JPH0254456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a linear feed mechanism that converts rotational motion into linear motion.

(Background Art) In general, to convert rotational motion into long-stroke linear motion, for example, a rack and pinion, a screw and a nut are used.

In such a transmission mechanism, the motion characteristics of the driving node (rotating body) directly become the motion characteristics of the driven node (sliding body), but for this reason, especially when the rotating body is driven by a motor etc., the movement characteristics of the sliding body are There was a problem that shock and vibration were likely to occur at the end.

To prevent this shock and vibration, drive the rotating body,
In other words, a device, such as a servo motor, is required to appropriately control the speed at which the motor or the like is started and stopped, which has the drawback of increasing the size and complexity of the device and significantly increasing the cost.

Furthermore, in the above transmission mechanism, the stopping position of the sliding body completely depends on the stopping angle of the rotating body, so it is necessary to strictly control the stopping angle of the rotating body in order to accurately maintain the stopping position of the sliding body. However, even if this is done, for example, it is not possible to release the breakdown of the gear mesh, and therefore a high degree of stopping accuracy cannot be expected.

(Objective of the Invention) This invention has been made in view of these problems, and eliminates shocks and vibrations at the beginning and end of the movement of the sliding body without having to particularly precisely control the drive of the rotating body. The purpose is to improve the positioning accuracy of sliding bodies.

(Structure and operation of the invention) Therefore, the present invention forms a rack on the output side sliding body along the sliding direction, and arranges rollers at the front and rear of the sliding body, while a rack is formed on the input side rotating shaft. A pinion is provided that meshes with the rotary shaft to move the sliding body linearly at a constant speed as the rotating shaft rotates at a constant speed, and feeds the sliding body through a roller before and after the constant velocity region of the sliding body, starting from the start. A cam is installed on the rotating shaft that causes the transition to a constant velocity range through gentle acceleration, or from a constant velocity range to slow deceleration and then to a stop. A stopping portion is provided to prevent the sliding body from being sent out in any direction.

In other words, as the rotating shaft rotates at a constant speed, the cam moves the roller disposed at the front of the sliding body from the stationary part to the shaped part, and begins to move the sliding body via the roller, increasing the speed with a gradual rise. increase.

When the rack and pinion engage at the point when the sliding body moves into a constant velocity range, the roller comes off the cam almost at the same time, and from then on, the sliding body moves through the rack and pinion to a predetermined stroke as the rotating shaft moves at a constant velocity. Go straight at a constant speed.

When the rack comes off the pinion almost at the same time as the roller disposed at the rear of the sliding body rests on the shaped part of the cam, from this point on, the cam is again attached to the sliding body via the roller as the rotating shaft rotates at a constant speed. While feeding is applied and the roller is gradually decelerated, when the roller moves to the stop portion, the sliding body is stopped.

Therefore, the sliding body should move linearly over a predetermined long stroke so that it begins to move as the rotating shaft rotates at a constant speed, gradually accelerates, moves to a constant speed range, and then slowly decelerates again and stops. Therefore, shock and vibration at the beginning and end of the sliding body's movement are eliminated.

In addition, while the roller is on the stationary part, the cam holds the sliding body in a stopped state via the roller even if the rotating shaft rotates a little, and therefore the cam holds the sliding body in a stopped state through the roller. The sliding body can achieve high positioning accuracy even if it is not precisely controlled.

(Example) This invention will be explained below according to the example shown in FIGS. 1 to 5.

Reference numeral 1 denotes a rotary shaft rotatably supported by a housing 4 via bearings 2 and 3, and 5 denotes a slider supported by a guide 6 so as to be slidable in the housing 4 in a direction orthogonal to the rotary shaft 1.

The slider 5 has a rack 7 formed in the sliding direction on the side surface facing the rotating shaft 1, and rollers 10, 11, 12 at the front and rear thereof, corresponding to cams 8 and 9, which will be described later. 13 are arranged.

On the other hand, a pinion 14 is integrally connected to the rotating shaft 1 in correspondence with the rack 7, and the pinion 14 meshes with the rack 7 to cause the slider 5 to move straight at a constant speed as the rotating shaft 1 rotates at a constant speed.

