JP5866950B2 - Axle connection structure - Google Patents

Description

  The present invention relates to an axle connection structure that connects a planetary gear type transmission to which a drive source output shaft that is rotated by a drive source is connected, and an axle that rotates integrally with a wheel.

  Conventionally, an axle connection in which a reduction gear that decelerates and outputs the rotation of an electric motor that is a drive source and an axle that rotates integrally with a wheel are swingably connected via a shaft coupling member that is a flexible coupling. The structure is known (for example, refer to Patent Document 1).

JP 2007-191027 A

  However, in the conventional axle connecting structure, the speed reducer, the shaft connecting member, and the axle are arranged side by side on the same axis. For this reason, the axial positions of these reduction gears and the like do not overlap and are arranged along the axial direction. As a result, there has been a problem that the axial length (axial length) of the entire axle connecting structure becomes long.

  The present invention has been made paying attention to the above problem, and an object thereof is to provide an axle connecting structure capable of shortening the axial length.

In order to achieve the above object, the axle coupling structure of the present invention includes a drive source output shaft, an axle, a planetary gear type transmission, and a shaft coupling member.
The drive source output shaft is a rotating shaft that is rotated by a drive source.
The axle is a rotating shaft that is arranged coaxially with the drive source output shaft and rotates integrally with a wheel.
The planetary gear type transmission has a plurality of pinion gears and a planetary carrier that rotatably supports the plurality of pinion gears, and transmits rotation from the drive source output shaft to the axle via the planetary carrier. To do.
The shaft connecting member is disposed radially inward of the plurality of pinion gears, and connects the planetary carrier and the axle.

In the axle coupling structure of the present invention, the shaft coupling member that couples the planetary carrier and the axle is disposed radially inward of the plurality of pinion gears.
That is, the axial position of the shaft connecting member and the axial position of the plurality of pinion gears overlap each other. Therefore, when the planetary carrier, the shaft coupling member, and the axle are coaxially arranged, the axial length (axial length) of the entire axle coupling structure is shortened by utilizing the radially inner region of the plurality of pinion gears. Can be achieved.

It is a longitudinal cross-sectional view which shows the in-wheel motor unit to which the axle connection structure of Example 1 was applied. It is an enlarged view which shows the principal part of the in-wheel motor unit shown in FIG. It is the A section enlarged view in FIG. It is an enlarged view which shows the principal part of the in-wheel motor unit to which the axle connection structure of the comparative example was applied. It is explanatory drawing which shows the flow path of the lubricating oil in the axle connection structure of Example 1. FIG. It is explanatory drawing explaining the rattling absorption effect in an axle connection structure, (a) shows typically the principal part of the axle connection structure of a comparative example, (b) is the principal part of the axle connection structure of Example 1. FIG. Is shown schematically.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the axle connection structure of this invention is demonstrated based on Example 1 shown on drawing.

  First, the configuration of the axle coupling structure of the first embodiment will be described by being divided into “configuration of application example of axle coupling structure”, “configuration of carrier”, “configuration of hub shaft”, and “configuration of shaft coupling member”.

[Description of application example of axle connection structure]
FIG. 1 is a longitudinal sectional view showing an in-wheel motor unit to which the axle connecting structure of the first embodiment is applied. FIG. 2 is an enlarged view showing a main part of the in-wheel motor unit shown in FIG. FIG. 3 is an enlarged view of part A in FIG.

  The in-wheel motor unit MU shown in FIG. 1 has an electric motor 20 that drives and brakes a wheel 50 arranged inside a wheel 51 that supports the wheel 50. A motor case 10, an electric motor 20, The reduction gear 30 and the shaft coupling member 40 are provided.

  The motor case 10 includes a case main body 11 and a cover 12, and is configured by combining the cover 12 with the left side surface of the case main body 11 in FIG. 1. In the motor case 10, an electric motor 20 serving as a drive source and a speed reducer 30 that decelerates and outputs the rotation of the electric motor 20 are coaxially arranged and housed. The motor case 10 is held so as to be swingable with respect to a vehicle body such as a side member via a suspension mechanism (not shown).

  The electric motor 20 is located inside the cover 12 and has an annular stator 21 and a rotor 22 disposed concentrically within the stator 21.

  The stator 21 is provided with a coil 21a and is fixed to the inner periphery of the cover 12 by a method such as shrink fitting the outer peripheral surface.

