JPH0694085A - Worm type reduction gear - Google Patents

Abstract

PURPOSE:To inexpensively provide a worm type reduction gear strong in durability, stable in accuracy, less in frictional drag and noise, compact in size, excellent in manufacturability and economic efficiency, and capable of securing high transmission efficiency and decelerating rate, by making the contact between a worm and a worm wheel a rolling contact. CONSTITUTION:More than one lines of each ball rolling groove 1 formed in spiral form on a peripheral surface are formed endlessly via a ball circulating passage 3 piercing through the inner part of a worm shaft 2. A worm 5 being composed of arraying a lot of balls 4 in the ball rolling groove 1 and the ball circulating passage 3 in a state of being circulated and rolled, is supported in a ball receiving outer cylinder 8 being clamped to a body case 6 in an irrational state and opened with an interlocking window hole 7, free of rotation in a state that the ball 4 contacts with the inner surface. Subsequently, a worm wheel 10 which installed a ball interlocking groove 9 on the peripheral surface at a pitch interval of the ball rolling groove 1 is interlocked with the ball 4 of the worm 5 at the interlocking window hole 7 of the ball receiving outer cylinder 8 and it is installed so as to transmit its motion, and this worm wheel is supported on the body case 6 free of rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a worm type speed reducer which is an improvement of the worm speed reducer used when a high speed reduction rate is required in all industrial fields.

[0002]

2. Description of the Related Art A worm speed reducer, which is widely used and well known, is a rotation transmitting means in which two axes are orthogonal to each other in a staggered state, and one gear has one to four threads (number of teeth).
Is formed, and the other gear is a worm wheel around which a large number of teeth that mesh with the teeth of the worm are provided.

[0003]

This worm speed reducer is advantageous in that it has a relatively high reduction ratio and is inexpensive and can be manufactured in a small size. However, since the contact portion between the worm and the worm wheel is frictional, the transmission is reduced. The efficiency is lower than other speed reducers, especially when the speed reduction rate is high, the transmission efficiency is extremely reduced, and expensive materials are used on the worm wheel side due to wear, heat generation, seizure, etc. There were issues that need to be solved, such as the points that need to be solved.

The object of the present invention is to make the contact between the worm and the worm wheel as rolling contact so that durability and strength are stable, accuracy is low, friction resistance and noise are small, and the product is compact and manufacturable.
It is an object to provide a worm-type speed reducer that is economical and excellent in transmission efficiency and speed reduction rate at low cost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, in which one or more ball rolling grooves 1 formed in a spiral shape on the peripheral surface are provided in the worm shaft 2. A worm 5 is formed in a circulation circuit through a ball circulation passage 3 penetrating through the main body case 6 and a plurality of balls 4 are arranged in the ball rolling groove 1 and the ball circulation passage 3 so as to circulate and roll. The ball 4 is rotatably supported in a state in which the ball 4 is in contact with the inner surface and is rotatably supported in the ball outer cylinder 8 which is fixed in a non-rotating state and has an occlusal window hole 7 formed therein. The worm wheel 10 engraved at the pitch of the moving groove 1 or the lead interval is occluded with the ball 4 of the worm 5 in the rolling window 7 of the ball receiving cylinder 8 to transmit the motion. And rotatably support it on the body case 6. Are summarized as worm type reduction gear, characterized in that is.

[0006]

As described above, the ball rolling groove 1 is endlessly formed through the ball circulation passage 3 penetrating the worm shaft 2, and a large number of balls 4 are arranged so as to circulate and roll. The worm 5 is fixed to the main body case 6 in a non-rotating state, and the ball receiving cylinder 8 having the bite window hole 7 is opened.
A worm wheel 10 in which the ball 4 is rotatably supported in an inscribed state, and a ball engaging groove 9 is formed on the peripheral surface at the pitch of the ball rolling groove 1 or the lead interval. By arranging the worm 5 in the biting window hole 7 so as to occlude and transmit the motion of the ball 4 of the worm 5, the rotation of the worm 5 causes the ball 4 to roll in contact with the inner surface of the ball receiving cylinder 8. As a result, the ball 4 moves endlessly along the ball rolling groove 1 and the ball circulation passage 3. Then, in the ball engagement groove 9 of the worm wheel 10 in the process, the ball 4 gives a rotational force to the worm wheel 10.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of a worm type speed reducer according to the present invention will be described. FIG. 1 is an explanatory structural view in which some balls 4 are omitted, and FIG. 2 is a ball rolling groove of a worm. It is a figure which shows the rolling movement locus | trajectory of the said ball. Warm 5
Is fixed by an axial key 13 to an input shaft 12 whose both ends are rotatably supported by bearing bearings 11, and a single ball rolling groove 1 is spirally formed on the peripheral surface of the worm shaft 2. A ball circulation passage 3 for penetrating the ball rolling groove 1 is formed through the worm shaft 2.

The worm 5 is fixed to the main body case 6 in a non-rotatable state by a rotation stop key 14, an occlusal window hole 7 is opened, and is further inserted into a ball receiving cylinder 8 fixed to the main body case 6 by a sleeve 18. , The occlusal window hole 7 is inserted downward, and is rotatably supported by the support bearings 16 that are pressed and held by the bearing retainers 15 attached to both end faces of the ball receiving cylinder 8, and the ball rolling groove 1 and A large number of balls 4 are arranged in the ball circulation passage 3, and the balls 4 are inscribed in the ball receiving cylinder 8 so as to circulate and roll.