Further, the rotating shaft 1 is fed to the slider 5 via rollers 10, 11 or 12, 13 before and after the constant velocity range of the slider 5, and is started to move through a gentle acceleration range to a constant velocity range or Two plate cams 8, 9 that transition from a constant velocity range to a slow deceleration range and then to a stop.
are connected in parallel.

These cams 8 and 9 have perfect circular portions 15 and 9, respectively.
16 (constituting the stop portion) and shaped portions 17 and 18
are formed in a symmetrical shape with respect to the axis l, and when the rollers 10, 11 or 12, 13 are lifted up on the shaped parts 17, 18, as the rotating shaft 1 rotates at a constant speed, the rollers in one shaped part 18 The other shaped portion 17 feeds the roller 10 or 12 while holding down the roller 11 or 13.

Note that the cam-shaped portions 17 and 18 are the rollers 10 and 11.
Alternatively, the cam curve is set so that the delivery speeds 12 and 13 become, for example, a modified constant velocity curve P shown in FIG. A dotted line Q in the figure shows the feed rate of the slider 5 by the rack 7 and pinion 14.

In the state shown in FIG. 1, when the rotating shaft 1 rotates at a constant speed in the direction of the arrow A, the cams 8 and 9 move as shown in FIG. The slider 5 begins to be moved in the direction of arrow B via the rollers 10 and 11, and its delivery speed is gradually increased.

When the slider 5 moves to a constant velocity range, the rack 7 and pinion 14 engage with each other at a predetermined rotation angle position (third
In the rotation angle range of Figures C to E, cams 8 and 9 also have roller 1.
Thereafter, the slider 5 moves straight at a constant speed through the rack 7 and pinion 14 along a predetermined long stroke as the rotary shaft 1 rotates at a constant speed.

The rollers 12, 13 are the shaped portions 17 of the cams 8, 9,
18, the cams 8 and 9 act in the opposite manner to that shown in FIG.
The rollers 12 and 13 are fed out at a constant speed by a rotation angle position (including the rotational angle position that deviates from
When the slider 5 moves to the perfect circular portions 15 and 16, the slider 5
to stop.

Therefore, as the rotating shaft 1 rotates at a constant speed, the slider 5 begins to move, accelerates slowly, moves to a constant speed range, and then comes to a stop while gradually decelerating again, as shown in Fig. 5. .

Note that when the rotating shaft 1 is reversely rotated, the slider 5 returns to its initial position through the same operation as described above.

By the way, according to this embodiment, a cam 8, which gently accelerates or decelerates the slider 5 when it starts or stops.
9 and rollers 10, 11 and 12, 13, shocks and vibrations at the beginning and end of the movement of the slider 5 can be eliminated.

In addition, the cams 8, 9 are rotated by a pair of rollers 10, 11 or 12, 13 that are offset from each other in the front and back direction as long as the roller parts 10, 11 or 12, 13 are on the perfectly circular parts 15, 16. The true circular parts 15 and 16, whose radii do not change, are sandwiched from the front and back, so even if the rotating shaft 1 rotates, the true circular part 1
As long as the slider 5 is in contact with the rotating shaft 1, the slider 5 cannot move from the stopped state.
Even if the drive start and stop positions of the slider 5 are not precisely controlled, high positioning accuracy can be obtained for the slider 5.

6 and 7 show another embodiment. In this case, the rotary shaft 1 has a flat grooved cam 2 instead of the plate cams 8 and 9.
0 and 21 are provided in parallel.

One cam 20 has a spiral cam groove 22 on one side from the outer periphery toward the center, and the other cam 21 has a reverse spiral cam groove symmetrically around the axis R with respect to the cam groove 22 on one side. 27 are formed respectively.

On the other hand, there are cams 20 at the front and rear of the slider 5.
and 21, rollers 23 and 24 are disposed at the same height as the centers of the cams 20 and 21 via leg portions 25 and 26, respectively.

