JPH0653332B2 - Moving mechanism - Google Patents

Description

The present invention relates to a moving mechanism, and more specifically, an industrial robot or
The present invention relates to a moving mechanism that is used for shuttles that move between NC machine tool devices and that requires precise linear movement.

[Prior art]

Conventionally, as a moving mechanism used in this type of machine, for example, it is disclosed in Japanese Patent Laid-Open No. 61-117043 in which a rod member is held by a combination of a plurality of friction rollers to move the rod member. There are known types, such as those that use a ball screw, attach a nut member screwed to the screw to the moving body side, and rotate the screw to move the moving body along the ball screw. ing.

As a device for feeding machine tools, as a device for frictionally driving a moving body along a guide bar with friction rollers, Japanese Patent Publication No. 58-549
Japanese Patent Laid-Open No. 48 and Japanese Patent Laid-Open No. 61-230835 are known.
In addition, as a device related to the applicant's earlier application, Japanese Utility Model Application No. 62-11386.
There is number 7.

[Problems to be Solved by the Invention] However, in such a conventional device, when trying to perform a linear motion by utilizing friction, a big problem is that when trying to move at high speed or move a heavy object. However, there is no choice but to enlarge the device. That is, a high torque is required to move the motor at high speed, and the torque of the motor must be increased. Also, in order to prevent rubbing, it is necessary to increase the pressure contact force,
If the surface pressure of the pressed portion is too high, it will be plastically deformed and become immovable, so it is necessary to increase the diameter of the drive shaft or lengthen the contact portion in order to reduce the surface pressure.
This is because the device eventually becomes large.

The object of the present invention is to solve the problems of the prior art, and even when moving at high speed or moving heavy objects, the device can be downsized as compared with the prior art without increasing the size of the device, which can prolong the life of the device and assemble it. It is to provide a moving mechanism that is easy to adjust and is low cost.

[Means for Solving the Problems] In order to achieve the above object, the moving mechanism of the present invention is provided with a fixed base, a guide member attached to the fixed base, and a movable member along the guide member. A movable base, a spring housing held at a fixed position of the movable base, a driven wheel housing movably held in the spring housing in a direction facing the guide member, and a shaft mounted on the driven wheel housing. Two driven wheels supported and in contact with the guide member, and movably held in the spring housing in a direction facing the guide member, and located on the opposite side of the guide member with the driven wheel housing interposed therebetween. A drive shaft housing, a drive shaft pivotally supported by the drive shaft housing and in contact with the two driven wheels, and a driven wheel housing housed in the spring housing. And a spring for urging the drive shaft housing in a direction approaching the guide member, and a drive source which is held by the moving base and rotationally drives the drive shaft.

[Operation] According to the present invention, the driven wheel housing that rotatably supports the two driven wheels and the drive shaft housing that rotatably supports the drive wheels contacting the two driven wheels are urged by the guide bar. It is urged in the direction to increase the pressure contact force to. When the drive wheels are driven by the drive source, this transmitted torque is 2
The driven wheel is divided and transmitted to the two driven wheels, and the driven wheel rotates while being pressed against the guide bar to move the movable table. At this time, the surface pressure between the drive shaft and the driven wheel and between the driven wheel and the guide bar is significantly reduced. Therefore, since the surface pressure can be reduced, the size can be reduced and the life can be extended.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 3 show an embodiment in which the present invention is applied to a moving mechanism of a robot.

In the figure, 1 is a fixed base, 2 is a movable base that can travel on the fixed base 1, and 3 is a robot arm attached to the movable base 2. Reference numeral 4 is a guide rail for guiding the movement of the movable table 2, and two guide rails are installed in parallel on the fixed base 1. Reference numeral 5 is also a guide bar installed on the fixed base 1 in parallel with the guide rail 4. Two driven wheels 6 rotate while being in contact with the guide bar 5, and are rotatably supported by shafts 9 fixed to the driven wheel housing 7 via bearings 8 respectively (see FIG. 3).

The driven wheel housing 7 has its lower portion passing through an opening 2A provided in the movable table 2 and the driven wheels 6 and 6 are in contact with the upper surface of the guide bar 5. Further, a cutout portion 7A is provided in the upper portion of the driven wheel housing 7, and the outer peripheral surfaces of the driven wheels 6 and 6 are exposed. Further, wipers 7B for removing foreign matters on the guide bar 5 are provided in front of and behind the driven wheel housing 7.

Reference numeral 10 denotes a drive shaft housing, which has a notch 10A formed at the center thereof, and the drive shaft 12 is rotatably supported by bearings 11 at both ends thereof. Further, vertical engaging grooves 10B are formed on both sides of the drive shaft housing 10 on both sides of the notch 10A.

The drive shaft 12 is connected to a drive motor 14 via a coupling 13, and the drive motor 14 is fixed to the movable table 2 via a motor mounting bracket 15 (see FIG. 2).

Further, 16 is a spring housing, which is formed in a substantially U-shaped cross section and has a cutout portion 16A in the center. Also, on both sides of the spring housing 16, notches 16A are provided on both sides of the notch 16A.
Is provided.

In the present embodiment, springs 17A, 17B and 17C for generating a pressure contact force are incorporated in the upper wall portion of the spring housing 16, and the springs 17A, 17C connect the driven wheel housing 7 to the spring via the piston 18. The drive shaft housings 10 are pressed against each other by 17B. The pressure contact force is adjusted by rotating the pressure contact force adjusting screw 19, and the nut 20 is fixed after the adjustment.

Therefore, the position of the driven wheel housing 7 is determined in the axial direction (X direction) of the driven wheel 6 by fitting the driven wheel housing 7 into the cutout portion 10A of the drive wheel housing 10, and the position of the moving table 2 is reduced. Regarding the moving direction (Y direction), the drive shaft 12 supported by the drive shaft housing 10 and the driven wheels 6, 6
It is decided naturally by the pressure contact of the three.