The rotor 22 has a rotor rotation shaft (drive source output shaft) 22a, a flange portion 22b, a laminated steel plate 22c, and a permanent magnet (not shown).
The rotor rotating shaft 22a is rotatably supported at one end by a first rotor bearing 23A fitted inside an opening 12a formed through the cover 12 and fitted inside a carrier 34 described later of the speed reducer 30. The other end of the second rotor bearing 23B is rotatably supported. And the laminated steel plate 22c is fixed to the outer periphery of the flange part 22b protruded from the rotor rotating shaft 22a in the radial direction, and a permanent magnet (not shown) is embedded in the outer periphery of the laminated steel plate 22c. In addition, a rotor oil passage 22d is formed in the rotor rotation shaft 22a so as to pass through the rotor rotation shaft 22a in the axial direction and through which oil for cooling and lubrication supplied from an oil pump (not shown) flows.
The rotor 22 has a permanent magnet embedded in the outer periphery of the laminated steel plate 22c disposed at an axial position facing the inner peripheral surface of the stator 21, and the rotor rotating shaft 22a is supported while maintaining this position.

As shown in FIG. 2, the speed reducer 30 includes a sun gear 31 formed on the rotor rotation shaft 22a, a ring gear 32 fixed to the case main body 11 by a projection claw or the like so as to be able to swing only slightly, and a sun gear 31. Three stepped pinions (pinion gears) 33 that are integrally formed of a meshed large diameter pinion portion 33a and a small diameter pinion portion 33b meshed with the ring gear 32, and these three stepped pinions 33. Is a planetary gear type transmission that is configured by a planetary gear set having a carrier (planetary carrier) 34 that is arranged at equal intervals in the circumferential direction and that is rotatably supported.
Here, the sun gear 31 and the ring gear 32 are arranged at different axial positions. The large-diameter pinion portion 33a and the small-diameter pinion portion 33b are displaced from each other in the axial direction so as to face the sun gear 31 or the ring gear 32, respectively.

  A hub shaft (axle) 52 fixed to the center of the wheel 51 is swingably connected to the carrier 34 which is an output member of the speed reducer 30 via a shaft connecting member 40.

[Composition of career]
The carrier 34 has a carrier body 34a, a pair of carrier plates 34b and 34c, and three pinion shafts 34d.

The carrier body 34a is a hollow shaft that is arranged coaxially with the rotor rotation shaft 22a and that is open at both ends. The second rotor bearing 23B is fitted on the inner peripheral surface of the electric motor 20 side, and the wheel 50 side. The first connection portion 34aA made of serration is formed. Here, “serration” refers to a plurality of irregularities extending in the axial direction and arranged in the circumferential direction, and the same applies hereinafter.
And as for this 1st connection part 34aA, while the front-end | tip of a convex part curves in the protrusion direction along an axial direction, it is chamfered along the axial direction. Furthermore, the side surface in the axial direction is subjected to a so-called crowning process with a middle height.

  The pair of carrier plates 34b and 34c are plates that are provided around the carrier body 34a and are arranged in parallel in the axial direction so as to face each other.

  The one carrier plate 34b projects directly in the radial direction from the peripheral surface of the end of the carrier body 34a on the wheel 50 side. In addition, a carrier oil passage 34f that opens to the inside of the carrier body 34a and communicates with a rotor oil passage 22d provided inside the rotor rotation shaft 22a is formed inside the one carrier plate 34b. The carrier oil passage 34f is an oil passage through which oil for cooling and lubrication from the rotor oil passage 22d of the rotor rotation shaft 22a flows. Further, the outer periphery of the one carrier plate 34 b is rotatably supported on the inner peripheral surface of the case body 11 via a carrier bearing 35.

  The other carrier plate 34c is a ring-shaped plate surrounding the rotor rotation shaft 22a. The other carrier plate 34c is held by a leg portion 34g extending from the peripheral surface of the carrier main body 34a on the electric motor 20 side to the electric motor 20 side.

  The pinion shaft 34d is a metal shaft that passes through a pair of shaft support holes (not shown) formed in the pair of carrier plates 34b and 34c. One end of the pinion shaft 34d is fixed to the carrier plate 34c by a pin 34h that penetrates the other carrier plate 34c in the radial direction. The pinion shaft 34d rotatably holds the stepped pinion 33 via a bearing 34i in a central portion located between the pair of carrier plates 34b and 34c.

