JP2014206188A - Displacement absorbing mechanism - Google Patents

Abstract

A displacement absorbing mechanism capable of absorbing parallel displacement of a pair of rotating shafts and capable of reducing production costs such as material costs and processing costs. A first internal gear portion formed on a drive output shaft, a second internal gear portion formed on a wheel hub shaft, a gear connection shaft portion, and one end of the gear connection shaft portion. The first external tooth portion 52 provided on the side and meshing with the first internal tooth portion 56, and the second external tooth portion 54 provided on the other end side of the gear connecting shaft portion 51 and meshing with the second internal tooth portion 57. A first end portion 53 provided on one end side of the gear connecting shaft portion 51 and spherically contacting the first rotating shaft 10, and provided on the other end side of the gear connecting shaft portion 51 on the second rotating shaft 70. In the displacement absorbing mechanism B having a gear coupling shaft 50 having a second end portion 55 capable of spherical contact, the gear coupling shaft 50 has at least one of the first end portion 53 and the second end portion 55. Any one of them is configured as a separate part with respect to the gear connecting shaft portion 51. [Selection] Figure 4

Description

  The present invention relates to a displacement absorbing mechanism that couples a pair of rotating shafts and transmits drive while absorbing displacement with respect to these rotating shafts.

  Conventionally, it consists of one outer cylinder and a pair of inner cylinders fixed to a pair of rotating shafts respectively. When power is transmitted by the engagement of the inner gear of the outer cylinder and the outer gear of the inner cylinder, the outer gear is crowned. A displacement absorbing mechanism that absorbs displacement with respect to a pair of rotating shafts is known (for example, see Patent Document 1).

JP 2009-190440 JP

However, in the conventional displacement absorbing mechanism, since the pair of inner cylinders are inserted into one outer cylinder, the other inner cylinder is displaced while maintaining the parallelness in the axial direction with respect to the axial direction of one inner cylinder. The so-called parallel displacement could not be absorbed.
In addition, when manufacturing such a displacement absorbing mechanism, it is necessary to reduce production costs such as material costs and processing costs as much as possible.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a displacement absorbing mechanism that can absorb parallel displacement of a pair of rotating shafts and can reduce production costs.

In order to achieve the above object, a displacement absorbing mechanism of the present invention includes a first internal gear portion formed on a first rotary shaft, a second internal gear portion formed on a second rotary shaft, a gear coupling shaft, The first rotary shaft and the second rotary shaft are connected, and the drive is transmitted to the first and second rotary shafts while absorbing the displacement.
Here, the gear coupling shaft includes a gear connecting shaft portion, a first outer tooth portion provided on one end side of the gear connecting shaft portion and meshing with the first inner tooth portion and having a displacement absorbing structure, A second external tooth portion provided on the other end side of the gear connection shaft portion and meshing with the second internal tooth portion and having a displacement absorbing structure; and provided on one end side of the gear connection shaft portion. A first end capable of making spherical contact with the rotation shaft; and a second end provided on the other end side of the gear coupling shaft and capable of making spherical contact with the second rotation shaft. Further, the gear coupling shaft has at least one of the first end portion and the second end portion as a separate part with respect to the gear connecting shaft portion.

In the displacement absorbing mechanism of the present invention, the universal joint action of the first external tooth part meshed with the first internal tooth part and the universal joint action of the second external tooth part meshed with the second internal tooth part are provided. The universal joint action can absorb the parallel displacement of the first rotating shaft and the second rotating shaft through the inclination of the gear coupling shaft.
In the present invention, since at least one of the first end portion and the second end portion of the gear coupling shaft is a separate part from the gear connecting shaft portion, the axial direction in the manufacturing process of the gear connecting shaft portion There is no need to keep the length longer than necessary. Thereby, the material yield can be improved and the material cost can be suppressed. Furthermore, since the first end or the second end, which is a separate part, can be manufactured separately from the processing step of the gear connecting shaft portion, it is not necessary to perform cutting or the like on both sides of the gear connecting shaft portion. . Thereby, the processing cost can be reduced.
As a result, the parallel displacement of the pair of rotating shafts can be absorbed, and the production costs such as material costs and processing costs can be reduced.

It is a whole sectional view showing an in-hole motor unit for vehicles to which a displacement absorption mechanism of Example 1 is applied. FIG. 3 is an exploded cross-sectional view illustrating a configuration in which the vehicle in-hole motor unit according to the first embodiment is divided into a drive unit main body, a displacement absorbing mechanism, and a wheel structure. It is the principal part expanded sectional view which expanded and showed the displacement absorption mechanism which is the principal part of the vehicle in-hole motor unit in Example 1. FIG. It is sectional drawing which shows the gear coupling shaft of Example 1. FIG. It is a figure explaining the displacement absorption effect | action which absorbs the displacement / inclination of a hub bearing in the displacement absorption mechanism of Example 1, (a) at the time of no displacement, (b) at the time of parallel displacement, (c) at the inclination displacement (D) shows the time of axial displacement. It is explanatory drawing which shows the manufacturing process of the gear coupling shaft of a comparative example, (a) shows a material installation process, (b) shows a blank processing process, (c) shows a hobbing and surface treatment process, (d) shows an end face finishing process. It is explanatory drawing which shows the manufacturing process of the gear coupling shaft of Example 1, (a) shows a raw material installation process, (b) shows a blank processing process, (c) shows a hobbing and surface treatment process. , (D) shows an end attachment process. It is sectional drawing which shows the gear coupling shaft of Example 2. FIG. FIG. 6 is a cross-sectional view showing a gear coupling shaft of Example 3.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the displacement absorption mechanism of this invention is demonstrated based on Example 1-Example 3 shown in drawing.

