JPH04290643A - Trochoid type toothed internal type planetary gear structure - Google Patents

Abstract

PURPOSE:To reduce the angular backlash without improving the working precision, in a trochoid type toothed internal type planetary gear structure. CONSTITUTION:An internal gear 110 is divided in the radial direction into (divided) internal gear bodies 110Xa and 110Xb having each wedge-shaped section including an internal gear part and a base body 110Y positioned on the outer peripheral side. Then, the wedge-shaped (divided) internal gear bodies 110Xa and 110Xb are assembled through the pressing in the direction parallel to the axial direction of the internal gear 110 between the external gears 105a and 105b and the base body 110Y, and shifted to the external gear 105a and 105b sides by reducing the pitch circle of the internal gear parts of the (divided) internal gear bodies 110Xa and 110Xb. Accordingly, the gap between the inner teeth of the internal gear 110 and the outer teeth of the external gear 110 can be reduced nearly to zero, and the angular backlash can be reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trochoidal tooth profile internal planetary gear structure which is particularly designed to reduce angular backlash.

0002

[Prior Art] Conventionally, a first shaft, an eccentric body that rotates due to the rotation of the first shaft, a trochoidal external gear attached to the eccentric body and capable of eccentric rotation, and the external gear A trochoidal tooth-shaped internal planetary gear structure includes an internal gear that internally meshes with the external gear, and a second shaft that is connected to the external gear through a means for extracting only the rotational component of the external gear. widely known.

Specific conventional examples of this structure are shown in FIGS. 3 and 4.
Shown below.

[0004] In this conventional example, the above structure is applied to a "reducer" by using the first shaft as an input shaft, the second shaft as an output shaft, and fixing an internal gear.

The input shaft 1 has a predetermined phase difference (in this example, 18
The eccentric bodies 3a and 3b are fitted together with an angle of 0°). The eccentric bodies 3a and 3b are each eccentric by an eccentric amount e (center O2) with respect to the input shaft 1 (center O1). Two external gears 5a, 5 are connected to each eccentric body 3a, 3b via bearings 4a, 4b.
b are installed in double rows. These external gears 5a, 5
b is provided with a plurality of inner roller holes 6a and 6b, into which an inner pin 7 and an inner roller 8 are loosely fitted.

[0006] The reason why there are two external gears (double row) is as follows.
This is mainly to increase transmission capacity, maintain strength, and maintain rotational balance.

External teeth 9 having a trochoidal tooth profile (arc tooth profile when a cycloidal portion, which is a special solution of the trochoid, is used) are provided on the outer periphery of the external gears 5a and 5b. The external teeth 9 are internally meshed with an internal gear 10 fixed to a casing 12. Specifically, the internal teeth of the internal gear 10 have a structure in which an external pin 11 is loosely fitted into an external pin hole 13 and is held so as to be easily rotated.

[0008] An inner pin 7 passing through the external gears 5a and 5b is fixed to or fitted into the output shaft 2.

When the input shaft 1 rotates once, the eccentrics 3a, 3
b rotates once. Due to one rotation of the eccentrics 3a, 3b, the external gears 5a, 5b try to perform rocking rotation around the input shaft 1, but their rotation is restrained by the internal gear 10, so the external gear 5a , 5b are inscribed in this internal gear 10 and perform almost only rocking.

For example, if the number of teeth of the external gears 5a and 5b is N and the number of teeth of the internal gear 10 is N+1, the difference in the number of teeth is 1. Therefore, for each rotation of the input shaft 1, the external gears 5a and 5b shift (rotate) by one tooth with respect to the internal gear 10 fixed to the casing 12. This means that one rotation of the input shaft 1 is -
This means that the rotation speed has been reduced to 1/N.

The rotation of the external gears 5a, 5b has its oscillating component absorbed by the gap between the inner roller holes 6a, 6b and the inner pin 7 (inner roller 8), and only the rotational component is transmitted through the inner pin 7. It is transmitted to the output shaft 2.

[0012] As a result, a deceleration of a reduction ratio of -1/N is finally achieved.

The above-mentioned internal meshing planetary gear structure is currently applied to various speed reducers or speed increasers. for example,
In the above structure, the first shaft was used as the input shaft and the second shaft was used as the output shaft, and the internal gear was fixed.
The first shaft is the input shaft, the internal gear is the output shaft, and the second
It is also possible to construct a speed reducer by fixing the shaft. Furthermore, by changing the input and output shafts in these structures, a "speed increaser" can be constructed.

Incidentally, FIG. 5 shows an example in which the above structure is of a unit type (Japanese Patent Laid-Open No. 62-2043).

