shaft gear mechanism (24, 24A, 224) of the present invention, the first shaft (31) and the second shaft (32) arranged in parallel with each other and the first shaft rotate together. The first gear (26) provided so as to be able to rotate with the second shaft and the second gear (27A, 227) meshed with the first gear so as to be able to rotate together, and the first and second shafts First and second bearings (40, 44) for rotatably supporting one end (34, 37) as the same end of each of the first and second shafts. Third and fourth bearings (41, 45) for rotatably supporting the other ends (35, 38), respectively, and a housing (58) for holding the first, second, third and fourth bearings; In order to fix the inner ring (75) of the first bearing to one end of the first shaft, the screw portion (83) at one end of the first shaft is screwed. The self-locking first nut (42) and the inner ring (85) of the second bearing are screwed onto the threaded portion (93) at one end of the second shaft in order to fix it to one end of the second shaft. A method of manufacturing a parallel shaft gear mechanism having a second nut (46) capable of being combined and self-locking, wherein a jig (132) is engaged with the other end of the first shaft, The first and second nuts corresponding to the first and second nuts in the state in which the rotation of the shaft is regulated, and the first and second gears are engaged and the rotation of the first shaft is regulated by the jig. And a nut tightening step for tightening and fixing to one end of the shaft.

  According to the present invention, in the state where the rotation of the first shaft is regulated by the jig, the rotation of the second shaft is regulated via the first and second gears that mesh with each other. Therefore, in the nut tightening step, the first nut can be assembled to one end of the first shaft whose rotation is restricted. Moreover, a 2nd nut can be assembled | attached to the end of the 2nd axis | shaft by which rotation was controlled as mentioned above. In order to regulate the rotation of the first and second shafts, the jig does not have to be engaged with both shafts, so that it does not take time and effort. Therefore, the manufacturing cost can be reduced.

  In the present invention, the other end of the first shaft is connected to one element (101) of the joint (33) for coaxially connecting the other end and the output shaft (29) of the electric motor (23). ) Is provided so as to be able to rotate along with the other end, and in the nut tightening step, the claw (110) provided in the one element is engaged with the groove (134) of the jig, thereby There are cases where the rotation of the shaft is restricted. In this case, since one element of the joint that is originally necessary for restricting the rotation of the first shaft can be used, the structure can be simplified. Therefore, the manufacturing cost can be further reduced.

  In the present invention, the maximum outer diameter Da of the one element, the outer diameter Db of the outer ring of the third bearing, and the maximum outer diameter Dc of the first gear may satisfy the relationship of Da <Db <Dc. is there. In this case, for example, when the first shaft is assembled to the housing, the first shaft can be assembled to the housing from above with the other end of the first shaft on the joint side facing down. Since the 1st axis | shaft assembled | attached to the housing has one end on the upper side, the effort for tightening a nut to this one end is reduced. That is, it is not necessary to turn the housing and first shaft assembly upside down to tighten the nut.

  In the present invention, the housing includes first and second housings (61, 62) fastened to each other, and the first and second bearings are respectively formed on the first housing. The third and fourth bearings are held in the third and fourth bearing holding holes (69, 70) formed in the second housing, respectively. A first shaft unit that is held and includes the first shaft, the one element of the joint, the third bearing, and the first gear with respect to the second housing in a state before assembly of the first housing (121) and the second shaft unit (122) including the second shaft, the fourth bearing, and the second gear may be assembled from the same direction. In this case, since the first and second shaft units can be assembled from the same direction, it is not necessary to turn the assembly upside down during the assembly, and as a result, labor during assembly can be reduced.

In the present invention, the maximum tightening torque Tmax of the second nut may be set based on an allowable additional torque Ta related to the first shaft. In this case, when tightening the second nut, it is possible to prevent an excessive torque from acting on the first shaft.
In addition, although the alphanumeric characters in the parentheses indicate reference signs of corresponding components in the embodiments described later, the scope of the claims is not limited by these reference signs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In the present embodiment, a method for manufacturing a parallel shaft gear mechanism will be described in accordance with the case where the parallel shaft gear mechanism is applied to an electric power steering apparatus. In addition, this invention is not restricted to this, For example, applying this manufacturing method to the parallel shaft gear mechanism of apparatuses other than an electric power steering apparatus is also considered.

  FIG. 1 is a schematic diagram of a schematic configuration of an electric power steering apparatus including a parallel shaft gear mechanism according to a first embodiment of the present invention. Referring to FIG. 1, an electric power steering system (EPS) 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, and a first universal joint 4 attached to the steering shaft 3. An intermediate shaft 5 connected via a pin, a pinion shaft 7 connected to the intermediate shaft 5 via a second universal joint 6, and a rack tooth 9 meshing with a pinion tooth 8 provided near the end of the pinion shaft 7. And a rack shaft 10 as a turning shaft extending in the left-right direction X of the automobile.

  The pinion shaft 7 and the rack shaft 10 constitute a steering gear 11 composed of a rack and pinion mechanism. The rack shaft 10 is supported in a housing 13 fixed to the vehicle body 12 so as to be linearly reciprocable via a plurality of bearings (not shown). A pair of tie rods 14 are coupled to the rack shaft 10. Each tie rod 14 is connected to a corresponding steered wheel 16 via a corresponding knuckle arm 15.

When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted by the pinion teeth 8 and the rack teeth 9 into a linear motion of the rack shaft 10 along the left-right direction X of the automobile. Thereby, the turning of the steered wheels 16 is achieved.
The steering shaft 3 is divided into an input shaft 17 connected to the steering member 2 and an output shaft 18 connected to the pinion teeth 8. The input shaft 17 and the output shaft 18 are connected to each other on the same axis via a torsion bar 19. When steering torque is input to the input shaft 17, the torsion bar 19 is elastically torsionally deformed, whereby the input shaft 17 and the output shaft 18 are rotated relative to each other.

  A torque sensor 20 that detects a steering torque based on the amount of relative rotational displacement between the input shaft 17 and the output shaft 18 via the torsion bar 19 is provided. A vehicle speed sensor 21 for detecting the vehicle speed is also provided. An ECU (Electronic Control Unit) 22 is provided as a control device. An electric motor 23 for generating a steering assist force and a reduction gear 24 as a parallel shaft gear mechanism for reducing the output rotation of the electric motor 23 are provided.

  Detection signals from the torque sensor 20 and the vehicle speed sensor 21 are input to the ECU 22. The ECU 22 controls the steering assisting electric motor 23 based on the torque detection result, the vehicle speed detection result, and the like. The output rotation of the electric motor 23 is decelerated by the speed reducer 24 and transmitted to the output shaft 18 of the steering shaft 3. As a result, steering is assisted.

