JPH05296307A - Table feed device - Google Patents

Abstract

PURPOSE:To provide a high feed precision and long service life table feed device for preventing distortion or the like at the meshing portion thereof, by enlarging the spacing between a rack member and guide rails of a guiding means while keeping the device in a small size. CONSTITUTION:The table feed device comprises a guiding means 20 including moving units 21L, 21R mounted on the underside of a table 12 and guide rails 22 fixed to a supporter 11 so as to guide the moving units 21L, 21R, and a rack member 31 disposed on the upper side part of the table 12 in a manner that its tooth portion 31a may be faced downwards. It further comprises an output unit 40 which includes output members 41 to 43 meshed with the tooth portion 31a of the rack member 31 and a drive source 49 for driving those output members, and which moves relatively to the rack member 31 when the drive source 49 operates. One of the rack member 31 and the output unit 40 is fixed to the supporter 11 and the other thereof is connected to the table 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a table feeding device, for example, a table feeding device for moving a moving table portion (table) in a machine tool or an industrial robot.

[0002]

2. Description of the Related Art Generally, a table feed device for a machine tool or the like has a linear movement mechanism for converting a rotational movement into a linear movement, and a high degree of accuracy of feeding by the linear movement mechanism is required. As a conventional table feed device of this type, there is known a device in which, for example, a ball screw mechanism or a rack and pinion mechanism constitutes a rectilinear mechanism, and this rectilinear mechanism and a linear guide mechanism are used together. The linear mechanism using the rack and pinion mechanism has a relatively simple structure and is suitable for downsizing,
It has excellent responsiveness and is widely used. The guide rail of the linear guide mechanism is usually installed parallel to the rack or ball screw and on the same horizontal plane.

[0003]

However, in such a conventional table feeding apparatus, since the rack is installed on the same horizontal plane as the guide rail of the linear guide mechanism, the space between the two is narrow and the deviation is uneven. When a moment around the rack acts on the table due to a load or the like, there is a problem that the meshing portion of the rack and pinion mechanism is twisted, and the feeding accuracy and the life of the table feeding device are reduced.

Further, since the rack and the pinion have a small number of teeth meshing with each other, the tooth surface pressure is large, and it is unsuitable for applications in which heavy load and high durability are required. To solve the former problem, it is conceivable to increase the distance between the linear guide rail and the rack, but simply increasing the distance (in the horizontal direction) leads to an increase in the size of the device, which is not preferable.

Therefore, an object of the present invention is to provide a table feeding device which is suitable for downsizing and which can prevent twisting of the meshing portion due to an eccentric load or the like, with high feed accuracy and long life.

[0006]

In order to achieve the above object, the invention according to claim 1 is a table feeding device which is provided between a support and a movable table and moves the table in a predetermined direction. A guide unit having a moving unit attached to a lower portion of the table and a guide rail fixed to the support so as to guide the moving unit in the predetermined direction; and an upper side of the table so that a tooth portion faces downward. Has a rack member located in one direction, an output member that meshes with the teeth of the rack member, and a drive source that drives the output member, and moves relative to the rack member when the drive source operates. And an output unit for controlling the rack member or the output unit, wherein one of the rack member and the output unit is fixed to the support and the other is connected to the table. Is shall.

According to a second aspect of the present invention, the output unit has a plurality of swing racks having tooth portions having the same pitch as the tooth portions of the rack member, and the tooth portions are opposed to the rack member. A crank shaft that supports a plurality of rocking racks while maintaining a predetermined phase difference and that meshes with the rack member; and a case that rotatably supports the crank shaft; And a driving source for driving.

[0008]

According to the first aspect of the invention, the guide means is provided on the lower side of the table, and the rack member is provided on the upper side of the table. Therefore, it is possible to widen the space between the rack member and the guide rail while reducing the size of the device. Further, since the teeth of the rack member face downward, dust such as cutting chips does not easily adhere to the tooth surface of the rack.

According to the second aspect of the invention, when the crankshaft rotates, the plurality of rocking racks alternately mesh with the rack member while maintaining a predetermined phase difference, whereby the case or the rack member slowly moves. Moving. Therefore, a table feed device with high feed accuracy can be realized. Also,
At this time, since the fixed rack and the swinging rack have a large number of teeth in contact with each other, the tooth surface pressure does not become so high even if both racks are made small, and a table feed device having excellent durability can be realized. ..