[Configuration of hub axle]
The hub shaft 52 has one end fixed to the wheel 51 and an opening 52a at the other end protruding toward the electric motor 20 side. This opening 52a has an inner diameter dimension into which the shaft connecting member 40 can be inserted, and a second connection portion 53 made of serration is formed on the inner peripheral surface.
And as for this 2nd connection part 53, while the front-end | tip of a convex part curves in the protrusion direction along an axial direction, it is chamfered along the axial direction. Furthermore, the side surface in the axial direction is subjected to a so-called crowning process with a middle height.

  Further, a cylindrical wheel hub 54 is fitted on the outer periphery of the hub shaft 52 and is fixed so as to be rotatable together with the hub shaft 52. On the other hand, a cylindrical hub bearing outer member 13 protruding in the axial direction is fixed to the opening 11 a facing the wheel 50 of the case body 11. A plurality of spherical rolling elements 55 are rotatably held between the hub bearing outer member 13 and the wheel hub 54 to form a hub bearing. The hub shaft 52 is rotatably held with respect to the case body 11 by a hub bearing including the hub bearing outer member 13, the wheel hub 54, and a plurality of rolling elements 55.

  Between the hub bearing outer member 13 and one carrier plate 34b, a partition wall 11b extending radially inward from the opening 11a of the case body 11 and the partition wall 11b and the outer peripheral surface of the hub shaft 52 are provided. An oil seal 11c that closes the gap is provided.

[Configuration of shaft coupling member]
The shaft connecting member 40 is a hollow cylindrical shaft member that is disposed coaxially with the carrier 34 and the hub shaft 52 and connects the carrier 34 and the hub shaft 52 coaxially. One end of the shaft connecting member 40 is inserted inside the carrier body 34 a of the carrier 34, and the other end is inserted inside the opening 52 a of the hub shaft 52.

  At this time, one end of the shaft coupling member 40 is disposed on the radially inner side of the three stepped pinions 33. Here, “the radially inner side of the stepped pinion 33” is a region surrounded by the three stepped pinions 33 and is a position overlapping the axial position of the stepped pinion 33. In particular, here, one end of the shaft coupling member 40 is disposed on the radially inner side of the small-diameter pinion portion 33b meshed with the ring gear 32 of the stepped pinion 33.

The shaft connecting member 40 has a first connecting portion 41 made of serration on one outer peripheral surface of the electric motor 20 side, and a second connection made of serration on the other outer peripheral surface of the wheel 50 side. A portion 42 is provided.
The first connecting portion 41 is engaged with and coupled to a first connecting portion 34aA formed on the inner peripheral surface of the carrier body 34a of the carrier 34. The second connecting portion 42 is engaged with and coupled to the second connecting portion 53 formed on the inner peripheral surface of the opening 52 a of the hub shaft 52.

  Next, “the configuration and problems of the axle coupling structure of the comparative example” will be described, and subsequently, the functions of the axle coupling structure of the first embodiment will be referred to as “axial displacement absorbing action”, “shaft length shortening action”, “oil lubricating action” "And" diameter size expansion inhibiting action "will be described separately.

[Configuration and issues of axle connection structure of comparative example]
FIG. 4 is an enlarged view showing a main part of the in-wheel motor unit to which the axle connecting structure of the comparative example is applied.

  Generally, an axle that rotates integrally with a wheel is connected to or integrated with a drive source output shaft that is rotated by a drive source such as an electric motor, and rotates as the drive source output shaft rotates. On the other hand, the axle is rotatably supported by a vehicle body side member that is swingably attached to a vehicle body such as a trailing arm via a hub bearing.

  Here, for example, when an excessive external force is input to the hub bearing via the wheel, an indentation is generated on the rolling element raceway surface of the hub bearing. Further, when muddy water or salt water enters the inside of the hub bearing, that is, between the outer member and the inner member, rust is generated on the rolling element starting surface. Then, although the indentation and rust cause separation on the rolling element raceway surface, abnormal noise and vibration increase when traveling is continued without sensing this separation. Further, if the vehicle continues to run after that, the rolling elements are worn out and rattling occurs in the hub bear rig, and the axle is tilted or swung around. And it is assumed that a malfunction occurs in the drive source output shaft or the like due to the inclination of the axle or the like.

