JPH025146Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a transmission torque switching device used in parts press-fitting machines and the like.

(B) Prior Art When transmitting rotation from a drive source to a driven object, a situation often arises in which it is desired to switch the rotation speed and the transmission torque accordingly. In such cases, a. Mechanically switch the speed at regular intervals. (Japanese Unexamined Patent Publication No. 57-120758) b. A high-speed drive source and a low-speed drive source are artificially switched and used as necessary. (Utility Model Application Publication No. 52-70268) Such methods have been proposed so far. It can be said that method a. is suitable for work where the torque switching timing is constant, and method b. is suitable for work that is infrequent. By the way, when considering press-fitting work, in order to increase efficiency, it is necessary to reduce the movement of the ram while the press-fitting ram is approaching the part or while the part held by the press-fitting ram is moving through the space. It is desirable to do this at high speed, and once the press-in begins, push in slowly but with strong force. Here, if the timing of switching from the high-speed, low-torque movement mode to the low-speed, high-torque movement mode is constant, method a. above can be applied. However, for example, if we assume the task of press-fitting a pin into a hole, the time to switch the movement mode will change if the length of the pin changes, so when handling pins of different lengths, method a. There is an inconvenience that the switching cycle must be reset each time.
In this respect, method b can be said to be flexible, but it requires a full-time worker to monitor the work all the time and manually switch the movement mode at an appropriate time, which reduces productivity. It is very impractical from this point of view.

(c) Problems to be solved by the invention The present invention attempts to provide a device that automatically switches from a high-speed, low-torque movement mode to a low-speed, high-torque movement mode in response to load fluctuations. . The present invention also attempts to realize such a device by combining inexpensive mechanical elements. Furthermore, the present invention ensures that when the driven body is returned to its original position by switching from the low-speed, high-torque movement mode to the high-speed, low-torque mode, the return is reliably performed.

(d) Means for solving the problem In the present invention, a high-speed transmission train and a low-speed transmission train are provided to connect the driving shaft and the driven shaft.
The high-speed transmission train includes a torque limiter and a one-way clutch that causes the torque limiter to function only when the driving shaft rotates in the normal direction, and disables the torque limiter when the driving shaft rotates in the reverse direction to directly transmit power to the driven shaft. The low-speed transmission train is located between a reducer that decelerates the rotation of the driving shaft, and the output shaft of this reducer and the driven shaft.While the high-speed transmission train rotates the driven shaft at high speed in the forward rotation direction, it idles and carries the load. A one-way clutch connects the reducer output shaft and the driven shaft when the speed of the driven shaft decreases due to exceeding the transmission capacity of the torque limiter, and an electromagnetic clutch disconnects the connection between the reducer output shaft and the driven shaft when the driving shaft reverses. Contains clutches.

(E) Effect: The high-speed transmission train causes the driven shaft to rotate at high speed until the driven body driven by the driven shaft encounters a load. This high-speed rotation is then transmitted back to the reducer of the low-speed transmission train, but at this time the one-way clutch is idling, so the reducer never brakes or locks. When the driven shaft encounters a load that exceeds the transmission capacity of the torque limiter and begins to stop rotating, the one-way clutch, which had been slipping until now, engages and the low-speed transmission train is connected to the driven shaft, transmitting large torque power. Start. When the driving shaft is reversed in order to return the driven body to its initial state, the direction of rotation corresponds to the direction in which the one-way clutch engages, so if this continues, the speed reducer will apply a brake to the driven shaft. Therefore, at this time, the electromagnetic clutch is disconnected to disconnect the driven shaft and the reducer output shaft. Also, at this time, the function of the torque limiter is disabled and the power from the driving shaft is directly transmitted to the driven shaft, so even if there is some resistance, it is not a problem and the driven body returns at high speed.

(F) Embodiment In the figure, 1 is a driving shaft, 2 is a driven shaft, and 3 is a base of a parts press-fitting device that supports the driven shaft 2 by a bearing portion 4. The driven shaft 2 has a feed screw portion 5,
This causes a ram (not shown) to move in the axial direction. A bevel gear 6 is fixed to the drive shaft 1, and a bevel gear 7 paired therewith is fixed to an intermediate shaft 9 supported in a cantilever manner by a bearing part 8 of the base 3. A pulley 10 is fitted onto the intermediate shaft 9 adjacent to the bevel gear 7. The pulley 10 is movable in the axial direction, is pushed by a spring 11, and is in pressure contact with the bevel gear 7 via a friction plate 12, which together constitute a torque limiter 13. Pulley 1
0 is connected to a pulley 14 fixed to the driven shaft 2 via a timing belt 15. Further, a one-way clutch 16 is inserted between the pulley 10 and the intermediate shaft 9. The one-way clutch 16 is set to be disconnected when the intermediate shaft 9 rotates in the forward rotation direction (the direction in which the driven shaft 2 is rotated in the direction of press-fitting parts), and to be connected when the intermediate shaft 9 rotates in the reverse direction. There is. Therefore, when the bevel gear 6 rotates in the normal rotation direction, the pulley 10 rotates following the bevel gear under the power transmission action of the torque limiter 13, but when the rotation direction is reversed, the pulley 10 engages with the one-way clutch 16. , and rotates as if directly connected to the bevel gear 6 via the intermediate shaft 9. This group of transmission elements from the bevel gear 6 to the pulley 14 constitutes a high-speed transmission train 17.