  FIG. 2 is a schematic cross-sectional view of the speed reducer 24 shown in FIG. Referring to FIG. 2, the speed reducer 24 includes a drive gear 26 as a first gear driven by the electric motor 23, and a first intermediate gear 27 </ b> A as a second gear that meshes with the drive gear 26. Have. Further, the speed reducer 24 includes a second intermediate gear 27B that rotates together with the first intermediate gear 27A, and a driven gear 28 that meshes with the second intermediate gear 27B.

  The drive gear 26 has a smaller diameter than the first intermediate gear 27A. The first intermediate gear 27A has a larger diameter than the second intermediate gear 27B. The second intermediate gear 27 </ b> B has a smaller diameter than the driven gear 28. The drive gear 26 and the first intermediate gear 27A decelerate the output rotation of the output shaft 29 of the steering assist electric motor 23. Further, the second intermediate gear 27B and the driven gear 28 decelerate the output rotation of the output shaft 29 of the steering assisting electric motor 23.

The speed reducer 24 also includes a first shaft 31 that supports the drive gear 26, a second shaft 32 that supports the first and second intermediate gears 27A and 27B, and a third shaft that supports the driven gear 28. It has the output shaft 18 as a shaft. The first shaft 31 is connected to the output shaft 29 of the electric motor 23 via a joint 33.
The first shaft 31 has one end 34 and the other end 35 with respect to the axial direction S1. Further, the second shaft 32 has one end 37 and the other end 38 with respect to the axial direction S2. The first shaft 31 and the second shaft 32 are arranged in parallel to each other.

The one end 34 of the first shaft 31 and the one end 37 of the second shaft 32 are on the same side with respect to the axial direction S1 of the first shaft 31 (or the axial direction S2 of the second shaft 32). It is an end. The other end 35 of the first shaft 31 and the other end 38 of the second shaft 32 are the same as each other with respect to the axial direction S1 of the first shaft 31 (or the axial direction S2 of the second shaft 32). This is the end of the side.
Referring to FIG. 2, the speed reducer 24 includes a bearing 40 that rotatably supports one end 34 of the first shaft 31 and a bearing 41 that rotatably supports the other end 35 of the first shaft 31. is doing. The one end 34 is provided with a first nut 42 that fixes the bearing 40 to the first shaft 31.

The speed reducer 24 includes a bearing 44 that rotatably supports one end 37 of the second shaft 32 and a bearing 45 that rotatably supports the other end 38 of the second shaft 32. The one end 37 is provided with a second nut 46 that fixes the bearing 44 to the second shaft 32. The speed reducer 24 has bearings 48 and 49 that rotatably support the output shaft 18.
With reference to FIG. 1, the steering shaft 3 is rotatably supported by a steering column 57 via a bearing (not shown). The steering column 57 is supported on the vehicle body 12 via a bracket (not shown). The steering column 57 includes a housing 58 that accommodates the plurality of gears 26, 27 </ b> A, 27 </ b> B, and 28 while supporting the electric motor 23, and a cylindrical sensor housing 60 that accommodates the torque sensor 20. The housing 58 and the sensor housing 60 are made of metal, are separated from each other, and are fixed to each other.

The housing 58 includes first and second housings 61 and 62. The first and second housings 61 and 62 are formed as separate parts, and are fixed to each other by a plurality of fixing bolts 63 (only one shown).
Referring to FIG. 2, the first housing 61 includes a bearing holding hole 65 that holds the bearing 40, a bearing holding hole 66 that holds the bearing 44, and a bearing holding hole that holds the bearing 48. 67 and a connecting portion 68 connected to the second housing 62.

The second housing 62 includes a bearing holding hole 69 that holds the bearing 41, a bearing holding hole 70 that holds the bearing 45, a bearing holding hole 71 that holds the bearing 49, and the electric motor 23. It has the support part 72 currently supported while positioning, and the connection part 73 connected with the connection part 68 of the 1st housing 61. As shown in FIG.
In a state where the first and second housings 61 and 62 are fixed to each other, the bearing holding hole 65 of the first housing 61, the bearing holding hole 69 of the second housing 62, and the support portion of the second housing 62 The output shaft 29 of the electric motor 23 positioned at 72 is arranged concentrically with each other. The bearing holding hole 66 of the first housing 61 and the bearing holding hole 70 of the second housing 62 are arranged concentrically with each other. The bearing holding hole 67 of the first housing 61 and the bearing holding hole 71 of the second housing 62 are arranged concentrically with each other.

Further, the drive gear 26 and the first shaft 31 are arranged concentrically with each other. The first intermediate gear 27A, the second intermediate gear 27B, and the second shaft 32 are arranged concentrically with each other. The driven gear 28 and the output shaft 18 are arranged concentrically with each other.
As a result, the rotation center axis of the output shaft 29 of the electric motor 23 and the rotation center axis of the drive gear 26 coincide with each other. At the same time, the rotation center axis of the drive gear 26, the rotation center axes of the first and second intermediate gears 27A and 27B, and the rotation center axis of the driven gear 28 are arranged in parallel to each other. Further, the output shaft 29 of the electric motor 23 is disposed in parallel to the axial direction S3 of the steering shaft 3. A predetermined distance is separated between the output shaft 29 of the electric motor 23 and the steering shaft 3. The predetermined distance is set to a minimum value corresponding to the outer shape of the electric motor 23 or a value approximate to this value. Thereby, the enlargement of the driven gear 28 can be suppressed while realizing a required reduction ratio. As a result, the external shape of the reduction gear 24 can be reduced in size.

The drive gear 26 is a bevel gear and is formed in a substantially cylindrical shape from metal, for example, steel. A plurality of gear teeth are formed on the outer periphery of the drive gear 26. The drive gear 26 and the first shaft 31 are fixed to each other so as to rotate together. For example, the drive gear 26 and the first shaft 31 are integrally formed as a single part by a single member.
The drive gear 26 is rotatably supported by the housing 58 via the first shaft 31 and the bearings 40 and 41 in a both-end supported state. The bearings 40 and 41 are disposed on both sides of the drive gear 26 with respect to the axial direction S1 of the first shaft 31. The bearings 40 and 41 are rolling bearings. The bearing 40 has an inner ring 75, an outer ring 76, and a plurality of balls 77 as rolling elements. The bearing 41 includes an inner ring 78, an outer ring 79, and a plurality of balls 80 as rolling elements.

