JPS6313053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) This invention relates to a bevel gear transmission without backlash due to elastic action.

(Prior Art) Gears require backlash between tooth surfaces for smooth meshing. On the other hand, if there is torsional vibration in the transmission system, the bumps will be struck and cause wear. Further, the rotational position accuracy is low due to the large backlash, and it is not possible to obtain high positioning accuracy in, for example, an industrial robot equipped with such a reduction gear.

When transmitting power between intersecting transmission shafts, for example, a bevel gear transmission as shown in FIG. 6 is used. In the case of bevel gears, by adjusting the axial mounting positions of the gears 2 and 5, the degree of backlash can be adjusted to a certain extent within a range that does not deteriorate the tooth contact. In order to adjust the axial mounting positions of the gears 2 and 5, for example, the lengths of the sleeves 3 and 6 that fit onto the transmission shafts 1 and 4 may be adjusted.

(Problem to be solved by the invention) However, in order to adjust the axial mounting position of the bevel gear as described above, it is necessary to match the actual item, and it is necessary to assemble it for measuring the gap and processing the sleeve or washer. It takes a lot of effort. In addition, the tooth surfaces are worn due to operation, resulting in cracking.

Therefore, this invention makes it possible to assemble a transmission device with no backlash through simple work.
The object of the present invention is to provide a bevel gear transmission that does not cause breakage even after long-term operation.

(Means for Solving the Problems) The bevel gear transmission device of the present invention includes a first transmission shaft to which a first bevel gear is fixed, and a second transmission shaft that meshes with the first gear.
a second transmission shaft to which a gear is fixed and intersects the first transmission shaft; a third bevel gear that is rotatable with respect to the second transmission shaft and meshes with the first bevel gear; and a third bevel gear that meshes with the first bevel gear;
It consists of a shaft coupling that operatively connects the transmission shaft and the third bevel gear. Further, the shaft joint has a plurality of long holes spaced apart in the circumferential direction, a flange that rotates integrally with the second power transmission shaft, and a plurality of long grooves spaced apart in the circumferential direction. a holding member that accommodates the flange and rotates together with the third bevel gear; a plurality of pairs of spring receivers having semi-cylindrical surfaces and facing each other in the circumferential direction; It consists of a spring inserted between a flat spring catch.
The center portion of the semi-cylindrical surface of the spring seat is supported by the arc-shaped end surface of the elongated hole, and the end portion of the semi-cylindrical surface is supported by the arc-shaped end surface of the elongated groove. The spring is compressed so that the three bevel gears repel each other in the direction of rotation.

(Function) The spring is compressed so that the second bevel gear and the third bevel gear repel each other in the rotational direction.
Therefore, when the transmission is assembled, a repulsive torque is always generated between the second bevel gear and the third bevel gear.

Due to the repulsive torque, the tooth surface of the second bevel gear is in contact with one tooth surface of the first bevel gear, and the tooth surface of the third bevel gear is in contact with the other tooth surface, and the repulsive torque is borne by the first bevel gear. . Since the repulsive torque acts to cancel the rotation of the first transmission shaft, the first transmission shaft does not rotate due to the repulsive torque. As a result, as long as the transmitted torque is smaller than the repulsive torque, there is no play between tooth surfaces in the rotational direction between the first bevel gear and the second or third bevel gear.

The transmission torque is transmitted from the first transmission shaft to the second transmission shaft or in the opposite direction via a bevel gear.

(Embodiment) FIGS. 1 and 2 show an embodiment of a bevel gear transmission according to the present invention. As shown in these drawings, the bevel gear transmission mainly includes a casing, a first transmission shaft, a first bevel gear, a second transmission shaft, a second bevel gear, a hub, a third bevel gear, and a shaft coupling.

The casing 11 has box-shaped first and second bodies 1.
2, 13, flange 15 and first and second
The covers 16 and 17 are longer. First body 12
A flange 15 is attached to both ends of the flange 15, and a first cover 16 is attached to the top of the holder with bolts. A side surface of the first body 12 is connected to one end of the second body 13 by bolts, and a second cover 17 is attached to the other end by bolts.

A first transmission shaft 21 is rotatably supported on the first body 12 of the casing 11 via a bearing 23, and a second transmission shaft 25 is supported on the second body 13 via a bearing 27 so as to intersect with each other. There is. A driving shaft or a driven shaft (neither of which is shown) is connected to these transmission shafts 21 and 25. First transmission shaft 21
A sleeve 24 is fitted into the sleeve.