Example 1
First, the configuration will be described.
The configuration of the displacement absorbing mechanism in the first embodiment includes [schematic configuration of the entire system], [detailed configuration of the drive unit main body], [detailed configuration of the displacement absorbing mechanism], [detailed configuration of the wheel structure], and [gear coupling shaft]. [Detailed Configuration] will be described separately.

[Schematic structure of the entire system]
Based on FIG. 1 which shows the whole cross section of the vehicle in-hole motor unit to which the displacement absorption mechanism of Example 1 is applied, schematic structure of the whole system is demonstrated.

  The vehicle in-hole motor unit is applied to left and right rear wheels of an electric vehicle, and includes a drive unit main body A, a displacement absorbing mechanism B, and a wheel structure C as shown in FIG.

  The drive unit main body A has a function as a drive source set for each of the left and right rear wheels and includes a motor generator MG and a gear train GT. In the drive unit main body A, when the motor generator MG is powered, a three-phase alternating current is applied to the stator coil 9b wound around the stator 9 to rotate the motor shaft 6 having the rotor 8 integrally therewith. Is reduced by the gear train GT and output from the drive output shaft 10. Further, during regeneration of the motor generator MG, the rotation input from the drive output shaft 10 is accelerated by the gear train GT, and the motor shaft 6 and the rotor 8 are rotated, so that the motor generator MG is disposed on the rotor 8 via an air gap. A three-phase alternating current is generated in the stator coil 9b of the stator 9.

  The displacement absorbing mechanism B has a function of preventing / suppressing transmission / displacement of the hub bearing 71 to the motor generator MG and the gear train GT of the drive unit main body A, and has a gear coupling shaft 50. The gear coupling shaft 50 connects the drive output shaft 10 from the drive unit main body A and the wheel hub shaft 70 supported by the hub bearing 71 to the axle case 72 so as to absorb displacement.

  The wheel structure C has a function of attaching a tire and a brake mechanism of each wheel, and has a wheel hub shaft 70. The wheel hub shaft 70 is rotatably supported with respect to the axle case 72 by a hub bearing 71 having a double-row angular bearing structure, and a brake disc 73 and a tire wheel 74 are fixed to a flange portion 70a of the wheel hub shaft 70. The Further, the wheel hub shaft 70 is connected to the drive output shaft 10 of the drive unit main body A via the displacement absorbing mechanism B.

[Detailed configuration of the drive unit body]
FIG. 2 shows a configuration in which the vehicle in-hole motor unit is divided into a drive unit main body, a displacement absorbing mechanism, and a wheel structure. Hereinafter, a detailed configuration of the drive unit main body A will be described with reference to FIGS. 1 and 2.

  The drive unit main body A is configured by incorporating a motor generator MG having a three-phase AC embedded magnet synchronous motor structure and a gear train GT having a planetary gear type reduction gear mechanism in a unit case member.

The unit case member includes a unit case 1, a unit cover 2, a motor shaft side cover 3, and an output shaft side cover 4. The unit cover 2 is bolted to one end side of the unit case 1, and the motor shaft side cover 3 is bolted to the unit cover 2 so as to close one end side of the motor shaft 6. The output shaft side cover 4 is bolted to the other end side of the unit case 1 so that a part of the drive output shaft 10 protrudes from the drive unit main body A.
An oil seal 5 is attached to the end position of the output shaft side cover 4, and the seal portion of the oil seal 5 is brought into contact with the outer peripheral surface of the drive output shaft 10 with a predetermined seal pressure. That is, the output shaft side cover 4 and the oil seal 5 are partition wall structural members that separate the drive unit main body A and the hub bearing 71.

The motor generator MG includes a motor shaft 6, a rotor flange 7, a rotor 8, and a stator 9. One end of the motor shaft 6 is supported to be rotatable with respect to the unit cover 2 via the first bearing 11, and the other end is supported to be relatively rotatable with respect to the drive output shaft 10 via the second bearing 12. . The rotor 8 is configured by a laminated steel plate that is fitted to a rotor flange 7 fixed to the motor shaft 6 and embedded with permanent magnets (not shown). The stator 9 is fixed to the inner surface of the unit case 1 and is disposed with respect to the rotor 8 via an air gap, and is configured by winding a stator coil 9b around each of the stator teeth 9a made of a punched laminated steel plate.
The harness is connected to the stator coil 9b via connection terminals 15 divided into U phase, V phase, and W phase. In addition, the motor shaft 6 is formed with an axial oil passage 16 through which lubricating oil for lubricating necessary portions such as a gear meshing portion and a bearing of the gear train GT is supplied.

  The gear train GT is disposed in the right space of FIG. 1 with the rotor flange 7 interposed therebetween, and includes a sun gear 17, a large pinion 18, a small pinion 19, a pinion carrier 20, and a ring gear 21. And the planetary gear type reduction gear mechanism that decelerates and outputs the input rotation is constituted by ring gear fixing, sun gear input, and pinion carrier output. The sun gear 17 is formed integrally with the motor shaft 6 and meshes with the large pinion 18. The large pinion 18 and the small pinion 19 are integrally formed adjacent to each other and supported so as to be rotatable with respect to the pinion carrier 20. The ring gear 21 is fixed in the rotational direction by serration coupling to the unit case 1 and meshes with the small pinion 19.

