JPS6283551A - Cam device - Google Patents

Abstract

PURPOSE:To reduce the impact force due to acceleration and deceleration by applying the driving power in the opposite direction to the inertia force generated on a working tool in accordance with the revolution position of a cam, onto a trailing link from an air cylinder. CONSTITUTION:A pushing tool 8 guided in free elevation onto a frame 2b is connected to the top edge part 4b of a trailing link 4 through a connecting link 9, and further the piston rod 11 of an air cylinder 10 onto which the edge part of the cylinder is pivotally installed onto the frame 2c is connected by a pin 12. An air pressure feeding circuit 13 for feeding the compressed air into the air cylinder 10 has a direction selector valve 15, and supplies the compressed air supplied from a pressure source 14 into either a downward driving conduit 16 or an upward driving conduit 17. Further, the direction selector valve 15 is controlled by an air pressure control circuit 31 to which a rotary encoder 30 installed onto the rotary shaft 1 of a cam 3 is connected.

Description

[Detailed description of the invention] 2. Scope of claims (Industrial application field) The present invention relates to a cam device.

(Prior art) A cam device is often used as a device that performs assembly (generally converts rotational motion of a shaft into reciprocating motion to process products), and Fig. 3 shows an example of this. There is thing C. In the figure, a driven link 42 driven by a cam 41 fixed to a rotating shaft 40 has a base end pivotally attached to a frame 43a, and a pusher 44 vertically guided by a frame 43b at the other end. The pushing tool 44 is used to push a product (not shown) with a relatively light load during the downward drive. A counterweight 45 that is slightly heavier than one piece of paper that balances the width 1 of the driven link 42 and the pushing tool 44 is connected to the tip of the driven link 42 via a wire row 146.

(Problem to be Solved by the Invention) However, in the above conventional device, the driven link 42
When the pushing tool 44 is not subject to acceleration or deceleration, the cam 4 is
1. Although the load applied to the driven link 42J3 and the cam contact roller 47 pivoted on the link is small, the cam 41
When the pushing tool 44 is subjected to acceleration or deceleration due to the rotation of A large inertial force multiplied by the speed will impact each part. This impact force includes the operating force of the load pushing tool 44 other than during acceleration and deceleration.
up to twice as much (usually about 5 times). As a result, the pivot portion of the driven link 42, the roller 47, the connecting portion between the driven link 42 and the pushing tool 44, the outer periphery of the cam 41, etc. are significantly worn, and the pushing tool 44 also vibrates, making it difficult to operate smoothly. In order to prevent this, there was no way to replace parts infrequently or manually upgrade each part, which increased the labor and production costs. Furthermore, even if a spring or the like is used instead of the above-mentioned counterweight 45, a similar impact force will be generated due to the inertia force caused by the purchase of the pushing tool 44, and this will be especially large when using the pushing tool 44 of doll quality. It became a small problem.

This invention solves the above-mentioned conventional problems, and aims to provide a cam device that reduces the impact force exerted on the cam device due to acceleration and deceleration, operates smoothly, and is highly durable.

(Means for Solving the Problems) However, the cam device of the present invention includes a cam, a driven link driven by the cam, an operating tool connected to the driven link, and a rotation of the cam. A position detector for detecting the position, an air cylinder connected to the slave link, an air pressure supply circuit for supplying compressed air to the air cylinder, and the cam moving to a predetermined position in response to an output signal from the position detector. When in the rotating position, an output signal is given to the air pressure supply circuit, and compressed air is supplied to the air cylinder so that the air cylinder generates a driving force in a direction opposite to the inertia force generated in the working tool. This cam device is equipped with a pneumatic control i1 device that controls the air pressure.