In this structure, the output shaft 2 is attached to a mating engine through a bolt hole 14, but the internal meshing planetary gear structure itself is the same as that shown in FIGS. 3 and 4. Therefore, members having the same functions as those shown in FIGS. 3 and 4 are given the same reference numerals. Internal meshing planetary gear structures are also used in these types of speed reducers and speed increasers.

Generally, in a gear transmission mechanism, there is play or play between the gears meshing with each other or in the means for attaching the gears to the shaft. Therefore, even if the driving side is reversed when changing from normal rotation to reverse rotation, it does not immediately appear as a reverse rotation on the driven side.

[0017] In this specification, for the sake of convenience, the play and wobbling that occur when changing from normal rotation to reverse rotation will be referred to as ``angular backlash.'' That is, this angular backlash indicates how much the input shaft must be reversed before the output shaft will follow it and reverse. In other words, this angular backlash can be defined as the amount (angle) by which one shaft (input shaft or output shaft) can be moved while the other is stopped, and when each gear is assembled, It does not indicate how much of a gap there is.

[0018] In a transmission mechanism employing a double-row internally meshing planetary gear structure as described above, play and backlash in the individual meshing parts interfere with each other, so such angular backlash occurs. The rush is expected to be relatively small.

However, even with such a double-row internally meshing planetary gear structure having a plurality of externally toothed gears, since power is originally transmitted through tooth-to-tooth meshing, there is a problem in correctness. Even though it is small, angular backlash still occurs when changing from a rotation to a reverse rotation.

The existence of such angular backlash means that
When the transmission mechanism is used as a control device that involves forward and reverse rotation, it is undesirable because the accuracy naturally decreases and shocks are more likely to occur from the standpoint of the pure mechanical durability of the transmission mechanism itself.

[0021] Conventionally, in order to reduce this angular backlash, methods have been taken such as increasing the machining accuracy of parts or selecting and combining the parts to be employed.

Furthermore, in Japanese Patent Application Laid-open No. 59-106744, etc., the eccentric body is divided into parts corresponding to the external gears, and the mounting means for attaching each eccentric body to the shaft is rotatable with respect to the shaft. A method is disclosed in which the angular backlash in the forward rotation direction is removed by one eccentric body and the angular backlash in the reverse rotation direction is eliminated by the other eccentric body in the mounted state.

[0023]

However, the method of increasing the precision of parts described above has the disadvantage of increasing manufacturing costs.

[0024] Furthermore, the method of selectively combining parts to be assembled has a problem in that workability is extremely poor because parts with small gaps are originally assembled in order to reduce angular backlash.

[0025] Furthermore, in the method disclosed in Japanese Patent Application Laid-Open No. 59-106744, a plurality of external gears are provided to form a double row, which itself can increase transmission capacity, maintain strength, maintain balance, etc. However, when rotating in the forward direction, power is transmitted only by the external gear that has essentially eliminated backlash in the forward direction, and when rotating in reverse, power is transmitted only by the external gear that has eliminated the angular backlash in the reverse direction. Because of the power transmission, a new problem arose in that the advantages of having a double row as described above had to be abandoned.

The present invention has been made in view of these conventional problems, and is capable of eliminating angular backlash with a simple configuration, and in cases where a plurality of external gears are provided. The object of the present invention is to provide an internally meshing planetary gear structure that does not lose its advantages.

[0027]

[Means for Solving the Problems] The first invention includes a first shaft, an eccentric body that rotates due to the rotation of the first shaft, and an external gear that is attached to the eccentric body and is capable of eccentric rotation. , a trochoidal tooth profile inscribed, comprising: an internal gear that internally meshes with the external gear; and a second shaft connected to the external gear via a means for extracting only the rotational component of the external gear. In the type planetary gear structure, the internal gear is divided in the radial direction into an internal gear body that includes an internal tooth portion and has a wedge-shaped cross section, and a base body located on the outer peripheral side of the internal gear body, and the wedge The above problem is solved by pressing and assembling a shaped internal gear between the base body and the external gear in a direction parallel to the axial direction of the internal gear.

[0028] The second invention also provides a first shaft, an eccentric body that rotates due to the rotation of the first shaft, a plurality of external gears that are attached to the eccentric body and are capable of eccentric rotation; an internal gear that internally meshes with the external gear via internal teeth constituted by an external pin; and a second shaft connected to the external gear via means for extracting only an autorotation component of the external gear. In the double-row trochoid tooth profile internal planetary gear structure, the internal gear is divided in the radial direction into an internal tooth body including an internal tooth portion and a base body located on the outer peripheral side of the internal gear body. At the same time, the internal tooth bodies of these are further divided in the axial direction in correspondence with the plurality of external gears to form a plurality of divided internal gear bodies each having a wedge-shaped cross section, and each of the divided internal gears having a wedge shape is divided into two parts. The body is assembled by pressing the body between the base body and the external gear in a direction parallel to the axial direction of the internal gear, and the circumferential phase of each divided internal gear is adjusted to match the external gear. By aligning them through pins, the above problem was also solved.

