JPS624961A - Power transmission gear - Google Patents

Abstract

PURPOSE:To prevent the deformation and damage of a groove by forming the contact side with a rolling body of a periodic function groove sectional surface into projecting form to the side of the opponent groove where the rolling body does not contact. CONSTITUTION:A fixed disc 7, input disc 19 and the grooves 7a and 19a as periodic function grooves are installed into a case body 3. Balls 23 as rolling bodies are arranged between the grooves 7a and 19a. The groove 7a has the part 7b projecting to the nonrolling side of the groove 19a, and said groove 19a has the part 19b projecting to the nonrolling side of the groove 7a. Therefore, even if the engagement is not so favorable or a preload is not applied, the contact area between the rolling body and the groove can be increased, and the deformation and damage of the groove can be prevented.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a power transmission device, and particularly to a power transmission device that transmits power by rolling elements rolling between grooves formed on opposing surfaces of two members. .

[Technical background of the invention and its problems]

Conventionally, as this type of power transmission device, a reduction gear as shown in FIG.
Publication No. 53). That is, the input shaft 10 is inside the case 101.
The rotation of the eccentric portion 103a formed in the bearing 105
an input plate 107 that moves eccentrically through an output shaft 109; an output disc 111 connected to an output shaft 109; An intermediate disk 115 that moves eccentrically via a bearing 113 due to rotation is housed.

In this reducer, the rotation of the input shaft 103 causes the case 1 to
The rolling element 1 passes between the periodic function grooves formed on the opposing surfaces of the fixed disk 117 and the input disk 107, which form the
19 rolls as shown in FIG. 8, which is a cross-sectional view taken along line X-X in FIG. It rotates and decelerates.

The rotational motion of the input disk 101 is directly transmitted to the intermediate disk 115 by the crank mechanism via the rolling elements 121.

Power is transmitted between the intermediate disk 115 and the output disk 111 in the same way as the power transmission between the input disk 107 and the fixed disk 117, that is, the rolling elements 123 roll in periodic function grooves. Deceleration takes place. As a result, the rotation of the input shaft 103 is reduced in two stages and transmitted to the output shaft 109.

However, this type of reducer has the following problems. That is, the engagement between the two grooves and the rolling element in the reduction section is as shown in Fig. 9, and the groove machining is a hit!
If the condition of the rolling element 123 (119) and the groove 111a (117
a), 115a (107a) and groove end 111b
(117b), contact at 115b (107b),
The tooth surface is deformed or damaged. As a result, power transmission with high precision, long life, high efficiency, and large transmission capacity is no longer possible.

[Object of the Invention] The present invention has been made in view of such conventional problems, and its purpose is to prevent the rolling elements and the groove from coming into contact at the groove end. The purpose of the present invention is to provide a power transmission device with high accuracy, long life, high efficiency, and large transmission capacity.

(Summary of the Invention) The gist of the present invention is to form the groove cross-sectional shape asymmetrically in order to prevent the rolling elements and the groove from coming into contact at the groove ends.

That is, in the present invention, a first member and a second member are disposed facing each other, periodic function grooves having mutually different periods are formed on the opposing surfaces of these members, and a plurality of rolling elements are arranged between these periodic function grooves. In the power transmission device that transmits rotational force between the first member and the second member by changing the speed, a ball is used as the front rolling element, and the above-mentioned part of the groove of the first member The groove wall on the side where the ball comes into contact when receiving a transmission force is extended to the side of the groove wall of the groove of the second member that the ball does not come into contact with, and similarly the groove wall on the side of the second member that comes into contact with the ball. The groove of the first member has a groove cross-sectional shape that extends toward the groove wall side that the ball does not contact.

〔Effect of the invention〕

According to the present invention, by making the cross section of the periodic function groove on the side where the rolling elements contact (transfer side) protrudes toward the side of the mating groove where the rolling elements do not contact (non-rolling side), the engagement is somewhat improved. The contact area between the rolling element and the groove can be increased even when the rolling element is not in use or when no preload is applied. Therefore, deformation and damage to the groove can be prevented, and a power transmission device with high precision, long life, high efficiency, and large transmission capacity can be realized.

[Embodiments of the invention]

Hereinafter, one embodiment of this invention will be explained in detail based on the drawings = 5- Explain.

FIG. 1 is a sectional view showing a schematic configuration of a reduction gear as a power transmission device. The case 1 includes a cup-shaped case main body 3 having an opening toward the right in the figure, and a first disk mounted on the case main body 3 to close the opening and form a mechanism chamber 5. A fixed disk (first member) 7. An output shaft 11 is rotatably provided on the case body 3 via a bearing 9, and an input shaft 15 is rotatably provided on the fixed disc 7 via a bearing 13.

An eccentric portion 15a that is eccentric with respect to the input shaft 15 is formed at the tip of the input shaft 15 on the side of the mechanism chamber 5. An input disk (second member) 19 serving as a second disk is provided facing the fixed disk 7.