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 8 are views showing an embodiment of the table feeding device according to the invention described in claims 1 and 2. First, the configuration will be described.

In FIGS. 1 to 3, 11 is a fixedly mounted support, 12 is a table for supporting a processing head, robot, or the like (not shown), and the table 12 has moving units 21L and 21R provided under the table. Is guided to the linear guide rail 22 attached to the front part of the support 11 through
It is movable in a predetermined straight direction. Mobile unit 21
The L and 21R are guided by the linear guide rail 22 via a plurality of balls 23A and 23B, and together with the linear guide rail 22 and the balls 23A and 23B form a known linear guide mechanism 20 (guide means).

A fixed rack 31 (rack member) which is parallel to the linear guide rail 22 is provided on the upper portion of the support 11 so as to be positioned on the upper side of the table 12. Fixed rack
The tooth 31 is fixed to the support 11 with its tooth portion 31a facing downward, and as shown in FIG. 4, the tooth shape of the tooth portion 31a is formed in a wave shape (for example, a trochoid curve shape or a cycloid curve shape). There is. Further, the fixed rack 31 is freely movably coupled to the case 51 of the output unit 40 through a plurality of circulating balls 33A and 33B only in the axial relative movement. Further, the case 51 is formed with circulation passages 51a and 51b for circulating the balls 33A and 33B, respectively.

FIGS. 4 to 7 are views showing the details of the output unit 40 as a rectilinear mechanism. In these figures, the output unit 40 is a plurality (for example, three) in which the tooth portions 41a, 42a, 43a of the same pitch as the tooth portion 31a of the fixed rack 31 are formed.
The rocking racks 41 to 43 (output members) and the drive motor 49 (driving source) that drives the rocking racks 41 to 43 via the crankshaft 47. Tooth portions 41a, 42 of the swing racks 41 to 43
Reference characters a and 43a are formed as arc-shaped teeth of the same tooth shape having the same radius R as the circle serving as the reference of the tooth shape of the tooth portion 31a of the fixed rack 31. In this embodiment, the fixed rack 31 and the swing rack 41 are formed. In order to reduce the frictional resistance between ~ 43, tooth portion 41a,
42a and 43a are formed by a roller 44 having a radius R.
The roller 44 is rotatably supported by a pin 45 fitted into the main body of the rocking racks 41 to 43 via a needle bearing 46. In this state, the roller 44 is the main body of the rocking racks 41, 42, 43. A plurality of arc-shaped tooth portions 41a, 42a, 43a are formed by being partially housed in.

The rocking racks 41-43 are provided with tooth portions 41a, 42.
Crankshaft so that sides a and 43a face the fixed rack 31
The eccentric circular cam portions 47a, 47b, and 47c of the crankshaft 48 support the eccentric circular cam portions 48b of the crankshaft 48, and the crankshafts 47 and 48 support the pair of bearings 44A.
By being rotatably supported by the case 51 via 44B, the tooth portions 41a, 42a, 43a of the swing racks 41 to 43 mesh with the fixed rack 31. The eccentric circular cam portions 47a to 47c of the crankshaft 47 are formed at equal angular intervals (for example, 120 ° intervals), and the eccentric circular cam portion 47 at the center in the axial direction is formed.
b has a larger diameter than the other cam portions 47a and 47c. This is the same for the crankshaft 48, and is for facilitating the assembling of the swing rack 42 to the crankshafts 47 and 48.

The drive motor 49 includes a table 12 or a case 51.
One of them, for example, is housed under the table 12 and connected to the motor bracket 12a, and the crankshaft 47 is driven by receiving electric power from the outside. The case 51 is also fixed to the bracket 12a. Then, when the crank shaft 47 is driven by the rotation of the drive motor 49, as shown in FIG. 8, each of the rocking racks 41 to 43 makes a circular motion with a predetermined radius while maintaining the predetermined phase difference (hereinafter, The movement of the rocking racks 41, 42 and 43 in this state will be collectively referred to as rocking), and at least one of the rocking racks 41 to 43 always meshes with the fixed rack 31 (b). The case 51 moves in the axial direction (predetermined movement direction) of the fixed rack 31 by receiving a force in the arrow X direction. That is, the table feeding mechanism of the present embodiment is provided between the support 11 and the table 12 and moves the table 12 in a predetermined straight traveling direction.

