JP6316142B2 - Gear type shaft coupling - Google Patents

Description

  The present invention relates to a gear-type shaft coupling. More specifically, the present invention relates to the prevention of electrolytic corrosion of tooth surfaces in a gear shaft coupling.

  The gear-type shaft joint is a joint that connects the drive shaft of the motor and the driven shaft of the gear device, and transmits the torque of the motor to the driven shaft while absorbing the displacement of the drive shaft and the driven shaft. The gear-type shaft coupling has a cylindrical pinion (inner cylinder) having external teeth connected to a rotating shaft that is a driving shaft or a driven shaft on an inner peripheral surface, and an inner surface that opposes the outer periphery of the pinion and meshes with the external teeth of the pinion. It is comprised from the cylindrical sleeve (outer cylinder) which has a tooth | gear. The gear-type shaft coupling is used in such a manner that the flange of the sleeve attached to the drive shaft and the flange of the sleeve attached to the driven shaft face each other, the drive shaft and the driven shaft are arranged on one straight line, and the flanges are fixed to each other.

  For example, as shown in Patent Document 1, there is a case where stopper means for restricting sliding of the sleeve in the longitudinal direction with respect to the pinion is provided. In the transmission joint of Patent Document 1, it is preferable to apply a coating made of a vibration absorbing material such as rubber or synthetic material to the stopper in order to remove noise and impact between metals.

  In some cases, a part connected to the rotating shaft and the end cover to close the gap between the rotating shaft and the end cover (hereinafter referred to as “waterproof”) is used to prevent water and dust from entering the gear shaft coupling. It is done. For the water shield, a rubber material is used so that it can function as a seal without being broken or broken even when the angle between the sleeve and the rotating shaft when absorbing the displacement between the shafts is large.

  In a gear-type shaft coupling, a potential difference may occur between the drive shaft of the motor and the driven shaft of the gear device due to factors such as a vehicle return current, a harmonic voltage from an inverter, and a charging action. Due to this potential difference, there is a case where electric discharge occurs through the thin lubricating oil film between the meshing tooth surfaces that are rotating, and the phenomenon that the tooth surface becomes uneven is called “electric corrosion”. When the stopper is coated with rubber or the like as in Patent Document 1 or an insulator is used as a water shield, electric corrosion cannot be prevented.

  In order to prevent electrolytic corrosion, it is effective to provide a separate energization path so that no potential difference occurs between the tooth surfaces. For example, in Patent Document 2, in a gear-type shaft coupling including a pinion and a conductive end cover that covers the side surface of the sleeve, a conductive bridging member is provided between the rotating shaft and the end cover. In Patent Document 2, as the conductive bridging member, carbon black as a conductive material is kneaded with a water shielding part, or a metal foil adhered to the water shielding part is used.

  Other than the shaft coupling, as in the rolling bearing of Patent Document 3, a conductive contact rubber seal formed by mixing carbon black and conductive fibers is fitted to the outer ring and the inner diameter is in sliding contact with the inner ring. It is possible to improve the conductivity by arranging it.

Special table 2001-509862 gazette JP 2004-116662 A JP 2002-089579 A

  However, as in Patent Document 2, kneading of carbon black as a conductive material and adhesion of metal foil have problems such as deterioration of rubber properties as a water shield and insufficient conductivity.

  This invention was made in order to solve the above-mentioned subject, and it aims at improving the performance which prevents the electric discharge between the tooth surfaces of a gear type shaft coupling, and prevents electrolytic corrosion.