On each opposing surface of the fixed disk 7 and the input disk 19, there are hypotrochoid gears as an internal tooth width and hypotrochoid gears as an external gear. Coid equidistant curve -〇- Full 7a of line drawing shape (hereinafter referred to as hypo 1 herocoid tooth profile)
and (2) a vitrochoid equidistant curved tooth profile (hereinafter referred to as an evitrochoid tooth profile) 19a are formed, respectively.

As shown in FIG. 2, which shows the meshing of the gears viewed from the left and right directions in FIG. Individually arranged.

That is, consider two sets of pin gears that mesh with the hypotrochoid tooth profile and ■ pin gears that mesh with the vitrochoid tooth profile.
By using a common pin gear in these two phases, the inscribed play ψI! has a difference in the number of teeth between the two gears as shown in FIG. s side is formed.

The cross-sectional shapes of the grooves of the hypotrochoid tooth profile and the tooth profile are as shown in FIG. 3 or 4. That is, the bitrochoid tooth grooves 7a and 198 are located on the transfer side where the rolling elements contact and roll, and the hypotrochoid tooth grooves 78 extend to the non-transfer side of the evitrochoid tooth grooves 198. The ebitrochoid tooth groove 19a has the hypotrochoid tooth groove 7b.
It has a portion 19b extending toward the non-rolling side of 8. Also, the non-rolling side of the groove 78.19a is removed so as to be flush with the groove bottom that contacts the ball 23. Note that FIG. 3 shows a shape that extends linearly in the tangential direction, and FIG. 4 shows a shape that projects in an arc shape to match the curvature of the groove.

In such a mechanism, the ball 23 (bin gear) rolls between the grooves 78 and 19a, so that the input disk 19
Along with the revolution, the input shaft 15 rotates (rotates) in a direction opposite to the rotation direction of the input shaft 15. If we extract this rotation as output, we get
The first stage of deceleration will be performed.

Further to the left end of the eccentric part 15a, an eccentric part 15b is integrally formed, which is eccentric in the same width in the opposite direction to the eccentric part 15a. The eccentric portion 15b is provided with an intermediate disk 27 that moves eccentrically (revolutions) and rotates about the input shaft 15 together with the input disk 19 via a bearing 25.

As shown in FIG. 5, which is an explanatory diagram of the opposing surfaces viewed from the left in FIG. A plurality of pairs of circular grooves 31 and circular grooves 33, each having a radius of , are formed facing each other. A crank mechanism is formed by disposing the balls 35 between these pairs of circles as shown in FIG. 6, and the input disk 19 and the intermediate disk 27 have a rotation ratio of 1. are combined with.

Therefore, the revolution and rotational motion of the input disk 19 is directly transmitted to the intermediate disk 27. At this time, since the eccentric parts 15a and 15b are eccentric by the same amount in opposite directions, the input disk 19 and the intermediate disk 27 are kept in balance with respect to their revolution.

An output disk 37 is arranged on the left side of the intermediate disk 27 to face it. This output disk 37 is attached to the output shaft 11 which is concentric with the input shaft 15. A small diameter portion 15c of the input shaft 15 protrudes from the left end of the eccentric portion 15b, and the small diameter portion 1
5G is supported by the output disk 37 via the bearing 39, so that one end of the input shaft 150 inside the case 3 is supported.

On the opposing surfaces of the intermediate disk 27 and the output disk 37, there are grooves 27a and hypotrochoidal grooves similar to the periodic function grooves formed on the opposing surfaces of the fixed disk 7 and the input disk 19, respectively. Trochoid tooth-shaped grooves 378 are formed respectively, and as shown in FIG. A plurality of balls 41 are arranged. That is, the ball 41 functions as a pin gear, and the ball 41 has the groove 27a.

378, the output disk 37 is decelerated and rotates. In other words, here too, the difference in the number of teeth shown in FIG. 2 forms a two-plane internal planetary mechanism.

Therefore, the first deceleration mechanism (inscribed M star mechanism) 43 formed between the input disk 19 and the fixed disk 7 performs the first stage of deceleration, and the intermediate disk 27 and the output disk 37 A second deceleration mechanism (internal planetary mechanism) 45 formed between the two performs second-stage deceleration.

Among the disks in the mechanism chamber 5, the intermediate disk 27 and the protruding horn disk 3
7, the output disk 37 corresponds to the fixed disk, and the intermediate disk 27 corresponds to the input disk 19, so the output disk 37 is the first disk, The intermediate disk 27 is the second disk.

Here, the number of teeth of the vitrochoid tooth profile, hypotrochoid tooth profile, and bottle tooth width in the first reduction mechanism III mechanism 43 are respectively Zle, Zth, and Z+p, and the number of teeth in the second reduction mechanism 45 is 72e, respectively.

