JPH0225300A - Spring type brake for press driving shaft - Google Patents

Abstract

PURPOSE:To relax a shock at the time of stop, while adjusting a rotating speed rate of a press driving shaft by providing a torque controller formed by containing an energizing force reducing means for reducing suitably energizing force of a spring of a control mechanism. CONSTITUTION:When a damping mechanism 10 is operating, it is detected by a rotating speed detector 41 that a press driving shaft 5 is immediately before a stop. Based on this detection, a damping force adjusting circuit 61 operates an energizing force reducing means 31 by a set time. The energizing force reducing means 31 reduces spring energizing force by applying force opposing the energizing force of a spring 13. Accordingly, a rotating speed decrease rate of the press driving axis 5 can be made small, and a shock at the time of stop can be relaxed. After the set time, desired damping force is secured by the maximum energizing force of the spring 13. Therefore, exact and smooth press working is guaranteed, and also, a long service life of a machine is attained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a spring type brake for a press drive shaft.

In particular, it is possible to adjust the torque of the press drive shaft just before it stops.

[Prior Art] FIG. 5 shows a general conventional structure of a spring type brake for braking the press drive shaft 5. As shown in FIG.

The spring brake is disposed in conjunction with a clutch (not shown) that transmits the rotational power of the drive source to the press drive shaft 5 during press operation, and brakes the rotation of the press drive shaft 5 after releasing the clutch and provides a predetermined braking force. This is to stop and hold the press drive shaft 5.

In the figure, the spring brake is used for braking tl! horizontal 10 and
It is composed of a release mechanism 20 and a drive control circuit 70. From the viewpoint of safety, the release mechanism 20 is mechanical, that is, operates the friction plate 11 by the urging force of the spring 13, and frictionally locks the press drive shaft 5 to the body 1. The press drive shaft 5 is rotatably attached to the body 1 with a bearing 4, and a hub 6 having a friction engagement portion 7 is fixed to the shaft end. Further, a similar frictional engagement portion 2 is provided inside the body 1 as well.

The friction plate 11 is engaged with both the friction engagement parts 2 and 7 via the push plate 12 by the biasing force of the spring 13, thereby integrally connecting the drive shaft 5 and the body 1. Here, the drive shaft 5 is braked and held stopped. The spring 13 is provided inside the flange 3 forming a part of the body 1.

On the other hand, the release mechanism 20 disengages the friction plate 11 from both friction engagement parts 2.7 against the biasing force of the spring 13, and allows press operation rotation of the drive shaft 5 based on the clutch operation. It is. The release mechanism 20 shown in FIG.
1 (cylinder 22° piston 25) and a brake release valve 2 that supplies compressed air from an air source 28 to the cylinder chamber 24.
It is formed from 7. The cylinder 22 is attached to the body 1, and the spring 13 is attached to a recess 23 on the outer periphery. The piston 25 is slidable in the axial direction in the cylinder 22 via a sealing material 29, and a flow path 26 is provided in the center thereof to communicate the brake release valve 27 and the cylinder chamber 24.

Further, a connecting rod 25a is attached to the outer peripheral portion of the cylinder 22, passing through the inside of the spring 13 and having a tip fixed to the push plate 12. Therefore, if the brake release valve 27 is operated to supply compressed air to the cylinder chamber 24, the piston 2
5 moves to the right in the figure. The connecting rod 25a is connected to the spring 13
By moving the push plate 12 to the right in the figure while compressing and deforming the friction plate 11, both I! The brake can be released by releasing (separating) from the J friction engagement portion 2.7.

Such a braking mechanism 10. The release mechanism 20 is actuated by controlling the brake release valve 27 at appropriate times by a drive control circuit 70 that includes switches, relays, auxiliary contacts, and the like. The brake release valve 27 is a solenoid valve, and has an air supply boat that supplies air into the cylinder chamber 24 and an exhaust boat that releases the air in the cylinder chamber 24 to the atmosphere. Further, the inching function is configured to maintain the pressure inside the cylinder chamber 24 at a set value.

Therefore, in the normal state, the spring 1 of the brake v1 mechanism 10
3, the friction plate 11 is biased leftward in the figure, and the press drive shaft 5 is braked by the engagement between the friction plate 11 and the two sliding engagement parts 2 and 7. On the other hand, drive control time i? If the brake release valve 27 is switched to the air supply boat by 870, the piston 2
5. The connecting rod 25a moves to the right in the figure against the biasing force of the spring 13, disengages the friction plate 11 and the friction engagement portions 2.7 of both r11, and connects the press drive shaft through the clutch operation. 5 rotations are allowed.

