JP2005076808A - Gear joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To resolve a problem in a conventional gear joint wherein lubricant leaked from a joint of a sleeve and an end cover since the end cover is attached to the sleeve. <P>SOLUTION: The gear joint is provided with a pinion 5 provided with an external gear 5a coupled to a first rotary shaft 3, and an internal gear 9a meshing with the external gear 5a of the pinion 5, and it has a sleeve 9 having openings in end faces of both sides, receiving the pinion 5 from at least one opening into an interior, and coupled to a second rotary shaft 4. The gear joint is provided with a first end member 8 blocking the opening of the sleeve 9 in an end face in a side of the first rotary shaft, and having a rotary shaft hole 8a for passing the first rotary shaft 3, and a second end member 11 blocking the opening in another end face of the sleeve 9, and the sleeve 9, the first end member 8, and the second end member 11 compose a space capable of holding the lubricant 10. The sleeve 9 and the first end member 8, or the sleeve 9 and the second end member 11 are integrally machined. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gear joint used for transmitting a rotational driving force.

In a conventional gear joint including a pinion provided with an external gear and a sleeve provided with an internal gear, a sleeve having openings on both end faces has been used. The opening on one end surface was closed by an end cover having a rotation shaft hole through which the rotation shaft passes, and the opening on the other end surface was also closed by a member. At least one of the openings is sized to allow the pinion to enter the sleeve. A mechanism for preventing the lubricant from leaking was provided at the joint between the sleeve and the member closing the opening. (For example, see Patent Document 1)
The method of attaching the pinion to the rotating shaft is generally by shrink fitting. Since the pinion cannot be put in the sleeve at the time of shrink fitting, the gear joint is assembled by the following procedure. First, the pinion is attached to the rotary shaft by shrink fitting with the rotary shaft passing through the rotary shaft hole of the end cover. Next, a pinion is put in the sleeve and the gear is engaged. Then, the end cover is attached to the sleeve. Finally, the opening at the other end face of the sleeve is closed.

JP-A-7-286622

In a conventional gear joint comprising a pinion provided with an external gear and a sleeve provided with an internal gear, there are openings on both end faces of the sleeve, and the lubricant leaks at the joint between the sleeve and the member that closes the opening. As a mechanism for preventing this was provided, there were the following problems.
(1) It is difficult to adjust the mechanism for preventing the lubricant at the joint portion between the sleeve and the member that closes the opening from leaking, and the lubricant sometimes leaks.
In addition, since the end cover has a rotation shaft hole through which the rotation shaft passes, there are the following problems.
(2) A substance (referred to as a deteriorated substance) that deteriorates the lubricant such as dust and water easily enters the inside of the gear joint from the rotation shaft hole through which the rotation shaft in the end cover passes, and deteriorates the lubricant quickly. The deteriorated substance can be any of solid, liquid, and gas.

The present invention has been made to solve the above-mentioned problems, and prevents the lubricant from leaking or prevents deterioration of the lubricant by preventing deterioration substances from entering the sleeve. The purpose is to facilitate maintenance of the lubricant.
If the lubricant leaks and the amount is insufficient or deteriorates to deteriorate the lubrication performance, there is a high possibility that the gear of the gear joint is damaged. If the gear is damaged, the power equipment provided with the gear joint for repair or replacement cannot be used for a long time. Gear joints are widely used in transportation such as trains, construction equipment such as cranes, heavy machinery used in factories, and the like. If these equipments can no longer be used, it has a great social impact. Therefore, facilitating maintenance of the gear joint lubricant for keeping the gear joint in a normal state is an important issue in the industry.

  A gear joint according to the present invention includes a pinion provided with an external gear coupled to a first rotating shaft, and an internal gear that meshes with the external gear of the pinion, and has openings on both end surfaces and at least one of the gears. The pinion is inserted through the opening, the sleeve coupled to the second rotation shaft, and the opening on the end surface on the side through which the first rotation shaft of the sleeve passes, and the rotation through the first rotation shaft A first end member having a shaft hole; and a second end member that closes the opening on the other end surface of the sleeve, the sleeve, the first end member, and the second end member. In the gear joint constituting the space in which the lubricant can be held, the sleeve and the first end material, or the sleeve and the second end material are integrally processed.

  In addition, a pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is internally provided from at least one opening with openings on both end faces. And a sleeve coupled to the second rotation shaft, and a first shaft having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that blocks the opening on the other end surface of the sleeve, and the sleeve, the first end member, and the second end member can hold the lubricant. In the gear joint constituting the space, a groove having a gradient in which the diameter increases toward the outer side of the axis is provided around the outside of the rotation shaft hole.

  Furthermore, a pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is internally provided from at least one opening with openings on both end faces. And a sleeve coupled to the second rotation shaft, and a first shaft having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that blocks the opening on the other end surface of the sleeve, and the sleeve, the first end member, and the second end member can hold the lubricant. In the gear joint constituting the space, the inner peripheral surface of the rotation shaft hole is provided with a gradient that increases in diameter toward the outer side of the axis.

  Furthermore, a pinion provided with an external gear coupled to the first rotation shaft, and an internal gear meshing with the external gear of the pinion are provided, and the pinion is opened from at least one of the openings having openings on both end faces. A sleeve that is inserted inside and is coupled to the second rotation shaft, and a rotation shaft hole that closes the opening on the end surface on the side through which the first rotation shaft passes and passes the first rotation shaft. 1 end material and a second end material closing the opening on the other end surface of the sleeve, and the sleeve, the first end material, and the second end material hold lubricant. In the gear joint that constitutes the space that can be formed, the surface that faces the inner peripheral surface of the rotation shaft hole is provided with a gradient that increases in diameter toward the outer side of the axis.

  Further, a pinion provided with an external gear coupled to the first rotating shaft, and an internal gear meshing with the external gear of the pinion are provided, and the pinion is opened from at least one of the openings having openings on both end faces. A sleeve that is inserted inside and is coupled to the second rotation shaft, and a rotation shaft hole that closes the opening on the end surface on the side through which the first rotation shaft passes and passes the first rotation shaft. 1 end material and a second end material closing the opening on the other end surface of the sleeve, and the sleeve, the first end material, and the second end material hold lubricant. In the gear joint constituting the space that can be formed, a circumferential groove is provided on a surface facing the inner peripheral surface of the rotary shaft hole.