Incidentally, the cam grooves 22 and 27 of the cams 20 and 21 are
As shown in the figure, the cam curve is set to gently accelerate and decelerate the slider 5 in the start and stop ranges. However, in the cam grooves 22 and 27, circular diameter portions (stop portions) 28 and 29 are formed at the center portions of the cams 20 and 21 and are equidistant from each other around the rotating shaft 1 within a predetermined rotation angle range.

In the illustrated state, when the rotating shafts 1 and C rotate at a constant speed in the direction of the arrow C, one of the cams 20 moves the roller 23 that has entered its cam groove 22 from the center to the outer periphery as the cam 20 rotates, that is, in the cam groove. 22, and the slider 5 is thereby sent out through the rollers 23 while being gently accelerated in the direction of arrow D.

When the slider 5 shifts to a constant velocity range, the rack 7 and pinion 14 engage with each other at a predetermined rotational angle position, and at the same time, the roller 23 comes off from the cam 20, and thereafter the slider 5 is moved evenly by the action of the rack 7 and pinion 14. Move in a straight line at high speed.

When the roller 24 is caught in the cam groove 27 of the cam 21 just before the rack 7 comes off the pinion 14, the cam 21 moves the roller 24 deeper into the groove 27 while decelerating the slider 5. When the roller 27 reaches the arc portion 29, it is stopped.

Therefore, this embodiment also provides the same effects as described above.

8 and 9 show an embodiment in which cylindrical grooved cams 30 and 31 are used to obtain the same effect, and rollers 32 and 33 are provided at the front and rear of the slider 5, respectively. On the other hand, the rotating shaft 1 includes a cam 30 that meshes with a roller 32 within a predetermined rotation angle range,
A cam 31 that also meshes with the roller 33 is connected.

The grooves 34 and 35 of the cams 30 and 31 have twisting portions 36 and 37 that feed out the roller 32 or 33 while gently accelerating or decelerating them as described above as the rotating shaft 1 rotates at a constant speed. It consists of straight parts 38 and 39 which sandwich and hold 33.

In this case, since the slider 5 is disposed parallel to the rotating shaft 1, the teeth of the rack 7 and the pinion 14 are formed obliquely at the same inclination angle.

(Effects of the Invention) In summary, according to the present invention, even if the drive of the rotating body on the input side is not precisely controlled, the sliding body on the output side can achieve high stopping accuracy, and
Shocks and vibrations at the beginning and end of the movement can be removed, improving the reliability and durability of the device, and reducing costs by eliminating the need for a device (such as a servo motor) that controls the drive of the rotating body. This effect can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of the first embodiment, Fig. 2 is a sectional view taken along the line X-X, Fig. 3 is a diagram of the operation stroke of the cam,
Fig. 4 is a characteristic diagram of the cam, Fig. 5 is a movement characteristic diagram of the slider, Fig. 6 is a schematic configuration diagram of the second embodiment, and Fig. 7 is a diagram of the movement characteristics of the slider.
The figure is a YY sectional view thereof, FIG. 8 is a schematic configuration diagram of the third embodiment, and FIG. 9 is a partial view taken along the Z arrow. 1... Rotating shaft, 5... Slider, 7... Rack, 8, 9, 20, 21, 30, 31... Cam,
10-13, 23, 24, 32, 33...roller, 14...pinion, 15,16...perfect circle part,
17, 18... shaped part, 22, 27... cam groove,
28, 29... Arc part, 36, 37... Twisted part,
38, 39...straight line section.

Claims (1)

[Claims] 1. A rack is formed along the sliding direction on the sliding body of the output shaft, and rollers are provided at the front and rear of the sliding body, and the rollers mesh with the rack on the rotating shaft on the input side and rotate at a constant speed of the rotating shaft. A pinion is provided to move the sliding body linearly at a constant speed, and the sliding body is fed through a roller before and after the constant velocity region of the sliding body.
A cam is installed on the rotating shaft that moves this from startup through gentle acceleration to a constant velocity region, or from a constant velocity region through gentle deceleration to a stop. A linear feed mechanism characterized in that the corner range is provided with a stop portion that prevents the sliding body from being sent out in any direction via rollers.