JP2017125573A - Speed reducer and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a speed reducer which reduces the number of components and inhibits leakage of grease from an internal space while inhibiting increase of an internal pressure of the internal space where the grease is enclosed.SOLUTION: A speed reducer 1 reduces a speed of rotation of a rotary input shaft 4 to output the rotation and includes: the input shaft 4; and shell bodies 1b, 1c through which the input shaft 4 penetrates. The shell bodies 1b, 1c have an internal space in which part of the input shaft 4 is exposed. The input shaft 4 is provided with: a first hole 11 which is formed from one end 4a to the other end 4b of the input shaft 4; and a second hole 12 which is formed from an exposed surface of the input shaft 4 exposed in the internal space to the first hole 11 and communicates with the first hole 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a speed reducer that decelerates and outputs rotation of an input shaft, and a robot using the same.

  Some reduction gears include grease enclosed in an internal space provided in an outer shell for the purpose of lubrication. Some reduction gears are provided with an oil seal for the purpose of closing the inner space and the outer space of the outer shell. Patent Document 1 discloses a configuration in which holes for communicating the internal space and the external space are formed in the outer shell in order to keep the internal pressure of the internal space within the pressure-resistant range of the oil seal.

JP2011-001899A

  However, in the configuration disclosed in Patent Document 1, grease may leak through a hole that connects the internal space and the external space. In order to prevent the leakage of grease from the hole communicating with the internal space and the external space, and to suppress the increase in the internal pressure of the internal space, a hole that can pass through the air but prevents the passage of the grease, such as felt, is used. Need to close. However, an increase in the number of parts due to the addition of members becomes a problem.

  The present invention has been made in view of the above, and a speed reducer capable of suppressing leakage of grease from the internal space by suppressing the number of components while suppressing an increase in internal pressure of the internal space in which the grease is enclosed. The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, a speed reducer according to the present invention is a speed reducer that decelerates and outputs the rotation of an input shaft that can be rotated. And a penetrating outer body. The outer body has an internal space in which a part of the input shaft is exposed. The input shaft has a first hole formed from one end of the input shaft toward the other end, and is formed from the surface exposed to the internal space of the input shaft toward the first hole and communicates with the first hole. Second holes are provided.

  According to the speed reducer according to the present invention, it is possible to suppress the leakage of the grease from the internal space by suppressing the number of components while suppressing the increase of the internal pressure of the internal space in which the grease is enclosed.

Sectional drawing which shows schematic structure of the joint structure using the reduction gear concerning Embodiment 1 of this invention. 1 is a cross-sectional view taken along line II-II shown in FIG. The figure which shows schematic structure of the robot using the joint structure shown in FIG.

  Hereinafter, a speed reducer and a robot according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a schematic configuration of a joint structure using the speed reducer according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II shown in FIG. The joint structure includes casings 2 and 3 constituting the outer shell of the joint structure, a reduction gear 1, a cross roller bearing 5, ball bearings 6 and 7, oil seals 8 and 9, and a key 10. Provided.

  The speed reducer 1 is a wave speed reducer including a circular spline 1a, a flex spline 1b, and a wave generator 1c. The speed reducer 1 further includes an input shaft 4.

  The input shaft 4 is fixed to the wave generator 1c. Specifically, as shown in FIG. 2, the input shaft 4 is inserted into a hole 16 formed in the wave generator 1c. A key groove 15 is formed in the hole 16, and the key 10 fitted in the input shaft 4 is fitted in the key groove 15. When the key 10 is fitted in the key groove 15, the idle rotation of the input shaft 4 is prevented. It should be noted that the D-cut portion may be provided on the input shaft 4 to prevent the input shaft 4 from idling regardless of the fitting between the key 10 and the key groove 15.

  The flex spline 1b and the wave generator 1c constitute an outer shell of the speed reducer 1. An internal space 17 is formed between the flex spline 1b and the wave generator 1c, and a part of the input shaft 4 is exposed to the internal space 17. In this internal space 17, a region including a region where the flex spline 1 b and the wave generator 1 c abut is a grease application region 13 to which grease is applied. The grease application region 13 is a region separated from the input shaft 4 to the outside in the radial direction of the input shaft 4 in the internal space 17.

  The housing 2 is fixed to the circular spline 1a. The housing 3 is fixed to the flex spline 1b. A cross roller bearing 5 is provided between the housing 2 and the housing 3. The housing 2 is fixed to the inner ring of the cross roller bearing 5. The housing 3 is fixed to the outer ring of the cross roller bearing 5.

  The housing 2 may be fixed to the outer ring of the cross roller bearing 5 and the housing 3 may be fixed to the inner ring of the cross roller bearing 5. Further, the bearing provided between the housing 2 and the housing 3 is not limited to the cross roller bearing 5, and any bearing that can support an axial load, a radial load, and a moment load may be used. For example, a pair of angular bearings may be used in place of the cross roller bearing 5.

  The input shaft 4 is rotatably supported by a ball bearing 6 fixed to the housing 2 and a ball bearing 7 fixed to the housing 3. The wave generator 1 c and the key 10 rotate together with the input shaft 4. The oil seal 8 is fixed to the housing 2 and seals between the housing 2 and the input shaft 4. The oil seal 9 is fixed to the housing 3 and seals between the housing 3 and the housing 2.

  In the joint structure using the speed reducer 1, when the input shaft 4 is rotated, the wave generator 1c to which the input shaft 4 is fixed rotates. The rotation of the wave generator 1c is decelerated by the speed reducer 1 and output to the flexspline 1b. That is, the flex spline 1b rotates at a lower rotation speed than the wave generator 1c. And the housing | casing 3 fixed to the flexspline 1b rotates at the same rotational speed as the flexspline 1b. That is, this joint structure has a configuration in which the rotation of the input shaft 4 is decelerated and transmitted to the housing 3.

