JPH0432516Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to improvement of a worm reducer.

Prior Art In general, worm reducers are widely used, which transmit power at a relatively large reduction ratio to a worm wheel that rotates around an axis perpendicular to the axis of a drum-shaped worm having a helical groove as it rotates. However, in such a worm reducer,
If the drum-shaped worm moves even slightly in a direction perpendicular to its longitudinal direction, the engagement will become poor.

In response to this, a device as described in Japanese Patent Application Laid-Open No. 58-211052 has been provided. Such a device includes a drum-shaped worm and a worm wheel, the axes of which are perpendicular to each other, and engages with grooves in the worm at hemispherical recesses provided on the periphery of the worm wheel at intervals corresponding to the pitch of the worm. A spherical tooth is disposed in a protruding state, and a plurality of small spheres having a smaller diameter than the spherical tooth are disposed between the spherical tooth and the recess to rotatably support the spherical tooth. It is made up of. According to such a device, wear and heat generation of the worm and worm wheel that occur when the drum-shaped worm and the worm wheel engage are prevented, and even if the worm moves slightly in a direction perpendicular to its longitudinal direction, Since only the spherical teeth protruding from the worm wheel are engaged with the grooves of the worm, there is no possibility of poor engagement between the worm and the worm wheel.
In addition, in the worm wheel body, the spherical teeth are rotatably supported around the center by multiple small spheres, and the rotation of the spherical teeth is smooth, resulting in high transmission efficiency and improved durability. It was hot.

Problems to be Solved by the Invention However, in such a device, the spherical teeth that mesh with the drum-shaped worm are supported by point contact with a plurality of small spheres between the recesses of the worm wheel, and the spherical teeth are If an excessive load or impact is instantaneously applied to the tooth for some reason, the load will be concentrated at the point of contact with the plurality of small spheres on which the spherical tooth is supported. In some cases, the spherical tooth was damaged or locally deformed at that point.

Means for Solving the Problems The present invention was made against the background of the above circumstances, and its gist is that the worm wheel body rotates around a single axis and the worm wheel body can rotate around the outer circumference of the worm wheel body. A worm speed reducer comprising a worm wheel having spherical teeth provided on the worm wheel and a drum-shaped worm that meshes with the worm wheel, wherein the worm wheel main body is provided with an annular flange portion protruding in the uniaxial direction, and the flange Guide holes penetrating in the radial direction are formed at regular intervals in the circumferential direction in the section, and the spherical teeth are respectively accommodated in the guide holes with a portion protruding toward the outer periphery, while the inner periphery of the guide holes is A radially elastically deformable C-shaped ring that closes the side opening is fitted onto the inner periphery of the flange portion, and a plurality of small spheres that rotatably support the spherical tooth around its center are connected to the spherical tooth and the C-shaped ring. The C-shaped ring is inserted between the ring and the C-shaped ring, and a rolling plane is formed at the portion of the outer peripheral surface of the C-shaped ring that comes into contact with the small sphere.

Function and Effect of the Invention By doing this, the spherical tooth accommodated in the guide hole with a part thereof protruding toward the outer circumferential side is connected to the C-shaped ring which can be elastically deformed in the radial direction via the plurality of small spheres. Supported by rolling planes. As a result, the spherical teeth are supported in a state where they can rotate around the center point while being in contact with all the small spheres, resulting in high transmission efficiency and durability. Moreover, even if excessive loads or shocks are applied to the spherical teeth,
The C-shaped ring, which receives the spherical teeth through the small sphere, shrinks in diameter due to elastic deformation to alleviate the excessive load and impact, which prevents damage or local deformation of the spherical teeth and small spheres that are in point contact with each other. is suitably prevented.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

The worm reducer of this embodiment shown in FIG. 1 has an input shaft 1 rotatably supported by a bearing in a machine frame 10 and connected to a drive device (not shown).
2, a drum-shaped worm 14 which has a spiral groove 13 formed on its surface, is provided integrally with the input shaft 12 and is driven to rotate when the input shaft 12 is rotated; The output shaft 16 is rotatably supported in the same manner as the input shaft 12 and is orthogonal to the input shaft 12 at a predetermined interval, and a worm wheel 18 is integrally provided on the output shaft 16 so as to mesh with the worm 14. has been done.

The worm wheel 18 is constructed as shown in FIGS. 1 and 2. A disc-shaped main body 20 provided around the axis of the output shaft 16 is provided with an annular flange portion 22 so as to protrude in the uniaxial direction of the output shaft 16, and this flange portion 22 includes:
Cylindrical through holes 24 passing through the worm 14 in the radial direction are formed at regular intervals in the circumferential direction, that is, at intervals corresponding to the pitches of the grooves 13 formed in the worm 14. In addition, an elastically deformable C-shaped ring 26 is fitted into the inner circumferential surface of the flange portion 22 with its diameter reduced to a shape with both ends slightly open. It's blocking the opening. This C-shaped ring 26 has screw members 28 screwed into screw holes 30 formed in the main body 20 at both ends thereof so as to close the gap between the flange portion 22 and the base end of the main body 20, and screwed into a nut 32. By being fastened in this manner, the flange portion 22 is prevented from falling off the inner circumferential surface.

