JPS6057058A - Lubricating oil seal device of harmonic gear device - Google Patents

Abstract

PURPOSE:To obtain a seal of lubricating oil with less time aging, by juxtaposing a circular separator plate in the side of a wave generator coaxially with a cam plate so as to be prevented from rotating with an external gear and fixing an O-ring to the periphery of the separator plate. CONSTITUTION:A wave generator 4 comprises an oval shaped cam plate 6 connecting a driving shaft 5 to the center and a ball bearing 7 rotating this cam plate 6 relating to an external gear 3, and the bearing 7 comprises an inner ring 8 secured to the peripheral surface of the cam plate 6, outer ring 9 fitted to an internal surface of the gear 3 and many balls 10. The wave generator 4 arranges a separator plate 22 coaxially with the cam plate 6, and the separator plate provides in its center a hole 23 through which the driving shaft 5 is extended. Then an oil seal 24 is provided between the separator plate 22 and the shaft 5, and a clearance between the separator plate 22 and the external gear 3 is tightly sealed by fitting an O-ring 26 to a recessed groove 25 on the peripheral surface of the separator plate 22.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a harmonic gear system, and more particularly to a lubricating oil sealing device for a harmonic gear system.

Prior art harmonic gear systems are already known, and their typical configuration is a rigid circular internal gear, a flexible external gear provided with a different number of teeth inside the internal gear, a wave generator that fits inside the external gear, bends the external gear into an elliptical shape, meshes with the internal gear on the length 111 of the ellipse, and rotates the elliptical shape; The wave generator includes an elliptical cam plate with a drive shaft connected to the center, and a pole bearing provided around the periphery of the cam plate and consisting of a flexible outer ring, a flexible inner ring, and a large number of poles between the two wheels. consists of In this harmonic gear system, the number of teeth of the internal gear and the external gear are not the same, but are increased (or decreased) by two teeth relative to the other, and the drive shaft of the wave generator cam plate is connected to, for example, a motor to When you rotate the cam plate,
The meshing points of the external gears are shifted by the difference in the number of teeth, and when one of the external gears or the internal gears is fixed with the drive shaft as the input, the other gear becomes the output, and the output gear has a large deceleration relative to the input shaft. It will rotate with the ratio.

To rotate the output gear as above, use a human power shaft,
Furthermore, in order to rotate the cam plate of the wave generator a lot, gamma lubricating oil is essential for the bearing.

In order to seal this 6-cell 11 oil into a bearing, conventionally there is an elastic body connected to a cam plate and sealed on both sides of the bearing, but as mentioned above, the bearing has an elliptical shape of an external gear. Since it is meant to be rotated, sweet Kamui fabrics tend to be rotated at high speeds, so the sealing body is rotated and deformed at high speed, causing rapid deterioration and making it impossible to obtain a sufficient sealing body. I couldn't.

Separately, in the case of grease lubrication, there is a type of lubricating device that pumps up the oil liquid and supplies it to the bearing because the Q dissipation of the grease is large, but it not only requires a special device for lubrication. , when the posture of the bearing changes constantly, for example when used in a robot arm, etc.
I didn't like spilling the oil and shaking it.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a harmonic gear device 8 incorporating a lubricating oil sealing device that is less likely to deteriorate over time and does not require pumping of oil.

Structure of the Invention In order to achieve the above object, in the harmonic gear device according to the present invention, a circular partition plate is juxtaposed coaxially with the cam plate on the side surface of the wave generator, and this partition plate is arranged in parallel with the cam plate. It is connected so as not to rotate, and in the center of the partition plate,
It is characterized in that an oil sealing means is provided between it and the drive shaft, and an O-ring made of an elastic material is fixed to the outer periphery of the partition plate to seal the gap between it and the inner surface of the foreign gear.

Effect of the Invention The partition plate is provided with an oil sealing means between the shaft and the shaft, and an O-ring also seals the oil between the external gear and the partition plate. Since it is connected to the cam plate, it is also connected to the external gear, so when the cam plate rotates, it does not rotate with it, and as the elliptical shape of the external gear changes, the elastic O-ring expands and contracts only in the radial direction, and the sealing effect is high.

Effects of the Invention Accordingly, oil sealing by the partition plate is extremely high, and since there is no relative rotation with the foreign gear which deforms into an elliptical shape, there is no deterioration due to wear etc., and deterioration over time is extremely reduced. Since a sealing device with such a high sealing effect essentially consists of a partition plate and an O-ring, the harmonic gear device δ can be kept in a container or in a flat trench for use in applications such as robot arms, etc. It can be used even in places with limited space, and has a high sealing effect, making it possible to use grease lubrication even when it was previously considered necessary. , 口y)? It can be used in all postures even when used as a cut arm. Also, due to its high oil sealing effect,
Of course, the lifespan of the harmonic gear device becomes longer, but even if another device such as a shaft encoder is installed immediately adjacent to the gear device, lubricating oil will not flow into the encoder, and the gear device with encoder f : Can be made extremely compact.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the invention.

