TWI718866B - High-precision clutch mechanism - Google Patents

Abstract

The present invention provides a high-precision clutch mechanism. The clutch mechanism includes: an upper clutch, a middle clutch, and a lower clutch. In particular, the middle clutch has a convex surface from one side and a concave surface on the other opposite side. A disc body with a shaped step surface, the convex step surface is combined with the upper clutch and the end surface is provided with an oil groove of unlimited type, and more than one steel ball is embedded in the oil groove, thereby reducing the friction between each other and The friction error caused by the steel ball rushing forward due to inertia; and the inner surface of the outer edge of the concave step surface of the middle clutch is formed with a slope, which forms an opposite slope with a surface of the peripheral surface of the lower clutch to achieve mutual contact; when When the clutch is working, there is no interference between the middle clutch and the lower clutch, and the two inclined surfaces can be more accurately matched with each other when the two inclined surfaces are engaged, so that the torque repeatability of the automatic tool driver can achieve a better improvement.

Description

High-precision clutch mechanism

The present invention is a clutch mechanism for automatic tooldrivers, in particular to a high-precision clutch mechanism that can specifically improve the precision of small torque.

According to the general commercial gas electric screwdriver, when the torque is used below 6Kgf-cmu, the repeated torque accuracy is often unable to reach the standard of ±3%, but the current trend of the product pursuit is light, thin, short, and small. , The size of screws will only get smaller and smaller, so in the future, it is conceivable that high-precision and small-torque screwdrivers will be the mainstream of the future market.

The design principles and units of the torque and clutch mechanism of the conventional automatic tool screwdriver include: upper clutch (cam), middle clutch, steel ball, lower clutch, plane bearing, torsion spring. The torque and the clutch mechanism will have the following effects on the torque accuracy under the environment and operating temperature. Taking the upper clutch (ie cam) commonly used in the internal clutch of automatic tooldrivers in the industry (the inventor of this case has previously had the same design), that is, the contact process between the upper clutch and the middle clutch is “surface” contact. This design will cause the The friction force of each contact element of the clutch is relatively large, and the change of the friction force will be affected due to the temperature change during use, and the accuracy error will increase, so that the small torque accuracy of the tool cannot reach the perfect standard of ±3%.

Secondly, another reason for the impact on accuracy is: when the upper clutch (cam) contacts the steel ball on the middle clutch, it will rise from the bottom dead center to the top dead center, and then push up and down the clutch, the lower plane bearing and the torsion spring at the same time , And then generate torsion, and complete a lock cycle action. In the conventionally known clutch design, the contact surface of the middle clutch and the lower clutch presents a right angle of 90 degrees. Therefore, when the clutch acts, the upper clutch (ie, the cam) will collide during the ascent process, and then The torque repeatability cannot reach the standard of ±3%.

The inventor felt this, and actively thought and started research. After self-expectation, continuous hard work and trial production, he finally developed and designed this more sophisticated and practical invention.

The purpose of the present invention is to provide a high-precision clutch mechanism, so as to achieve an effective and reliable improvement of the torque accuracy of the lifting automatic screwdriver under small torque operations.

In order to achieve the above purpose, the inventor of the present case made the following improvements to the existing clutch mechanism used for automatic tooldrivers, including: 1. An unlimited type of oil groove is set at the middle clutch, and butter is put in to increase the service life, And put more than one steel ball in the oil tank, which can reduce the friction loss caused by the clutch ascending and descending, thereby reducing the frictional force and the friction error caused by the inertia of the steel ball, and reducing the contact of the clutch. The surface temperature increase caused by friction between the components can effectively achieve the cooling effect, so as to improve the torque repeatability of the clutch. And 2. Change the type of mutual contact between the middle clutch and the lower clutch in the clutch mechanism from a right angle to an inclined plane. The improved design is that when the upper clutch (ie cam) rises, the relative contact between the middle clutch and the lower clutch The movement will not cause interference. When the upper clutch (ie cam) is lowered and returned to its original position, the two opposite inclined surfaces are in contact with each other, which can be more accurately matched with each other, so that the torque repeatability of the self-pneumatic electric screwdriver can also be comparable. Correspondingly get better promotion.

The above-mentioned oil grooves may be arranged in at least two or more relative types, or may be arranged in an annular type.

(1): Clutch mechanism

(10): Upper clutch shaft hole

(11): Shaft hole

(12): The inner ring of the shaft

(13): Inner Ring Road

(14): Outer Ring Road

(15): Convex

(20): Middle clutch

(21): Convex class surface

(22): Concave class surface

(23): Bevel

(24): Oil tank

(25): Steel Ball

(30): Lower clutch slope

(31): Bevel

The first figure is a schematic diagram of the clutch mechanism assembly of a preferred embodiment of the present invention.

The second figure is an exploded view of the clutch mechanism of a preferred embodiment of the present invention.

The third figure is a top view and A-A cross-sectional view of the clutch in a preferred embodiment of the present invention.

The fourth figure is a schematic diagram of the lower clutch assembly in a preferred embodiment of the present invention.

First of all, the present invention provides a high-precision clutch mechanism that can be applied to various automatic tooldrivers, including electric screwdrivers, or pneumatic screwdrivers, etc. The specific structure of the automatic tooldriver includes: an outer shell that is convenient to hold The set can be either vertical or gun type; internally, it has at least: motor mechanism, gear mechanism, clutch mechanism, torsion mechanism, chuck mechanism; because the above mechanisms are the basic structure of common automatic tooldrivers And the basic functions, and the functions of each unit are not the focus of the application of this case, so it is not allowed to repeat them.