In FIG. 1, reference numerals 11a and 11b denote reinforcing ribs (for example, a plurality of ribs are provided at predetermined intervals) of the support body 11, and the support body 11 has a substantially U-shaped cross section. By having the reinforcing ribs 11a and 11b, the reinforcing ribs 11a and 11b have sufficient rigidity against an external force in the direction of falling the vertical wall portion 11h. Further, in FIG. 6, 61, 62 and 63 are needle bearings for supporting the swing racks 41 to 43 on the crankshafts 47 and 48.

Next, the operation will be described. When the crankshaft 47 is driven by the rotation of the drive motor 49, the plurality of rocking racks 41 to 43 rock while maintaining the predetermined phase difference (FIG. 8).
(See), the crankshafts 47 and 48 rotate synchronously. At this time, the plurality of rocking racks 41 to 43 are alternately meshed with the fixed rack 31, and the case 51 receiving the reaction force from the tooth portion 31a of the fixed rack 31 is fixed corresponding to the rotation of the crankshafts 47 and 48. The rack 31 slowly moves in the longitudinal direction (straightening direction). That is, the rocking racks 41 to 43 have a predetermined phase difference (12
Since it swings while maintaining 0 °), at least one of the plurality of swing racks 41 to 43 always comes into contact with the fixed rack 31 during one revolution of the crankshaft 47. The case 51 and the other members housed therein are pushed and moved in the straight direction, and the table 12 moves in the same direction. Then, when the crank shafts 47 and 48 make one revolution,
The table 12 moves by one tooth (pitch) of the tooth portion 31a. When the drive motor 49 is rotated in the reverse direction, the crankshaft 4
7 and 48 reversely rotate, and the fixed rack 31 advances straight in a direction opposite to the direction of straight advance.

By the way, when the machining head or the robot mounted on the table 12 is operated, a lateral moment load, for example, a moment around the fixed rack due to an unbalanced load as shown by an arrow M in FIG. 6 acts on the table 12. I have something to do. With respect to such a moment, in the present embodiment, the linear guide rail 22 and the fixed rack 31 are diagonally separated from each other, so that the fixed rack 31 and the linear guide rail 22 are not widened without expanding the width of the table feeding device. The space can be widened, and the unnecessary moment M caused by the unbalanced load or the like does not cause twisting in the meshing portions of the fixed rack 31 and the swing racks 41 to 43. Therefore, while reducing the size of the table feeding device, it is possible to reliably prevent the feeding accuracy and the life of the table feeding device from being deteriorated due to an eccentric load from the mounted object.

Further, since the tooth portion 31a of the fixed rack 31 faces downward on the tooth surface, dust such as cutting chips which hinders the operation is less likely to adhere to the tooth portion 31a of the fixed rack 31. It is possible to reduce the number of parts by eliminating the dust proof cover such as bellows that prevents the adhesion of various dusts. Further, the plurality of tooth portions 41a, 42a, 43a of the swing racks 41 to 43 are fixed to the fixed rack 31.
Of the tooth portions 31a, 41a, 42
The tooth surface pressure applied to a and 43a is small, and the feeding device can withstand a heavy load. Further, since the swing racks 41 to 43 swing, a deceleration output for one tooth of the tooth portion 31a of the fixed rack 31 is obtained for one rotation of the crank shafts 47 and 48.
By adjusting the input rotation, extremely precise feed can be realized, and the fixed rack 31 extending in the straight direction does not rotate unlike the ball screw etc., so stable straight feed can be performed even with a long stroke. .. Further, since the fixed rack 31 is fixed to the sturdy support 11 having the reinforcing ribs 11a and 11b, and the rocking racks 41 to 43 are directly engaged with the fixed rack 31, the holding rigidity at the time of positioning becomes high,
Highly accurate positioning can be realized. Therefore, it is also suitable for applications where heavy load and high durability are required.

In the above embodiment, the feeding accuracy and the durability are improved by using the plurality of rocking racks 41 to 43. However, the output unit in the present invention is not limited to this, and the rack member may be used. It may have a meshing pinion. Even in this case, the positional relationship between the rack member and the guide rail of the guide means is the same. Also,
In the above example, the table 12 is assumed to go straight, but the table may move not only linearly but also curvedly.
Further, the case 51 may be fixed to the support body 11, and a rack member corresponding to the fixed rack 31 may be connected to the table 12 and moved.