One end 34 of the first shaft 31 is provided with a fitting portion 81 fitted in a gap-fitting state with the inner circumference of the inner ring 75 of the bearing 40, and provided radially adjacent to the fitting portion 81. And an annular step 82 extending in the direction of the axis 82 and a screw portion 83 adjacent to the fitting portion 81 on the opposite side of the axial direction S1. The screw portion 83 is formed with a male screw.
The first nut 42 is screwed to the threaded portion 83 of the one end 34 of the first shaft 31 in order to fix the inner ring 75 of the first bearing 40 to the one end 34 of the first shaft 31. The first nut 42 has a self-locking function. For the self-locking function, the first nut 42 includes, for example, a synthetic resin plate (not shown) having an inner diameter smaller than the outer diameter of the screw portion 83. This plate is provided at the end of the screw hole of the first nut 42.

With respect to the axial direction S <b> 1 of the first shaft 31, the inner ring 75 of the bearing 40 is fastened between the first nut 42 and the step portion 82 of the one end 34 of the first shaft 31. Thereby, relative movement between the first shaft 31, the inner ring 75 of the bearing 40, and the first nut 42 is restricted with respect to the axial direction S <b> 1 of the first shaft 31.
The outer periphery of the other end 35 of the first shaft 31 is fitted with the inner periphery of the inner ring 78 of the bearing 41 in a press-fit state.

  The bearing holding hole 65 of the first housing 61 supports the one end 34 of the first shaft 31 via the bearing 40 so as to be rotatable. The bearing holding hole 65 is fitted into the outer periphery of the outer ring 76 of the bearing 40 in a press-fit state. Thereby, the outer ring 76 of the bearing 40 is fixed to the first housing 61. The bearing holding hole 65 has an opening 84 that opens in the axial direction S1. Through this opening 84, the first nut 42 can be attached to the one end 34 of the first shaft 31.

The bearing holding hole 69 of the second housing 62 rotatably supports the other end 35 of the first shaft 31 via the bearing 41. The bearing holding hole 69 is fitted to the outer periphery of the outer ring 79 of the bearing 41 with a gap fitted.
The first and second intermediate gears 27A and 27B are bevel gears, and are formed in a substantially cylindrical shape from metal, for example, steel. A plurality of gear teeth are formed on the outer periphery of each of the first and second intermediate gears 27A and 27B. The first intermediate gear 27A, the second intermediate gear 27B, and the second shaft 32 are fixed to each other so that they can rotate together.

  Specifically, the second shaft 32, the first intermediate gear 27A, and the second intermediate gear 27B are formed separately from each other. The first intermediate gear 27A and the second shaft 32 are fixed to each other so that they can rotate together. At the same time, the second intermediate gear 27B and the second shaft 32 are fixed to each other so that they can rotate together. Note that at least two of the first intermediate gear 27A, the second intermediate gear 27B, and the second shaft 32 may be integrally formed by a single member.

  The first and second intermediate gears 27A and 27B are rotatably supported by the housing 58 via the second shaft 32 and the bearings 44 and 45 in a both-sided state. The bearings 44 and 45 are disposed on both sides of the first and second intermediate gears 27A and 27B with respect to the axial direction S2 of the second shaft 32. The bearings 44 and 45 are rolling bearings. The bearing 44 has an inner ring 85, an outer ring 86, and a plurality of balls 87 as rolling elements. The bearing 45 has an inner ring 88, an outer ring 89, and a plurality of balls 90 as rolling elements.

One end 37 of the second shaft 32 is provided with a fitting portion 91 in which the inner circumference of the inner ring 85 of the bearing 44 is fitted in a gap-fitting state, and is provided adjacent to the fitting portion 91 and extends radially outward. The annular step 92 has a threaded portion 93 adjacent to the fitting portion 91 on the opposite side of the step S92 in the axial direction S2. The screw portion 93 is formed with a male screw.
The second nut 46 is screwed to the threaded portion 93 of the one end 37 of the second shaft 32 in order to fix the inner ring 85 of the bearing 44 to the one end 37 of the second shaft 32. The second nut 46 has a self-locking function and has a structure similar to that of the first nut 42.

With respect to the axial direction of the second shaft 32, the inner ring 85 of the bearing 44 is clamped between the second nut 46 and the stepped portion 92 of the one end 37 of the second shaft 32. Thereby, relative movement between the second shaft 32, the inner ring 85 of the bearing 44, and the second nut 46 is restricted with respect to the axial direction S <b> 2 of the second shaft 32.
The outer periphery of the other end 38 of the second shaft 32 is fitted with the inner periphery of the inner ring 88 of the bearing 45 in a press-fit state.

  The bearing holding hole 66 of the first housing 61 rotatably supports the one end 37 of the second shaft 32 via the bearing 44. The bearing holding hole 66 of the first housing 61 is fitted into the outer periphery of the outer ring 86 of the bearing 44 in a press-fit state. As a result, the outer ring 86 of the bearing 44 is fixed to the first housing 61. Further, the bearing holding hole 66 has an opening 94 that can be opened in the axial direction S2. The second nut 46 can be attached to one end 37 of the second shaft 32 through the opening 94.

The bearing holding hole 70 of the second housing 62 rotatably supports the other end 38 of the second shaft 32 via the bearing 45. The bearing holding hole 70 is fitted to the outer periphery of the outer ring 89 of the bearing 45 in a gap fitting state.
The driven gear 28 is a bevel gear, and is formed in an annular shape from metal, for example, steel. A plurality of gear teeth are formed on the outer periphery of the driven gear 28. The driven gear 28 and the output shaft 18 are fixed to each other so that they can rotate together. Specifically, the output shaft 18 and the driven gear 28 are formed separately from each other and are fixed to each other. The output shaft 18 and the driven gear 28 may be formed integrally with each other by a single member.

The driven gear 28 is supported in a both-end supported state. Bearings 48 and 49 are arranged on both sides of the driven gear 28 with respect to the axial direction S3 of the output shaft 18. The bearings 48 and 49 are rolling bearings. Each of the bearings 48 and 49 has an inner ring, an outer ring, and a plurality of balls as rolling elements.
The bearing holding hole 67 of the first housing 61 rotatably supports the output shaft 18 via the bearing 48. The bearing holding hole 71 of the second housing 62 supports the output shaft 18 through a bearing 49 so as to be rotatable. The inner ring of the bearing 48 is fitted to the output shaft 18 with a gap fitted. The outer ring of the bearing 48 is fitted in the bearing holding hole 67 in a press-fitted state. The inner ring of the bearing 49 is fitted to the output shaft 18 in a press-fitted state. The outer ring of the bearing 49 is fitted in the bearing holding hole 71 with the gap fitted.