  Therefore, a shaft connection structure capable of absorbing rattling is interposed between the driving source rotating shaft that rotates by the driving source and the axle, and the driving source output is maintained even if the axle tilts due to rattling generated in the hub bearing. A configuration is conceived in which this inclination is not transmitted to the shaft. The “shaft connection structure capable of absorbing rattling” is, for example, a CVJ (Constant Velocity Joint) structure, a rubber coupling structure, a gear coupling structure, or the like.

  Here, the gear coupling structure 100 includes, for example, as shown in FIG. 4, a first rotating member 101, a second rotating member 102, and a connecting cylindrical member 103.

  The first rotating member 101 is connected to the tip of the carrier 34 of the speed reducer 30 and can rotate integrally with the carrier 34. On the outer peripheral surface of the first rotating member 101, first gear teeth 101a arranged in the circumferential direction are formed. The first gear teeth 101a are subjected to crowning processing in which the tooth tip is curved along the axial direction and is chamfered and the center of the tooth surface becomes a middle height.

  The second rotating member 102 is formed integrally with an end portion of a hub shaft 52 that rotates integrally with a wheel (not shown here), and can rotate integrally with the hub shaft 52. Second gear teeth 102 a arranged in the circumferential direction are formed on the outer peripheral surface of the second rotating member 102. The second gear teeth 102a are crowned in which the tooth tip is curved along the axial direction, chamfered, and the center of the tooth surface becomes a middle height.

  The connecting cylindrical member 103 is a cylindrical body whose both ends are open. A first connecting portion 103a that serration-couples with the first gear teeth 101a is formed at one end of the inner peripheral surface, and a first connecting portion 103a is formed at the other end of the inner peripheral surface. A second connecting portion 103b that is serrated and connected to the two gear teeth 102a is formed.

  In the gear coupling structure 100, since the first gear teeth 101a and the second gear teeth 102a are each toothed, even if the relative positions of the carrier 34 and the hub shaft 52 are displaced, The displacement can be absorbed by the gear coupling structure 100. That is, as the carrier 34 and the hub shaft 52 are displaced, the contact surface between the first gear teeth 101a and the first connecting portion 103a is inclined, or the contact surface between the second gear teeth 102a and the second connecting portion 103b is changed. Tilt.

However, in the axle coupling structure using the gear coupling structure 100 shown in FIG. 4, the reduction gear 30 and the gear coupling structure 100 serving as the axle coupling structure and the hub shaft 52 are arranged in series along the axial direction. ing. That is, the reduction gear 30 and the gear coupling structure 100 are sequentially arranged in the axial direction between the second rotor bearing 23B that supports the rotor rotation shaft 22a and the rolling elements 55 that constitute the hub bearing that supports the hub shaft 52. Therefore, the axial length (axial length) from the second rotor bearing 23 </ b> B to the rolling element 55 is increased by the amount of the gear coupling structure 100 interposed.
In particular, in the in-wheel motor unit MU in which the electric motor 20 as a driving source is disposed inside the wheel 51, the electric motor 20 protrudes greatly from the wheel 51 when the axial length becomes long, and the in-wheel motor unit MU The problem of not being appropriate arises.

  Further, in this gear coupling structure 100, in order to facilitate the coupling between the first rotating member 101 and the connecting cylindrical member 103 and the coupling between the second rotating member 102 and the connecting cylindrical member 103, It is necessary to perform grease lubrication in which grease is sealed. Therefore, grease has to be supplied periodically, and there is a problem of grease maintenance.

  Further, in the gear coupling structure 100, the connecting cylindrical member 103 is configured to cover the outer peripheral surfaces of the first rotating member 101 and the second rotating member 102. Therefore, when the contact surface between the first gear teeth 101a and the first connecting portion 103a is inclined, or when the contact surface between the second gear teeth 102a and the second connecting portion 103b is inclined, the connecting cylindrical member 103 is in the radial direction. Tilt outward. Therefore, a clearance for displacing the connecting cylindrical member 103 to the outer periphery is required, and there is a problem that the radial dimension is increased.