  A gear joint according to the present invention includes a pinion provided with an external gear coupled to a first rotating shaft, and an internal gear that meshes with the external gear of the pinion, and has openings on both end surfaces and at least one of the gears. The pinion is inserted through the opening, the sleeve coupled to the second rotation shaft, and the opening on the end surface on the side through which the first rotation shaft of the sleeve passes, and the rotation through the first rotation shaft A first end member having a shaft hole; and a second end member that closes the opening on the other end surface of the sleeve, the sleeve, the first end member, and the second end member. Since the sleeve and the first end material or the sleeve and the second end material are integrally processed in the gear joint that constitutes a space in which the lubricant can be held, the one end material and the sleeve The effect that the lubricant does not leak from the joint. There.

  In addition, a pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is internally provided from at least one opening with openings on both end faces. And a sleeve coupled to the second rotation shaft, and a first shaft having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that blocks the opening on the other end surface of the sleeve, and the sleeve, the first end member, and the second end member can hold the lubricant. In the gear joint constituting the space, since a groove with a gradient that increases in diameter toward the outer side of the axis is provided around the outer side of the rotation shaft hole, the deteriorated substance is transmitted along the outer surface of the sleeve to the gear joint. There is an effect of preventing the inside of the.

  Furthermore, a pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is internally provided from at least one opening with openings on both end faces. And a sleeve coupled to the second rotation shaft, and a first shaft having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that blocks the opening on the other end surface of the sleeve, and the sleeve, the first end member, and the second end member can hold the lubricant. In the gear joint constituting the space, the inner peripheral surface of the rotary shaft hole is provided with a gradient in which the diameter increases toward the outer side of the axis, so that the deteriorated substance is transmitted along the surface of the inner peripheral surface of the rotary shaft hole. There is an effect of preventing the inside of the.

  Furthermore, a pinion provided with an external gear coupled to the first rotation shaft, and an internal gear meshing with the external gear of the pinion are provided, and the pinion is opened from at least one of the openings having openings on both end faces. A sleeve that is inserted inside and is coupled to the second rotation shaft, and a rotation shaft hole that closes the opening on the end surface on the side through which the first rotation shaft passes and passes the first rotation shaft. 1 end material and a second end material closing the opening on the other end surface of the sleeve, and the sleeve, the first end material, and the second end material hold lubricant. In the gear joint constituting the space that can be formed, the surface facing the inner peripheral surface of the rotation shaft hole is provided with a gradient in which the diameter increases toward the outer side of the axis. Prevents deteriorating substances from entering the inside of the gear joint through the surface. Effect there.

  Further, a pinion provided with an external gear coupled to the first rotating shaft, and an internal gear meshing with the external gear of the pinion are provided, and the pinion is opened from at least one of the openings having openings on both end faces. A sleeve that is inserted inside and is coupled to the second rotation shaft, and a rotation shaft hole that closes the opening on the end surface on the side through which the first rotation shaft passes and passes the first rotation shaft. 1 end material and a second end material closing the opening on the other end surface of the sleeve, and the sleeve, the first end material, and the second end material hold lubricant. In the gear joint that constitutes the space that can be formed, the circumferential groove is provided on the surface facing the inner peripheral surface of the rotation shaft hole, so that a deteriorated substance that moves in the space is prevented from entering the gear joint. There is an effect.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a part of the entire structure of a gear joint according to Embodiment 1 of the present invention. This gear joint connects between the drive motor 1 and the reduction gear device 2 of the railway vehicle. More specifically, it is a gear joint that connects between the drive rotary shaft 3 driven by the drive motor 1 and the driven rotary shaft 4 of the reduction gear device 2. This gear joint is substantially symmetrical on the left and right. FIG. 2 shows an enlarged view of the left drive motor 1 side in FIG. Hereinafter, the drive rotary shaft 3 or the driven rotary shaft 4 may be simply referred to as a rotary shaft for the sake of simplicity.
Since it will be described on the side of the driving motor 1, it is assumed that the drive rotating shaft 3 is a first rotating shaft and the driven rotating shaft 4 is a second rotating shaft. When viewed from the reduction gear device 2 side, the driven rotary shaft 4 is the first rotary shaft, and the drive rotary shaft 3 is the second rotary shaft.

A pinion 5 is fixed to the drive rotary shaft 3 and the driven rotary shaft 4 by a shaft end nut 6. On the outer periphery of the pinion 5, an external gear 5 a having a crowned tooth is formed. The two pinions 5 have the same size and the same shape, and the shape of the external gear 5a is also the same. The drive rotary shaft 3 and the driven rotary shaft 4 are inserted into the joint body 7.
Here, the term “crowning” refers to processing the gear teeth so that the central portion in the streak direction is convex. The purpose of crowning the teeth of the external gear 5a is to function as a gear joint even if the positions and axial directions of the drive rotary shaft 3 and the driven rotary shaft 4 are deviated. A gear joint that can transmit power even when the position and the axial direction of the rotating shaft are shifted is generally called a flexible gear joint.

  The first embodiment is a flexible gear joint because the present invention is applied to a gear joint used on an axle of a railway vehicle. The reason is as follows. In the railway vehicle, the drive motor 1 is disposed on the bogie frame, and the reduction gear device 2 is disposed on the axle. Since the track has curves and gradients, the positional relationship between the bogie frame and the axle is often shifted, and the positions and directions of the axes of the drive rotary shaft 3 and the driven rotary shaft 4 are often shifted. It is necessary to use a flexible joint so that power can be transmitted even if the position and the axial direction of the rotating shaft are shifted.

The joint body portion 7 has a cylindrical shape, and end covers 8 that close the openings on both sides of the cylinder are provided on both end surfaces of the joint body portion 7. Each end cover 8 has one rotation shaft hole 8a, and the drive rotation shaft 3 or the driven rotation shaft 4 to which the pinion 5 is fixed is inserted into the rotation shaft hole 8a.
The joint body 7 has two sleeve members 7a formed by integrally processing the sleeve 9 and the end cover 8, and the end surfaces on the side without the end cover 8 are overlapped with each other, like a cap collar on this end surface. The part with the increased diameter is assembled by fixing with a predetermined number of bolts 7b and nuts 7c. The two sleeve members 7a have the same shape. The outer shape of the sleeve member 7a is cylindrical, the cylindrical portion is a sleeve 9 having openings on both end faces, and an end cover 8 that closes one end face is a first end member in the present invention.