The drive gear 26 and the first intermediate gear 27A mesh with each other. Further, the second intermediate gear 27B and the driven gear 28 mesh with each other. The other end 35 of the first shaft 31 and the output shaft 29 of the electric motor 23 are coaxially connected via a joint 33. These parts 29, 31, and 33 are connected so that they can rotate together.
FIG. 3 is an exploded perspective view of the joint 33 of FIG. With reference to FIGS. 2 and 3, the joint 33 rotates along with the first member 101 connected to the other end 35 of the first shaft 31 and the output shaft 29 of the electric motor 23. And the elastic member 103 that is interposed between the first member 101 and the second member 102 and transmits torque between the members 101 and 102. The first member 101 and the second member 102 are made of metal, for example. The elastic member 103 is made of, for example, synthetic rubber or synthetic resin such as polyurethane.

With reference to FIG. 3, the elastic member 103 includes a ring-shaped main body portion 105 and a plurality of engagement arms 106 extending from the main body portion 105 in the radial direction. The plurality of engaging arms 106 are formed with a pair of power transmission surfaces 107 facing the circumferential direction T1 of the first shaft 31.
The first member 101 has an annular main body 108 and a plurality of first claws 110 as a plurality of engaging projections formed on the opposing surfaces 109 of the main body 108. Each 1st nail | claw 110 has a pair of power transmission surface 111 which opposes the circumferential direction T1. The power transmission surface 111 of the first claw 110 and the power transmission surface 107 of the corresponding engagement arm 106 of the elastic member 103 are engaged with each other in the circumferential direction T1. The main body portion 108 is formed with a fitting hole 112 for fitting the other end 35 of the first shaft 31.

  The second member 102 includes an annular main body 113 and a plurality of second claws 115 as a plurality of engaging protrusions formed to protrude from the opposing surfaces 114 of the main body 113. Each second claw 115 has a pair of power transmission surfaces 116 facing each other in the circumferential direction T1. The power transmission surface 116 of the second claw 115 and the power transmission surface 107 of the corresponding engagement arm 106 of the elastic member 103 are engaged with each other in the circumferential direction T1. The main body 113 is formed with a fitting hole 117 for fitting the output shaft 29 of the electric motor 23.

The plurality of first claws 110 of the first member 101 have the same shape and dimensions, and are arranged at equal intervals in the circumferential direction of the main body 108. The plurality of second claws 115 of the second member 102 have the same shape and dimensions, and are arranged at equal intervals in the circumferential direction of the main body 113.
In the assembled state of the joint 33, the first claws 110 of the first member 101 and the second claws 115 of the second member 102 are alternately arranged in the circumferential direction T1. A corresponding engaging arm 106 of the elastic member 103 is sandwiched between the first claw 110 and the second claw 115 adjacent to each other in the circumferential direction T1.

  FIG. 4 is an exploded view of the parallel shaft gear mechanism of FIG. Referring to FIG. 4, the bearings 41, 45, corresponding to the bearing holding holes 69, 70, 71 of the second housing 62 with the first connecting portion 76 of the second housing 62 facing upward. 49 can be inserted from above. Further, the maximum outer diameter Da of the first member 101 of the joint 33, the outer diameter Db of the outer ring 79 of the bearing 41, and the maximum outer diameter Dc of the drive gear 26 satisfy the relationship Da <Db <Dc.

  The maximum outer diameter Da, the outer diameter Db, and the distance Df between the center of the first shaft 31 and the outer periphery of the first intermediate gear 27A are (Da / 2) <(Db / 2) <. The relationship of Df is satisfied. As a result, the first intermediate gear 27A is assembled to an integral unit (first shaft unit 121 described later) including the first shaft 31, the drive gear 26, the bearing 41, and the first member 101. The second housing 62 can be assembled from above. The above-mentioned distance Df is the difference (Df = Dd−De) between (the center distance Dd between the first shaft 31 and the second shaft 32) and (the radius De of the outer periphery of the first intermediate gear 27A). ).

  Further, in the method for manufacturing the parallel shaft gear mechanism of the present embodiment, the first partial assembly process for assembling the first shaft unit 121 including the drive gear 26 and the second shaft unit 122 including the first intermediate gear 27A. A second partial assembly process for assembling the third shaft unit 123 including the driven gear 28, and the housing unit 124 by assembling the bearings 40, 44, 48 to the first housing 61. (See FIG. 5B), a fourth partial assembling step, a unit assembling step for assembling the assembled units 121, 122, 123, and 124 to the second housing 62, a first nut 42 and a second nut And a nut tightening step for tightening 46.

  Referring to FIG. 4, in the first partial assembly process, first shaft unit 121 is assembled. The first shaft unit 121 includes the first shaft 31, the first member 101 of the joint 33, the bearing 41, and the drive gear 26. In the first partial assembly process, the other end 35 of the first shaft 31 to which the drive gear 26 is fixed and the inner ring 78 of the bearing 41 are fitted in a press-fitted state. Next, the other end 35 of the first shaft 31 and the first member 101 of the joint 33 are fitted in a press-fitted state. Thereby, the first shaft unit 121 is obtained.

  In the second partial assembly process, the second shaft unit 122 is assembled. The second shaft unit 122 includes a second shaft 32, a bearing 45, a first intermediate gear 27A, and a second intermediate gear 27B. In the second partial assembly step, the other end 38 of the second shaft 32 to which the first and second intermediate gears 27A and 27B are fixed and the inner ring 88 of the bearing 45 are fitted in a press-fitted state. As a result, the second shaft unit 122 is obtained.

In the third partial assembly process, the third shaft unit 123 is assembled. The third shaft unit 123 includes the output shaft 18, the bearing 49, and the driven gear 28. In the third partial assembly process, the output shaft 18 to which the driven gear 28 is fixed and the inner ring of the bearing 48 are fitted in a press-fitted state. Thereby, the third shaft unit 123 is obtained.
In the fourth partial assembly process, the housing unit 124 is assembled. The housing unit 124 includes a first housing 61, a bearing 40, a bearing 44, and a bearing 48. In the fourth partial assembly process, the outer ring 76 of the bearing 40 is press-fitted into the bearing holding hole 65 of the first housing 61. The outer ring 86 of the bearing 44 is press-fitted into the bearing holding hole 66 of the first housing 61. The outer ring of the bearing 48 is press-fitted into the bearing holding hole 67 of the first housing 61.