A first bevel gear 31 is fixed to the first transmission shaft 21 via a key 33. Further, the second bevel gear 35 that meshes with the first bevel gear 31 is connected to the second transmission shaft 2.
5 through a key 37.

A hub 41 having a flange 42 at the rear end is rotatably fitted near the front end of the second power transmission shaft 25 . A third bevel gear 45 that meshes with the first bevel gear 31 is fixed to the front end of the hub 41 via a key 47.

The shaft coupling 51 connecting the second transmission shaft 25 and the hub 41 mainly includes a flange 53 and a holding member 6.
1, a spring seat 71 and a coil spring 75.

The flange 53 is fixed at approximately the center of the second power transmission shaft 25 by a key 54 so as to face the flange 42 of the hub 41, and is spaced at intervals of 90 degrees in the circumferential direction as shown in FIG. Four elongated holes 55 are provided. The elongated hole 55 penetrates in the axial direction, and both side surfaces 56 are arcuate.

The holding member 61 consists of a pair of cylindrical bodies 62, and both bodies 62 are connected by a bolt 69. Each main body 62 has an annular flange 63 when facing each other.
and a holding plate 65, and four long grooves 67 are provided at intervals in the circumferential direction so as to correspond to the long holes 55 of the flange 53 fixed to the second transmission shaft 25. . Similar to the elongated hole 55, the elongated groove 67 has both side surfaces 68 in an arc shape. The two main bodies 62 of the holding member 61 configured in this manner are rotatably fitted to the second power transmission shaft 25 and the hub 41 so as to accommodate the flanges 53, respectively.

The spring seat 71 has a semi-cylindrical surface 72, and a cylindrical projection 73 is provided on the spring receiving surface following the semi-cylindrical surface 72.

The coil spring 75 is inserted between a pair of spring seats 71 whose spring receiving surfaces face each other. At this time, the cylindrical protrusion 7
It fits into 3.

The spring seat 71 on which the coil spring 75 is mounted passes through the elongated hole 55 of the flange 53 fixed to the second transmission shaft 25, and the center portion of the semi-cylindrical surface 72 is inserted into the elongated hole 55.
The end of the semi-cylindrical surface 56 is supported by the arcuate end surface 68 of the long groove 67. The radius of curvature of the semi-cylindrical surface 72 is the same as that of the elongated hole 5.
5 and the side end surfaces 56 and 68 of the long groove 67. Therefore, when transmitting torque, the spring seat 71 can freely roll on the side end surfaces 56, 68 of the elongated hole 55 and the elongated groove 67, and no excessive force is applied to the coil spring 75 in the lateral direction. .

The coil spring 7 is arranged so that the paired main bodies 62 of the holding member 61 are mutually displaced in the circumferential direction.
5 is compressed and deformed, and both main bodies 62 are connected by bolts 69. As a result, a repulsive torque greater than or equal to the rated transmission torque, for example, 1.5 times the rated transmission torque, is provided between the second bevel gear 35 and the third bevel gear 45.

In the bevel gear transmission configured as described above, when a transmission torque equal to or less than the repulsive torque is applied to the first transmission shaft 21, the first bevel gear 31 moves from the first bevel gear 31 to the second or third bevel gear 35, depending on the direction of the torque. 45
from the first transmission shaft 21 to the second transmission shaft 25 via one of the bevel gears, for example, the second bevel gear 35.
The transmission torque is transmitted to. When a transmission torque equal to or greater than the repulsive torque is applied to the first transmission shaft 21, the transmission torque is transmitted from the first transmission shaft 21 to the second transmission shaft 25 via both bevel gears 35, 45. of course,
Contrary to the above, from the second transmission shaft 25 to the first transmission shaft 21
The same effect applies when transmitting torque to.

FIGS. 4 and 5 show other embodiments of the invention. Members having the same functions as those in the above embodiment are given the same reference numerals, and their explanations will be omitted.

A hub 82 of the second bevel gear 81 fixed to the second transmission shaft extends rearward, and a flange 53 is attached thereto via a key 54. The flange 53 is provided with the same elongated hole 55 as in the above embodiment.