A drive output shaft (first rotation shaft) 10 is provided integrally with the pinion carrier 20. The drive output shaft 10 is formed in a cylindrical sleeve shape having one end side extending in the axial direction to the inside of the small pinion 19 and the other end side extending in the axial direction until protruding from the output shaft side cover 4. The rotation support structure of the drive output shaft 10 is formed together with the pinion carrier 20, is supported so as to be relatively rotatable with respect to the motor shaft 6 via the third bearing 13, and is supported by the fourth bearing 14 with respect to the output shaft side cover 4. It is supported rotatably through the.
Inside the drive output shaft 10, the partition wall seal member 22 is disposed in an oil-tight state at a position separating the motor shaft 6 and the gear coupling shaft 50. That is, the partition seal member 22 is a partition structure member that separates the drive unit main body A and the displacement absorbing mechanism B from each other.
In the left space of FIG. 1 with the rotor flange 7 in between, a resolver 23 for detecting the rotation angle of the motor and a park gear 24 for fixing the motor shaft 6 by meshing with a parking pole (not shown) are arranged.

[Detailed configuration of displacement absorption mechanism]
FIG. 2 shows a configuration in which the in-hole motor unit for a vehicle is divided into a drive unit main body, a displacement absorbing mechanism, and a wheel structure, and FIG. 3 is an enlarged cross-sectional view of the displacement absorbing mechanism that is a main part. Hereinafter, based on FIGS. 1-3, the detailed structure of the displacement absorption mechanism B is demonstrated.

  The displacement absorbing mechanism B is configured by fitting an independently replaceable gear coupling shaft 50 to the drive output shaft 10 and the wheel hub shaft 70 so as to be able to transmit the drive while absorbing the displacement.

  The gear coupling shaft 50 is configured by providing a first external tooth portion 52 and a first end portion 53, a second external tooth portion 54 and a second end portion 55, respectively, on both side positions of the gear coupling shaft portion 51. Is done. The first outer tooth portion 52 is serrated to the first inner tooth portion 56 of the drive output shaft 10 so as to be capable of absorbing displacement, and the first end portion 53 can be spherically contacted with the partition wall seal member 22. The The second outer tooth portion 54 is serrated and fitted so as to absorb displacement with respect to the second inner tooth portion 57 of the wheel hub shaft 70, and the second end portion 55 can be brought into spherical contact with the end cap seal member 76. Is done.

The first internal gear portion 56 formed on the drive output shaft 10 and the second internal gear portion 57 formed on the wheel hub shaft 70 have a cylindrical shape extending linearly in the axial direction on the top and valley surfaces of the internal teeth. It is said. On the other hand, the first external tooth portion 52 and the second external tooth portion 54 formed on the gear coupling shaft 50 have a spherical shape on the top and bottom surfaces of the external teeth. In addition to this, a crowning shape with a thickened tooth thickness at the center and a smaller tooth thickness toward both ends (see FIG. 3) absorbs inclinations in all directions centered on the tilt center point D and the tilt center point E. (Displacement absorption structure). The first end portion 53 and the second end portion 55 have a smooth spherical shape with the axial center position as the maximum projecting surface, and the displacement (rigidity) of the hub bearing 71 disposed between the tilt center point D and the tilt center point E. A structure that absorbs displacement with respect to the center point F is employed. That is, the meshing of the first external tooth portion 52 and the first internal tooth portion 56 becomes the output shaft side drive transmission fitting portion 58 between the gear coupling shaft 50 and the drive output shaft 10, and the second external tooth portion 54 and the first 2. The meshing of the inner tooth portion 57 becomes a hub shaft side drive transmission fitting portion 59 between the gear coupling shaft 50 and the wheel hub shaft 70 (see FIG. 3).
The gear coupling shaft 50 is mounted together with lubricating grease (not shown) in a coupling space where the entire circumference is sealed.

[Detailed configuration of wheel structure]
FIG. 2 shows a configuration in which the in-hole motor unit for a vehicle is divided into a drive unit main body, a displacement absorbing mechanism, and a wheel structure, and FIG. 3 is an enlarged cross-sectional view of the displacement absorbing mechanism that is a main part. Hereinafter, based on FIGS. 1-3, the detailed structure of the wheel structure C is demonstrated.

  The wheel structure C includes a wheel hub shaft (second rotation shaft) 70, a hub bearing 71, an axle case 72, a brake disc 73, and a tire wheel 74.

  The wheel hub shaft 70 is a rotating member connected to the drive output shaft 10 via the gear coupling shaft 50, and has an inner race function of the hub bearing 71. A wheel bolt 75 that fixes the brake disc 73 and the tire wheel 74 together with a wheel nut (not shown) is fixed to the flange portion 70a of the wheel hub shaft 70 in advance. Further, an end cap seal member 76 that is in contact with the second end portion 55 of the gear coupling shaft 50 is fixed by a spring pin 77 at an inner end portion position of the wheel hub shaft 70. A tire (not shown) is attached to the outer peripheral position of the tire wheel 74.

  The hub bearing 71 is a bearing that supports the wheel hub shaft 70 with respect to the axle case 72, and is configured by arranging two rows of balls with a contact angle of back-to-back alignment. Since the hub bearing 71 is a bearing having the wheel hub shaft 70 as an inner race and the axle case 72 as an outer race, carburizing quenching, shot peening, or the like is performed on the ball contact surfaces of the wheel hub shaft 70 and the axle case 72. The surface hardening treatment is applied. The hub bearing 71 is filled with grease for lubrication.