Any one of the first to fourth partial assembly steps may be performed before or after the other, or each partial assembly step may be performed simultaneously.
In the unit assembling step, the units 121, 122, 123, and 124 assembled in the first to fourth partial assembling steps are assembled to the second housing 62. At this time, the jig 130 is used.

  The jig 130 includes a first holding jig 131 that holds the second housing 62 and a second holding jig 132 that holds the first shaft unit 121. The first holding jig 131 and the second holding jig 132 are fixed to each other. The second holding jig 132 includes a receiving portion 133 that receives the main body portion 108 of the first member 101 of the joint 33, and a groove 134 that is formed in the receiving portion 133. The first claw 110 of the first member 101 of the joint 33 can be fitted into the groove 134. When the first claw 110 is fitted into the groove 134, the rotation of the first shaft unit 121 is restricted.

  The unit assembling step includes a first step of holding the second housing 62 on the jig 130 and a second step of assembling the second and third shaft units 122 and 123 to the second housing 62 set on the jig 130. 2, a third step of assembling the first shaft unit 121 to the second housing 62, and a fourth step of assembling the housing unit 124 to the second housing 62. The first step, the second step, the third step, and the fourth step are performed in this order. Note that either the second or third step may be performed first or simultaneously.

5A and 5B are schematic cross-sectional views showing a state during the assembly process of the speed reducer 24 of FIG. 2, and FIG. 5B shows a state following FIG. 5A. 6A and 6B are schematic cross-sectional views showing a state during the assembly process of the speed reducer 24 of FIG. 2, FIG. 6A shows a state following FIG. 5B, and FIG. 6B follows FIG. 6A. The process of tightening the nut is shown.
With reference to FIG. 5A, in the first step of the unit assembling step, first, the second housing 62 is held by the first holding jig 131 with the connecting portion 73 facing upward.

  Referring to FIGS. 5A and 5B, in the next second step, the second and third shaft units 122 and 123 are placed on the second housing 62 held by the first holding jig 131 from above. Assembled. At this time, the second housing 62 is in a state before the first housing 61 is assembled, and is opened upward. The bearing 49 of the third shaft unit 123 is fitted into the bearing holding hole 71 of the second housing 62. The bearing 45 of the second shaft unit 122 is fitted into the bearing holding hole 70 of the second housing 62. The second intermediate gear 27B and the driven gear 28 are meshed with each other. A case where the positional relationship between the first and second intermediate gears 27A and 27B in the axial direction S2 is reversed is also conceivable. It is also conceivable that the outer diameter of the second intermediate gear 27 </ b> A (the root diameter may be larger) than the outer diameter of the bearing 45.

  Next, in the third step, the first shaft unit 121 is assembled from above into the second housing 62 to which the second shaft unit 122 is assembled. The third step includes a step of engaging the drive gear 26 of the first shaft unit 121 and the first intermediate gear 27A of the second shaft unit 122 with each other. The third step is to rotate the first shaft 31 by engaging the second holding jig 132 of the jig 130 with the first member 101 provided at the other end 35 of the first shaft 31. The process which regulates is included.

  That is, the first member 101 and the bearing 41 of the joint 33 of the first shaft unit 121 are inserted into the bearing holding hole 69 of the second housing 62 from above. Along with this, the first intermediate gear 27A and the drive gear 26 are engaged with each other. Further, the first member 101 of the joint 33 of the first shaft unit 121 is held by the second holding jig 132. Accordingly, the first claw 110 and the groove 134 are engaged with each other in a state where the first claw 110 of the first member 101 is fitted in the groove 134 of the second holding jig 132. Thereby, the rotation of the first shaft 31 of the first shaft unit 121 is restricted.

Referring to FIG. 5B, in the next fourth step, first housing 61 of housing unit 124 is assembled to second housing 62 from above. At the same time, the first shaft 31 is fitted to the bearing 40. Further, the second shaft 32 is fitted to the bearing 44. The output shaft 18 is fitted to the bearing 48. The first and second housings 61 and 62 are fixed to each other.
As described above, the first shaft unit 121, the second shaft unit 122, the third shaft unit 123, and the housing unit 124 are related to the axial direction S 1 of the first shaft 31 with respect to the second housing 62. They are assembled in the same direction, for example, from above.

With reference to FIG. 6A, in the nut tightening step, first, first nut 42 is temporarily fixed to one end 34 of first shaft 31. A second nut 46 is temporarily fixed to one end 37 of the second shaft 32. The temporarily fixed nuts 42 and 46 do not generate an axial tightening force.
Referring to FIG. 6B, as described above, before the nut tightening step (specifically, in the third step of the unit assembling step), the drive gear 26 and the first intermediate gear 27A are engaged, and the jig The rotation of the first shaft 31 is restricted by 130. In this state, the first nut 42 is fastened and fixed to the one end 34 of the first shaft 31 in the nut tightening step. At this time, for example, a tool 136 is used. Similarly to the first nut 42, the second nut 46 is fastened and fixed to one end 37 of the second shaft 32. Thereby, the assembly of the reduction gear 24 is completed.

  Further, the maximum tightening torque Tmax of the second nut 46 is set based on the allowable additional torque Ta related to the first shaft 31. For example, when the transmission ratio from the drive gear 26 to the first intermediate gear 27A is P, Tmax is set so as to satisfy the relationship of Tmax <(Ta × P). Here, the gear ratio P = (the number of teeth of the first intermediate gear 27A) / (the number of teeth of the drive gear 26).

  Further, the allowable additional torque Ta may be set as the minimum torque Ta <b> 1 that allows the first member 101 of the joint 33 to rotate relative to the other end 35 of the first shaft 31. Further, the allowable additional torque Ta may be set as the maximum torque Ta2 that can be permitted by at least one tooth surface of the drive gear 26 and the first intermediate gear 27A. Further, the allowable additional torque Ta may be set as a relatively small value of the above-described torques Ta1 and Ta2.