  The sleeve member 7 a is obtained by integrally processing the end cover 8 and the sleeve 9. Here, the integral processing in this specification is defined as integral processing so that separation is not possible. As an integral processing method, processing may be performed from one material, or the end cover 8 and the sleeve 9 may be processed separately and joined by welding or brazing. Any method may be used as long as it can be integrally processed so that it cannot be separated. However, it must be in close contact so that the lubricant inside the joint does not leak due to centrifugal force.

An internal gear 9 a is formed inside the sleeve 9. The internal gear 9a meshes with the external gear 5a of the pinion 5 described above. The end surface of the sleeve 9 on the side without the end cover 8 has an opening having the same diameter as the inner diameter of the sleeve 9, and this opening becomes a pinion receiving hole 9b.
The meshing portion of the external gear 5a and the internal gear 9a is filled with grease 10 as a lubricant. A lubricant other than grease 10 may be used as a lubricant. An appropriate type of lubricant may be selected in consideration of the operating environment such as the gear joint material and the operating temperature.

When viewed from the meshing portion of the external gear 5a of the pinion 5 and the internal gear 9a of the sleeve 9 on the drive motor 1 side, the pinion 5 is coupled to the drive rotary shaft 3 which is the first rotary shaft, and the sleeve 9 Is coupled to the driven rotary shaft 4 as the second rotary shaft via another set of sleeve 9 and pinion 5.
The end cover 8 has a circular rotation shaft hole 8a whose center coincides with the axis of the internal gear 9a. The outer periphery of the rotation shaft hole 8a of the end cover 8 has a predetermined length in a short cylindrical shape. On the peripheral surface of the protruding portion, there is a groove 8b having a gradient whose diameter increases toward the outside of the axis of the rotating shaft (on the side of the driving motor 1). The angle of the groove 8b with respect to the X axis parallel to the rotation axis is an angle θA as shown in FIG.

  A center plate 11 as a second end member is fitted in the pinion receiving hole 9b, and the inside of the joint main body portion 7 is divided into left and right by the center plate 11. Each of the pinions 5 attached to the rotating shaft is placed in the space partitioned to the left and right. As described above, the position and the axial direction of the rotating shaft may be shifted, and even if the position of the rotating shaft is shifted, the shaft end nut 6 does not contact the center plate 11 and the center plate 11 is not damaged. A circular elastic cushion 12 is attached to the end nut 6.

The pinion receiving hole 9b of the sleeve 9 is closed by the center plate 11, and the end cover 8 is provided on the other end surface of the sleeve 9. Therefore, the sleeve 9, the center plate 11 and the end cover 8 are connected to the inside of the sleeve member 7a. Constitutes a space in which the grease 10 can be held. Since the sleeve 9 and the end cover 8 are integrally processed, the joint where the grease 10 may leak is only the joint between the center plate 11 and the sleeve 9. As shown in FIG. 2, an O-ring 13 is inserted as a sealing material at the joint between the center plate 11 and the sleeve 9 in order to prevent the grease 10 from leaking from the joint. In FIG. 1, the illustration of the O-ring 13 that is a sealing material is omitted to avoid the complexity of the drawing.
As long as the grease 10 can be held inside the sleeve member 7a, the center plate 11 may have a through hole. If the through hole is large enough to prevent the shaft end nut 6 from coming into contact, the cushion 12 is not necessary.

The inner peripheral surface 8c of the rotation shaft hole 8a has a length enough to enter the inside of the internal gear 9a in the axial direction. In order to increase the length of the inner peripheral surface 8c of the rotary shaft hole 8a in this way, a cylindrical cylindrical portion 8d is provided on the inner side of the axis around the rotary shaft hole 8a (on the side other than the drive motor 1). The side surface of the pinion 5 has a recess 5b that opens outward from the axis, and the cylindrical portion 8d enters the recess 5b from the outer side of the axis.
About half of the inner peripheral surface 8c of the rotating shaft hole 8a close to the outer side of the axis has a gradient that increases in diameter toward the outer side of the axis at an angle θB with respect to the X axis parallel to the rotating shaft, as shown in FIG. It is attached. The half near the inner side of the axis is also provided with a gradient that increases in diameter toward the inner side of the axis. Note that the gradient is smaller in the half closer to the inner side of the axis.

The space between the inner peripheral surface 8c of the rotation shaft hole 8a and the outer peripheral surface 5c of the pinion 5 facing the rotation shaft hole 8a is narrowed to form a narrow portion. The length of the narrow portion is substantially equal to the length of the inner peripheral surface 8c of the rotation shaft hole 8a.
One or more predetermined numbers (three in this embodiment) of grooves 5d are formed on the outer peripheral surface 5c of the pinion 5 that faces the portion of the inner peripheral surface 8c of the rotation shaft hole 8a that is inclined at the angle θB. There is. The side surfaces on both sides of the groove 5d are inclined at the same angle θC with respect to the X axis, and the bottom is rounded. Therefore, the diameter of the side surfaces on both sides of the groove 5d increases toward the outside of the axis.

  This gear joint is assembled as follows. The pinion 5 is inserted into the sleeve member 7a from the pinion receiving hole 9b, and the pinion 5 is passed through the rotation shaft hole 8a. A rotary shaft is press-fitted into the pinion 5 inside the sleeve member 7 a by hydraulic pressure or the like, and is fixed by a shaft end nut 6. The center plate 11 is fitted into the pinion receiving hole 9b, the two sleeve members 7a are overlapped, and the bolt 7b and the nut 7c are fastened and assembled.

  Now, the description of the structure is finished and the operation will be described. First, the operation for preventing the lubricant from leaking will be described. In a state where the gear joint is not rotating, the grease 10 is accumulated on the bottom surface inside the sleeve member 7a. Since the fluidity of the grease 10 is low, a part of the grease 10 is also attached to the meshing portion of the external gear 5a and the internal gear 9a. In the state where the gear joint rotates, the centrifugal force works, and the grease 10 is filled to the inner surface of the sleeve member 7a with a substantially uniform thickness, and the grease 10 is evenly applied to the meshing portion of the external gear 5a and the internal gear 9a. Go around. 1 and 2 represent the state when rotating.