The axle case 72 is a case member that is fastened to the unit case 1 and the output shaft side cover 4 by bolts 78 and has an outer race function for the hub bearing 71. A wheel cylinder 79 is fixed to the axle case 72 as a brake component, and a brake caliper 81 that supports a pair of brake shoes 80 and 80 is integrally extended. A splash guard 82 that covers the brake disk 73 and prevents muddy water from entering the hub bearing 71 is fixed. Further, by fixing the axle case 72 to the output shaft side cover 4, a closed space 90 having a liquid sealing property is formed between the drive unit main body A and the hub bearing 71, and the wheel speed is set in the closed space 90. An ABS sensor 91 for detecting the above is disposed. In the ABS sensor 91, a sensing component 91 a is provided in the upper position of the axle case 72 so as to penetrate to the closed space 90, and the sensed component 91 b is fixed to the wheel hub shaft 70 by press fitting.
Note that a breather 92 communicating with outside air is connected to the closed space 90 (see FIG. 3).

[Detailed configuration of gear coupling shaft]
FIG. 4 is a cross-sectional view showing a gear coupling shaft of the displacement absorbing mechanism. The detailed configuration of the gear coupling shaft will be described below with reference to FIG.

  The gear coupling shaft 50 is integrally formed with a gear connecting shaft portion 51, a first external tooth portion 52, and a second external tooth portion 54, and the first end portion 53 and the second end portion 55 are connected to the gear connection. It is a separate component with respect to the shaft portion 51.

  That is, the first outer tooth portion 52 is formed on the peripheral surface of the gear connecting shaft portion 51 by cutting the outer peripheral surface of one end portion of the gear connecting shaft portion 51 made of a solid metal round bar. Further, the second outer tooth portion 54 is formed on the peripheral surface of the gear connecting shaft portion 51 by cutting the outer peripheral surface of the other end portion of the gear connecting shaft portion 51.

On the other hand, the first end portion 53 has a so-called screw shape, and has a fixed shaft portion 53a formed with a thread groove on the peripheral surface and a head portion 53b formed at one end portion of the fixed shaft portion 53a. doing. The fixed shaft portion 53 a is screwed into a screw hole 51 b formed in one end surface 51 a of the gear connecting shaft portion 51, and fixes the first end portion 53 to the gear connecting shaft portion 51. The head 53b has a spherical shape on the upper surface and an outer dimension R2 larger than the opening diameter R1 of the screw hole 51b. As a result, the head portion 53 b interferes with the one end surface 51 a of the gear connection shaft portion 51 and does not sink into the screw hole 51 b, and protrudes from the one end surface 51 a of the gear connection shaft portion 51 in the axial direction.
In addition, the taper surface which makes it easy to insert the fixed shaft part 53a is formed in the opening end of the screw hole 51b.

Further, the second end portion 55 has the same shape as the first end portion 53, and a fixed shaft portion 55a having a threaded groove formed on the peripheral surface, and a head formed at one end portion of the fixed shaft portion 55a. Part 55b. The fixed shaft portion 55 a is screwed into a screw hole 51 d formed in the other end surface 51 c of the gear connection shaft portion 51, and fixes the second end portion 55 to the gear connection shaft portion 51. The head 55b has a spherical shape on the upper surface and an outer dimension R4 larger than the opening diameter R3 of the screw hole 51d. As a result, the head portion 55b protrudes in the axial direction from the other end surface 51c of the gear connection shaft portion 51 without interfering with the other end surface 51c of the gear connection shaft portion 51 and being recessed into the screw hole 51d.
In addition, the taper surface which makes it easy to insert the fixed shaft part 55a is formed in the opening end of the screw hole 51d.

Next, the operation will be described.
The operation of the displacement absorbing mechanism of the first embodiment will be described separately for [displacement absorbing operation], [manufacturing operation of the gear coupling shaft of the comparative example], and [manufacturing operation of the gear coupling shaft of the first embodiment].

[Displacement absorption]
For example, when the race surface wear of the hub bearing 71 proceeds due to long-term use under a high load, the wheel hub shaft 70 supported by the hub bearing 71 is displaced or tilted. The displacement / inclination of the wheel hub shaft 70 is transmitted to the gear train GT and the motor generator MG of the drive unit body A,
(1) Abnormal noise / vibration: Gear noise due to gear tooth contact (2) Reduction in gear life: Increase in extreme stress / surface pressure due to gear tooth contact (3) Increase in friction: Loss due to backlash change between gear teeth Increase (4) Motor performance: It causes problems such as output reduction and torque fluctuation due to motor air gap change.

  Therefore, the displacement / inclination of the wheel hub shaft 70 is prevented / suppressed from being transmitted to the gear train GT and the motor generator MG, thereby preventing / suppressing the influence on the gear meshing portion of the gear train GT and the motor generator MG. Absorption mechanism B is required. Hereinafter, the displacement absorbing action of the displacement absorbing mechanism B will be described with reference to FIG.

  When the wheel hub shaft 70 is parallel displaced by y in the direction perpendicular to the axis from the non-displaced state of FIG. 5A, as shown in FIG. 5B, the parallel displacement is converted to the output shaft side drive transmission fitting portion 58. And the hub shaft side drive transmission fitting portion 59 can absorb through the illustrated inclination of the gear coupling shaft 50 by two universal joint actions. Therefore, the parallel displacement of the wheel hub shaft 70 does not affect the drive output shaft 10 to displace it.

  Further, when the wheel hub shaft 70 is tilted and displaced by θ around the displacement center point F as shown in FIG. 5C from the non-displaced state of FIG. The displacement can be absorbed through the illustrated inclination of the gear coupling shaft 50 by the two universal joint actions by the output shaft side drive transmission fitting portion 58 and the hub shaft side drive transmission fitting portion 59. Therefore, the tilt displacement of the wheel hub shaft 70 does not affect the drive output shaft 10 to displace it.