  As described above with reference to FIGS. 2, 6A, and 6B, the speed reducer 24 as a parallel shaft gear device that is the object of the manufacturing method of the present embodiment includes the following (1) to (8). I have. In other words, (1) a first shaft 31 and a second shaft 32 arranged in parallel to each other are provided. (2) The first shaft 31 is provided with a drive gear 26 as a first gear provided so as to be able to rotate along with the first shaft 31. (3) The second shaft 32 is provided with a first intermediate gear 27A as a second gear which is provided so as to be able to rotate along with the second shaft 32 and meshes with the first gear. (4) First and second bearings 40 and 44 are provided which rotatably support one ends 34 and 37 as end portions on the same side of the first and second shafts 31 and 32, respectively. (5) 3rd and 4th bearings 41 and 45 which rotatably support the other ends 35 and 38 as end portions on the same side of the first and second shafts 31 and 32 are provided. (6) A housing 58 for holding the first, second, third and fourth bearings 40, 44, 41, 45 is provided. (7) A first nut capable of self-locking that is screwed into the threaded portion 83 of the one end 34 of the first shaft 31 in order to fix the inner ring 75 of the first bearing 40 to the one end 34 of the first shaft 31. 42 is provided. (8) A second self-locking nut that is screwed into the threaded portion 93 of the one end 37 of the second shaft 32 in order to fix the inner ring 85 of the second bearing 44 to the one end 37 of the second shaft 32. 46.

  The manufacturing method of this embodiment is a manufacturing method of an above-mentioned parallel shaft gear mechanism, Comprising: The process of (a), (b) is included. That is, (a) a step of restricting the rotation of the first shaft 31 by engaging the jig 130 with the other end 35 of the first shaft 31 is included. (B) Corresponding to the first and second nuts 42 and 46 in a state in which the drive gear 26 and the first intermediate gear 27A are engaged and the rotation of the first shaft 31 is restricted by the second holding jig 132. A nut tightening step for tightening and fixing the first and second shafts 31 and 32 to the one ends 34 and 37 of the first and second shafts 31 and 32.

  As a result, in a state where the rotation of the first shaft 31 is restricted by the second holding jig 132, the rotation of the second shaft 32 is restricted via the drive gear 26 and the first intermediate gear 27A that mesh with each other. Is done. Therefore, in the nut tightening step, the first nut 42 can be assembled to the one end 34 of the first shaft 31 whose rotation is restricted. Moreover, the 2nd nut 46 can be assembled | attached to the end 37 of the 2nd axis | shaft 32 by which rotation was controlled as mentioned above. Since the jig 130 does not need to be engaged with both the shafts 31 and 32 in order to restrict the rotation of the first and second shafts 31 and 32, it is possible to save time and effort. Therefore, the manufacturing cost can be reduced.

  In the present embodiment, the other end 35 of the first shaft 31 is connected to the other end 35 and the output shaft 29 of the electric motor 23 as a first element as one element of the joint 33. The member 101 is provided so as to be able to rotate with the other end 35. In the nut tightening step, the rotation of the first shaft 31 is restricted by engaging the first claw 110 provided on the first member 101 with the groove 134 of the jig 130. In this case, since the first member 101 constituting the joint 33 that is originally necessary for restricting the rotation of the first shaft 31 can be used, the structure can be simplified. Therefore, the manufacturing cost can be further reduced.

  Referring to FIG. 4, the maximum outer diameter Da of the first member 101, the outer diameter Db of the outer ring 86 of the third bearing 44, and the maximum outer diameter Dc of the drive gear 26 as the first gear are Da < The relationship of Db <Dc is satisfied. In this case, for example, when the first shaft 31 is assembled to the housing 58, the first shaft 31 is assembled to the housing 58 from above with the other end 35 of the first shaft 31 on the joint 33 side facing down. Can do. Since the first shaft 31 assembled to the housing 58 has the one end 34 on the upper side, the labor for tightening the first nut 42 on the one end 34 is reduced. That is, it is not necessary to turn the assembly of the second housing 62 and the first shaft 31 of the housing 58 in order to tighten the first nut 42.

  In the present embodiment, the housing 58 includes first and second housings 61 and 62 fastened to each other. The first and second bearings 40 and 44 are respectively held in bearing holding holes 65 and 66 as first and second bearing holding holes formed in the first housing 61. The third and fourth bearings 41 and 45 are respectively held in bearing holding holes 69 and 70 as third and fourth bearing holding holes formed in the second housing 62. Drive as the first shaft 31, the first member 101 of the joint 33, the third bearing 41, and the first gear with respect to the second housing 62 before the first housing 61 is assembled. The first shaft unit 121 including the gear 26, and the second shaft unit 122 including the second shaft 32, the fourth bearing 45, and the first intermediate gear 27A as the second gear are assembled from the same direction. It is done. In this case, since the first and second shaft units 121 and 122 can be assembled from the same direction, it is not necessary to turn the assembly upside down during the assembly, and as a result, labor during assembly can be reduced.

In the present embodiment, the maximum tightening torque Tmax of the second nut 46 is set based on the allowable additional torque Ta related to the first shaft 31. In this case, it is possible to prevent an excessive torque from acting on the first shaft 31 when the second nut 46 is tightened.
In the manufacturing method of the present embodiment, the first and second shafts 31 and 32 are in the first state with the other end 35 of the first shaft 31 and the second holding jig 132 engaged with each other. And when tightening the 2nd nuts 42 and 46, it is not limited. For example, at least two nuts may be screwed into at least two of the first shaft 31, the second shaft 32, and the output shaft 18. At this time, the second holding jig 132 may be engaged with any one of a plurality of shafts into which the nuts are screwed.

Moreover, the following modifications can be considered about this embodiment. In the following description, the difference from the above-described embodiment will be mainly illustrated, and this point will be mainly described. Although explanation is omitted about other composition, it is the same as that of the above-mentioned embodiment, and attaches the same numerals.
For example, FIG. 7 is a schematic cross-sectional view of a speed reducer 24A as a parallel shaft gear mechanism according to the second embodiment of the present invention. With reference to FIG. 7, the speed reducer 24 </ b> A of the present embodiment is used in place of the speed reducer 24 described above. In the speed reducer 24A, the corresponding bearings 45 and 49 can be inserted into the bearing holding holes 70 and 71 of the second housing 62 from above with the first connecting portion 76 of the second housing 62 facing upward. It is like that. At the same time, the bearing 41 and the drive gear 26 can be inserted into the bearing holding hole 69 from below. Further, the maximum outer diameter Da of the first member 101 of the joint 33, the outer diameter Db of the outer ring 86 of the bearing 44, and the maximum outer diameter Dc of the drive gear 26 satisfy the relationship of Da>Db> Dc.

