TWI548491B - Two-stage lock with electric screwdriver - Google Patents

Description

Two-stage lock with electric screwdriver

The invention relates to an improvement of an electric screwdriver, in particular to a two-stage locking electric screwdriver with externally adjustable torque, convenient adjustment, accurate torque, power saving and reduced number of parts and cost saving.

According to the lock wire (plug) locking technology, it plays an indispensable role in various industries and modern processes. Especially the screw (plug) assembly technology in the fields of automobile, aviation aerospace and bolt manufacturing is particularly important.

SCHATZ, which has accumulated more than 50 years of technical experience, has been committed to developing various bolt assembly and quality assurance solutions. It has become the industry standard and even the technical standards have been the current international or national standards or guidelines; especially Volker Schatz In his book "10 Step for Reliable Bolted Assembly", the doctor detailed 10 steps that affect all the factors in the assembly program, and affects the bolt connection. The causal relationship of fastening quality was analyzed and studied. These 10 steps can be made into a step checklist for monitoring the degree of sophistication of the method implemented during the tightening of the bolt joint. Of course, these 10 steps can also be used as guidelines for developing current standards that reflect the most sophisticated quality systems. Through this book, the quality assurance of the lock is raised to the highest level and meets the current standards and methods.

In the book, the tightening method is to install the fastening of the threaded secondary connection. One of the most important aspects of the strategy. For each bolting operation that assembles the assembly together, a guide is required to describe the steps to be taken when tightening and the measurement data to be used. To this end, the parameters of the assembly step should be calculated based on the abstract model. Since it is an abstract model, these parameters are only approximations of the actual conditions. The series of assumptions and estimates provided here can be used as the basis for fastener connection design. In addition, the results of charts, standards, and tests often fail to reflect the factors that affect assembly in actual assembly operations, and these results are often used as the basis for assembly operations. The tightening specifications currently used in production typically specify a torque with a corresponding tolerance range, or a cornering method that uses a tightening fastener to rotate the fastener to a certain angle to achieve a predetermined torque. When looking at the bolting fastening process, it seems very simple at first glance. When a fastening connection is made using a rotary power tool, the bolt is screwed into the screw hole until the head contacts the component to be mounted, and the wrench tool suddenly stops rotating. In this process, most of the time is used to screw in the fasteners. In the actual assembly process, that is, when two or more parts are connected together, this action is instantaneously utilized in 1 second. Completed.

Because the locking assembly process is completed relatively quickly and quickly, it is prone to defects in the locking operation of the elastic material connection. As shown in the first figure, elastic deformation occurs when the fastener is momentarily locked. The elastic material is plastically deformed, like a spring. Even if the screw (bolt) is locked and fixed within its elastic limit, it may also cause loosening of the locking connection, so-called clamping force loss.

Referring to the second figure (A), (B), the multi-purpose bolt fastening analysis system in the Schatz laboratory in Germany analyzes the performance of the screw (plug) for the screw (plug) lock, and the second The graphical analysis of Figure (A) shows the performance of the bolt lock with a material that is thinner than the length of the bolt. The second figure (B) shows the performance of the bolts being fixed to a material that is thicker than the length of the bolt.

As can be seen from the description, the meaning expressed in the second diagram (B) above is that if the screw (plug) is rotated at a very fast torque until the lock is completed, although the torque is kept within the tolerance, in fact, the The locking operation is incomplete and the screws (plugs) are not properly secured. The significance shown in the second diagram (A) is that if the two-stage locking will avoid the situation of the second figure (B), the screw (bolt) lock is fixed correctly and completely tight.

In addition, Xizhi's electric screwdriver, for the torque adjustment section, can be divided into internal adjustment torque and external adjustment torque. Please refer to the third figure. The torsion spring of the internal adjustment type is set inside (that is, between the coupling shaft and the torque cylinder), and the outer part is combined with a torsion sheath to cover the operation of adjusting the torque. The torsion spring is located inside the structure, so a specially designed torque wrench (or tool) must be used to rotate the special angle to adjust the torque. Once the special wrench (or tool) is lost, the torque cannot be adjusted; the internal torque is adjusted. Although it is not easy to achieve in the adjustment, the advantage is that the motor does not change the no-load current due to the torque of the clutch, so it is more energy efficient.

Secondly, the externally-torque torsion spring is also disposed inside, but a torque adjustment ring is provided on the outside (commonly available in the market). In operation, the hand can be directly adjusted externally, which is quite convenient; but the disadvantage is that : When the motor starts, it will adjust to the torque or the hour. The no-load current will change with the torque, so it consumes more power.

Furthermore, in addition to the motor, the general electric screwdriver mechanism includes at least a gear set, a clutch set and a screwdriver head set. When the internal or external adjustment torque is in the starting operation, the motor drives the gear set, and then drives the clutch group in succession. The screwdriver head group operates, which increases the turning weight and generates a power consumption situation.