In order to achieve the above object, a gear-type shaft coupling according to an aspect of the present invention includes a cylindrical pinion fixed to a rotary shaft on an inner peripheral surface and having external teeth, an outer periphery of the pinion facing the outer periphery of the pinion, A cylindrical sleeve having internal teeth meshing with the sleeve, a conductive end cover fixed to the sleeve and covering the axial end surface of the sleeve, a conductive outer ring contacting the end cover, and a conductive contact contacting the pinion The inner peripheral ring and the outer peripheral edge are positioned on the outer peripheral side of the outer peripheral ring and contact the inner peripheral surface of the end cover, and the inner peripheral edge is positioned on the inner peripheral side of the inner peripheral ring. It includes a rubber film that contacts the outer peripheral surface, and is connected to the water shield that covers the opening between the rotating shaft and the end cover, and to the outer ring and the inner ring. The pinion and the sleeve are electrically connected to each other through the end cover. A flexible conductive wire to be connected.

  According to the present invention, since the pinion and the sleeve are electrically connected by the conductive wire having flexibility, it is possible to improve the performance of preventing electrical corrosion from occurring between the tooth surfaces of the gear-type shaft joint.

It is sectional drawing of the gearwheel type shaft coupling which concerns on Embodiment 1 of this invention. 3 is an enlarged cross-sectional view of a water shielding portion of the gear-type shaft coupling according to Embodiment 1. FIG. FIG. 3 is a diagram showing an arrangement example of conductive wires according to the first embodiment. FIG. 5 is a diagram showing an assembly process of the gear shaft coupling according to the first embodiment. It is a figure which shows the state which fitted the pinion to the rotating shaft. It is a figure which shows the state which fixed the nut to the rotating shaft. It is a figure which shows the state which inserted the pinion in the sleeve. It is a figure which shows the state which fixed the sleeve and the end cover. It is a figure which shows the state which made the drive shaft side and the driven shaft side oppose. It is a figure which shows the state which fastened the sleeves. It is sectional drawing of the gearwheel type shaft coupling which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
1 is a cross-sectional view of a gear-type shaft coupling according to Embodiment 1 of the present invention. FIG. 1 shows a cross section of a gear-type shaft joint 10 passing through the center of the rotary shaft 1. The gear joint 10 is mirror-symmetrical except for the fastening bolt, with the drive shaft side and the driven shaft side facing each other. For example, if the left rotating shaft 1 in FIG. 1 is a drive shaft of an electric motor, the right rotating shaft 1 is a driven shaft that is input to the gear device. Torque is not always transmitted from the drive shaft side to the driven shaft side. Conversely, when performing regenerative braking, torque is transmitted from the driven shaft side to the drive shaft side due to the inertia of the load, and the electric motor is rotated. Since the gear-type shaft coupling 10 is symmetrical on the drive shaft side and the driven shaft side, the drive shaft and the driven shaft are collectively referred to as the rotary shaft 1.

  A pinion 2 is fitted and fixed to the tip of the rotating shaft 1. The pinion 2 is fixed to the rotary shaft 1 on its inner peripheral surface. The pinion 2 has external teeth 21 on the outer periphery. A cylindrical sleeve 3 is disposed so as to surround the outer periphery of the pinion 2. The sleeve 3 has inner teeth 31 that face the outer periphery of the pinion 2 and mesh with the outer teeth 21. The number of teeth of the external teeth 21 of the pinion 2 and the internal teeth 31 of the sleeve 3 are the same, and the external teeth 21 and the internal teeth 31 are rotated together around the central axis of the rotary shaft 1 in a state where the external teeth 21 and the internal teeth 31 are engaged. Since the external teeth 21 are formed in a mountain shape along the axial direction, rotation is transmitted even if the central axis of the pinion 2 and the central axis of the sleeve 3 are inclined. Further, the pinion 2 and the sleeve 3 can slide within the range of the tooth width.

  The rotary shaft 1 on the drive shaft side (drive shaft) and the rotary shaft 1 on the driven shaft side (driven shaft) are arranged to face each other, and the sleeve 3 on the drive shaft side and the sleeve 3 on the driven shaft side face each other and contact each other. In this state, the sleeves 3 are fastened together. The torque of the drive shaft is from the rotary shaft 1 on the drive shaft side to the pinion 2, from the pinion 2 to the sleeve 3, from the sleeve 3 to the opposite driven shaft side sleeve 3, and from the driven shaft side sleeve 3 to the drive shaft side. It is transmitted to the rotating shaft 1 on the driven shaft side via the pinion 2. As described above, the pinion 2 and the sleeve 3 are allowed to transmit rotation even if the drive shaft and the driven shaft are displaced within the allowable range because the inclination of the central axis and the sliding in the axial direction are allowed.