[0029]

[Operation] In the first invention, the internal gear is divided in the radial direction into an internal tooth body that includes an internal tooth portion and has a wedge-shaped cross section, and a base body located on the outer peripheral side of the internal tooth body. There is. Then, the wedge-shaped internal gear is assembled between the base body and the external gear while being pressed in a direction parallel to the axial direction of the internal gear.

As a result, the distance between the base body of the internal gear and the external gear is expanded by the wedge-shaped internal gear. Since the base body of the internal gear is stronger than the internal tooth body, as a result, the pitch circle of the internal tooth portion of the internal tooth body is reduced and is moved toward the external gear (inward in the radial direction) by that amount.

The distance between the internal gear and the external gear can be changed by adjusting the pressing force of the internal gear. Since the amount of angular backlash depends on this spacing, by pressing the internal gear until it contacts the external gear, the angular backlash can be reduced to approximately zero.

On the other hand, the second invention is mainly intended to be applied to a double-row internal planetary gear structure having a plurality of external gears.

That is, according to the second invention, the internal gear is first divided into an internal tooth body including the internal tooth portion and a base body located on the outer periphery of the internal tooth body. At this time, the internal gear body is further divided in the axial direction in correspondence with the plurality of external gears, so that as a result of the division, a plurality of divided internal gear bodies each having a wedge-shaped cross section are formed.

As a result, by pressing each of the wedge-shaped divided internal gear bodies between the external gear and the base body of the internal gear in a direction parallel to the axial direction of the internal gear, The pitch circle of the internal tooth portion of the tooth body can be reduced.

In this case, if the external pins constituting the internal teeth of the internal gear are also divided in the axial direction corresponding to the external gears, the phase difference in the circumferential direction of each divided internal gear (external tooth There is no way to prevent the pitch circle from shifting (180° if there are two gears, 120° if there are three gears) when reducing the pitch circle.
As a result, it may become difficult to maintain an accurate phase difference.

[0036] Therefore, in the second invention, the outer pin is not divided into parts, and the phase difference in the circumferential direction of each internal tooth body can always be accurately maintained using one outer pin. This is how it was done.

As a result, an internal planetary gear structure without angular backlash and in which accurate phase difference is always maintained can be obtained.

Furthermore, since the power is transmitted in both forward and reverse directions by the cooperation of the external gears, the advantages of the double-row system as described above can be enjoyed as is.

Furthermore, since both the first and second inventions do not make the gaps between the members close to zero by increasing the machining accuracy, the cost does not increase much and assembly is relatively easy.

Further, by adjusting the pressing force, manufacturing variations can be absorbed and a state in which the internal gear and the external gear are in exact contact can be formed.

[0041]

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
2 is a diagram illustrating the configuration of the main parts in FIG. 1 more clearly.

Conventionally, the internal gear, which has been integrated, is divided in the radial direction into an internal gear body 110X including an internal tooth portion, and a base body 110Y located on the outer peripheral side of the internal gear body 110X.

The internal gear body 110X has two external gears 1.
05a and 105b, it is further divided in the axial direction to form two divided internal tooth bodies 110Xa and 110Xb.

[0045] Each divided internal tooth body 110Xa, 11
0Xb has a wedge-shaped cross section, and its short sides are arranged in directions facing each other.

Numeral 114 is a bolt that fixes the base body 110Y of the internal gear 110 to the casing 112. By tightening this bolt 114, each divided internal gear body 110Xa, 11 is removed from the casing 112 side.
A pressing force in the axial direction is applied to each of 0Xb.

FIG. 2 shows a state in which the bottle 114 has not yet been tightened.

As is clear from the figure, when not tightened, each divided internal tooth body 110Xa, 110Xb is
Each protrudes by δ with respect to the axial length L of the base body 110Y.

Now, when the bolt 114 is tightened,
Via the pressing surface 112a of the casing 112, the divided internal gear bodies 110Xa and 110Xb are connected to the external gear 105a.
, 105b and the base body 110Y in a direction parallel to the axial direction of the internal gear. As a result, split internal tooth body 1
The pitch circles of the internal tooth portions (specifically, the external pins 111) of 10Xa and 110Xb are reduced, resulting in external gears 105a and 110Xb.
105b and will soon come into contact with it, so stop tightening the bolt 114 at this point.