  8A and 8B are schematic cross-sectional views showing a state during the assembly process of the speed reducer 24A of FIG. 7, and FIG. 8B shows a state following FIG. 8A. 9A and 9B are schematic cross-sectional views showing a state during the assembly process of the speed reducer 24A of FIG. 7, FIG. 9A shows a state following FIG. 8B, and FIG. 9B shows a state following FIG. 9A. Show. 10A and 10B are schematic cross-sectional views showing a state during the assembly process of the speed reducer 24A in FIG. 7, FIG. 10A shows a state following FIG. 9B, and FIG. 10B follows FIG. 10A. The process of tightening the nut is shown.

  First, referring to FIGS. 8A and 8B, the manufacturing method of the parallel shaft gear mechanism of the present embodiment differs from the manufacturing method described in the first embodiment in the following points, and other points. Are the same. That is, the jig 130A is used in the unit assembling process of this embodiment. The jig 130A includes a first holding jig 131, a second holding jig 132, and a moving mechanism 135 that moves the second holding jig 132 in the vertical direction. The second holding jig 132 is restricted from rotating with respect to the first holding member 131 around the first shaft 31.

  The unit assembling step includes a first step (see FIGS. 8A and 8B) for holding the second housing 62 and the first shaft unit 121 on the jig 130A, and a second housing 62 set on the jig 130A. A second step of assembling the first shaft unit 121 (see FIG. 9A), a third step of assembling the second and third shaft units 122, 123 to the second housing 62 (see FIG. 9A), And a fourth step (see FIG. 9B) for assembling the housing unit 124 to the second housing 62. The first step, the second step, the third step, and the fourth step are performed in this order. Note that either the second or third step may be performed first or simultaneously. After the unit assembly process, a nut tightening process (see FIGS. 10A and 10B) is performed in the same manner as in the above-described embodiment.

  With reference to FIGS. 8A and 8B, in the first step, first, the first shaft unit 121 is held by the second holding jig 132 of the jig 130A. The first member 101 of the joint 33 of the first shaft unit 121 is held by the second holding jig 132. Further, the first claw 110 and the groove 134 are engaged with each other in a state where the first claw 110 of the first member 101 is fitted in the groove 134 of the second holding jig 132. Thereby, the rotation of the first shaft unit 121 is restricted. As described above, the first step includes a step of restricting the rotation of the first shaft 31 by engaging the jig 130 </ b> A with the other end 35 of the first shaft 31.

The second holding jig 132 of the jig 130 </ b> A is lowered by the moving mechanism 135 while holding the first shaft unit 121. Thus, the entire held first shaft unit 121 is disposed below the upper surface of the first holding jig 131. Next, the second housing 62 is held on the upper surface of the first holding jig 131 of the jig 130A.
Referring to FIG. 9A, in the next second step, second holding jig 132 and first shaft unit 121 held thereby are displaced upward by moving mechanism 135. The first shaft unit 121 held by the second holding jig 132 is inserted from below into the bearing holding hole 69 of the second housing 62 held by the first holding jig 131. The bearing 44 of the first shaft unit 121 is fitted into the bearing holding hole 69.

  In the next third step, the second and third shaft units 122 and 123 are placed on the second housing 62 from above in the same manner as the second step of the unit assembly step of the first embodiment described above. Assembled. At this time, the second intermediate gear 27B and the driven gear 28 are engaged with each other. Further, the first intermediate gear 27A and the drive gear 26 are engaged with each other. As described above, the third step includes a step of engaging the drive gear 26 of the first shaft unit 121 and the first intermediate gear 27A of the second shaft unit 122 with each other.

  Also in the present embodiment, the first and second nuts 42 and 46 are in the first state in a state where the drive gear 26 and the first intermediate gear 27A are engaged and the rotation of the first shaft 31 is restricted by the jig 130A. And is fastened to the second shaft 31, 32. As a result, only the first shaft 31 needs to be engaged with the second holding jig 132 of the jig 130 </ b> A, so that it is possible to reduce the labor of tightening the first and second nuts 42 and 46. .

  FIG. 11 is a schematic diagram of an electric power steering apparatus 200 including a reduction gear 224 as a parallel shaft gear mechanism according to a third embodiment of the present invention. Referring to FIG. 11, in electric power steering apparatus 200, pinion shaft 7 has an input shaft 17, an output shaft 18, and a torsion bar 19. In addition, the electric power steering device 200 is a speed reducer 224 as a parallel shaft gear mechanism that decelerates the rotation of the output shaft 29 of the electric motor 23, and a motion that converts the output rotation of the speed reducer 224 into axial movement of the rack shaft 10. A conversion mechanism 225. The electric power steering device 200 is different from the electric power steering device 1 of the first embodiment in the following points, but is the same in other points.

The reduction gear 224 has a drive gear 26 as a first gear, an intermediate gear 227 that is an idle gear that meshes with the drive gear 26 and meshes with the intermediate gear 227, and a driven gear 28 that meshes with the intermediate gear 227. is doing. The drive gear 26, the intermediate gear 227, and the driven gear 28 are sequentially meshed.
The speed reducer 224 includes the first shaft 31 described above, the second shaft 32 supporting the intermediate gear 227, the bearings 40, 41, 44, 45, 48, and 49 described above, and the first and second shafts. Nuts 42 and 46 and a housing 58. The intermediate gear 227 and the second shaft 32 are fixed to each other so as to be able to rotate together.

In the speed reducer 224, the driven gear 28 is coupled to the rotary cylinder 252 of the motion conversion mechanism 225 so as to be able to rotate together. The driven gear 28 is supported by a rotating cylinder 252 as a support shaft. A rotating cylinder 252 is supported by a housing 58 so as to be rotatable by bearings 48 and 49. The housing 58 is fixed to the rack housing 13.
The motion conversion mechanism 225 includes a ball screw mechanism. The ball screw mechanism has a rotating cylinder 252 and a screw shaft as a linear moving member driven by the rotating cylinder 252 via a plurality of balls. This screw shaft is connected to the rack shaft 10 so as to be able to move together. The output shaft 29 of the electric motor 23, the first shaft 31, the second shaft 32, and the rack shaft 10 are arranged in parallel to each other.

  The reducer 224 is assembled in the same manner as the reducer 24 described above. For example, in a state where the drive gear 26 and the intermediate gear 227 are engaged and the rotation of the first shaft 31 is restricted by the jig 130 (see FIG. 4), the first and second nuts 42 and 46 are the first and first nuts. It is fastened to the two shafts 31 and 32. As a result, only the first shaft 31 needs to be engaged with the second holding jig 132 of the jig 130, so that it is possible to reduce the labor of tightening the first and second nuts 42 and 46. .