In this figure, the auxiliary gear device 1 basically consists of a rigid internal gear 2 and external teeth provided inside the internal gear 2 with a different number of teeth (for example, 2 fewer teeth). A wave generator 4 which bends the external gear 3 into an elliptical shape and engages the external tooth J1 (3) with the internal gear 2 at a point on the long axis of the ellipse and rotates the elliptical shape. It consists of

The wave generator 4 includes an elliptical cam &6 with a drive shaft 5 connected to the center, and rotates the cam plate 6 relative to the external gear 3. - a ring bearing 7, which is provided between an inner ring 8 fixed to the outer circumferential surface of the cam plate 6, an outer ring 9 fitted to the inner surface of the external gear 3, and between both rings. It has a large number of poles 10, and the inner ring and outer ring are made of flexible material that can be bent into the elliptical shape of the cam plate 6. In addition, ball 10f: It is preferable that a spacer is provided to be arranged in a uniform concavity.

The drive shaft 5 is connected to be rotated by ground motion means such as a motor 12, and when the wave generator 4 is rotated by the rotation of the motor 12, the external gear 3. The elliptical shape is rotated along the internal teeth of the internal gear 2, and as mentioned above, since there is a difference in the number of teeth between the external gear 3 and the internal gear 2, the difference in the number of teeth causes the two to rotate. The meshing point of gears. If one of the two gears is fixed,
The other rotates at a speed that is significantly reduced from the 40 rotations of the wave generator, and becomes the output member.

In this example, the external gear 3 is fixed and the internal gear 2 is used as an output member. External gear 3 is on one side 11]ll
It extends toward the left side in FIG. 1, and its final QfM converges inward in the radial direction to form a tip. This end face 13 is fixed to the end plate of the housing 14 of the harmonic gear device 1 with screws 15 or the like, and the housing 14 is fixed to the motor case 16. On the other hand, the internal gear 2 has an output plate 17 formed in a cover shape so that the other side (the internal gear 2f on the right (1u) in FIG. etc., and a suitable bearing 19 is provided between the housing 14 and the outer surface of the internal gear 2 so that the internal gear 2 can rotate relative to the housing.7i :b, output board 1
It is preferable to provide a sealing means such as an O-ring 20 on the outer peripheral surface of the bearing 19 (or the outer surface of the internal gear) to seal the bearing 19 with oil and prevent dirt from entering.

In the present invention, a circular partition plate 22 is provided with a slight gap on the side opposite to the output plate 1γ of the wave generator I.
are coaxially juxtaposed with the cam plate 6. This partition plate 22
A hole 23 is provided in the center of the center, through which the drive shaft 5 passes without contact, and the partition plate 22 and the drive shaft 5 are connected to each other.
A known shaft layer oil seal 24 is provided between the two. The outer diameter of the partition plate 22 is 1\-more than the inner diameter of the external gear 3.
＼A groove 25 is formed on the outer circumferential surface of the groove, and a QIJ song 6 made of an elastic material is inserted into the groove 25.
is fitted. This O-ring is preferably made of a material that has good air-tight (or liquid-tight) properties and does not vibrate with oil; for example, nitrile rubber, neozolene, etc. are used. As for the hardness, it is preferable that the Shore hardness Hs is O~GO. This O-ring 26 protrudes outward from the outer peripheral surface of the partition plate 26 so as to seal the gap between the outer peripheral surface of the partition plate 22 and the inner surface of the external gear 3. A dead man,
The cross-sectional diameter of this O-ring 26 is preferably 0.0 g DF-(A/ODF) with respect to the pitch diameter DF of the external gear 3, and this O-ring 26 is in contact with the inner surface of the external gear 3. The amount x of deflection due to contact is 0.0 gD to 0 on the long axis of the ellipse with respect to the cross-sectional diameter of the O-ring.
．． /LtX is 0.23D to 0 on the short axis of the short circle of D1
．． It has been found that 3D is preferable and that this allows good liquid tightness to be maintained, high efficiency, and also improves the ability to insert the partition plate as a harmonic gear device.

A predetermined space 28 is provided between the partition plate 22 and the terminal end surface 13 of the external gear 3. A shaft encoder that detects, for example, the number of rotations, rotation speed, rotation angle, etc. of the drive shaft 5 is provided in this space. This shaft encoder includes a slit plate 29 fixed to the shaft 5, and a light source and a light receiving element (
(not shown), and this light source and light receiving element are accommodated in the encoder housing 30. This housing 30 is fixed to the housing 14 via the terminal end surface 13 of the external gear 3 with screws or the like.

Note that it is preferable to provide a bearing 31 between the slit plate support portion and the housing 30 so that the slit plate 29 rotates smoothly.

A partition plate 22 forms a predetermined space 28 and is fixed to the encoder housing 30 with screws or the like. Therefore,
The partition plate 22 is joined to the housing 30 and connected to the external gear 3, and is held so that there is no relative rotation with the external gear 3. When the wave generator 4 is rotated, the cam plate 6 rotates and rotates the tiτ circular shape of the external gear.
As described above, the partition plate 22 does not rotate relative to the external gear 3 (both are fixed members in this example), and the partition plate 22 does not rotate relative to the external gear 3 (both are fixed members in this example).
The second elastic O-ring 26 only bends in the radial direction.