  Further, when the wheel hub shaft 70 is axially displaced in the axial direction by X as shown in FIG. 5 (d) from the non-displaced state of FIG. 5 (a), this axial displacement is transmitted to the output shaft side drive transmission. It can be absorbed by a sliding action by at least one of the fitting portion 58 and the hub shaft side drive transmission fitting portion 59. Therefore, the axial displacement of the wheel hub shaft 70 does not affect the drive output shaft 10 to displace it.

  Thus, the wheel hub shaft 70 is configured by disposing the displacement center points F of the displacement absorbing mechanism B (two rows of ball center positions of the hub bearing 71) at a position between the tilt center points D and E. However, the output shaft side drive transmission fitting portion 58 and the hub shaft side drive transmission fitting portion 59 can reliably absorb these displacements even if any of parallel displacement, tilt displacement, and axial displacement occurs. That is, the displacement of the wheel hub shaft 70 does not reach the drive output shaft 10 and displace it in the corresponding direction.

  Therefore, the in-hole motor unit for a vehicle can prevent the displacement of the wheel hub shaft 70 from being transmitted from the drive output shaft 10 to the gear train GT and the motor generator MG by the displacement absorbing mechanism B. As a result, any of the above problems (1) to (4) does not occur.

[Production action of the gear coupling shaft of the comparative example]
FIG. 6 is an explanatory view showing a manufacturing process of a gear coupling shaft of a comparative example, (a) shows a material installation process, (b) shows a blanking process, and (c) shows hobbing / surface treatment. The process is shown, and (d) shows the end face finishing process. Hereinafter, the manufacturing operation of the gear coupling shaft 100 of the comparative example will be described with reference to FIG. The “gear coupling shaft of the comparative example” means that the first external tooth portion 102, the first end portion 103, the second external tooth portion 104, and the second end portion 105 are all integrated with the gear connecting shaft portion 101. This is a molded gear coupling shaft.

  In the gear coupling shaft 100 of the comparative example, first, a metal round bar material S1 to be a gear coupling shaft is set at a predetermined position by the material installation step shown in FIG. Here, the shaft length dimension L1 of the round bar material S1 is such that the first and second end portions 103 and 105 can be formed on both sides of the gear connecting shaft portion 101 so that the product axis of the gear connecting shaft portion 101 can be formed. It is sufficiently longer than the long dimension L2. Also, the outer dimension φ1 of the round bar material S1 is such that the first and second external tooth portions 102 can be formed on the peripheral surface of the gear connecting shaft portion 101 so that the first and second external tooth portions 102 and 104 can be formed. , 104 is approximately the same as the external dimension φ2.

  In the blank processing step shown in FIG. 6B, the round bar material S1 set at a predetermined position in the material installation step is cut to form the contour shape of the gear coupling shaft 100. That is, the outer diameters of the gear connecting shaft portion 101 and the first and second outer teeth portions 102 and 104 are cut out from the round bar material S1. At this time, the processing reference center portion O is formed on both end faces of the round bar material S1.

  In the hobbing / surface treatment process shown in FIG. 6 (c), the first and second external teeth 102, 104 are formed on the round bar material S1 having the contour shape formed in the blanking process using a hobbing machine. Gear cutting. And the surface hardening process by carburizing quenching, shot peening, etc. is given with respect to the 1st, 2nd external tooth part 102,104. Thereafter, the shaft of the gear connecting shaft portion 101 is finished, and finally the gear grinding of the first and second external tooth portions 102 and 104 is performed. This completes the processing of the gear connecting shaft portion 101 and the first and second external tooth portions 102 and 104.

  In the end face finishing step shown in FIG. 6 (d), the first and second round bar material S1 in which the gear connecting shaft portion 101 and the first and second external teeth portions 102 and 104 are processed in the hobbing and surface treatment step are processed in the first, The part which protruded from the both sides of the 2nd external tooth part 102,104 is cut off. Then, the first and second end portions 103 and 105 are formed by grinding both side positions of the gear connecting shaft portion 101. Thereby, the gear coupling shaft 100 of the comparative example is completed.

  As described above, in the gear coupling shaft 100 of the comparative example, the shaft length dimension L1 of the round bar material S1 needs to be sufficiently longer than the product shaft length dimension L2 of the gear coupling shaft portion 101. I cut off the important part. Therefore, there is a problem that the material yield is poor and the material cost is high. Furthermore, in the end face finishing process, a procedure for cutting off the processing reference center portion O is required, which takes time for processing and increases the processing cost.

  Further, the first and second external tooth portions 102 and 104 are subjected to surface hardening treatment before the first and second end portions 103 and 105 are formed by cutting. For this reason, it is difficult to perform surface hardening treatment including heat treatment such as quenching on the first and second end portions 103 and 105 formed on both sides of the first and second external tooth portions 102 and 104. It was. In addition, if the first and second end portions 103 and 105 cannot be sufficiently surface hardened, there is a concern that the first and second end portions 103 and 105 may be worn out quickly.

  Further, in the gear coupling shaft 100 of this comparative example, the machining reference center portion O is separated from the gear coupling shaft 100 when both side portions of the first and second external tooth portions 102 and 104 are cut off. . For this reason, in the finished product state of the gear coupling shaft 100, there is no dimension measurement reference, and it is difficult to measure the dimensions of the first and second external tooth portions 102 and 104 after completion.