[Problems to be Solved by the Invention] However, the conventional spring type brake described above has many problems.

That is, since the braking force is determined by the maximum biasing force of the spring 13 and the maximum biasing force is constant, if the maximum biasing force is determined from the viewpoint of ensuring sufficient braking force, the rotational speed of the press drive shaft 5 will suddenly increase. For example, in a transfer feed means that uses the drive shaft 5 as the operation drive source, which has a large impact when it descends and stops, not only the blank conveyance accuracy deteriorates, but the blank may fall off, and the machine life is shortened.

On the other hand, if the maximum biasing force is selected small, the friction plate 1
In the event of a loss of first class, sufficient braking force cannot be established, which is dangerous. Furthermore, even if the friction plates 11 and the like are not completely destroyed, the engagement between the friction plates 11 and the friction engagement parts 2 and 7 will be delayed, and the slide will not be able to be stopped at a predetermined position, which will not only hinder the next process. There is a risk of personal and mechanical damage.

On the other hand, if the braking torque decreases due to deterioration of the friction plate 11 etc. over time, the friction plate 11. The mutual positional relationship of the springs 13, etc. must be adjusted.

Since this work is performed by fine adjustment of shims and screws, it is complicated, takes a long time, requires skill, and has the disadvantage that it reduces the operating efficiency of the press machine.

Furthermore, since the urging force of the spring 13 is constant, the friction plate 1
1 and both frictional engagement parts 2.7 are either engaged or released (disengaged), and the transition from the released state to the engaged state must be quick, therefore, the transition The velocity is linear according to the Kerr extension characteristics of the spring 13. Furthermore, the rate of decrease in rotational speed of the press drive shaft 5 after entering the engaged state remains constant. This has the inherent technical drawback that it is impossible to increase the transition speed and avoid sudden stop of the drive shaft 5 while keeping the biasing force of the spring 13 constant.

SUMMARY OF THE INVENTION An object of the present invention is to provide a spring-type brake for a press drive shaft that can adjust the rotational speed reduction rate of the press drive shaft and reduce the shock when it stops by changing the biasing force of the spring. It's about doing.

[Means for Solving the Problems] The present invention has a biasing force reducing means that generates a biasing force that resists the biasing force of a spring, and by appropriately operating the biasing force reducing unit, brakes are applied to the press drive shaft. The press is equipped with a torque control device that can adjust the braking torque of the press drive shaft, and is designed to reduce the impact when the press drive shaft stops.

That is, a braking mechanism is formed including a friction plate and a spring that biases the friction plate, and engages the friction plate with the biasing force of the spring to brake the press drive shaft, a cylinder device, and operates the cylinder device. In a spring-type brake having a brake release valve that releases the friction plate against the biasing force of a spring by actuation of a cylinder device,
urging force reducing means for reducing the urging force of the spring while pulling back the friction plate in the releasing direction against the urging force of the spring; A rotational speed detector that outputs a speed reduction signal, and a brake braking force applied for a set time while operating a biasing force reduction means, provided that the braking mechanism is in operation and the rotational speed reduction signal is output. The configuration includes a torque control device consisting of a drive adjustment circuit for relaxation control,
Achieve the above objectives.

[Operation] In the present invention having the above configuration, while the braking mechanism is in operation, the rotational speed detector detects just before the press drive shaft stops. Based on this detection, the braking force adjustment circuit operates the biasing force reducing means for a set time. The biasing force reducing means reduces the spring biasing force by applying a biasing force that opposes the biasing force of the spring. Therefore, the rotational speed reduction rate of the press drive shaft can be reduced, and the impact at the time of stopping can be reduced. After the set time, the desired braking force is established by the maximum biasing force of the spring.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In this embodiment, as shown in FIGS. 1 to 4, the braking v1
Structure 10. Release mechanism 20. The torque control device 40 and the drive control circuit 70 constitute a spring brake for the press drive shaft.

Note that this embodiment has a brake structure similar to that of the conventional spring type brake shown in FIG. In addition, in particular, the structural description of the control mechanism 10 and the release mechanism 20 will be simplified or omitted.

Here, the torque control device 40 has a biasing force reducing means 311.
Rotation speed detector 41. It is formed from a regulating valve 51 and a braking force regulating circuit 61.

The biasing force reducing means 31 includes a spring 1 forming a brake a ellipse 10.
3, while pulling back the friction plate 11 in the release <U release) direction, the urging force of the spring 13 is reduced.
This embodiment consists of a second cylinder device.