Since the grease 10 is subjected to centrifugal force, it tries to leak out from the joint of the sleeve 9 or the like. However, since the joint of the sleeve 9 is only the joint with the center plate 11, the leakage can be reduced. That is, since the end cover 8 which is the first end material is integrally formed with the sleeve 9, there is no joint between the end cover 8 and the sleeve 9, so that the grease 10 does not leak from this portion. There is an effect that the assembly work for attaching the end cover 8 to the sleeve 9 becomes unnecessary, and in addition, since there is no joint between the end cover 8 and the sleeve 9, it is possible to prevent leakage of the lubricant attached between the two. Parts such as rings and gaskets are also unnecessary.
By integrally processing the end cover 8 and the sleeve 9, the shape of the end of the gear joint can be simplified, the gear joint can be made compact, and the weight can be reduced. As a result, the rotation balance of the gear joint is improved, and noise and vibration are reduced.

Next, an operation for preventing a deteriorated substance from entering the inside of the gear joint will be described. To that end, first, consider the path through which the deteriorating material enters the gear joint. FIG. 3 is a diagram for explaining a path through which the deteriorated substance enters. The path of the deteriorated substance intrusion is spatially outside the gear joint (referred to as external space A), and the rotary shaft hole 8a of the end cover 8. And the pinion 5 (referred to as a connecting space B) and the inside of the sleeve 9 (referred to as an internal space C). The connection space B is from end to end of the inner peripheral surface 8c of the rotation shaft hole 8a. The internal space C is a space inside the sleeve 9 other than the connection space B.
The path through which the deteriorated substance enters can be classified by moving in space (referred to as spatial movement) or moving along the surface of a member constituting the gear joint (referred to as surface movement). Gaseous degradants can only move by space movement, but liquid or solid degradants can move by both space movement and surface movement.

Based on the consideration of the path through which the deteriorated substance enters the inside of the gear joint, measures for preventing the deteriorated substance from entering the inside of the gear joint are classified as follows. However, none of the measures according to the present invention is classified as measure 1B. The measures according to the present invention are mainly measures at the rotating gear joint.
Measure 1A: Prevent surface movement from the external space A to the connection space B.
Countermeasure 1B: Space movement from the external space A to the connection space B is prevented.
Measure 2A: Prevent surface movement from the connection space B to the internal space C.
Measure 2B: Prevent space movement from the connection space B to the internal space C.
FIG. 4 is a diagram for explaining the concept of the countermeasure classification. In FIG. 4, (1a) shows countermeasure 1A, (1b) shows countermeasure 1B, (2a) shows countermeasure 2A, and (2b) shows countermeasure 2B.

  The groove 8b on the side surface of the short cylindrical portion in which the periphery of the rotation shaft hole 8a outside the end cover 8 protrudes by a predetermined length corresponds to the countermeasure 1A. By providing the groove 8b, as will be described later, a force in the axial outward direction acts on the deteriorated substance on the surface of the groove 8b, and the force is splashed outward by receiving this force. That is, the groove 8b has an effect of preventing the deteriorated material entering the groove 8b through the outer surface of the end cover 8 from entering the connecting space B inside the rotary shaft hole 8a.

In order to quantitatively evaluate the force in the axial outward direction (X-axis direction) acting on the deteriorated substance on the surface of the groove 8b, the following variables are defined. The variables that represent the angles that have already been defined are also shown below.
K: Vector of adsorption force on the surface acting on the deteriorated substance. Work perpendicular to the surface.
S: Centrifugal force vector acting on the deteriorated substance. Works perpendicular to the axis of rotation.
H: Vector of reaction force from the surface acting on the deteriorated substance. Work perpendicular to the surface.
G: A vector of synthetic force acting on a deteriorated substance.
θA: the angle of the gradient of the groove 8b with respect to the X axis.
θB: The angle of the gradient of the inner peripheral surface 8c of the rotation shaft hole 8a with respect to the X axis.
θC: An angle of the inclination of the groove 5d with respect to the X axis.

FIG. 5 shows an explanatory diagram of the force acting on the deteriorated substance on the surface of the groove 8b on the outer peripheral surface outside the rotation shaft hole 8a of the end cover 8. As shown in FIG. Here, the following are defined as force components. Note that the Z-axis component in the depth direction, that is, the rotation direction is not considered here. The reason is that it does not relate to the movement of the deteriorated material in the X-axis direction.
p component: a component parallel to the surface. Positive when going to the outside of the axis. The subscript is p.
q component: a component perpendicular to the surface. Positive when moving away from the surface. The subscript is q.
x component: a component parallel to the X axis. Positive when going to the outside of the axis. The subscript is x.
y component: Y-axis component in the height direction. Positive when facing up. The subscript is y.

First, the nature of the force will be briefly explained. The adsorption force K acts on the deteriorated substance perpendicular to the direction toward the surface when the deteriorated substance adheres to the surface of the groove 8b. The centrifugal force S acts on the deteriorated substance in a direction perpendicular to the rotation axis (a direction orthogonal to the X axis at the position of the cross section in FIG. 2) when the deteriorated substance is rotating. The reaction force H is generated by canceling the force when the deteriorated substance is attached to the surface of the groove 8b and the q component of the force obtained by combining other forces is negative, that is, in the direction toward the surface. The q component of the force G acts on the deteriorated substance perpendicular to the direction away from the surface so that the q component becomes zero, that is, Gq = 0.
Since gravity is small compared to other forces, it is not considered in rotating gear joints.

From these, the resultant force G acting on the deteriorated substance is as follows.
(1) When Sq> | K | When reaction force H does not act.
G = S + K (Formula 1)
Gp = Sp = | S | × sin θA (Formula 2)
Gq = Sq + Kq = | S | × cos θA− | K | (Formula 3)
Gx = Kx = | K | × sin θA (Formula 4)
Gy = Sy + Ky = | S | − | K | × cos θA (Formula 5)
(2) When Sq ≦ | K |. When reaction force H acts.
G = S + K + H (Formula 6)
Gp = Sp = | S | × sin θA (Expression 7)
Gq = Sq + Kq + Hq
= | S | × cos θA− | K | + Hq = 0 (Formula 8)

  FIG. 5A shows the case (1) in which the deteriorated substance moves away from the surface of the groove 8b, and FIG. 5B shows the case (2) in which the deteriorated substance moves on the surface of the groove 8b. is there. In either case, the resultant force G has a component of force in the axial outward direction. The deteriorated substance is accelerated in the direction of the synthetic force G and moves. When the deteriorated substance moves, air resistance and resistance due to adsorption force on the surface also act on the deteriorated substance, but are not considered here. Even if there is a resistance, the speed of movement only slows down, and the deteriorated substance moves in the direction of the resultant force G.