Further, in the above-mentioned example, the tooth shape of the fixed rack 31 is corrugated, and the tooth shape of the rocking racks 41 to 43 is arcuate. However, conversely, an arcuate tooth profile is formed on the fixed rack 31. It is also possible to form a wavy tooth profile on the rocking racks 41 to 43. In that case, the plurality of arc-shaped teeth can be composed of a plurality of columnar pins mounted in the plurality of semicircular recesses of the rack body so that the pins can be easily rotated with respect to the rack body. It is also possible to lubricate them or to circulate around the rocking racks 41 to 43 by connecting these pins in a chain shape. Further, in this embodiment, the drive motor 49
Although the crankshaft 47 is directly driven by the above, the crankshafts 47 and 48 can be indirectly driven simultaneously via an appropriate gear or the like.

[0022]

According to the invention described in claim 1, since the guide means is provided on the lower side of the table and the rack member is provided on the upper side of the table, the guide rail of the guide means and the rack member are inclined. Since it is separated in the direction, it is possible to widen the space between the rack member and the guide rail while reducing the size of the device. As a result, it is possible to prevent the meshing portion from twisting due to an eccentric load or the like in the table feeding device suitable for downsizing, and to prevent high feeding accuracy and shortening of life. Further, since the tooth portion of the rack member faces downward, it is possible to prevent dust such as cutting chips from adhering to the tooth surface of the rack without using a dust cover or the like, and it is possible to reduce the number of parts. ..

According to the second aspect of the present invention, the plurality of rocking racks are meshed with the rack member while maintaining a predetermined phase difference by the rotation of the crankshaft, whereby the case or the rack member is moved. Therefore, a table feed device with high feed accuracy can be realized. Further, since the rack member and the swinging rack contact a plurality of teeth, it is possible to realize a table feed device having excellent durability while keeping the tooth surface pressure small while making both racks small.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of a table feeding device according to the present invention.

FIG. 2 is a front view of an embodiment.

FIG. 3 is a view on arrow A in FIG.

4 is a sectional view taken along line BB of FIG.

FIG. 5 is an external front view of the output unit.

6 is a cross-sectional view taken along line CC of FIG.

FIG. 7 is an external side view of the output unit.

FIG. 8 is an operation explanatory view of the swing rack.

[Explanation of symbols] 11 Support 12 Table 12a Motor bracket 20 Linear guide mechanism (guide means) 21L, 21R Moving unit 22 Linear guide rail 31 Fixed rack (rack member) 31a Teeth 40 Output unit 41 to 43 Swing rack ( Output member) 41a, 42a, 43a Teeth 47, 48 Crankshaft 47a, 47b, 47c Eccentric circular cam 49 Drive motor (drive source) 51 Case

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Nachi 1110-1 Ozaki, Miyashiro, Tarui-cho, Fuwa-gun, Gifu Prefecture Teijin Seiki Co., Ltd. Gifu No. 1 Factory

Claims (2)

[Claims] 1. A table feeding device provided between a support (11) and a movable table (12) for moving the table (12) in a predetermined direction, the lower part of the table (12). Mobile unit attached to
(21) and a guide means (20) having a guide rail (22) fixed to the support body (11) so as to guide the moving unit (21) in the predetermined direction, and a tooth portion (31a) downward. The rack member (31) provided on the upper side of the table (12) and the output member (4) meshing with the tooth portion (31a) of the rack member (31).
1, 42, 43) and a drive source (49) for driving the output member (41, 42, 43), and moves relative to the rack member (31) when the drive source (49) operates. The output unit (40), which is provided with, the one of the rack member (31) or the output unit (40) is fixed to the support (11), the other is connected to the table (12). A table feeding device characterized in that 2. The output unit (40) has a tooth portion (4) having the same pitch as the tooth portion (31a) of the rack member (31).
1a, 42a, 43a), and a plurality of rocking racks (41, 4a) in which the tooth portions (41a, 42a, 43a) face the rack member (31).
2, 43) and a plurality of rocking racks (41, 42, 43) while maintaining a predetermined phase difference, and the crank shaft (4
7, 48) and a case (51) for rotatably supporting the crankshaft (47, 48)
The table feed device according to claim 1, further comprising: a drive source (49) attached to the case (51) to drive the crankshaft (47).