In other words, even when the wave generator 4 rotates, the Q-ring 26 of the partition plate 22 does not move in the circumferential direction on the inner surface of the external tooth i--car, so there is almost no wear, and its sealing effect is large, and the bearing When grease 32 is filled between the wave generator 4 and the
This allows the device to be placed in the closest position, making it possible to make the entire device smaller. Note that since the output plate 17 closes the other side of the bearing 1, the grease will not scatter to the outside.

Next, the inventor examined the shape of the O-ring 26 (7i) regarding the shape of the surface that contacts the inner surface of the external gear 3. As a result, a simple O-ring 26 with a circular cross section was sufficient, but a more preferable case would be one with a trapezoidal cross section and in flat contact with the inner surface of the external gear 3, or one with external teeth t. :・
It was formed into a gold mountain shape facing the inner surface of the 7th wheel 3.

It has been found that when the cross section is made into a square shape, one side overlaps the other, or it spreads out, making it impossible to maintain the V-shape. This is because, while the outer 1a gear is fixed at the end face 13, the gear part that is away from this fixed end is deformed into an elliptical shape and bends with the end face as the fixed end.
This is because it makes a slight reciprocating motion in the axial direction, gradually deforming the side portions forming the V-shape.

FIG. 2 shows a λth embodiment of a harmonic gearing device with a lubricating oil sealing device according to the present invention. This figure differs from the one in Figure 1 in that the external gear is formed as a flange that expands radially outward at its terminal end.
Other than that, the embodiment is substantially the same as the embodiment shown in FIG. 7, although the shape is slightly different. The external gear 33 is formed as a shift flange 34 that expands radially outward at its terminal end surface, and the flange 34 is fixed to the device housing 14 with screws or the like. The partition plate 22 is arranged with a predetermined distance of 28″f between it and the flange 34, and the shaft encoder shown in FIG. It is fixed to the gear 33.In addition, the output plate 35 & inner teeth (1 is fixed to the wheel 2, but the 1st
The shape may be slightly different from that shown in the figure'), b
'+p'j) is attached to the extension j5s of the shaft 5 via a bearing 36. 1, O-ring 2 of the partition plate 22
6 has the same diameter as the second embodiment, and its shape is as described above.
A: Those in the shape of hills are used. This partition plate 22 is mounted so as not to rotate relative to the external toothed wheel 1'', and its sealing effect is high.

In this embodiment, since the outer teeth of the chopsticks extend outward, the space between them and the partition plate can be
t-'] K-mounted encoder kit has the advantage of being easy to handle, and the device can be attached to the motor by simply inserting the motor shaft as a shaft, and it is even more compact as a motor-embedded device. .

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a first embodiment of a harmonic gear device according to the present invention, and FIG. 2 is a partial vertical cross-sectional view of a device according to a first embodiment of the present invention. 1... Harmonic gear device, 2... Internal gear, 3.33.
・・External gear, 4・Wave generator, 5・・
・Drive shaft, 1...Ball bearing, 12...
- Motor, 14... Device housing, 16... Motor case, 1γ, 35... Output plate, 22... Partition plate, 24... Oil seal, 26... O ring, 28
...Space, 30...Encoder housing.

Claims (1)

[Claims] / A rigid circular internal gear, a flexible external gear provided with a different number of teeth inside the internal gear, and a foreign gear fitted inside the external gear. It is equipped with a wave generator which is shaped like an ellipse and is meshed with an internal gear on a long sleeve of a case circle, and also rotates the ellipse. It consists of an oval-shaped cam plate, a flexible outer ring and inner ring provided on the outer periphery of the cam plate, and a number of goals between the two rings. - in a harmonic gear device having a lupea cylinder, a circular partition plate is arranged coaxially with the cam plate on the side surface of the wave generator, and the partition plate is connected to the external gear so as not to rotate; An oil sealing means is provided in the center of the partition plate between it and the drive shaft, and a QIJ ring made of an elastic material is fixed to the outer periphery of the partition plate to seal the gap between it and the inner surface of the external gear. % to become
The outer Q gear extends laterally beyond the partition plate, and its terminal end converges inward in the radial direction to form a tip, and is connected to the wall surface that becomes the bottom of the tip. 2. The device according to item 1, wherein a predetermined space is formed between the device and the partition plate. 3 Does the external gear cross over the partition plate to the side? 1. long,
2. The device according to claim 1, wherein the terminal end is formed as a flange that opens outward in the radial direction, and a predetermined space is formed between the flange surface and the partition plate. The device according to item 2 or item 3 j12, wherein an encoder for detecting the rotation speed and rotation angle of the shaft is installed in the space. 3. The O-ring has a circular cross section.
This device. B. The device according to item 47, wherein the O-ring is formed so that the outer circumferential surface in contact with the external gear is flat. 7. The device 1τ according to item 1, wherein the O-ring has a surface in contact with the external gear having a corrugated cross section.