[Production Action of Gear Coupling Shaft of Example 1]
FIG. 7 is an explanatory view showing the manufacturing process of the gear coupling shaft of Example 1, (a) showing the material installation process, (b) showing the blanking process, and (c) hobbing / surface. A process process is shown, (d) shows an edge part attachment process. Hereinafter, the manufacturing operation of the gear coupling shaft 50 according to the first embodiment will be described with reference to FIG.

  In the gear coupling shaft 50 of the first embodiment, first, a metal round bar material S2 to be a gear coupling shaft is set at a predetermined position by the material installation step shown in FIG. Here, the shaft length dimension L3 of the round bar material S2 is not required to form the first and second end portions 53 and 55 at both side positions of the gear connecting shaft portion 51. It is about the same as the dimension L4. In addition, the external dimension φ3 of the round bar material S2 is such that the first and second external tooth portions 52 can be formed on the peripheral surface of the gear connecting shaft portion 51 so that the first and second external tooth portions 52 and 54 can be formed. , 54 and the outer dimension φ4.

  In the blank processing step shown in FIG. 7B, the round bar material S2 set at a predetermined position in the material installation step is cut to form the contour shape of the gear coupling shaft 50. That is, the outer diameter of the gear connecting shaft portion 51 is cut out from the round bar material S2. At this time, screw holes 51b and 51d having a processing reference center portion O on the bottom surface are formed in both end faces 51a and 51c of the round bar material S2.

  In the hobbing / surface treatment step shown in FIG. 7 (c), the first and second external teeth portions 52, 54 are applied to the round bar material S2 having the contour shape formed in the blanking step using a hobbing machine. Gear cutting. And the surface hardening process by carburizing quenching, shot peening, etc. is given with respect to the 1st, 2nd external tooth part 52,54. Then, the shaft finish of the gear connection shaft part 51 is performed, and finally the gear grinding of the first and second external tooth parts 52 and 54 is performed. This completes the processing of the gear connecting shaft portion 51 and the first and second external tooth portions 52 and 54.

In the end portion attaching step shown in FIG. 7 (d), the gear connecting shaft portion 51 in which the first and second external tooth portions 52 and 54 are formed at both side positions in the hobbing / surface treatment step is previously prepared in a separate step. The formed first and second end portions 53 and 55 are attached. Here, the first and second end portions 53 and 55 are subjected to a heat treatment such as carburizing and quenching and a surface hardening treatment such as shot peening when manufacturing in a separate process.
That is, the fixed shaft portion 53a of the first end portion 53 is screwed into one screw hole 51b, and the first end portion 53 is screwed and fixed to the one end surface 51a of the gear connecting shaft portion 51. Further, the fixed shaft portion 55a of the second end portion 55 is screwed into the other screw hole 51d, and the second end portion 55 is screwed and fixed to the other end surface 51d of the gear connecting shaft portion 51. Thereby, the gear coupling shaft 50 of Example 1 is completed.

  As described above, in the gear coupling shaft 50 of the first embodiment, the first and second end portions 53 and 55 are not formed at the both side positions of the gear coupling shaft portion 51. Therefore, the axial length dimension of the round bar material S2 L3 can be made substantially equal to the product shaft length dimension L4 of the gear connecting shaft portion 51. Therefore, the material is not wasted, the material yield can be improved, and the material cost can be suppressed. Further, as in the case of the gear coupling shaft 100 of the comparative example, there is no procedure for cutting off the processing reference center portion O in the end face finishing process, so that the processing cost can be suppressed. As a result, the production cost can be reduced.

  In addition, the shaft length dimension L3 of the round bar material S2 is set to be approximately equal to the product axis length dimension L4 of the gear connecting shaft portion 51, so that the round bar material S1 is formed at both ends of the gear coupling shaft 100 of the comparative example. The distance between the processed reference center portions O can be shortened. Thereby, the axial rigidity at the time of hobbing the 1st, 2nd external tooth parts 52 and 54 can be improved, and a gear cutting precision can be improved. That is, by supporting the round bar material S2 at a relatively narrow interval, vibration and bending during gear cutting can be suppressed, and accuracy can be improved.

  In addition, since the first and second end portions 53 and 55 are manufactured in a separate process from the first and second external tooth portions 52 and 54, the first and second end portions 53 and 55 and the first and second end portions 53 and 55 are manufactured. Each of the two external tooth portions 52 and 54 can be subjected to surface hardening treatment. Thereby, the concern of the early wear when the 1st, 2nd end parts 53 and 55 slide can be wiped off. In addition, since the first and second end portions 53 and 55 are relatively small parts, the processing cost can be kept low.

  Furthermore, since the first and second end portions 53 and 55 are screwed and fixed to the gear connecting shaft portion 51, they can be easily attached and the attachment strength is increased, so that they can be attached relatively firmly.

  Since the machining reference center portion O is formed on both end faces 51a and 51c of the gear connecting shaft portion 51, it is possible to easily measure the dimensions of the first and second external tooth portions 52 and 54 after completion. Can do.

Next, the effect will be described.
In the displacement absorbing mechanism of the first embodiment, the effects listed below can be obtained.