  In the gear-type shaft coupling 10 of the first embodiment, an end cover 4 that covers the end surface in the axial direction of the sleeve 3 is attached to protect the outer teeth 21 and the inner teeth 31. Further, in order to prevent water and dust from entering the sleeve 3, a water shield 5 is provided to cover the opening between the rotary shaft 1 and the end cover 4. Grease is applied to the outer teeth 21 of the pinion 2 and the inner teeth 31 of the sleeve 3, and a lubricating oil film is formed between the tooth surfaces of the outer teeth 21 and the inner teeth 31.

  If a potential difference occurs between the external teeth 21 and the internal teeth 31 that are engaged with each other during the rotation of the gear shaft coupling 10, electric corrosion occurs that discharges through the lubricating oil film and the teeth surface becomes uneven. The gear-type shaft coupling 10 according to the first embodiment is provided with a conducting wire 9 that electrically connects the end cover 4 and the pinion 2. Since the end cover 4 is made of steel and has electrical conductivity, and the sleeve 3 and the end cover 4 are in metal contact, the conductor 9 electrically connects the sleeve 3 and the pinion 2 via the end cover 4.

  FIG. 2 is an enlarged cross-sectional view of a water shielding portion of the gear-type shaft coupling according to the first embodiment. FIG. 2 is an enlarged view of the water shielding portion on the right side of FIG. The water shield 5 includes a rubber film 6, a steel outer ring 7 that contacts the end cover 4, and a steel inner ring 8 that contacts the pinion 2 or the rotating shaft 1. The outer peripheral edge of the rubber film 6 is in contact with the end cover 4, and the inner peripheral edge is in contact with the rotating shaft 1. The water shield 5 has a grasping force due to the rigidity of the outer ring 7 and the inner ring 8 and the elasticity of the rubber film 6. By adopting such a configuration, the outer peripheral surface of the rotary shaft 1 and the inner peripheral surface of the end cover 4 are not in metal contact, so that it is not necessary to shrink fit the water shield 5 and the attachment can be performed easily.

  The conducting wire 9 is composed of a conductor, for example, a stranded wire formed of a copper wire, and has flexibility. Preferably, a composite annealed copper strand in which several to dozens of small-diameter annealed copper wires are gathered together and a plurality of more joined wires are joined together is used. The conducting wire 9 is disposed along the surface of the rubber film 6 and is connected to the outer ring 7 and the inner ring 8. The outer ring 7 and the inner ring 8 are electrically conductive, and the outer ring 7 is in contact with the end cover 4 and the inner ring 8 is in contact with the pinion 2. As a result, the end cover 4 and the pinion 2 are electrically connected by the conducting wire and are kept at the same potential. Since the end cover 4 and the sleeve 3 are electrically connected, the conductor 9 electrically connects the sleeve 3 and the pinion 2 via the end cover 4.

  FIG. 3 is a diagram illustrating an arrangement example of the conductive wires according to the first embodiment. FIG. 3 is a view of the water shield 5 of FIG. 1 as viewed from the pinion 2 side. In the example of FIG. 3, four conducting wires 9 are arranged at equal intervals along the circumference. One conducting wire 9 may be used. Even when a plurality of conductors 9 are provided, the conductors 9 need not be arranged at equal intervals. Since the conducting wire 9 rotates together with the pinion 2 and the sleeve 3, it is preferable that the conducting wire 9 be arranged rotationally symmetrically with respect to the central axis of the rotating shaft 1 in order to balance the rotation.