That is, by using the recess 23 on the lower side in FIG. 1 of the cylinder 22 forming the release mechanism 20 (cylinder device 21) and the collar 3 of the body 1, the main cylinder (cylinder chamber 32) is opened.
This main cylinder has a base end 35 or a piston 25.
A second cylinder device is formed by fitting the main piston 33 fixed to the cylinder. The cylinder chamber 32 has a flow passage 36.
'Compressed air is supplied via the AM valve 51. Note that pressure regulating valves and the like are not shown.

Therefore, by operating the regulating valve 51 to supply compressed air to the cylinder chamber 32 through the flow path 36, the piston 25 can be displaced to the right in FIG. 1 with respect to the cylinder 22. That is, the braking torque of the brake can be adjusted by generating a force that resists the biasing force of the spring 13 and changing the degree of frictional engagement between the friction plate 11 and both frictional engagement portions 2.7.

Further, the rotational speed detector 41 is connected to an encoder 42. as shown in FIG. Consisting of a digital rotary cam 43 and an output circuit 44, it outputs a rotation speed reduction signal when the rotation speed of the press drive shaft 5 falls below a set value indicating that the press drive shaft 5 is about to come to a complete stop. The signal is output by opening contact 45.

The encoder 42 is an optical detection method that performs detection by cooperation with an optical slit disk (not shown) attached to the drive shaft 5. Also, the digital rotary cam 43 processes the output from the encoder 42 in a predetermined manner and performs driving. Axis 5 is 0.
Outputs one pulse signal every five degrees of rotation. Here, the output circuit 43 is configured to determine that the rotation speed is below the corresponding rotation speed and output a closed contact 45 when the pulse signal from the digital rotary cam 43 is not input within a set predetermined time. There is.

On the other hand, the braking force adjustment circuit 61 operates the biasing force reducing means 31 to reduce the braking force of the brake under the condition that the braking mechanism 10 is in operation and the rotational speed reduction signal is not output (the contact 45 is closed). It is used to perform relaxation control for a predetermined period of time, and in this embodiment, it is formed of a relay sequence circuit as shown in FIG.

In Figure 2, auxiliary relay CR4, time relay T1
are connected in series to the contact 45. Auxiliary relay CR4
has a contact CR4a that closes an electric circuit when excited. The time relay T1 has a so-called time-limited instantaneous return type contact Tlb that opens an electric circuit after a set time has elapsed from the time it is energized, and instantly closes the electric circuit when it is de-energized.

Further, the auxiliary relay CR5 is connected in series with a contact CR1a and a contact Tlb that are closed when the auxiliary relay CRI of the drive control circuit 70 is excited, and the rotation speed of the press drive shaft 5 is set during press operation. When it is confirmed that the value is below the value and before a predetermined time has elapsed, the contact CR5a is output.

Note that the contact CRLa and the contact CR5a connected in parallel form a self-hold circuit.

Here, the regulating valve 51 has contacts CR5a connected in series,
'y! on condition of each closure of CR1b, CR4a and Tlb. The 6-rotation speed reduction signal generated by fJ is outputted, and operates only for a set time period after being outputted. Further, as shown in FIG. 4(B), the regulating valve 51 has an inching R function (not shown) that opens and closes inching so that the pressure in the cylinder chamber 32 is maintained according to a set curve.
is built-in.

Note that the circuit shown in the upper half of FIG. 2 is the same drive control circuit as the conventional drive control circuit 70.

That is, when the switch 71a, the contact 71a, the contact CR2b, and the contact CR3a of the two-handed press operation button 71 are all closed, they are energized, and the auxiliary contacts CR1a and CR
A press operation circuit consisting of relay CR1 that outputs 1b,
A restart prevention circuit consisting of a relay CR2 that is energized when the press operation button 71 is released, a drive circuit for the brake release valve (specifically, a known clutch/brake solenoid valve having a pair of solenoids) 27, and a second It is formed from a restart prevention circuit. Here, the drive circuit of the brake release valve 27 is set according to the conditions for exciting the relay CR1 of the press operation circuit or the crank angle (20 to 340 degrees).
Detection switch 74. Crank angle (170-340 degrees)
Both the detection switch 75 and the safe operation mode contact 91 are closed, and the crank angle detection switch 74. Both continuous operation mode contacts 92 are closed or contact CR3a, both continuous operation mode contacts 92 are closed, and contact CR3a
When 1a is closed, the brake release valve 27 is energized.

In addition, the second restart prevention circuit includes the inching operation mode contact 9
3. Continuous operation mode contact 92 and crank angle (27
0 to 210 degrees) Wh magnetizes relay CR3a based on the conditions that one of the detection switches 76 is closed, the continuous stop button 77 is not operated (closed), and the series-connected contacts CR1b and CR2a are both closed. .