A pulley 18 is fixed to the driving shaft 1, and this pulley 18 is connected by a timing belt 22 to a pulley 21 fixed to an input shaft 20 of a worm gear reducer 19. A pulley 24 is fitted to the output shaft 23 of the reducer 19 via a one-way clutch 25. The one-way clutch 25 is set so that it is connected when the output shaft 23 rotates in the normal rotation direction (the direction in which the driven shaft 2 is rotated in the component press-fitting direction), and disconnected when the output shaft 23 rotates in the reverse direction. The pulley 24 is connected to a pulley 26 that is loosely fitted to the driven shaft 2, and a timing belt 27 is connected to the pulley 26 that is loosely fitted to the driven shaft 2
It is connected with. The pulley 26 is an electromagnetic clutch 28
It is connected to the driven shaft 2 by
The electromagnetic clutch 28 is “ON” when the driving shaft 1 rotates in the normal direction.
It is controlled to be “OFF” when the rotation is reversed. this,
The transmission elements from pulley 18 to electromagnetic clutch 28 constitute a low speed transmission train 29.

The operation of the above device is as follows. When the driving shaft 1 rotates normally (in the direction of rotation indicated by the arrow), the high-speed transmission train 17 causes the driven shaft 2 to rotate at high speed. The pulley 24 is also rotated by the pulley 26, but this rotation is in a direction in which the one-way clutch 25 is disconnected from the output shaft 23, so it is not braked by the slowly rotating output shaft 23. . Now, when a ram (not shown) hits a component and a load exceeding the transmission capacity of the torque limiter 13 is applied to the driven shaft 2, a slip occurs in the torque limiter 13, and the rotational speed of the driven shaft 2 suddenly decreases.
The rotational speed of the pulley 24 also decreases accordingly, until the rotational speed of the output shaft 23 exceeds that of the pulley 24, at which point the one-way clutch 25 engages and transfers the high-speed transmission from the low-speed transmission train 29 to the driven shaft 2. Torque power is transmitted.

After the press-fitting work is completed, the driving shaft 1 is reversed to return the ram to its origin. At this time, high-speed transmission train 1
7, the high-speed return is performed, but if the pulley 24 rotates along with this, a coupling action will occur in the one-way clutch 25 and the entire device will be locked, so the electromagnetic clutch 28 is turned "OFF" and the low-speed transmission train 29 is turned off. Separate. In addition, during the press-fitting process, there may be "sticking" or "hitching" between the ram and the parts.
When this happens, if the low resistance exceeds the transmission capacity of the torque limiter 13, the ram will no longer return, but during this reverse drive, the one-way clutch 16 kills the function of the torque limiter 13. The high-speed transmission train 17 powerfully rotates the driven shaft 2, and the ram reliably returns despite some resistance.

(g) Effects of the invention According to the invention, it is possible to automatically switch from high-speed, low-torque movement mode to low-speed, high-torque movement mode at the exact moment when high torque is required, and the mode switching mode can be changed automatically. Even if variations in timing occur, for example due to a change in the length of the part to be press-fitted, no action is required to adapt the timing. Moreover, this device can be easily constructed by combining general mechanical elements without using a complicated control system. Furthermore, the device that reverses the driving shaft returns to its original state in high-speed mode, but at this time, the function of the torque limiter in the high-speed transmission train is destroyed, so even if there is some resistance, the device will return to its original state without fail.

[Brief explanation of the drawing]

The figure is a partially sectional front view showing an embodiment of the invention. 1... Driving shaft, 2... Driven shaft, 17... High speed transmission train, 29... Low speed transmission train, 13...
...Torque limiter, 16...One-way clutch, 1
9... Reduction gear, 23... Output shaft, 25... One-way clutch, 28... Electromagnetic clutch.

Claims (1)

[Claims for Utility Model Registration] A driving shaft, a driven shaft, and a high-speed transmission train and a low-speed transmission train that connect these two shafts, the high-speed transmission train comprising a torque limiter,
The low-speed transmission train includes a one-way clutch that causes the torque limiter to function only when the driving shaft rotates in the normal direction and disables its function when the driving shaft rotates in reverse to directly transmit power to the driven shaft, and the low-speed transmission train decelerates the rotation of the driving shaft. A high-speed transmission train between a speed reducer, the output shaft of this speed reducer, and a driven shaft rotates idly while the driven shaft rotates at high speed in the normal rotation direction, and the load exceeds the transmission capacity of the torque limiter and the driven shaft The transmission torque switching device includes a one-way clutch that connects the reducer output shaft and the driven shaft when the speed decreases, and an electromagnetic clutch that disconnects the reducer output shaft and the driven shaft when the driving shaft reverses.