Assuming Z2b and Z2p, Ztp=Z+e+ 1 =Zsh -1221)=2
There is a relationship of 2e+1 = Z2h 1, and the reduction ratio 11 of the first stage and the final reduction ratio 12 of the second stage are as follows.

i i =-(Zth-Zte) /Zte--2/Z
1e...■i 2 = 1-
(Zxh-Z2e/V+e-Z2h) -■Here, the angle sign indicates that the rotation direction on the input side and the rotation direction on the output side are opposite. Further, when Z1p=22p, no output rotation is obtained. In this example, 71e=1
0. Ztp=11, Zth-12, Z2e=1
1. Z2p=12. Z2+1=13, and by substituting these values into the above formula 0, the R final reduction ratio 12 is -(
1/65).

In addition, the symbols 47, 49, and 51 in Fig. 2 are the pitch circle of the hypo1 herocoid tooth profile, the pitch circle of the pin gear, and the pitch circle of the pin gear, respectively.
[Shrimp] It is a pitch circle with a heloid tooth shape.

Next, the effect of the above configuration will be explained.

In response to the 150 rotations of the input shaft, the human power disk 19 makes an eccentric movement (revolution), and at the same time, the first speed reducer 4M43 causes it to rotate at a reduced speed (rotation movement) in a direction opposite to the rotation direction of the input shaft 150. This revolution and rotation motion is directly transmitted to the intermediate disk 27 via a crank mechanism having a ball 35.

The rotational motion of the intermediate disk 27 is further decelerated by the second speed reduction mechanism 45 and reaches the output shaft 11 via the output disk 37.

As shown in FIGS. 3 and 4, the cross section of the tooth profile groove forming the deceleration mechanism 43.45 is as shown in FIGS. The tooth profile groove 19a (27a) has a portion 7b (37b) extending toward the non-rolling side, and conversely, the transfer side of the ebittrochoid tooth profile 19a (27a) is the non-transfer side of the hypotrochoid tooth profile 7a (37a>) on the other side. For this reason, even when there is no preload in the axial direction or when the engagement is somewhat poor due to machining accuracy, the rolling element and the two tooth grooves are connected to the groove end. There is no contact between the parts, and a certain amount of contact area is always maintained.Therefore,
Deformation of the tooth profile and damage to the south face due to contact pressure are extremely reduced.

As described above, according to this embodiment, it is possible to prevent the ball and the groove from coming into contact with each other at the groove end. As a result, deformation of the tooth profile forming the groove and damage to the tooth surface are extremely reduced, resulting in high precision, long life, and high efficiency.

A reduction mechanism with a large transmission capacity can be realized.

=13- Note that the present invention is not limited to the embodiments described above. For example, the speed reduction mechanism is not limited to two stages,
Of course, it may be one stage or three or more stages. Further, conditions such as the period, groove width, and depth of the periodic function grooves of the first and second members may be appropriately determined according to specifications. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

1 to 6 are for explaining the schematic structure of a reduction gear according to an embodiment of the invention, respectively. FIG. 1 is a sectional view showing the overall structure, and FIG. 2 is a schematic diagram showing the meshing state of gears. Figures 3 and 4 are cross-sectional views showing the groove shape, Figures 5 and 6 are schematic diagrams showing the crank mechanism in the reducer, and Figures 7 to 9 are respectively sectional views of the conventional reducer. For illustrative purposes, FIG. 7 is a sectional view showing the overall configuration, FIG. 8 is a schematic diagram showing the meshing state of gears, and FIG. 9 is a sectional view showing the groove shape. 1... Case, 7... Fixed disk (first member), 1
9... Input disk (second member), 31.33... Circumferential groove, 23.35.41... Ball (rolling element), 27
... Intermediate disc, 37... Output disc, 7a, 378.
・Hypo l-n Iid tooth profile iM (number of period grooves)
, 19a, 27a...[bit[]-1id tooth profile @(
cycle period number groove). Applicant's agent Patent attorney 1 Suzuki Ni〇〇Figure 5 71 bags ＼ Figure 7

Claims (3)

[Claims] (1) A first member and a second member are arranged facing each other, periodic function grooves with mutually different periods are formed on the opposing surfaces of these members, and a plurality of rolling elements are arranged between these periodic function grooves. do,
In the power transmission device that transmits rotational force between the first member and the second member at variable speed, balls are used as the rolling elements, and the groove of the first member is located on the side where the balls contact. A groove wall is extended to the side of the groove wall of the second member that the ball does not contact, and similarly, a groove wall of the second member that is in contact with the ball is extended to the side of the groove wall of the groove of the first member that is in contact with the ball. 1. A power transmission device characterized in that the groove has a cross-sectional shape that extends toward a groove wall side that is not in contact with the groove. (2) A patent claim characterized in that the first and second members are each coaxially provided with a rotating shaft via a bearing, and these rotating shafts are fixed in an eccentric state relative to each other. The power transmission device according to item 1. (3) Each of the periodic function grooves of the first and second members is formed such that the groove wall side that the rolling element does not contact is at the same height as the groove bottom. 1st
The power transmission device described in section.