It is also conceivable to provide the speed reducer 224 of the third embodiment on the steering column 57 as in the first and second embodiments. Conversely, the speed reducers 24 and 24A of the first and second embodiments may be provided in the rack housing 13 in combination with the motion conversion mechanism 225 as in the third embodiment.
Thus, the speed reducers 24, 24A and 224 as the parallel shaft gear mechanism may be applied to the column assist type electric power steering apparatus 1 of the first embodiment. The speed reducers 24, 24A, and 224 may be applied to the rack assist type electric power steering apparatus 200 of the third embodiment. Further, the speed reducers 24, 24A, 224 may be applied to an electric power steering device other than the above-mentioned type, or may be applied to other machines other than the electric power steering device.

  In the above-described embodiments, the gears 26, 27A, 27B, 28, and 227 are bevel gears. However, the present invention is not limited to this, and at least a pair of gears that mesh with each other may be spur gears. Conceivable. In addition, various changes can be made within the scope of the matters described in the claims.

1 is a schematic diagram of a schematic configuration of an electric power steering apparatus including a parallel shaft gear mechanism according to a first embodiment of the present invention. It is typical sectional drawing of the parallel shaft gear mechanism shown in FIG. FIG. 3 is an exploded perspective view of the joint of FIG. 2. FIG. 3 is an exploded view of the parallel shaft gear mechanism of FIG. 2. 5A and 5B are schematic cross-sectional views showing a state during the assembly process of the parallel shaft gear mechanism of FIG. 2, and FIG. 5B shows a state following FIG. 5A. 6A and 6B are schematic cross-sectional views showing a state in the middle of the assembly process of the parallel shaft gear mechanism of FIG. 2, FIG. 6A shows a state following FIG. 5B, and FIG. The process of tightening the subsequent nut is shown. It is typical sectional drawing of the parallel shaft gear mechanism of the 2nd Embodiment of this invention. 8A and 8B are schematic cross-sectional views showing a state during the assembly process of the parallel shaft gear mechanism of FIG. 7, and FIG. 8B shows a state following FIG. 8A. 9A and 9B are schematic cross-sectional views showing a state in the middle of the assembly process of the parallel shaft gear mechanism of FIG. 7, FIG. 9A shows a state following FIG. 8B, and FIG. 9B is a state following FIG. 9A. Indicates. 10A and 10B are schematic cross-sectional views showing a state during the assembly process of the parallel shaft gear mechanism of FIG. 7, FIG. 10A shows a state following FIG. 9B, and FIG. The process of tightening the subsequent nut is shown. It is a schematic diagram of the electric power steering apparatus containing the parallel shaft gear mechanism of the 3rd Embodiment of this invention.

Explanation of symbols

23 ... Electric motor, 24, 24A, 224 ... Reduction gear (parallel shaft gear mechanism), 26 ... Drive gear (first gear), 27A ... First intermediate gear (second gear), 29 ... (Electric motor) Output shaft, 31 ... first shaft, 32 ... second shaft, 33 ... joint, 34 ... one end of (first shaft), 35 ... other end of (first shaft), 37 ... (first) One end of 38, the other end of 38 (second shaft), 40 bearing (first bearing), 41 bearing (third bearing), 42 first nut, 44 bearing ( Second bearing), 45 ... bearing (fourth bearing), 46 ... second nut, 58 ... housing, 61 ... first housing, 62 ... second housing, 65 ... bearing holding hole (first bearing) Bearing holding hole), 66 ... Bearing holding hole (second bearing holding hole), 69 ... Bearing holding hole (third bearing holding hole), 70 ... Bearing holding hole (fourth bearing holding hole) Holes), 75... (First bearing) inner ring, 79... (Third bearing) outer ring, 83... Threaded portion (at one end of the first shaft), 85... (Second bearing) inner ring, 93 ... Screw part (at one end of the second shaft), 101 ... First member (one element), 110 ... First claw (claw), 121 ... First shaft unit, 122 ... Second shaft unit 132 ... 1st holding jig (jig), 134 ... groove, 227 ... intermediate gear (second gear), Da ... (first member) maximum outer diameter, Db ... (third bearing) Outer diameter (outer ring), Dc ... (outside of first gear)

Claims (5)

A first axis and a second axis arranged parallel to each other;
A first gear provided so as to be able to rotate with the first shaft;
A second gear provided so as to be able to rotate along with the second shaft and meshing with the first gear;
First and second bearings rotatably supporting one ends as end portions on the same side of the first and second shafts;
Third and fourth bearings rotatably supporting the other ends of the first and second shafts on the same side;
A housing holding the first, second, third and fourth bearings;
A self-lockable first nut screwed into a threaded portion of one end of the first shaft to fix the inner ring of the first bearing to one end of the first shaft;
Manufacture of a parallel shaft gear mechanism including a self-locking second nut screwed into a threaded portion at one end of the second shaft to fix the inner ring of the second bearing to one end of the second shaft A method,
Engaging a jig with the other end of the first shaft to restrict the rotation of the first shaft;
A nut that fastens and fixes the first and second nuts to one end of the corresponding first and second shafts in a state where the first and second gears are engaged and the rotation of the first shaft is restricted by a jig. A method of manufacturing a parallel shaft gear mechanism, comprising: a tightening step.   2. The other end of the first shaft according to claim 1, wherein one element of a joint for coaxially connecting the other end and the output shaft of the electric motor is provided so as to be able to rotate along with the other end. In the nut tightening step, the rotation of the first shaft is regulated by engaging a claw provided on the one element with a groove of a jig, and the parallel shaft gear mechanism is characterized in that Manufacturing method.   In Claim 2, the maximum outer diameter Da of the one element, the outer diameter Db of the outer ring of the third bearing, and the maximum outer diameter Dc of the first gear satisfy a relationship of Da <Db <Dc. A method for manufacturing a parallel shaft gear mechanism. In claim 3,
The housing includes first and second housings fastened together;
The first and second bearings are respectively held in first and second bearing holding holes formed in the first housing,
The third and fourth bearings are respectively held in third and fourth bearing holding holes formed in the second housing,
A first shaft unit including a first shaft, the one element of the joint, a third bearing, and a first gear with respect to the second housing in a state before the first housing is assembled; A method of manufacturing a parallel shaft gear mechanism, wherein a second shaft unit including two shafts, a fourth bearing, and a second gear is assembled from the same direction.   The parallel shaft gear mechanism according to any one of claims 1 to 4, wherein the maximum tightening torque Tmax of the second nut is set based on an allowable additional torque Ta related to the first shaft. Production method.

Images