The position of the drive shaft housing 10 is
The notch of the spring housing 16 in the engaging groove 10B provided on the
It is determined by the engagement of ears 16B provided on both sides of 16A. The spring housing 16 is fixed to the moving table 2 by screwing or the like, and its position is determined.

In this way, the driven wheels 6 and 6 form one driven wheel housing 7
Since it is built in and supported, the pressure contact force generated by the spring 17B can be efficiently transmitted to the guide bar 5 via the drive shaft 12 and the two driven wheels 6 and 6, and the driven wheel housing 7 can be driven by the driven wheel. Even if the distance W between the shafts 6 and 6 is machined with high accuracy, the machining cost can be reduced. Further, at the time of assembly, the positional relationship between the drive shaft 12 and the driven shafts 6 and 6 is determined only by applying a force to the drive shaft housing 10 by the spring 17B, so that the assembly becomes very easy.

The operation of this embodiment having the above configuration will be described below mainly with reference to FIG.

When the motor 14 rotates in the clockwise direction (α direction) shown by the outputs of the position detection device and the control device of the moving base 2 (not shown), the drive shaft 12 connected via the coupling 13 also rotates in the α direction. To do. Since the drive shaft 12 and the driven shafts 6 and 6 are pressed by the spring 17B so as not to cause sliding, the rotational movement of the drive shaft 12 is applied to the driven wheels 6 and 6 in the counterclockwise directions (β and γ directions, respectively). ) Is transmitted as. further,
In addition to the biasing force of the springs 17A and 17C, the component force of the spring 17B acts on the driven wheels 6 and 6, and the movable base 2 can move in the Y direction without sliding due to the pressure contact force with the guide bar 5. Become.

And the above-described embodiments, as shown in the 4 (A) Fig., And conventional example so as to move into contact directly the guide bar by adding P _O becomes pressure contact force to the drive shaft of diameter d (= 25 mm) Let's compare. The force balance in the conventional example is balanced by the pressure contact force of P _O acting on the contact point A.

Therefore, the balance of forces of the moving mechanism in this embodiment is shown in FIG. 4 (B).

If the angle θ formed by the contact point between the drive shaft 12 having the diameter d (= 25 mm) and the driven wheels 6 and 6 having the diameter D (= 110 mm) is 120 °, the torque transmitted from the drive shaft 12 is , 6 to 2
Will be divided. Therefore, the pressure contact force of the drive shaft required to transmit the torque equivalent to the conventional one is P _N which is half of P _O. However, since the pressure contact force acting on the contact point B ′ of the guide bar 5 of the driven wheels 6 and 6 acts only on the vertical component P _V of P _N , the contact force on the transmission torque is insufficient at the contact point B ′. I will end up. Therefore, by applying the auxiliary pressure contact force of P _S to the driven wheels 6 and 6, respectively, the movable table 2 can be moved without sliding. And the width of the contact point is l (= 35m
When the surface pressure acting on each contact point A, A'and B'when m) is calculated from the logical expression of HERTS, the contact pressure is compared with the contact pressure at the contact point A of the conventional example. The surface pressure can be reduced by 21% at the point A'and 67% at the contact point B '. This means that if the same transmission torque is applied, the mounting life can be extended due to the low surface pressure, and conversely, if the life is the same, a large torque can be transmitted.
Since all the members are pressed against each other, there is no play.

Although the angle formed by the contact point between the driven wheel and the drive shaft is 120 ° in the above embodiment, there is no problem even if there is some angular error, and a spring is used as the means for generating the pressure contact force. Alternatively, hydraulic pressure or the like may be used.

Further, the present embodiment is applied to one axis of the orthogonal robot, but it goes without saying that it can also be applied to an NC machine tool, a shuttle, and the like.

[Effects of the Invention] As is apparent from the above description, according to the present invention, two driven wheels are incorporated into one driven wheel housing, and the drive shaft 2
Since the driven wheels are pressed against each other by the biasing means and the driven wheel housing is also biased by the biasing means, the life of the apparatus is prolonged without increasing the size of the apparatus even when moving at high speed or moving heavy objects. Moreover, since the surface pressure can be extremely reduced, the guide bar and the like can be made of a cheap material, and the cost can be reduced.

In addition, the number of parts requiring dimensional accuracy is small, the processing cost is reduced, and the assembly and adjustment are easy.

[Brief description of drawings]

1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, FIG. 3 is a sectional view taken along the line III-III in FIG. The figure is an explanatory view showing the balance of forces between the conventional example and the present embodiment. 1 ... Fixed base, 2 ... moving base, 4 ... guide rail, 5 ... guide bar, 6 ... driven wheel, 7 ... driven wheel housing, 10 ... driving shaft housing, 12 ... driving shaft, 16 …… Spring housing, 17A, 17B, 17C …… Spring.

Claims (1)

[Claims] 1. A fixed base, a guide member attached to the fixed base, a movable base movably provided along the guide member, and a spring housing held at a fixed position of the movable base, A driven wheel housing movably held in the spring housing in a direction opposite to the guide member; two driven wheels pivotally supported by the driven wheel housing and in contact with the guide member; A drive shaft housing that is movably held in a direction opposite to the guide member, and is located on the opposite side of the guide member with the driven wheel housing interposed therebetween; and the two driven wheels that are axially supported by the drive shaft housing. And a drive shaft that is housed in the spring housing and that drives the driven wheel housing and the drive shaft housing toward the guide member. Spring and, moving mechanism, characterized in that a drive source for rotationally driving the drive shaft is held in the moving base to be.