Secondly, please refer to the first figure, which discloses a schematic diagram of a preferred embodiment of the clutch mechanism and the torque mechanism. The clutch mechanism is mainly used to set the torque value in conjunction with the torsion mechanism, so as to be used as an automatic tool screwdriver. When the preset torque value is reached, the clutch mechanism will have a tripping effect. As for the main improvement of the present invention, the key point is to improve the accuracy of the clutch mechanism. Its specific feature is to separately improve the various units that make up the clutch mechanism (1), in other words, to improve the contact type of the mutual coupling of the units.

Please refer to the second to fourth figures again. The clutch mechanism (1) includes: an upper clutch (10), which is a T-shaped cam type, and a shaft hole (11) for coupling in the center of the face. One side has a rotating shaft (12), the type is not limited, it is the best polygon, There is an inner ring (13) and an outer ring (14) on the surface of the cam, and the relative positions of the inner and outer ring (13, 14) are respectively provided with dislocation convex parts (15) to form a running The required top and bottom dead points when reaching the preset torque value; a middle clutch (20), from the side view, presents a recessed form from one side to the other, in other words, a convex surface (21), The inner part is regarded as a disc body of a concave step surface (22). The inner surface part of the concave edge of the first step of the concave step surface (22) and the outer edge form a slope (23). The convex step surface (21) ) Is in contact with the cam surface of the upper clutch (10), and an oil groove (24) is provided on the end surface. In practice, at least two or more than two relative types can be arranged, or even a ring type. The oil groove (24) Corresponding more than one steel ball (25) is embedded and embedded, the convex step surface (21) is inserted into the shaft hole (11) of the upper clutch (10) and the steel ball (25) is in contact with the inner bottom surface ; And the lower clutch (30) is a disc body, which can be fitted into the concave step surface (21) of the middle clutch (20), and the peripheral surface and a surface of the disc body are formed with another inclined surface (31 ), the two opposite inclined surfaces (23, 31) are attached to each other when the lower clutch (13) is engaged with the middle clutch (12).

The operating principle of the present invention is: when the clutch mechanism (1) is operating, the upper clutch (10) is in contact with the middle clutch (20), and the clutch mechanism (1) will trip when the torque value is reached , So that the middle clutch (20) will be pushed up, and the opposite steel ball on its surface will rise to the top dead center via the bottom dead center of the convex portion (14) of the cam surface of the upper clutch (10), and will push the bottom clutch (30) ) And the lower plane bearing and torsion spring, and generate torsion, and complete a locking cycle. Therefore, when the cam surface of the upper clutch (10) rises to the highest point, that is, it reaches the set maximum value. At this time, the power motor will stop running, but under the action of inertia, the convex surface of the middle clutch (20) The relative steel ball of the first-order surface It still pushes forward, so the torque will increase, causing torsion instability. Therefore, the combined structure of the oil groove (24) designed on the end face of the convex step surface of the middle clutch (20) and the inner majority of steel balls (25) , It can reduce the friction force and the friction error caused by the inertia of the steel ball, and achieve the effect of improving the torque repeatability of the clutch.

Secondly, since the contact surface of the middle clutch (20) and the lower clutch (30) has been improved to present an inclined slope (23, 31), when the cam surface of the upper clutch (10) rises, the middle clutch (20) There will be no interference with the lower clutch (30). After descending and returning, the two inclined surfaces (23, 31) can be engaged for more precise coordination, so that the torque repeat accuracy of the automatic screwdriver can also be corresponding Get better promotion.

Summarizing the above content, it can be seen that when the automatic tool screwdriver is implemented online, the environment and operating temperature have the greatest impact on the torque accuracy, but after the improved clutch mechanism design (the new oil groove and steel ball combination is designed on the middle clutch, and the middle clutch and The two opposite slopes between the lower clutches are engaged), which can effectively reduce friction loss, thereby reducing the surface temperature rise caused by friction between the clutches, and can be effectively cooled. The final result can further improve the torque accuracy of the clutch mechanism. Promote.

(1): Clutch mechanism

(10): Upper clutch shaft hole

(11): Shaft hole

(12): The inner ring of the shaft

(13): Inner Ring Road

(14): Outer Ring Road

(15): Convex

(20): Middle clutch

(21): Convex class surface

(22): Concave class surface

(23): Bevel

(25): Steel Ball

(30): Lower clutch slope

(31): Bevel

Claims (2)

A high-precision clutch mechanism includes: an upper clutch, a shaft hole in the center, and a rotating shaft on the other surface. The peripheral surface of the shaft hole is a cam surface and has two inner and outer ring channels that are misaligned with each other. , The outer ring road respectively has opposite and dislocation convex parts; a middle clutch is a disc body with one convex step surface and the other concave step surface, the convex step surface is in contact with the cam surface, And an oil groove is provided on the end surface, the oil groove is embedded with steel balls, and the inner surface of the outer side edge of the concave step surface is formed with an inclined surface; and the lower clutch is a disc body, and one side can be fitted with the concave step surface of the middle clutch And the peripheral surface of the disc body and a surface form an inclined surface, which can be mutually attached to the middle clutch. For example, the high-precision clutch mechanism described in item 1 of the scope of patent application, wherein the oil grooves can be arranged in at least two or more relative patterns, or in a ring pattern.

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