  In the case of FIG. 5 (a), the deteriorated substance moves away from the surface of the groove 8b. When the deteriorating substance is subjected to the force (Formula 4) acting until it leaves the surface of the groove 8b, it has a velocity component in the axial outward direction at the time of leaving the surface of the groove 8b. After leaving the surface of the groove 8b, only the centrifugal force S, which is the force in the Y-axis direction, acts on the deteriorated substance, and moves in the axial outward direction while being accelerated in the Y-axis direction. (Expression 4) means that Gx is proportional to the magnitude of the adsorption force | K |, and as the adsorption force K increases, the moving speed of the deteriorated substance in the axial outward direction increases.

In the case of FIG. 5B, the deteriorated substance moves on the surface of the groove 8b. Since Gq = 0, the x component Gx of the resultant force G is obtained from Gp as follows.
Gx = Gp × cos θA = | S | × sin θA × cos θA (Formula 9)
However, (Equation 10) shown below after converting Sq ≦ | K | must also hold.
| S | × cos θA ≦ | K | (Formula 10)
From (Equation 9), Gx is proportional to the magnitude of centrifugal force | S |. When the magnitude of centrifugal force | S | is constant, Gx is maximized when θA is 45 degrees. If the magnitude | size | K | of adsorption | suction force is constant, the case of FIG.5 (b) will be materialized with respect to the centrifugal force S with larger (theta) A near 90 degree | times from (Formula 10). Since the magnitude of the centrifugal force | S | is proportional to the rotational speed, the case of FIG. 5B is a case where the rotational speed is small.
In the first embodiment, the outer periphery of the rotary shaft hole 8a is projected in a short cylindrical shape by a predetermined length, but it may not be projected, or the projected length may be arbitrarily selected. . As long as the groove 8b whose diameter increases toward the outside of the axis can be provided, the outer periphery of the rotation shaft hole 8a may have any shape.

The fact that the narrow space is formed by narrowing the distance between the inner peripheral surface 8c of the rotation shaft hole 8a and the outer peripheral surface 5c of the pinion 5 opposed thereto corresponds to the countermeasure 2B. There is an effect that the deteriorated material is less likely to enter the internal space C from the connection space B than when the interval is wide.
Providing the groove 5d on the outer peripheral surface 5c of the pinion 5 facing the inner peripheral surface 8c of the rotation shaft hole 8a also corresponds to the countermeasure 2B. A straight labyrinth seal is formed between the groove 5d on the outer peripheral surface 5c of the pinion 5 and the inner peripheral surface 8c of the rotary shaft hole 8a, and the deteriorated substance enters from the connecting space B to the inner space C by space movement. There is an effect of preventing. The effect of configuring the labyrinth seal does not depend on whether the gear joint is rotating. The direct labyrinth seal is a labyrinth seal in which a portion having a large cross-sectional area and a portion having a small cross-sectional area can be alternately formed in a linear passage through which a fluid passes.

By having the groove 5d, the cross-sectional area of the narrow portion changes in the X-axis direction, and a direct labyrinth seal is configured in the X-axis direction. In a direct labyrinth seal, the pressure and moving speed change so that the pressure is low and the fluid moving speed is small in the area where the cross-sectional area is large, and the pressure is high and the fluid moving speed is high in the area where the cross-sectional area is small. To do. This change in pressure and moving speed acts as a resistance against the force to move the fluid, making it difficult for the fluid to move.
The number, width, and depth of the grooves 5d, the interval between the grooves 5d, the interval between the inner peripheral surface 8c and the outer peripheral surface 5c, and the like are adjusted so that a labyrinth seal having a predetermined effect can be configured.

  Deteriorating substances that have entered the connection space B during rotation of the gear joint rotate with the rotating air dragged by the pinion 5 and the end cover 8 due to the viscosity of the air, particularly in the portion where the groove 5d of the connection space B does not exist. Deteriorating substances will be subjected to centrifugal force. The deteriorated material that has received the centrifugal force moves in the radial direction until it contacts the inner peripheral surface 8c of the rotary shaft hole 8a. Thus, the effect | action which puts out the deteriorating substance which moves to the internal peripheral surface 8c to the external space A by surface movement exists in the gradient which a diameter becomes large toward the axial line outward of the internal peripheral surface 8c of the rotating shaft hole 8a. . Therefore, providing the inner peripheral surface 8c with a gradient that increases in diameter toward the outside of the axis corresponds to the countermeasure 2A.

  As shown in FIG. 6, an adsorption force K, a centrifugal force S, and a reaction force H from the inner peripheral surface 8c act on the deteriorated substance on the inner peripheral surface 8c of the rotation shaft hole 8a. The inner peripheral surface 8c is inclined at an angle θB whose diameter increases toward the outer side of the axis, so that the resultant force G acts on the outer side of the axis along the inner peripheral surface 8c. For this reason, there is an effect that the deteriorated substance existing on the inner peripheral surface 8c of the rotating shaft hole 8a moves outward along the inner peripheral surface 8c and prevents the deteriorated substance from entering the internal space C. .

The resultant force G is as follows, as in the case of FIG. However, since the q component Sq of the centrifugal force S is in the direction toward the inner peripheral surface 8c, it is a negative value.
Gp = Sp = | S | × sin θB (Formula 11)
Gq = Sq + Kq + Hq
= − | S | × cos θB− | K | + Hq = 0 (Formula 12)
Since Gq = 0, Gx, which is the x component of the resultant force G, is obtained from Gp as follows.
Gx = Gp × cos θB = | S | × sin θB × cos θB (Formula 13)
(Expression 13) indicates that Gx is proportional to the magnitude of the centrifugal force | S |, and when the magnitude of the centrifugal force | S | is constant, Gx becomes maximum when θB is 45 degrees. However, if θB is increased, it becomes difficult to form a labyrinth seal.