[Absorption of axis deviation]
In the in-wheel motor unit MU according to the first embodiment, excessive external force is input or muddy water enters the hub bearing outer member 13 that holds the hub shaft 52, the wheel hub 54, and the hub bearing that includes a plurality of rolling elements 55. Consider a case where rattling occurs in the hub bear rig and the hub shaft 52 tilts or swings.

  At this time, as for the 2nd connection part 53 of the hub axis | shaft 52, while the front-end | tip of a convex part curves in the protrusion direction along an axial direction, it is chamfered along the axial direction. Furthermore, the side surface in the axial direction is subjected to a so-called crowning process with a middle height. Therefore, the second connection portion 53 meshes with the second connection portion 42 of the shaft connection member 40 that is serrated and coupled with a gap.

  As a result, even if the hub shaft 52 is tilted, the contact position of the second connecting portion 53 with respect to the second connecting portion 42 varies according to the tilt, and tilt or deviation is transmitted to the shaft connecting member 40. Absent. That is, the contact portion between the second connection portion 53 and the second coupling portion 42 can absorb the inclination and deviation of the hub shaft 52.

  In addition, the first connection portion 34aA formed on the carrier body 34a serrated with the first connection portion 41 of the shaft connection member 40 is also curved in the protruding direction along the axial direction, and the axial direction Chamfered along. Furthermore, the side surface in the axial direction is subjected to a so-called crowning process with a middle height. Therefore, the first connecting portion 34aA meshes with the first connecting portion 41 of the shaft connecting member 40 that is serrated and connected with a gap.

  As a result, the contact position of the first connecting portion 34aA can also be changed with respect to the first connecting portion 41, and the inclination and displacement of the shaft connecting member 40 are not transmitted to the carrier 34. That is, the inclination and deviation of the hub shaft 52 can also be absorbed at the contact portion between the first connecting portion 34aA and the first connecting portion 41.

  As a result, even if the hub shaft 52 that is an axle is tilted or swung due to an abnormality occurring in the hub bearing, it is between the hub shaft 52 and the shaft coupling member 40 and between the shaft coupling member 40 and the carrier 34. This inclination or the like can be prevented from being absorbed and transmitted to the carrier 34.

[Axis length shortening action]
As shown in FIGS. 2 and 3, in the axle coupling structure of the first embodiment, the shaft coupling member 40 that couples the carrier 34 and the hub shaft 52 is disposed on the radially inner side of the stepped pinion 33.
Here, in the three stepped pinions 33, the large-diameter pinion portion 33 a meshes with the sun gear 31, and the small-diameter pinion portion 33 b meshes with the ring gear 32. That is, the rotor rotating shaft 22a formed with the sun gear 31 is inserted inside the large-diameter pinion portion 33a, but it is not necessary to insert the rotor rotating shaft 22a inside the small-diameter pinion portion 33b that meshes with the ring gear 32. . Therefore, the shaft connecting member 40 is disposed in a so-called dead space, which is a radially inner position of the small-diameter pinion portion 33b of the stepped pinion 33 that does not require the rotor rotating shaft 22a to be inserted.

  As a result, the shaft connecting member 40 overlaps with the small-diameter pinion portion 33b of the stepped pinion 33 in the axial direction, and the hub bearing that supports the hub shaft 52 from the second rotor bearing 23B that supports the rotor rotating shaft 22a. The axial length to the rolling element 55 which comprises can be shortened with respect to the axle connection structure of a comparative example.

  In particular, when the axle connection structure of the present invention is applied to the in-wheel motor unit MU in which the electric motor 20 as a driving source is arranged inside the wheel 51 as in the first embodiment, the axial length can be shortened. It becomes difficult for the electric motor 20 to protrude from the wheel 51, and it can be made appropriate as the in-wheel motor unit MU.

[Oil lubrication]
FIG. 5 is an explanatory diagram illustrating a lubricating oil flow path in the axle coupling structure of the first embodiment.

  In the in-wheel motor unit MU of the first embodiment, oil is sealed in the motor case 10 in order to cool the electric motor 20 and lubricate the speed reducer 30.

  This cooling / lubricating oil is normally supplied from the end of the rotor rotating shaft 22a on the cover 12 side by an oil pump (not shown) and flows through the rotor oil passage 22d. Here, the rotor oil passage 22d passes through the rotor rotation shaft 22a and is opened at the end of the rotor rotation shaft 22a on the wheel 50 side supported by the second rotor bearing 23B. Further, since the second rotor bearing 23 </ b> B is fitted on the inner peripheral surface of the carrier 34, the rotor oil passage 22 d opens to the inside of the carrier 34.