  According to the gear-type shaft coupling 10 of the first embodiment, since the pinion 2 and the sleeve 3 are electrically connected by the conductive wire 9 having flexibility, electric discharge between the tooth surfaces of the gear-type shaft joint 10 is prevented. The performance to prevent electrolytic corrosion can be improved. Further, since carbon black is not kneaded into the rubber material of the water shield 5 or conductive fibers are not mixed, the rubber characteristics as the water shield 5 are not deteriorated.

  4A to 4G are diagrams showing an assembly process of the gear shaft coupling according to Embodiment 1. FIG. Prior to the assembly of the gear shaft coupling 10, a water shield 5 incorporating a conductor 9 is prepared. First, as shown in FIG. 4A, the water shield 5 and the end cover 4 are attached to the rotating shaft 1. Next, as shown in FIG. 4B, the pinion 2 is fitted into the rotating shaft 1. In this state, the outer peripheral ring 7 of the water shield 5 is in contact with the end cover 4, and the inner peripheral ring 8 is in contact with the pinion 2. In this state, as shown in FIG. 4C, a nut 11 is attached to the rotating shaft 1 to securely fix the pinion 2 to the rotating shaft 1.

  FIG. 4D is a diagram illustrating a state in which the pinion is inserted into the sleeve. Grease is applied to the external teeth 21 of the pinion 2 and the internal teeth 31 of the sleeve 3, and the pinion 2 is inserted into the sleeve 3 with the pinion 2 fixed to the rotary shaft 1, and the external teeth 21 and the internal teeth 31 are engaged. Adjustment is made so that the bolt holes of the sleeve 3 and the end cover 4 are aligned, and the sleeve 3 and the end cover 4 are fastened with bolts 12 as shown in FIG. 4E.

  FIG. 4F is a diagram illustrating a state in which the drive shaft side and the driven shaft side are opposed to each other. The assembly shown in FIGS. 4A to 4E is performed on each of the drive shaft side and the driven shaft side. Although not shown, for example, an electric motor on the drive shaft side and a gear device on the driven shaft side are arranged so that the sleeves face each other as shown in FIG. 4F. The sleeve 3 (rotating shaft 1) is rotated so that the bolt holes of the sleeves 3 are aligned with each other, and the sleeves 3 are fastened with the bolts 13. FIG. 4G is a diagram illustrating a state in which the sleeves are fastened together.

  As described above, the assembly of the gear shaft coupling 10 according to the first embodiment is special in comparison with the conventional gear shaft coupling except that the conductor 9 is incorporated in the water shield 5. Absent.

  In the first embodiment, the inner peripheral ring 8 is in contact with the pinion 2, but the inner peripheral ring 8 may be configured to be in contact with the rotating shaft 1. For example, a rib is attached to the rotating shaft 1 and a step is provided so that the water shield 5 can be fitted from the sleeve 3 side of the end cover 4. And if the direction which fits the water shield 5 is made reverse to FIG. 2, the inner peripheral ring 8 can be made to contact the collar part of the rotating shaft 1. FIG.

  Further, the configuration is not limited to the configuration in which the outer ring 7 and the inner ring 8 of the water shield 5 are brought into contact with the end cover 4 and the pinion 2 or the rotating shaft 1. The lead wire 9 may be connected to the end cover 4 and the pinion 2, or the lead wire may be directly connected to the sleeve 3 and the pinion 2. For example, the conductor 9 can be connected to the sleeve 3 and the pinion 2 by giving the conductor 9 an appropriate deflection in the space in the sleeve 3 on the distal end side of the rotating shaft 1.

  The conducting wire 9 of the first embodiment is not necessarily a copper stranded wire as long as it is a good electrical conductor and is flexible and can follow the relative displacement between the pinion 2 and the end cover 4. Aluminum, iron, or other metal can be used for the conductive wire 9. In addition to the stranded wire, a coil spring can also be used.