(Function) In the cam device of the present invention, the position detector detects the rotational position of the cam, and in response to this detection signal, the pneumatic control device issues an output signal when the cam is at a predetermined rotational position to reduce the pneumatic pressure. The supply circuit is operated, thereby supplying compressed air to the air cylinder, and a driving force is applied from the air cylinder to the driven link in a direction opposite to the inertial force generated on the working tool due to the acceleration/deceleration drive acting on the cam. This driving force partially cancels out the inertial force of the driven system such as the operating tool and the driven link, and only a small force corresponding to the difference between the driving force and the inertial force is transmitted to the driven link. The weight of each part of J3 and the cam is reduced.

(Embodiment) An embodiment of the invention by Riko J. will be described below with reference to FIGS. 1 and 2.

In the figure, reference numeral 1 denotes a rotating shaft rotatably supported by a frame 2a, which is driven by a motor (not shown).

The cam 3 fixed to the rotary shaft 1 is of a positive cam type which drives the roller 5 which is pivotally attached to the slave 4 and is restrained by the cam 3. The driven link 4 is a link that swings around a pin 7 whose end 4a is pivoted to the frame 2a, and a driving tool 8 that is guided by the frame 2b in a vertically movable manner is attached to the connecting link at its tip 4b. A piston rod 11 of an air cylinder 10 is connected to the air cylinder 10 via a bingo 2 and whose cylinder end is roughly Nm apart from the frame 2c. Reference numeral 13 denotes a pneumatic supply circuit that supplies compressed air to the air cylinder 10, in which compressed air from a pressure source 14 consisting of a compressor and an air tank is switched by a directional control valve 15, which is an electromagnetic third-position valve, to supply compressed air to the air cylinder 10. It is supplied to either the downward drive conduit 16 or the upward drive conduit 17 connected to the. The downward drive conduit 76 and the upward drive conduit 77 are provided with pressure reducing valves 18 and 19 for regulating supply pressure that operate during air supply, throttle valves 20 and 21 for adjusting back pressure that operate during exhaust, and these respective parts. Bypass check valves 22.23 and 24.25 are connected. 26
and 27 is a pressure gauge. On the other hand, 1 on the rotation axis 1 of the cam 3
A rotary encoder 30, which is a position detector, is connected, and its output signal SR is given to the pneumatic control 20 device 31. The pneumatic control device 31 is a rotary encoder 30
Count the output signal SR of and compare it with the internal setting value,
The cam 3 rotates and the roller 5 moves from point A to 8 on the contour of the cam 3.
17! When the roller 5 is in the rotational position touching the points 8 to 0, it emits a downward drive signal S, which energizes the solenoid 32 of the directional valve 15. When the point is in the rotational position where contact is made between D and E, an upward drive signal SU is generated that energizes the solenoid 33.
Point B is the start point of downward acceleration, Point C is the point of end of deceleration, Dot is the point of start of downward acceleration, Point E is the start point of deceleration, and Point F is the end point of deceleration.

In the device configured as described above, the cam 3 is intermittently rotated one rotation at a time in the direction of arrow R to drive the driven link 4, and the pushing tool 8 is raised and lowered to push a component (not shown) into the pushing tool 8. Let's do it. At this time, the cam 3 causes the roller 5 to
is driven downward and then driven upward, and as a result, an inertial force shown by a chain line in FIG. 2 is applied to the tip end 4b of the driven link 4 via the connecting link 9. That is, the point Δ of cam 3
-B is in contact with the roller 5, the driven systems such as the driven link 4 and the pusher 8 are accelerated downward (in the direction of arrow X in Figure 1), so the mass of this driven system (the tip of the driven link The quality of the part position (converted to ω) is multiplied by the acceleration of the cam 3, which generates an inertial force F1 in the upward arrow Y direction), and similarly between points 8 and 0, the mass of the driven system moving downward is decelerated. Downward inertial force F2, between points D and E, the driven system at the lowest position is accelerated upward, so downward inertial force "3, point E ~
Since the driven system moving upward is decelerated between F and F, an upward inertial force F4 is generated.