  As a result, the oil that has flowed through the rotor oil passage 22 d flows into the inside of the carrier 34. At this time, since the shaft connecting member 40 is connected to the inside of the carrier 34, the oil flowing from the rotor oil passage 22 d flows into the shaft connecting member 40 and then from both ends of the shaft connecting member 40. Flows out. The oil flows between the shaft connecting member 40 and the carrier 34 and between the shaft connecting member 40 and the hub shaft 52 and flows into the carrier oil passage 34f formed in one carrier plate 34b. The oil that has flowed into the carrier oil passage 34f lubricates the bearing 34i that rotatably supports the stepped pinion 33.

  In this way, the oil that cools the electric motor 20 and lubricates the reduction gear 30 flows between the rotor oil passage 22d and the carrier oil passage 34f, and between the shaft coupling member 40 and the carrier 34 and the shaft. It passes between the connecting member 40 and the hub shaft 52. As a result, the shaft connecting member 40 is disposed on a lubrication path of oil that lubricates from the inside of the rotor rotation shaft 22a to the stepped pinion 33.

  Therefore, the oil is lubricated between the shaft connecting member 40 and the carrier 34 and between the shaft connecting member 40 and the hub shaft 52 by this oil. As a result, the existing lubrication mechanism can be used effectively, and maintenance of the lubricating grease becomes unnecessary.

[Inhibition of diameter expansion]
FIGS. 6A and 6B are explanatory views for explaining the rattling absorption action in the axle connection structure, in which FIG. 6A schematically shows the main part of the axle connection structure of the comparative example, and FIG. 6B is the axle connection of the first embodiment. The principal part of a structure is shown typically.

  As shown in FIG. 6 (a), in the axle connecting structure of the comparative example, the connecting cylindrical member 103 is arranged outside the first rotating member 101 and the second rotating member 102 arranged coaxially.

  Therefore, when the positions of the first and second rotating members 101 and 102 are relatively displaced, the connecting cylindrical member 103 disposed on the outer side is inclined toward the outer side in the radial direction. As a result, a clearance for tilting the connecting cylindrical member 103 is required in the radially outer region of the connecting cylindrical member 103 (the portion surrounded by the broken line in FIG. 6A).

  On the other hand, as shown in FIG. 6 (b), in the axle coupling structure of the first embodiment, the shaft coupling member 40 has a first connection portion formed on the inner circumferential surface of the carrier 34 on the outer circumferential surface of one end. It has the 1st connection part 41 connected with 34aA, and has the 2nd connection part 42 connected with the 2nd connection part 53 formed in the inner peripheral surface of the hub shaft 52 in the other end part outer peripheral surface. In other words, the shaft coupling member 40 is arranged inside the carrier 34 and the hub shaft 52 arranged coaxially.

  Therefore, when the positions of the carrier 34 and the hub shaft 52 are relatively displaced, the shaft coupling member 40 disposed on the inner side is inclined toward the inner side in the radial direction. Thereby, a clearance for tilting the shaft connecting member 40 is required in a radially inner region of the shaft connecting member 40 (a portion surrounded by a broken line in FIG. 6B).

  For this reason, in the axle connection structure of the first embodiment, the space in the radially inner region of the carrier 34 and the hub shaft 52 can be effectively used, and no clearance is required in the radially outer region of the carrier 34 and the hub shaft 52. Thereby, it can prevent that the radial direction dimension of the whole axle connection structure expands.

  In the axle coupling structure of the first embodiment, the shaft coupling member 40 is disposed on the radially inner side of the stepped pinion 33, so that the shaft coupling member 40 is disposed at a position shifted in the axial direction from the electric motor 20. Therefore, the shaft coupling member 40 having a structure that absorbs the inclination and rattling of the hub shaft 52 can be provided without increasing the radial dimension of the electric motor 20.

Next, the effect will be described.
In the axle connection structure of the first embodiment, the following effects can be obtained.