  Since the inner peripheral surface 8c of the rotation shaft hole 8a has a gradient that increases in diameter toward the outer side of the axis, the lower inner peripheral surface 8c is lower on the outer side of the axis. Therefore, even when not rotating, gravity acts on the deteriorated material on the inner peripheral surface 8c of the rotary shaft hole 8a, and the deteriorated material is likely to go out from the connection space B through the lower inner peripheral surface 8c. There is an effect of preventing the deteriorated material from entering the internal space C.

  Inclining the side surface of the groove 5d on the outer peripheral surface 5c of the pinion 5 so that the diameter increases toward the outside of the axis corresponds to the measure 2A. The deteriorated material that travels along the outer peripheral surface 5c of the pinion 5 enters the groove 5d. FIG. 7 shows the force acting on the deteriorated material on the surface of the groove 5d. FIG. 7 (a) shows the case where the deteriorated material moves away from the side surface (referred to as the A side surface) closer to the outer side of the axis of the groove 5d, and FIG. 7 (b) shows the case where the deteriorated material moves on the surface of the A side surface. FIG. 7 (c) shows the case of being on the side surface (referred to as the B side surface) far from the axis, and FIG. 7 (d) shows the case of being on the bottom surface. The difference between FIG. 7A and FIG. 7B is the difference in the magnitude of centrifugal force | S |, as in FIG. FIG. 7A shows the case of Sq> | K |, and FIG. 7B shows the case of Sq ≦ | K |. Since the magnitude of the centrifugal force | S | is proportional to the rotational speed, FIG. 7 (a) shows the case where the rotational speed is large, and FIG. 7 (b) shows the case where the rotational speed is small.

In the rotating gear joint, as described above, the adsorptive force K, the centrifugal force S, and the reaction force H from the surface of the groove 5d act on the deteriorated material, and are accelerated in the direction of the resultant force G to be deteriorated. Move.
Since the side surface of the groove 5d is inclined so that its diameter increases toward the outer side of the axis, the deteriorated substance moves in the outer direction of the axis in FIGS. 7 (a) to 7 (c). The force that moves the deteriorating substance to the outside of the axis can be expressed by the following equation. In the case of FIG. 7A, an expression obtained by modifying (Expression 1) to (Expression 5) so as to replace θA with θC. In the case of FIG. 7B, an expression obtained by modifying (Expression 6) to (Expression 10) so as to replace θA with θC. In the case of FIG.7 (c), it is the type | formula which deform | transformed (Formula 11)-(Formula 13) so that (theta) B might be substituted to (theta) C.

In FIG. 7 (a), the deteriorating substance moves away from the side surface of the groove 5d. When the deteriorated substance reaches the B side surface of the groove 5d or the inner peripheral surface 8c of the rotary shaft hole 8a, it subsequently travels outward along the surface along the surface.
In FIGS. 7B and 7C, the deteriorated substance moves outward along the axis along the surface of the side surface of the groove 5d.
In FIG. 7 (d) in the case where it is on the bottom surface of the groove 5d, the deteriorated substance moves toward the B side surface of the groove 5d, and after reaching the B side surface, as in the case of FIG. Will move in the direction of. Note that the bottom surface of the groove 5d also moves toward the A side surface at a position close to the A side surface, and thereafter moves in the direction outward of the axis as in the case of FIG. 7 (a) or FIG. 7 (b). become.

As described above, since the side surface of the groove 5d is inclined so that the diameter increases toward the outer side of the axis, the deteriorated substance entering the groove 5d along the surface of the pinion 5 exerts a force in the outer direction of the axis. Receiving and moving from the connection space B to the external space A. That is, there is an effect that it is possible to prevent the deteriorated material that has entered the connection space B from entering the inner space C. In the first embodiment, the side surfaces on both sides of the groove 5d are inclined. However, it is effective to incline only one of the side surfaces.
When the centrifugal force S is large as shown in FIG. 7 (a), the deteriorated substance in the connection space B reaches the inner peripheral surface 8c of the rotary shaft hole 8a, so that the inner peripheral surface 8c faces the outer side of the axis. It is necessary to provide a gradient that increases the diameter. Otherwise, it will not be possible to prevent the deteriorated material from entering the internal space C along the surface of the inner peripheral surface 8c.

The first embodiment is a case where the present invention is applied to a flexible gear joint having two pinions 5 and two sleeve members 7a attached to a rotating shaft. One pinion is attached to each rotating shaft. A gear joint having five and one sleeve 9 has the same effect. Further, the same effect can be obtained when applied to a gear joint that is not a flexible gear joint.
In a gear joint having one pinion 5 and one sleeve 9, an end cover 8 having a rotation shaft hole 8a may be attached to the pinion receiving hole 9b.

In the first embodiment, the center plate 11 is provided. However, since the lubricant can be held inside the sleeve member 7a without the center plate 11, the center plate 11 may be omitted. When the center plate 11 is not provided, the mating sleeve member 7a functions as a second end member that closes the pinion receiving hole 9b.
The size of the opening that the center plate 11 closes may be smaller than the cross section of the space inside the sleeve 9 as long as the pinion 5 can be inserted. The size of the opening on the end surface where the end cover 8 is located may be the same as or smaller than the cross section of the space inside the sleeve 9, and in the case of being small, the ratio of the area of the opening to the cross section may be any.
Even when the size of the opening of the sleeve 9 is small and only the sleeve 9 and the end cover 8 as the first end member or the sleeve 9 alone can hold the lubricant inside the sleeve member 7a, the sleeve 9 and the first end are also included. It is assumed that this is included in the case where a space capable of holding the lubricant is constituted by the end material and the second end material.

In the first embodiment, since the groove 5d has the pinion 5 at a position facing the inner peripheral surface 8c of the rotation shaft hole 8a, the groove 5d is provided in the pinion 5. When there is a member that is not the pinion 5 such as a rotating shaft at a position facing the inner peripheral surface 8c, a groove is provided in the member.
In the first embodiment, the pinion 5 is provided with the recess 5b in the axial direction, and the cylindrical portion 8d enters the recess 5b from the outer side of the axis. Therefore, the narrow portion constituted by the cylindrical portion 8d and the like The length of the entire gear joint in the axial direction is shorter than that in the case where the pinion 5 does not have the axial recess 5b even if the length of the shaft is longer than the distance from the end surface having the rotation shaft hole to the end of the internal gear. it can. When the predetermined length of the narrow portion can be made shorter than the distance from the end face having the rotation shaft hole to the end of the internal gear, the pinion 5 does not have to be provided with the recess 5b. Further, if the narrow portion having a predetermined length can be formed, the cylindrical portion 8d may be omitted.