  Next, a configuration for preventing the grease applied to the grease application region 13 in the reducer 1 from leaking from the internal space 17 will be described.

  In the speed reducer 1, a first hole 11 is formed from one end 4 a to the other end 4 b of the input shaft 4. The first hole 11 overlaps the central axis C when the input shaft 4 rotates. One end 4 a of the input shaft 4 is exposed to the external space of the speed reducer 1.

  The input shaft 4 is provided with a second hole 12 that is formed from the exposed surface 4 c to the internal space 17 toward the first hole 11 and communicates with the first hole 11. The starting point 12a of the second hole 12 formed toward the first hole 11 is in the same phase as the position where the key 10 is provided, and a position facing the key groove 15 formed in the wave generator 1c. It has become. Thereby, the internal space 17 and the external space of the reduction gear 1 are communicated with each other by the first hole 11 and the second hole 12.

  As described above, the internal space 17 and the external space of the speed reducer 1 are communicated with each other by the first hole 11 and the second hole 12, thereby suppressing an increase in the internal pressure of the internal space 17 of the speed reducer 1. Can do. Thereby, the internal pressure of the internal space 17 can be suppressed within the pressure resistance range of the oil seals 8 and 9.

  In addition, since the first hole 11 and the second hole 12 are formed in the input shaft 4 away from the grease application region 13, the grease applied to the grease application region 13 is independent of the attitude of the speed reducer 1. It is difficult to reach the first hole 11 and the second hole 12. Therefore, it is difficult for the grease to leak into the external space from the first hole 11 and the second hole 12 provided to suppress the increase in internal pressure. Accordingly, a member that absorbs grease at the outlet of the first hole 11, that is, the one end 4 a portion of the input shaft 4 becomes unnecessary, and the number of parts can be suppressed.

  In addition, since the start point 12a of the second hole 12 is located at a position facing the key groove 15 formed in the wave generator 1c, the grease does not pass through the gap between the input shaft 4 and the key groove 15 so that the second The hole 12 cannot be reached. Therefore, it is difficult for the grease applied to the grease application region 13 to reach the first hole 11 and the second hole 12 regardless of the attitude of the speed reducer 1.

  When the input shaft 4 rotates because the first hole 11 overlaps the central axis C of rotation of the input shaft 4 and the second hole 12 is formed toward the first hole 11. In addition, a centrifugal force directed to the starting point 12a acts on the grease that has entered the second hole 12. Accordingly, the grease that has entered the second hole 12 is discharged to the internal space 17 through the starting point 12a when the input shaft 4 rotates. Therefore, it can suppress more reliably that grease leaks to external space through the 1st hole 11 and the 2nd hole 12.

  The starting point 12a of the second hole 12 may be a position that does not face the key groove 15 and the hole 16 formed in the wave generator 1c. That is, the position of the starting point 12a may be shifted to the other end 4b side as shown in FIG. Compared with the case where the start point 12a is provided at a position facing the key groove 15 hole 16, the grease easily reaches the start point 12a, but the second hole 12 is formed in the input shaft 4 away from the grease application region 13. However, since the grease that has entered the second hole 12 can be discharged by centrifugal force, it is possible to prevent the grease from leaking through the first hole 11 and the second hole 12. .

  If the input shaft 4 is provided with a D-cut portion without using the key 10, the start point 12a of the second hole 12 is provided in the D-cut portion, and the inner wall surface of the hole 16 and the start point 12a are opposed to each other. You may let them.

  In the first embodiment, the wave reducer has been described as an example. However, as long as the reducer has the internal space 17 in which grease is enclosed, the configuration of the present invention is applied to a reducer other than the wave reducer. It is possible to apply.

  FIG. 3 is a diagram showing a schematic configuration of a robot using the joint structure shown in FIG. The robot 30 rotates the input shaft 4 of the speed reducer 1 with an electric motor 31 that is a power unit. Then, the output from the speed reducer 1 based on the rotation of the input shaft 4, that is, the rotation of the housing 3 rotates the arm portion 32 which is a rotation output unit connected to the housing 3. Since the robot 30 uses the joint structure shown in FIG. 1, it is possible to suppress the leakage of grease from the internal space 17 by suppressing the number of components while suppressing an increase in the internal pressure of the internal space 17 at the joint portion. .

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1 Reducer, 1a Circular spline, 1b Flex spline (outer body), 1c Wave generator (outer body), 2, 3 housing, 4 input shaft, 4a one end, 4b other end, 5 cross roller bearing, 6, 7 balls Bearing, 8, 9 Oil seal, 10 key, 11 1st hole, 12 2nd hole, 12a Start point, 13 Grease application area, 15 Key groove, 16 hole, 17 Internal space, 30 Robot, 31 Electric motor (Power unit) ), 32 Arm part (rotation output part), C center axis.

Claims (3)

A speed reducer that decelerates and outputs the rotation of the input shaft that is allowed to rotate.
The input shaft;
An outer body through which the input shaft is penetrated,
The outer body has an internal space in which a part of the input shaft is exposed,
In the input shaft, a first hole formed from one end of the input shaft toward the other end, and an exposed surface of the input shaft to the internal space are formed from the exposed surface toward the first hole. A speed reducer, wherein a second hole communicated with the first hole is provided.   The speed reducer according to claim 1, wherein the outer body includes a wave generator in which the input shaft is fixed, and a flexspline that forms the internal space between the wave generator. The speed reducer according to claim 1 or 2,
A power unit for rotating the input shaft;
And a rotation output unit that rotates by an output from the speed reducer based on the rotation of the input shaft.

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