A spherical tooth 34 is accommodated in the through hole 24 with a portion thereof protruding toward the outer circumferential side, and between the spherical tooth 34 and the C-shaped ring 26, as shown in FIG. A plurality of small spheres 36 (six in this embodiment) having a diameter considerably smaller than that of the spherical tooth 34 are inserted to rotatably support the spherical tooth 34 . This reduces the rotational resistance of the spherical teeth 34. Further, when an overload or impact is applied to the spherical teeth 34, the C-shaped ring 26 is elastically deformed and the spherical teeth 34 are
can be pushed into the through hole 24. Therefore, the through hole 24 has a spherical tooth 34.
It functions as a guide hole that guides in the radial direction.
In addition, at the peripheral edge of the through hole 24 of the flange portion 22,
A pair of claws 38 functioning as stopper means are formed to prevent the spherical teeth 34 from falling. Further, the imaginary line (two-dot chain line) in FIG. 3 indicates the locus of the contact point between the small sphere 36 and the spherical tooth 34, and the small sphere 36 supports the spherical tooth 34 while rolling. Here, a rolling plane 40 is formed in each portion of the outer peripheral surface of the C-shaped ring 26 that closes the opening on the inner peripheral side of the through hole 24, so that the small spheres 36 can be rolled within one plane. There is. By forming this rolling plane 40, the spherical tooth 34 is elastically supported within the through hole 24 by the C-shaped ring 26 for alleviating overload and impact applied thereto. It is supported in a state in which it is in contact with all the small spheres 36 and can rotate around its center point.

The effects of this embodiment configured as described above will be explained below.

When a rotational force is supplied to the input shaft 12 from a drive device (not shown) and the worm 14 is rotated, the spherical teeth 34 of the worm wheel 18 that mesh with the groove 13 formed on the worm 14 move smoothly. By rotating and moving the worm wheel 18, the worm wheel 18 rotates around the axis, and rotational force is efficiently transmitted to the output shaft 16 at a relatively large reduction ratio.

At this time, if an excessive load or impact is instantaneously applied to the spherical tooth 34 for some reason, the spherical tooth is supported by a plurality of small spheres in a hemispherical recess formed in the worm wheel. In conventional speed reducers, the spherical teeth are damaged by concentrated loads at the points of contact with the supported small spheres.

In contrast, in the worm reducer of this embodiment, even if an excessive load is applied to the spherical teeth 34, the C-shaped As the ring 26 elastically deforms inward, the spherical teeth 34 are released from engagement with the worm 14, and the load on the spherical teeth 34 is reduced. Therefore, according to this embodiment, when an excessive load is applied to the spherical tooth 34, the spherical tooth 34 is prevented from being damaged at the contact point with the supported small sphere 36. is obtained.

Furthermore, in the past, it was very difficult to form a hemispherical recess with high precision to accommodate the spherical teeth, but in this embodiment, it is difficult to form the through hole 24 that accommodates the spherical teeth 34. is flange part 2
It is only necessary to machine a hole through the hole 2 in the radial direction using a well-known rotary cutting tool and a rotary polishing tool, making the machining very easy.

The above-mentioned embodiment is merely an embodiment of the present invention, and various changes may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a cutaway front view of a main part of a worm reducer which is an embodiment of the present invention. FIG. 2 is a cutaway view of the main parts of FIG. 1 viewed from the side. FIG. 3 is an enlarged plan view of the vicinity of the spherical teeth in FIGS. 1 and 2. FIG. 4 is a cutaway view of the main part seen from the - line in FIG. 3, and is a diagram showing the state when the spherical teeth are subjected to a load. 14... Worm, 18... Worm wheel, 20... Main body, 22... Flange portion, 24...
...Through hole (guide hole), 26...C-shaped ring (elastic member), 34...Spherical tooth, 36...Small sphere, 38
...Claw part (stopper means).

Claims (1)

[Claims for Utility Model Registration] A worm wheel having a worm wheel main body that rotates about one axis, spherical teeth rotatably provided on the outer periphery of the worm wheel main body, and a drum-shaped worm that meshes with the worm wheel. In the worm speed reducer, the worm wheel main body is provided with an annular flange portion protruding in the uniaxial direction, and guide holes passing through the flange portion in the radial direction are formed at regular intervals in the circumferential direction so that the spherical teeth are accommodated in the guide hole with a portion protruding toward the outer circumference, while a C-shaped ring that is elastically deformable in the radial direction and closes the inner circumference opening of the guide hole is fitted to the inner circumference of the flange portion. A plurality of small spheres are inserted between the spherical teeth and the C-shaped ring, and the small spheres are arranged on the outer peripheral surface of the C-shaped ring. A worm reducer characterized by forming rolling planes on the contacting parts.