(1) a first internal gear portion 56 formed on the first rotating shaft (drive output shaft) 10,
A second internal tooth portion 57 formed on the second rotation shaft (wheel hub shaft) 70;
A gear connecting shaft portion 51; a first outer tooth portion 52 provided on one end side of the gear connecting shaft portion 51 and meshing with the first inner tooth portion 56 and having a displacement absorbing structure; and the gear connecting shaft portion 51. A second external tooth portion 54 which is provided on the other end side of the gear and meshes with the second internal tooth portion 57 and has a displacement absorbing structure, and is provided on one end side of the gear connecting shaft portion 51 and the first rotating shaft. A gear coupling having a first end portion 53 that can be spherically contacted to 10 and a second end portion 55 that is provided on the other end side of the gear connecting shaft portion 51 and can be spherically contacted with the second rotating shaft 70. A shaft 50;
In the displacement absorbing mechanism B that connects the first rotating shaft 10 and the second rotating shaft 70 and transmits the drive while absorbing the displacement to the first and second rotating shafts 10, 70.
The gear coupling shaft 50 is configured such that at least one of the first end portion 53 and the second end portion 55 is a separate component with respect to the gear connecting shaft portion 51.
Thereby, the parallel displacement of a pair of rotating shafts 10 and 70 can be absorbed, and production costs such as material costs and processing costs can be reduced.

(2) The first external tooth portion 52, the second external tooth portion 54, the first end portion 53, and the second end portion 55 are subjected to a surface hardening process.
Thereby, the surface hardness of the part in which early wear fears can be improved, and wear concerns can be wiped out.

(3) Screw holes 51b and 51d are formed in at least one end face 51a and 51c of the gear connecting shaft portion 51;
The first end portion 53 or the second end portion 55 which is a separate part is screwed and fixed into the screw holes 51b and 51d.
Thereby, the 1st end part 53 or the 2nd end part 55 which was made into a separate component can be fixed to the gear connection shaft part 51 easily and firmly.

(4) The first rotation shaft is the drive output shaft 10 from the drive unit main body A set to the drive wheel,
The second rotation shaft is a wheel hub shaft 70 supported by a hub bearing 71 with respect to the drive unit main body A,
The configuration is applied to an in-hole motor unit having the drive output shaft 10 and the wheel hub shaft 70.
Thereby, in the in-wheel motor unit, the parallel displacement of the drive output shaft 10 and the wheel hub shaft 70 can be absorbed, and the production cost such as the material cost and the processing cost can be reduced.

(Example 2)
The second embodiment is an example in which the first and second end mounting structures are configured differently from the first embodiment.

  FIG. 8 is a cross-sectional view illustrating a gear coupling shaft according to the second embodiment. Hereinafter, based on FIG. 8, the gear coupling shaft of Example 2 is demonstrated. In addition, about the structure equivalent to Example 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  In the gear coupling shaft 50 </ b> A shown in FIG. 8, the first end portion 53 and the second end portion 55, which are separate parts from the gear connection shaft portion 51, are fitted holes 51 e formed in the gear connection shaft portion 51. , 51f.

  That is, a fitting hole 51e having a smooth inner peripheral surface is formed on one end surface 51a of the gear connecting shaft portion 51. On the other hand, the first end portion 53 has a fixed shaft portion 53c having a smooth outer peripheral surface and a head portion 53b formed at one end portion of the fixed shaft portion 53c. Then, by making the inner diameter dimension of the fitting hole 51e slightly larger than the outer dimension of the fixed shaft part 53c of the first end part 53, the fixed shaft part 53c of the first end part 53 is press-fitted into the fitting hole 51e. Can be fitted.

  In addition, the other end surface 51c of the gear connecting shaft portion 51 is formed with a fitting hole 51f having a smooth inner peripheral surface. On the other hand, the second end portion 55 includes a fixed shaft portion 55c having a smooth outer peripheral surface and a head portion 55b formed at one end portion of the fixed shaft portion 55c. Then, by making the inner diameter dimension of the fitting hole 51f slightly larger than the outer dimension of the fixed shaft part 55c of the second end part 55, the fixed shaft part 55c of the second end part 55 is press-fitted into the fitting hole 51f. Can be fitted.

  Thus, by fitting and fixing the first end portion 53 and the second end portion 55 in the fitting holes 51e and 51f formed in the gear connecting shaft portion 51, the first end portion 53 and the second end portion The part 55 can be easily attached, and assemblability can be improved.

  That is, in the displacement absorption mechanism of Example 2, the effects listed below can be obtained.

(5) Fitting holes 51e and 51f are formed in at least one end face 51a and 51c of the gear connecting shaft portion 51,
The first end 53 or the second end 55 as a separate part is configured to be fitted and fixed in the fitting holes 51e and 51f.
Thereby, the assemblability with respect to the gear connection shaft part 51 of the 1st end part 53 or the 2nd end part 55 which was made into a separate component can be aimed at.

Example 3
The third embodiment is an example in which the structure of the gear connecting shaft portion and the first and second end portions are configured differently from the first and second embodiments.

  FIG. 9 is a cross-sectional view illustrating the gear coupling shaft of the third embodiment. Hereinafter, based on FIG. 9, the gear coupling shaft of Example 3 is demonstrated. In addition, about the structure equivalent to Example 1 or Example 2, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  In the gear coupling shaft 50B shown in FIG. 9, the gear connecting shaft portion 61 is formed by a hollow metal steel pipe whose both ends are open. Further, the first end portion 63 and the second end portion 65 are formed of metal spheres that are separate parts with respect to the gear connecting portion 61. In addition, the 1st external tooth part 62 and the 2nd external tooth part 64 are formed in the outer peripheral surface of the both ends position of the gear connection shaft part 61, respectively.

  The first end portion 63 and the second end portion 65 are fitted into openings 61 a and 61 b that are open on both sides of the gear connecting shaft portion 61, respectively. That is, the openings 61a and 61b correspond to fitting holes. Here, the inner diameter R5 of the gear connecting shaft portion 61 is set to be slightly smaller than the diameter R6 of the first end portion 63 and the diameter R7 of the second end portion 65. Thereby, as for the 1st end part 63 and the 2nd end part 65, a part of outer peripheral surface protrudes the gear connection axial part 61 slightly from both ends.