Further, a third bevel gear 85 is rotatably fitted into the hub 82 of the second bevel gear 81 . The third bevel gear 85 accommodates the flange 53 together with the spring seat 71 and the spring 75 in the hub 86, and is covered with a cover 91. The cover 91 is fixed to the hub 86 with screws 93, and the hub 86 and the cover 91 are provided with long grooves 87 and 92, respectively, as in the above embodiment.

The spring seat 71 on which the coil spring 75 is mounted passes through the elongated hole 55 of the flange 53 fixed to the hub 82 of the second bevel gear 81, and the center portion of the semi-cylindrical surface 72 is connected to the arc-shaped end surface 56 of the elongated hole 55. Also, the ends of the semi-cylindrical surface 56 are supported by the arcuate end surfaces 89, 93 of the long grooves 87, 91.

The device of this embodiment operates in exactly the same way as the previous embodiment.

Note that the second bevel gear 81 and the third bevel gear 85 are connected via a taper pin 99 while applying a required repulsive torque, and the shaft hole machining and gear cutting are performed as one unit. Then, after the first bevel gear and the second bevel gear 81 and the third bevel gear 85 are engaged and assembled, the taper pin 99
is removed to eliminate backlash between the first bevel gear and these second bevel gears 81 and third bevel gears 85.

This invention is not limited to the above embodiments. For example, one of the main bodies of the pair of holding members may be omitted so that only one body fits into the flange of the second power transmission shaft, and the flange of this main body may be fixed to the flange of the hub with bolts. Further, the number of elongated holes and elongated grooves may be increased or decreased, and a disc spring may be used instead of a coil spring. Furthermore, although the above embodiment is a miter transmission, the gear ratio of the bevel gear may be appropriately selected to form a reduction gear or a speed increaser.

(Effects of the Invention) In the bevel gear transmission according to the present invention, the shaft coupling and the hub may be connected by applying repulsive torque between the bevel gears. Therefore, it is possible to eliminate conflicts between the bevel gears by a simple assembly operation. Furthermore, since repulsive torque is always applied between the bevel gears, there is no possibility of backlash even during long hours of operation.

Recently, the automation of factories such as machining centers and industrial robots has progressed, and there is a demand for faster and more accurate conveyance of workpieces, and there is a strong demand for reducing the breakdown of the speed reducer, which is the central part of the drive device. ing.

In particular, bevel gear transmissions that change the drive direction have greater backlash than other speed reducers, and the effects of this invention are particularly great for semiconductor manufacturing equipment, especially applications that require strict rotational accuracy. .

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an embodiment of the bevel gear transmission device of the present invention, Fig. 2 is a sectional view taken along line - in Fig. 1, and Fig. 3 is a part of a shaft coupling used in the above device. 4 is a vertical sectional view showing another embodiment of the present invention, FIG. 5 is a front sectional view of FIG. 4, and FIG. 6 is a cross sectional view showing an example of a conventional bevel gear transmission. It is a diagram. 1, 4...Transmission shaft, 2, 5...Bevel gear, 3, 6...
Sleeve, 11...Casing, 21, 25...Transmission shaft, 31, 35, 45...Bevel gear, 41...Hub,
51... Shaft coupling, 53... Shaft coupling flange, 55... Long hole, 56... Long hole end face, 61... Holding member, 67... Long groove, 68... Long groove end face, 71... Spring seat, 72... Spring seat semi-cylindrical surface. , 75...Spring, 81, 85...Bevel gear, 91...Cover.

Claims (1)

[Claims] 1 A first transmission shaft to which a first bevel gear is fixed, and a first
a second transmission shaft having a second gear fixedly meshing with the gear and intersecting the first transmission shaft; a third bevel gear rotatable with respect to the second transmission shaft and meshing with the first bevel gear; and a third bevel gear meshing with the first bevel gear; a shaft coupling that operatively connects the shaft and a third bevel gear, the shaft coupling having a plurality of elongated holes spaced apart in the circumferential direction, and the second
a flange that rotates together with the transmission shaft; a holding member that has a plurality of circumferentially spaced long grooves that accommodates the flange and rotates together with the third bevel gear; It has a cylindrical surface and consists of a plurality of pairs of spring seats facing each other in the circumferential direction, and a spring inserted between the pairs of spring seats,
The center portion of the semi-cylindrical surface of the spring seat is supported by the arc-shaped end surface of the elongated hole, and the end portion of the semi-cylindrical surface is supported by the arc-shaped end surface of the elongated groove. A bevel gear transmission characterized in that the spring is compressed so that the gear and the gear repel each other in the rotational direction.