Note that the contacts CR1b and CR2a are provided with a self-hold circuit in which the contact CR3a is connected in parallel. This is to perform automatic clutch/brake operation according to the driving mode, and to prevent restart in other cases to ensure safety.

Of course, these circuits and the control force adjustment circuit 61 are not activated when the emergency stop button 73 is operated or when mechanical and electrical conditions are not satisfied (interlock contact 78 is closed). A braking force is generated by the biasing force of the spring 13.

Next, the effect will be explained.

(Rotation of the drive shaft) If the press operation button 71 is operated with both hands, provided that the drive control circuit 70 is normal and various conditions are established,
The brake release valve 27 operates to the compressed air supply side.

Therefore, release 11!4W20 is activated and piston 2
5 (continuous rod 25a, push plate 12) moves to the right in FIG. When the brake release valve 27 is operated, a clutch (not shown) is operated. Therefore, the press drive shaft 5 is operated at a predetermined rotational speed and in accordance with the operating mode.

(Stopping the Drive Shaft) When the press operation button 71 is released or a stop command corresponding to each operation mode is issued, the auxiliary relay CRI of the drive control circuit 70 becomes de-energized at time t1 as shown in FIG. 4. Therefore, contact CR1a is opened and CR1a is opened.
lb is closed and the brake release valve 27 is energized. When the clutch is released, the release mechanism 20 is released and the braking mechanism 10 is activated.

That is, the air in the cylinder chamber 24 is released to the atmosphere from the brake release valve 27 via the flow path 26. The air pressure inside the cylinder chamber 24 gradually decreases as shown in FIG. 3(B).

In this case, the rotational speed of the press drive shaft 5 is ω0 as shown in (A). Then, at time t1, the air pressure inside the cylinder chamber 24 (more specifically, the piston 25, the connecting rod 2
5a) decreases to the point where it can no longer resist the biasing force of the spring 13, the friction plate 11 is moved leftward in FIG. 1 by the biasing force of the spring 13, and both rgl11! It engages with the engagement part 2.7.

Therefore, the press drive shaft 5 is decelerated linearly from time t1 due to the frictional force, as shown in FIG. 3(A). In the case of the conventional structure, as shown by the dotted line, the speed is linearly decelerated until a complete stop, so the impact force immediately before the stop is large.

Here, in the present invention, the torque control device 30 is activated.

That is, the encoder 42 outputs a signal corresponding to the rotational speed of the press drive shaft 5 detected through optical intervention to the f-digital rotary cam 43.

The digital rotary cam 43 outputs a pulse signal with a resolution of 0.5 degrees. The output circuit 44, which receives the signal of 0.5 degree/1 pulse, closes the contact 45 when the number of rotations becomes lower than a preset rotation speed (ω1).

The time is t2 shown in FIGS. 3 and 4.

In this way, when the rotation speed decrease signal (contact 45 is closed) is output from the rotation speed detector 41, the relay CR4 of the braking force adjustment port #I61 and the time relay T1 are activated as shown in FIG.
is excited.

When both auxiliary contacts CR5a and CRI b are open, auxiliary contact CR4a is open and timed contact Tlb is open.
It also remains in Kaisei. Therefore, the regulating valve 51 is excited, and compressed air is supplied to the cylinder chamber 32 through the flow path 36.

Here, the piston 33 forming the biasing force reducing means 31 moves to the right in FIG. 1 and generates a force (F2) resisting the biasing force (Fl) of the spring 13 via the connecting rod 25a, The biasing force of the spring 13 is reduced to P (=F1-F2).

Specifically, as shown in FIG. 3(C), the regulating valve 51 is operated by a built-in inching function (not shown) to increase the air pressure in the cylinder chamber 32 based on a set curve. As a result of the frictional engagement force between the friction plate 11 and both frictional engagement portions 2.7, which are engaged by the biasing force of the spring 13, being reduced just before the press drive shaft 5 stops, the rotational speed reduction rate of the press drive shaft 5 is reduced. As shown in FIG. 3(A), Enoki becomes a quadratic curve. Therefore, sudden stop of the press drive shaft 5 is avoided, and the impact force can be dramatically reduced.

Subsequently, immediately after the press drive shaft 5 has completely stopped, the auxiliary contacts Tlb, Tlb of the time relay T1 open the electric circuit after the delay time T shown in FIG. 4 has elapsed.