  Here, in the gear coupling shaft of the comparative example, the first end portion 103 and the second end portion 105 are formed in both end positions of the gear coupling shaft portion 101 in the end face finishing step. Therefore, it was necessary to use a solid material as the round bar material S1. That is, the hollow steel pipe cannot be used, and the material cost is further increased and the weight is increased.

  On the other hand, in the gear coupling shaft 50B of the third embodiment, since the gear connecting shaft portion 61 is configured by a hollow metal steel pipe, the material cost is suppressed as compared with the case of using a solid round bar material. The weight can be reduced.

  In addition, since metal spheres are used as the first end portion 63 and the second end portion 65, the processing of the first end portion 63 and the second end portion 65 becomes easy, and the production cost can be further reduced. it can.

  That is, in the displacement absorption mechanism of Example 3, the effects listed below can be obtained.

(6) The first end 63 or the second end 65, which is a separate part, is formed by a sphere that can be fitted and fixed in the fitting holes (openings 61a and 61b).
Thereby, the process of the 1st end part 63 or the 2nd end part 65 made into a separate component becomes easy, and the further reduction of production cost can be aimed at.

  As mentioned above, although the displacement absorption mechanism of this invention has been demonstrated based on Examples 1-3, it is not restricted to these Examples about a concrete structure, Each claim of a claim Design changes and additions are allowed without departing from the gist of the invention.

  In each of the above-described embodiments, an example in which the mounting structure of the first end portions 53 and 63 and the second end portions 55 and 65 is fixed by screwing or fitting by press-fitting is shown. However, the mounting structure of the first and second end portions as separate parts with respect to the gear connecting shaft portion is not limited to these, and may be attached by welding such as laser welding or friction welding, It may be fixed by shrink fitting or spline fitting. Further, when fitted and fixed, it may have a retaining structure using a fitting claw, a snap ring or the like.

  Moreover, in Example 1 and Example 2, although the example which comprises the gear connection shaft part 51 by a solid bar was shown, you may comprise by a hollow pipe member like Example 3. FIG. Thereby, reduction of material cost and weight reduction can be achieved.

Further, in each of the above-described embodiments, the example in which both the first end portion 53 and the second end portion 55 are separate parts with respect to the gear connecting shaft portion 51 is shown. However, the present invention is not limited to this, and at least one of the first end portion 53 and the second end portion 55 may be a separate component.
Even in this case, it is not necessary to secure the length of the gear coupling shaft portion to which the end portion as a separate part is attached more than necessary, and the material cost can be suppressed.

  Furthermore, in Example 1, the example which applies the displacement absorption mechanism of this invention to the in-hole motor unit set to a drive wheel was shown. However, the displacement absorbing mechanism of the present invention can be applied as long as it is between a pair of rotational axes that are relatively displaced.

A Drive unit B Displacement absorption mechanism C Wheel structure 10 Drive output shaft (first rotating shaft)
50 gear coupling shaft 51 gear coupling shaft portion 52 first outer tooth portion 53 first end portion 54 second outer tooth portion 55 second end portion 56 first inner tooth portion 57 second inner tooth portion 70 wheel hub shaft (first 2 rotation axes)
71 Hub bearing

Claims (6)

A first internal tooth portion formed on the first rotation shaft;
A second internal tooth portion formed on the second rotation shaft;
A gear connecting shaft portion, a first outer tooth portion provided on one end side of the gear connecting shaft portion and meshing with the first inner tooth portion and having a displacement absorbing structure; and on the other end side of the gear connecting shaft portion. A second outer tooth portion that is provided and meshes with the second inner tooth portion and has a displacement absorbing structure; and a first end that is provided on one end side of the gear connecting shaft portion and is capable of spherical contact with the first rotation shaft. And a gear coupling shaft having a second end portion that is provided on the other end side of the gear connecting shaft portion and is spherically contactable with the second rotation shaft,
In the displacement absorbing mechanism that connects the first rotating shaft and the second rotating shaft and transmits the drive while absorbing the displacement with respect to the first and second rotating shafts,
The gear coupling shaft is characterized in that at least one of the first end and the second end is a separate component with respect to the gear connecting shaft. In the displacement absorbing mechanism according to claim 1,
A displacement-absorbing mechanism, wherein surface hardening treatment is performed on the first external tooth portion, the second external tooth portion, the first end portion, and the second end portion. In the displacement absorption mechanism according to claim 1 or 2,
A screw hole is formed in at least one end face of the gear connecting shaft portion,
The displacement absorbing mechanism, wherein the first end or the second end as a separate part is screwed into the screw hole. In the displacement absorption mechanism according to claim 1 or 2,
A fitting hole is formed in at least one end surface of the gear connecting shaft portion,
The displacement absorbing mechanism, wherein the first end or the second end as a separate part is fitted and fixed in the fitting hole. In the displacement absorbing mechanism according to claim 4,
The displacement absorbing mechanism, wherein the first end or the second end as a separate part is formed by a sphere that can be fitted and fixed to the opening. In the displacement absorption mechanism according to any one of claims 1 to 5,
The one rotation shaft is a drive output shaft from a drive unit body set on a drive wheel,
The other rotating shaft is a wheel hub shaft supported by a hub bearing with respect to the drive unit main body,
A displacement absorbing mechanism that is applied to an in-hole motor unit having the drive output shaft and the wheel hub shaft.