Embodiment 2. FIG.
FIG. 5 is a cross-sectional view of the gear-type shaft coupling according to Embodiment 2 of the present invention. The gear-type shaft coupling 10 according to the second embodiment has no water shield 5 and connects the end cover 4 and the pinion 2 with a conducting wire 9. If the gear-shaped shaft coupling 10 is not splashed with water and the amount of dust is small, the water shield 5 may not be provided. When used in an environment where there is little dust, the gear type shaft coupling 10 without the water shield 5 may be used.

  As shown in FIG. 5, in the gear-type shaft coupling 10 of the second embodiment, the configuration of the rotating shaft 1, the pinion 2 and the sleeve 3 is the same as that of the first embodiment. In the second embodiment, there is no water shield 5, and instead, the inner periphery of the end cover 4 extends to the vicinity of the pinion 2. In the second embodiment, the outer peripheral ring 7 is fitted to the step portion of the end cover 4, and the inner peripheral ring 8 is fitted to the rotating shaft 1. For example, the inner peripheral side of the outer peripheral ring 7 and the inner peripheral side of the inner peripheral ring 8 are rubber materials, and the outer peripheral ring 7 and the inner peripheral ring 8 are held by the elasticity of the rubber material. The outer ring 7 and the inner ring 8 may be springs and may be held by their elasticity.

  As in FIG. 2, the metal portion of the outer peripheral ring 7 contacts the end cover 4, and the metal portion of the inner peripheral ring 8 contacts the pinion 2. The conducting wire 9 is connected to the metal part of the outer ring 7 and the metal part of the inner ring 8. As a result, the end cover 4 and the pinion 2 are electrically connected by the conducting wire and are kept at the same potential. In the configuration of FIG. 5, the rubber film is removed from the water shield shown in FIG. The second embodiment can be assembled in the same manner as the first embodiment.

  According to the gear type shaft joint 10 of the second embodiment, the pinion 2 and the sleeve 3 are electrically connected by the flexible conductor 9 even without the water shield 5. It is possible to improve the performance of preventing electric corrosion by preventing discharge between tooth surfaces.

  Also in the second embodiment, the conductive wire 9 may be connected to the end cover 4 and the pinion 2, or the conductive wire may be directly connected to the sleeve 3 and the pinion 2. The conductive wire 9 is not necessarily a copper stranded wire as long as it is a good electrical conductor and is flexible and can follow the relative displacement between the pinion 2 and the end cover 4. Aluminum, iron, or other metal can be used for the conductive wire 9. In addition to the stranded wire, a coil spring can also be used.

  1 Rotating shaft, 2 Pinion, 3 Sleeve, 4 End cover, 5 Water shield, 6 Rubber film, 7 Outer ring, 8 Inner ring, 9 Conductor, 10 Gear shaft coupling, 11 Nut, 12 Bolt, 13 Bolt, 21 external teeth, 31 internal teeth.

Claims (3)

A cylindrical pinion fixed to the rotary shaft on the inner peripheral surface and having external teeth;
A cylindrical sleeve facing the outer periphery of the pinion and having internal teeth meshing with the external teeth;
A conductive end cover fixed to the sleeve and covering an axial end surface of the sleeve;
A conductive outer ring in contact with the end cover, a conductive inner ring in contact with the pinion, and an outer peripheral edge located on the outer peripheral side of the outer ring and in contact with the inner peripheral surface of the end cover. The inner peripheral edge includes a rubber film that is located on the inner peripheral side of the inner peripheral ring and contacts the outer peripheral surface of the rotary shaft, and a water shield that covers an opening between the rotary shaft and the end cover;
A flexible conductive wire connected to the outer ring and the inner ring, and electrically connecting the pinion and the sleeve via the end cover ;
A gear-type shaft coupling comprising: The gear-type shaft coupling according to claim 1, wherein the conducting wire is provided at a rotationally symmetric position with respect to a central axis of the rotating shaft. The gear-type shaft coupling according to claim 1 or 2 , wherein the conducting wire is a stranded wire formed of a conductor.

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