  About half of the inner peripheral surface 8c of the rotation shaft hole 8a that is close to the outside of the axis is provided with a gradient that increases in diameter toward the outside of the axis, but the portion to be provided with the gradient may be made longer. Further, if a predetermined effect can be obtained, it may be shortened. The portion close to the inside has a slight gradient in which the diameter increases toward the inside, and the gradient may be eliminated or may be a gradient in which the diameter increases toward the outside of the axis.

In the first embodiment, the gear joint in which the end cover 8 and the sleeve 9 are integrally processed is used to take measures to prevent the deterioration material from entering the gear joint. These measures can be applied even when the end cover 8 is attached to the sleeve 9 with a bolt or the like, and the same effect is obtained.
In the first embodiment, a plurality of measures for preventing deterioration substances from entering the inside of the gear joint have been implemented at the same time. However, it is not necessary to implement all of the plurality of measures at the same time, and at least one of the measures is taken. Just do it. As for the implemented measures, the effect of those measures can be obtained.
The above also applies to other embodiments.

Embodiment 2. FIG.
The second embodiment is a modification of the first embodiment so that the outer peripheral surface 5c of the pinion 5 facing the inner peripheral surface 8c of the rotation shaft hole 8a has a gradient that increases in diameter toward the outer side of the axis. is there. FIG. 8 shows an enlarged view of the gear coupling of the second embodiment on the side of the driving motor 1. The outer peripheral surface 5c of the pinion 5 that faces the inner peripheral surface 8c of the rotation shaft hole 8a is also inclined such that the diameter increases toward the outer side of the axis at an angle θD with respect to the X axis that is the rotation shaft, as with the inner peripheral surface 8c. Is attached. Note that θB>θD> 0.
The portion of the inner peripheral surface 8c having the angle θB is a portion outside the substantially center of the X-axis length of the inner peripheral surface 8c. A portion of the same range parallel to the X axis has a slope of an angle θD on the outer peripheral surface 5c.
Other structures are the same as those in FIG. 2 in the first embodiment.

The restrictions regarding the shape of the rotating shaft hole 8a and the pinion 5 will be described. For this purpose, the following variables are defined. The definition of the angle θD is also shown below.
R1: radius at the portion where the diameter of the pinion 5 is the maximum.
R2: radius at the portion where the diameter of the rotary shaft hole 8a is the smallest.
W: The portion with the largest diameter of the pinion 5 and the portion with the smallest diameter of the rotary shaft hole 8a
Spacing in the X axis direction.
D1: Distance in the Y-axis direction of the narrow portion at the portion where the diameter of the pinion 5 is the maximum.
D2: Distance in the Y-axis direction of the narrow portion at the portion where the diameter of the rotation shaft hole 8a is the smallest.
θD: An angle of the gradient of the outer peripheral surface 5c with respect to the X axis.

In order to be able to insert the pinion 5 into the rotary shaft hole 8a, it must be as follows.
R2> R1 (Formula 14)
D1 and D2 can be calculated from the following equations.
D1 = R2-R1 + W × sin θB (Formula 15)
D2 = R2-R1 + W × sin θD (Formula 16)
From these equations, the following can be understood. In order to reduce the interval between the narrow portions, it is necessary to reduce R2-R1 to zero and make the angles θB and θD close to zero. However, if R2-R1 is reduced to zero, it becomes difficult to insert the pinion 5 into the rotary shaft hole 8a.

Next, the operation will be described. The difference in operation compared to the first embodiment is in the case of a deteriorated substance that travels along the surface of the pinion 5. In other cases, the operation is the same as in the first embodiment.
Since the outer peripheral surface 5c has a gradient that increases in diameter toward the outside of the axis, the resultant force G acting on the deteriorated material on the surface of the outer peripheral surface 5c is similar to that of the groove 8b. The synthetic force acting on the deteriorated material on the surface can be expressed by an equation modified so that θA is replaced with θD in (Equation 1) to (Equation 10). Therefore, as in the case of the groove 8b, the component Gx of the resultant force G in the axially outward direction causes the deteriorated substance to move in the axially outward direction and exit from the connected space B to the external space A. Deteriorating substances are less likely to move into the internal space C.

  If the outer peripheral surface 5c is provided with a gradient whose diameter increases toward the outer side of the axis, the lower outer peripheral surface 5c becomes lower on the outer side of the axis. Therefore, even when the gear joint does not rotate, the deteriorated substance on the surface of the outer peripheral surface 5c is likely to move to the outside of the axis line due to gravity. It has the effect of preventing the intrusion of substances.

  The effect of preventing the deteriorating substance from moving from the connection space B to the internal space C by providing the outer peripheral surface 5c with a gradient that increases in diameter toward the outside of the axis is great because the rotational speed is not so large. In this case, ≦ | K |. The reason is that when Sq ≦ | K |, the deteriorating substance on the surface of the pinion 5 moves along the surface of the pinion 5. When the rotational speed is large and Sq> | K |, the deteriorated substance on the surface of the outer peripheral surface 5c leaves the surface by the centrifugal force S and moves toward the inner peripheral surface 8c of the rotary shaft hole 8a. Therefore, when Sq> | K | is satisfied, the gradient of the inner peripheral surface 8c of the rotation shaft hole 8a is prevented from entering the inner space C from the connecting space B than the gradient of the outer peripheral surface 5c. Is important.

  In the second embodiment, θB> θD is set, but θB ≦ θD may be set. The inner peripheral surface 8c has a gradient from the center to the outside of the X axis, but the gradient is made longer or shorter if a predetermined effect can be obtained. Also good. Although the portion to be inclined is opposed to the inner peripheral surface 8c and the outer peripheral surface 5c of the rotary shaft hole 8a, the gradient is also applied to a range not facing either or both of the inner peripheral surface 8c and the outer peripheral surface 5c. It may be.