Therefore, the regulating valve 51 becomes inoperable and the cylinder chamber 32
The air inside is released to the atmosphere. The biasing force reducing means 31 is released, the brake R mechanism 10 operates as expected based on the maximum biasing force (Fl) of the spring 13, and the press drive shaft 5 is integrally locked with the body 1. This is where the full braking force is generated.

Note that the auxiliary contact Tlb is instantaneously restored, but the relay C
R5 becomes de-energized and the self-hold circuit (contact CR5a
Since the parallel connection between the contact point CRla and the contact point CRla is disconnected, the torque control device 30 will not operate unless the press operation is performed again (contact CRla is closed).

According to this embodiment, the brake ami.

Since a torque control device 30 is provided to reduce the biasing force of the spring 13 in a timely manner, the press drive shaft 5 can be stopped without abruptly stopping. Therefore, the impact force on the transfer feed mechanism etc. driven by the press drive shaft 5 can be significantly reduced, accurate and smooth press working can be achieved, and the life of the machine can be extended.

The torque control device 30 also includes a biasing force reducing means 31, a rotational speed detector 41. Adjustment valve 51 and braking force adjustment circuit 6
1, and the biasing force of the spring 13 can be reduced by adjusting the air pressure in the cylinder chamber 32, so the braking torque can be easily adjusted without the conventional complicated work of adjusting shims and screws.

Furthermore, since the torque control device 30 is activated by the rotational speed detector 41 immediately before the press drive shaft 5 is stopped, the stopping impact force can be alleviated without substantially delaying the activation time of the braking mechanism 10. Further, the torque control device 30 is automatically released after the press drive shaft 5 has completely stopped due to time management. Complete braking can be achieved with the maximum biasing force of the spring 13. This is effective as a means for making the biasing force of the spring 13 much larger than in the past and achieving higher operating speed of the brake mechanism 10 while alleviating the stopping impact force.

Furthermore, since the biasing force reducing means 31 is composed of a second cylinder device (32, 33) interposed between the cylinder 22 and the piston 25 forming the release machine +1120, the structure is simple and economical. The load is small, and it can be implemented without significantly modifying the braking mechanism 10 and the release mechanism 20.

Note that in the above embodiment, the torque control device 30 was configured as Fl including a cylinder device type biasing force reducing means 31, etc.
In short, it is sufficient to adjust the braking torque immediately before stopping the press drive shaft 5 by applying an external force that resists the biasing force of the spring 13 of the brake 111110, and to perform a relaxing stop, so the configuration is not limited to the above disclosed range. Braking mechanism 10. release m
The same applies to structure 20.

[Effects of the Invention] The present invention is configured to include a torque control device that includes a biasing force reducing means for appropriately reducing the spring biasing force of the control mechanism, so that the braking torque can be adjusted. The impact when the rotation stops can be dramatically reduced. Therefore, it is beneficial to ensure accurate and smooth press working and to extend the life of the R machine.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, FIG. 1 is a side sectional view, FIG. 2 is a configuration diagram of a brake adjustment circuit, and FIG. 3 is a timing chart for explaining the operation. , Fig. 4 is a diagram for explaining the relationship between the rotational speed of the press drive shaft, the cylinder internal pressure of the release mechanism, and the cylinder internal pressure of the biasing force reducing means, and Fig. 5 is a diagram showing the side of the conventional control mechanism/release mechanism. FIG. 2...Frictional engagement part, 5...Press drive shaft, 7...
Frictional engagement part, 10... Braking mechanism, 11... Traction plate,
DESCRIPTION OF SYMBOLS 13... Spring, 20... Release mechanism, 21... Cylinder device, 27... Brake release valve, 30... Torque control device, 31... Biasing force reduction means, 41... Rotation Speed detector, 51... Adjustment valve, 61... Braking force adjustment circuit, 70... Drive control circuit.

Claims (1)

[Claims] (1) A braking mechanism that includes a friction plate and a spring that biases the friction plate, and that brakes the press drive shaft by engaging the friction plate with the biasing force of the spring, a cylinder device, and the cylinder device. and a release mechanism that releases a friction plate against the urging force of a spring by actuation of a cylinder device, wherein the brake release valve is actuated to release the friction plate against the urging force of the spring. a biasing force reducing means for reducing the biasing force of the spring while pulling the plate back in the release direction; and a rotational speed detector that outputs a rotational speed reduction signal when the rotational speed of the press drive shaft becomes below a set value. , a torque comprising a drive adjustment circuit for controlling the brake braking force to be moderated for a set time while operating the biasing force reducing means on the condition that the braking mechanism is in operation and the rotational speed reduction signal is output. Spring brake on press drive shaft with control device.