(1) a drive source output shaft (rotor rotation shaft) 22a rotated by a drive source (electric motor) 20,
An axle (hub shaft) 52 disposed coaxially with the drive source output shaft 22a and rotating integrally with the wheel 50;
A plurality of pinion gears (stepped pinion gears) 33 and a planetary carrier (carrier) 34 that rotatably supports the plurality of pinion gears 33, and the rotation from the drive source output shaft 22 a via the planetary carrier 34. A planetary gear type transmission (reduction gear) 30 that transmits the transmission to the axle 52;
A shaft connecting member 40 that is disposed radially inside the plurality of pinion gears 33 and connects the planetary carrier 34 and the axle 52;
It was set as the structure provided with.
For this reason, shortening of the axial direction length of the whole axle connection structure can be achieved.

(2) The shaft connecting member 40 is configured to be disposed on an oil lubrication path for lubricating from the inside of the drive source output shaft 22a to the plurality of pinion gears 33.
For this reason, the existing lubrication mechanism can be used effectively and maintenance of the lubricating grease is not required.

(3) The shaft connecting member 40 has a first connecting portion 41 connected to an inner peripheral surface of the planetary carrier 34 on one end outer peripheral surface, and an inner peripheral surface of the axle on the other end outer peripheral surface. It has the structure which has the 2nd connection part 42 connected to.
For this reason, it can prevent that the radial direction dimension of the whole axle connection structure expands.

  As described above, the axle connecting structure of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to this embodiment, and the gist of the invention according to each claim of the claims is described. Unless it deviates, design changes and additions are allowed.

  In the first embodiment, the example in which the axle coupling structure of the present invention is applied to the in-wheel motor unit MU is shown, but the present invention is not limited to this. If the vehicle has a drive source output shaft that is rotated by a drive source, an axle that is arranged coaxially with the drive source output shaft and rotates integrally with the wheels, and a planetary gear type transmission that is disposed therebetween, The present invention can be applied to general vehicles such as an engine vehicle, a hybrid vehicle, and an electric vehicle that is driven by a single drive motor. That is, the drive source is not limited to the electric motor 20.

Further, although the reduction gear 30 is used as the planetary gear type transmission, the planetary gear type transmission has a function of a so-called forward / reverse switching device that reverses the rotation of the drive source output shaft and transmits it to the axle, for example. It may be a planetary gear type transmission having a plurality of planetary gear sets.
Further, although the stepped pinion 33 is used as the pinion gear of the first embodiment, the pinion gear diameter of the portion meshing with the sun gear 31 is the same as the pinion gear diameter of the portion meshing with the ring gear 32. May be.

  Even in this case, the axial length of the shaft coupling structure can be shortened by arranging the shaft coupling member 40 on the radially inner side of the portion meshing with the ring gear 32.

DESCRIPTION OF SYMBOLS 10 Motor case 11 Case main body 12 Cover 13 Hub bearing outer member 20 Electric motor (drive source)
22a Rotor rotation shaft (drive source output shaft)
30 Reducer (Planetary gear type transmission)
33 Stepped pinion (pinion gear)
33a Large-diameter pinion portion 33b Small-diameter pinion portion 34 Carrier (planetary carrier)
34a Carrier body 34aA First connecting portion 40 Shaft connecting member 41 First connecting portion 42 Second connecting portion 50 Wheel 51 Wheel 52 Hub axle (axle)
53 Second connection

Claims (3)

A drive source output shaft rotated by a drive source;
An axle disposed coaxially with the drive source output shaft and rotating integrally with the wheel;
A planetary gear type transmission that includes a plurality of pinion gears and a planetary carrier that rotatably supports the plurality of pinion gears, and transmits rotation from the drive source output shaft to the axle via the planetary carrier;
A shaft connecting member that is disposed radially inward of the plurality of pinion gears and whose axial position overlaps with the axial position of the plurality of pinion gears, and connects the planetary carrier and the axle;
An axle connecting structure characterized by comprising: In the axle connecting structure according to claim 1,
The axle coupling structure is characterized in that the shaft coupling member is arranged on an oil lubrication path for lubricating from the inside of the drive source output shaft to the plurality of pinion gears. In the axle connecting structure according to claim 1 or 2,
The shaft connecting member has a first connecting portion connected to the inner peripheral surface of the planetary carrier on one end outer peripheral surface, and a second connection connected to the inner peripheral surface of the axle on the other outer peripheral surface. An axle connecting structure characterized by having a portion.