Embodiment 3 FIG.
The third embodiment is a case where the sleeve 9 and the second end material are integrally processed. FIG. 9 is a cross-sectional view showing the entire structure of the gear joint of Embodiment 3 with a part thereof broken. A pinion 5 is fixedly coupled to the drive rotary shaft 3 by a shaft end nut 6. One sleeve member 7a obtained by integrally processing the sleeve 9 and the second end member is coupled to the driven rotating shaft 4 by a bolt 9c and a nut 9d.

  An internal gear 9a that meshes with the external gear 5a of the pinion 5 is provided in the cylindrical sleeve 9 portion of the sleeve member 7a. The axes of the internal gear 9a, the drive rotary shaft 3, and the driven rotary shaft 4 all coincide. Grease 10 is present inside the sleeve 9 as a lubricant. The end surface of the sleeve 9 having the second end member is a flat surface. The coupling plate 4a integrally processed with the driven rotary shaft 4 is coupled to this plane by the bolt 9c and the nut 9d. The driven rotary shaft 4 is perpendicular to the coupling plate 4a.

  The other end surface of the sleeve 9 has a pinion receiving hole 9 b having the same diameter as the inner diameter of the sleeve 9. The pinion accommodation hole 9b is closed by an end cover 8 that is a first end member. The end cover 8 has a rotation shaft hole 8a. The end cover 8 is attached to the sleeve member 7c by the bolt 8e and the nut 8f. An O-ring 14 is provided as a sealing material at the joint between the end cover 8 and the sleeve member 7c.

  Next, the operation will be described. When the gear joint rotates, the centrifugal force acts on the grease 10 as in the case of the first embodiment, so that it leaks out from the joint of the sleeve 9. In the third embodiment, since the sleeve 9 and the second end material are integrally processed, there is no seam between the sleeve 9 and the second end material, and there is an effect that the grease 10 can be prevented from leaking from the seam. Yes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a partially broken entire configuration of a gear joint according to Embodiment 1 of the present invention. It is an enlarged view by the side of the drive motor of the gear coupling of Embodiment 1 of this invention. It is a figure explaining the division of the space inside and outside the gear joint. It is a figure explaining the concept of the classification | category of the countermeasure which prevents that a degradation substance penetrate | invades into the inside of a gear joint. It is a figure explaining the force which acts on the degradation substance in the surface of the groove | channel of the outer peripheral surface of the outer peripheral surface of the rotating shaft hole of the sleeve of the gear joint of Embodiment 1 of this invention. It is a figure explaining the force which acts on the degradation substance which exists in the internal peripheral surface of the rotating shaft hole of the sleeve of the gear joint of Embodiment 1 of this invention. It is a figure explaining the force which acts on the degradation substance in the surface of the groove | channel provided in the pinion of the gear joint of Embodiment 1 of this invention. It is an enlarged view by the side of the drive motor of the gear coupling of Embodiment 2 of this invention. It is sectional drawing which fractures | ruptures and shows the whole structure of the gear coupling of Embodiment 3 of this invention.

Explanation of symbols

1: Electric motor for driving 2: Reduction gear device 3: Drive rotating shaft (first rotating shaft)
4: Driven rotating shaft (second rotating shaft)
4a: coupling plate 5: pinion 5a: external gear 5b: recess 5c: outer peripheral surface 5d: groove 6: shaft end nut 7: joint body 7a: sleeve member 7b: bolt 7c: nut 8: end cover (first cover) End material)
8a: Rotating shaft hole 8b: Groove 8c: Inner peripheral surface 8d: Cylindrical portion 8e: Bolt 8f: Nut 9: Sleeve 9a: Internal gear 9b: Pinion accommodation hole (opening)
9c: Bolt 9d: Nut 10: Grease (lubricant)
11: Center plate (second end material)
12: Cushion 13: O-ring 14: O-ring A: External space B: Connection space C: Internal space

Claims (6)

A pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is inserted into the inside through at least one opening having openings on both end faces. A sleeve coupled to the second rotation shaft, and a first end having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that closes the opening on the other end surface of the sleeve, and a space in which the sleeve, the first end member, and the second end member can hold a lubricant. The gear joint which comprises, The gear joint characterized by integrally processing the said sleeve and said 1st end material, or the said sleeve and said 2nd end material. A pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is inserted into the inside through at least one opening having openings on both end faces. A sleeve coupled to the second rotation shaft, and a first end having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that closes the opening on the other end surface of the sleeve, and a space in which the sleeve, the first end member, and the second end member can hold a lubricant. A gear joint comprising a gear joint, wherein a groove having a gradient in which the diameter increases toward the outside of the axis is provided around the outside of the rotation shaft hole. A pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is inserted into the inside through at least one opening having openings on both end faces. A sleeve coupled to the second rotation shaft, and a first end having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that closes the opening on the other end surface of the sleeve, and a space in which the sleeve, the first end member, and the second end member can hold a lubricant. In the gear joint to be configured, a gear joint characterized in that an inner peripheral surface of the rotation shaft hole is provided with a gradient in which the diameter increases toward the outer side of the axis. A pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is inserted into the inside through at least one opening having openings on both end faces. A sleeve coupled to the second rotation shaft, and a first end having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that closes the opening on the other end surface of the sleeve, and a space in which the sleeve, the first end member, and the second end member can hold a lubricant. In the gear joint to be configured, a gear joint characterized in that a surface of the rotating shaft hole facing the inner peripheral surface is provided with a gradient in which the diameter increases toward the outer side of the axis. A pinion provided with an external gear coupled to the first rotating shaft and an internal gear meshing with the external gear of the pinion are provided, and the pinion is inserted into the inside through at least one opening having openings on both end faces. A sleeve coupled to the second rotation shaft, and a first end having a rotation shaft hole that closes the opening on the end surface of the sleeve through which the first rotation shaft passes and passes the first rotation shaft. And a second end member that closes the opening on the other end surface of the sleeve, and a space in which the sleeve, the first end member, and the second end member can hold a lubricant. A gear joint, comprising: a groove in a circumferential direction provided on a surface facing the inner peripheral surface of the rotation shaft hole. The gear joint according to claim 5, wherein at least one side surface of the groove is inclined so that the diameter increases toward the outside of the axis.

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