As a result, external gears 105a and 105b
Since there is no gap between the external pin 111, which is the internal tooth of the internal gear, the angular backlash can be reduced to zero or almost zero.

[0051] Here, since the outer pin 111 is not divided in the axial direction and is made into one piece as before, the pitch circles of the divided internal tooth bodies 110Xa and 110Xb are reduced in this way when assembled. Even if this happens, the phase difference in the circumferential direction can always be maintained at a predetermined value (180° in this example), making it possible to maintain good rotational balance.

Furthermore, since the external pin 111 and the external gears 105a and 105b are brought into contact by tightening the bolt 114, the machining error itself of each member is not required to be very high, and therefore the manufacturing cost is reduced. can suppress the rise in

Furthermore, since the degree of contact at one end of the external gear 105a in the axial direction is loose, in the unlikely event that
Even if there are manufacturing variations in the dimensions of each component, the presence of this loose side makes it possible to appropriately absorb this, and also prevents the accumulation of a lubricating oil film on this warmer side. It becomes possible.

As a result, by increasing the machining accuracy, it is possible to reduce machining costs, reduce transmission loss, and improve durability compared to the method of completely eliminating the gap between the external gear and the external pin. Become.

Furthermore, since power is transmitted in both the forward and reverse directions through the two external gears 105a and 105b, the advantages of using two external gears, namely, increased transmission capacity and maintenance of strength, can be achieved. , the benefits of maintaining balance can be enjoyed without being diminished.

Since the configuration and basic operation of other parts are completely the same as those of the conventional one, similar parts in the drawings are designated by the same reference numerals having the same last two digits, and redundant explanation will be omitted.

Note that in the above embodiment, the outer pin 11
Although so-called outer rollers are not provided around the outer roller, it is obvious that the present invention can be applied to an internally meshing planetary gear structure that uses outer rollers.

[0058]

[Effects of the Invention] As explained above, according to the present invention, while maintaining most of the basic advantages of the internal planetary gear structure,
An excellent effect can be obtained in that angular backlash can be efficiently reduced with a low cost and simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a speed reducer to which a double-row trochoidal tooth-shaped internal planetary gear structure according to an embodiment of the present invention is applied.

FIG. 2 is a partial cross-sectional view that enlarges the main part of FIG. 1 and clearly shows its configuration.

FIG. 3 is a sectional view showing a reduction gear to which a conventional double-row trochoidal tooth-shaped internal planetary gear structure is applied.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

FIG. 5 is a sectional view showing an example in which a conventional double-row trochoidal tooth profile internal planetary gear structure is applied to another speed reducer.

[Explanation of symbols]

1, 101...Input shaft, 2, 102...Output shaft, 3a, 3b, 103a, 103b...Output shaft, 5
a, 5b, 105a, 105b...external gear, 7
, 107...Inner pin, 8, 108a, 108b...Inner roller, 10, 110
...Internal gear, 11, 111...Outer pin, 110X...Internal gear body, 110Xa, 110Xb...Segmented internal gear body, 110Y...
base body.

Claims (2)

[Claims] Claim 1: A first shaft, an eccentric body that rotates by rotation of the first shaft, an external gear attached to the eccentric body and capable of eccentric rotation, and internally meshing with the external gear. A trochoidal tooth profile internal planetary gear structure comprising an internal gear and a second shaft connected to the external gear through a means for extracting only an autorotation component of the external gear, wherein the internal gear is divided in the radial direction into an internal tooth body including an internal tooth portion and having a wedge-shaped cross section, and a base body located on the outer peripheral side thereof, and the wedge-shaped internal tooth body is A trochoidal tooth-shaped internal planetary gear structure, characterized in that the base body and the external gear are assembled by pressing in a direction parallel to the axial direction of the internal gear. 2. A first shaft, an eccentric body that rotates by rotation of the first shaft, a plurality of external gears that are attached to the eccentric body and capable of eccentric rotation, and an external pin on the external gears. and a second shaft connected to the external gear through a means for extracting only the rotational component of the external gear. In the trochoidal tooth-shaped internal planetary gear structure of the formula, the internal gear is divided in the radial direction into an internal tooth body including an internal tooth portion and a base body located on the outer peripheral side of the internal gear body, and The tooth body is further divided in the axial direction in correspondence with the plurality of external gears to form a plurality of divided internal gear bodies each having a wedge-shaped cross section, and each of the wedge-shaped divided internal gear bodies is attached to the base body. and the external gear by pressing in a direction parallel to the axial direction of the internal gear, and the circumferential phase of each divided internal gear body is aligned via the external pin. A double-row trochoidal tooth profile internal planetary gear structure.