On the other hand, as the cam 3 rotates once, the pneumatic control device 31 receives the output signal S9 from the rotary encoder 30. , signal g3° is output to energize the solenoid 32, compressed air is supplied to the air cylinder 10 via the downward drive conduit 16, and the screw P is downwardly driven. (
(shown in broken lines in FIG. 2). Similarly, when the contact point of the roller 5 is between points 8 and 0 of the cam 3 and between points D and E, the pneumatic control 11 device 31 emits a signal SU to energize the solenoid 33 and compressed air Upward drive conduit 17
is supplied to the air cylinder 10 through the piston rod 11.
An upward driving force PU is generated between points E and F, and a downward driving force P is generated between points E and F in the same way as described above. As a result, the inertial forces F1 to F4 generated in the driven system cause driving forces P and P of the piston rod 11 that act in the opposite direction to this inertial force. As shown by the solid line in Fig. 2, only the force corresponding to the difference between these inertias and the driving force is transmitted to the driven link, and acts on the driven link 4, pin 7, roller 5, etc. The force exerted by the roller 5 and the pressing force between the roller 5 and the cam 3 are greatly reduced. Note that between points 0 and 0 and points F and Δ of the cam 3 where the driven system does not move up or down, the pneumatic control device 31 does not issue a signal and the directional control valve 15
is held at the neutral position and the air cylinder 10 does not generate any driving force.

The present invention is not limited to the above-mentioned embodiments; for example, the pushing tool 8 may move horizontally, and in addition to the pushing tool 8, various working tools such as a bending tool or a product gripping tool may be used. I can do it.

Further, the generation of the driving force by the air cylinder 10 is as follows.
The timing may be slightly shifted with respect to the start and end points of acceleration/deceleration by the cam, such as in a narrower section than between each point of F. Furthermore, as a position detector for detecting the rotational position of the cam 3, instead of the rotary encoder 30, a separate cam fixed to the rotation @1 is used and the cam is operated. ! Two or more limit switches or the like may be used, and in this case, the pneumatic control device 31 is configured in the form of an hour wheel mainly consisting of a contactor operated by these limit switches.

In addition to the positive cam, the present invention can also be applied to a cam device in which a roller is pressed against a normal plate cam and restrained by a spring force or the like.

(Effects of the Invention) As explained above, according to the present invention, the driving force generated by the air cylinder according to the rotational position of the cam cancels out the inertia force of the driven system, thereby reducing the force acting on the driven link. Therefore, the impact force caused by acceleration and deceleration in the cam device is reduced,
The durability of various parts such as driven links, cams, and rollers has been improved,
An excellent cam device is obtained that allows the operating tool to operate smoothly with little vibration.

[Brief explanation of drawings]

Fig. 1 is an equipment system diagram of a cam BH showing an embodiment of the present invention, Fig. 2 is a load Φ diagram on the tip of the driven link, and Fig. 3 is a diagram of the load on the tip of the driven link.
The figure is a diagram corresponding to FIG. 1 showing an example of a conventional link device. 1... Rotating shaft, 3... Cam, 4... Driven link,
5... Roller, 8... Push tool, 10... Air cylinder, 11... Piston rod, 13... Air pressure supply circuit, 14... Pressure source, 15... Directional switching valve , 16
...Downward drive conduit, 17...Upward drive conduit, 30.
...Rotary encoder, 31...Pneumatic control'n device, 32...Trail, 33...Solenoid.

Claims (1)

[Claims] a cam, a driven link driven by the cam, a working tool connected to the driven link, a position detector for detecting the rotational position of the cam, an air cylinder connected to the driven link, and an air cylinder connected to the driven link. A pneumatic supply circuit supplies compressed air to the cylinder, and when the cam is at a predetermined rotational position in response to an output signal from the position detector, an output signal is given to the pneumatic supply circuit, and an inertial force is generated in the working tool. and a pneumatic control device for supplying compressed air to the air cylinder so that the air cylinder generates a driving force in the opposite direction.