The worm wheel 10 has a ball engaging groove 9 on its peripheral surface for engaging the ball rolling groove 1 of the worm 5 and the ball 4 held by the ball receiving cylinder 8 in a rolling state. The groove is formed at the pitch of the moving groove 1 or the lead interval, and is fixed and supported on a shaft (not shown) orthogonal to the input shaft 12 at a position where the input shaft 12 is offset.

A ball retainer 17 for preventing the ball 4 from falling is provided in the occlusal window hole 7 of the ball receiving cylinder 8 which is the occlusal portion of the worm 5 and the worm wheel 10. But it is not absolutely necessary.

Reference numeral 19 in the drawing denotes a bearing holding hole cover, 20
Is a bearing pressing cover, and 21 is an oil seal for sealing the worm 5 and the like.

In the worm type speed reducer of the present invention constructed as described above, the rotation of the worm 5 causes the spiral ball rolling groove 1 and the ball receiving outer cylinder 8 corresponding to the outer cylinder of the bearing.
Therefore, the ball 4 rolls in contact with the inner surface of the ball receiving cylinder 8, so that the ball 4 rolls endlessly along the ball rolling groove 1 and the ball circulation passage 3. And the worm wheel 10 which becomes the rolling process
In the ball engagement groove 9 of the ball 4, the ball 4 applies a rotational force to the worm wheel 10.

In the above embodiment, the case where one spiral ball rolling groove 1 is formed has been described.
The same applies to the case of three or four rows, and each ball rolling groove is formed endlessly by the ball circulation passage 3. Further, the worm 5 has been described as being fixed to the input shaft 12 whose both ends are rotatably supported by the bearings 11 by the shaft key 13, but may be formed as an integral part.

[0014]

According to the worm type speed reducer of the present invention described above, the portions corresponding to the teeth of the worm are formed by arranging the balls so that they engage with the worm wheel in a rolling state. Therefore, since the contact part of both is rolling instead of friction, remarkably good transmission efficiency, excellent durability, and because it continuously presses the tooth surface of the worm wheel like a gear without continuously hitting it, As a result, there is no uneven rotation, noise and vibration are small, and by providing a mechanism for applying a preload, backlash can be reduced and accuracy can be improved.

Furthermore, since there is no wear, heat generation, or seizure, it is not necessary to use expensive non-ferrous materials such as BC and AlBC as in the conventional case, and it can be provided at a low cost.

[Brief description of drawings]

FIG. 1 shows a worm type speed reducer according to an embodiment of the present invention,
FIG. 6 is an explanatory configuration diagram showing a part of balls 4 omitted.

FIG. 2 is a diagram showing a rolling movement locus of a ball in a worm rolling groove.

[Explanation of symbols]

1 Ball Rolling Groove 2 Worm Shaft 3 Ball Circulation Passage 4 Ball 5 Worm 6 Main Body Case 7 Engagement Window Hole 8 Ball Outer Cylinder 9 Ball Engagement Groove 10 Worm Wheel 11 Bearing Bearing 12 Input Shaft 13 Shaft Key 14 Stop Key 15 Bearing Presser foot 16 Support bearing 17 Ball retainer 18 Sleeve 19 Bearing presser hole cover 20 Bearing presser cover 21 Oil seal

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[Procedure amendment]

[Submission date] April 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

A ball retainer 17 for preventing the ball 4 from falling is provided in the occlusal window hole 7 of the ball receiving cylinder 8 which is the occlusal portion of the worm 5 and the worm wheel 10. .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

In the above embodiment, the case where one spiral ball rolling groove 1 is formed has been described.
The same applies to the case of three or four rows, and each ball rolling groove is formed endlessly by the ball circulation passage 3. Further, the worm 5 has been described with respect to the case where the both ends are fixed to the input shaft 12 rotatably supported by the bearings 11 by the shaft key 13, but the worm 5 may be formed as an integral part. Although not shown, a drum-shaped worm may be used in some cases. In this case, since the hitting portion increases and the gap portion disappears, it is also preferable to use the ball.

Claims (1)

[Claims] 1. A ball rolling groove 1 is formed by forming one or more ball rolling grooves 1 spirally formed on a circumferential surface in a circulation circuit through a ball circulation passage 3 penetrating the inside of a worm shaft 2. And a ball receiving tube 8 in which a worm 5 in which a large number of balls 4 are arranged to circulate and roll in the ball circulation passage 3 is fixed to a main body case 6 in a non-rotating state and an occluding window hole 7 is formed. A worm wheel 10 in which a ball 4 is rotatably supported in a state of being in contact with the inner surface, and ball engaging grooves 9 are formed on the peripheral surface at the pitch of the ball rolling groove 1 or the lead interval.
Is arranged so as to occlude the ball 4 of the worm 5 and transmit the motion in the occlusal window hole portion 7 of the ball receiving cylinder 8, and the rotatably supported by the main body case 6. Worm type speed reducer.