The primary object of the present invention is to provide a two-stage locking electric screwdriver. By designing an internal tooth clutch having an internal tooth staggered and a misaligned cam, the inner ring track of the cam can be firstly provided with a torque to achieve a pre-locking function. And during operation, when the cams of the inner and outer ring tracks are staggered, a maximum torque is generated to achieve a perfect locking effect.

Another object of the present invention is to provide a two-stage locking electric screwdriver, whereby the torque can be directly adjusted and the torsion spring can be replaced in time to achieve the effect of accurately improving the torque accuracy.

Still another object of the present invention is to provide a two-stage locking electric screwdriver whereby the number of components constituting the electric screwdriver is greatly reduced to achieve a substantial benefit of cost reduction and power saving.

In order to achieve the above objectives, the inventor of the present invention has devised a new two-stage locking electric screwdriver which has a pair of matching housings on the outside, and at least includes a motor group in the housing to provide a power source. a clutch set coupled to the motor and driven to operate, the clutch set having power transmission and shifting action, and providing a two-stage torque output; a sub-head set, driven by the clutch set, and providing various screwdriver heads Plug-in connection; a board unit for providing operation start control of the motor for the electric screwdriver, and having the function of preventing button reset; and a control group having a micro-controller (MCU) board, and A source of electrical power that provides the required power.

The motor group described above further includes: a motor, an accelerator/supercharger, and the shaft of the motor power output is provided with an accelerator/supercharger.

Preferably, the motor described above employs a brushless motor.

The accelerator/supercharger described above includes one or more bearings (or sleeves) of a certain proportion by weight and made of metal.

The clutch group further includes: an internal tooth clutch, a lower clutch, an adapter shaft, a torsion tube, a torsion spring, and a torsion sheath; the internal tooth clutch is a star gear type formed by combining a gear and a toothed disc on one side, and a motor The rotating shaft is coupled and driven, and the other side is provided with a set of staggered (inner and outer ring) planetary orbits, and a cam surface design with misaligned convex portions on the planetary orbits, and steel balls are arranged on the planetary orbits of the group. The lower clutch is engaged with the cam surface of the internal tooth clutch, the adapter shaft is disposed on the lower clutch and one end is coupled to the star gear of the internal tooth clutch, and the other end of the adapter shaft is provided with a torque cylinder, and the The torsion tube is sheathed with a torsion spring and covered with a torsion sheath.

The above-mentioned screwdriver head group has a connecting shaft and is coaxially connected with the adapter shaft in the clutch group, and the connecting shaft has a coupling groove for providing various types of screwdriver head insertion and connection, and three slots are provided in the slot. Steel ball for positioning.

The shape of the groove of the above-mentioned coupling groove may be any geometric shape, such as any one of a circular shape, a square shape and a polygonal shape.

The power source described above may be a rechargeable battery.

The electric screwdriver described above further includes a torque adjustment wrench.

The embodiments of the present invention are described below in conjunction with the drawings. The following examples are set forth to illustrate the invention and are not intended to limit the scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

(1)‧‧‧Electric screwdriver

(10) ‧‧‧Shell

(20)‧‧‧ Motor Group

(21)‧‧‧Motor

(211) ‧‧ ‧ shaft

(22)‧‧‧Accelerator/supercharger

(30)‧‧‧Clutch Set

(31)‧‧‧Internal clutch

(311)‧‧‧ Gears

(312)‧‧‧ toothed disc

(32)‧‧‧ Lower clutch

(33)‧‧‧Transfer shaft

(34)‧‧‧Torque cylinder

(35)‧‧‧Torque spring

(36)‧‧‧Torque sheath

(37) ‧‧‧ cam surface

(371) ‧‧‧ convex

(372)‧‧‧ Steel Balls

(40) ‧‧‧Starter head group

(41)‧‧‧ Connecting shaft

(42) ‧ ‧ ‧ screwdriver head

(411) ‧‧‧ Combination slot

(412)‧‧‧ Steel Balls

(50) ‧‧‧ board unit

(60) ‧‧‧Control Group

(61)‧‧‧ board

(62) ‧‧‧Power source

(70)‧‧‧Torque adjustment wrench

The first figure is a schematic view of a known screw (bolt) locking elastic material.

The second figure (A) is a graph showing the performance of a screw (plug) that is thinner than the length of the screw (bolt).

The second figure (B) is a graph showing the performance of a screw (tether) that is thicker than the length of the screw (bolt).

The third figure is a schematic diagram of the adjustment torque of a known internal adjustable torque electric screwdriver.

The fourth figure is a construction diagram of an electric screwdriver according to a preferred embodiment of the present invention.

Figure 5 is a structural view of an internal clutch of a preferred embodiment of the present invention.

Fig. 5(A) is a diagram showing the action of the internal tooth unit (1) according to a preferred embodiment of the present invention.

Fig. 5(B) is a diagram showing the action of the internal tooth unit (2) according to a preferred embodiment of the present invention.

Fig. 5(C) is a diagram (3) of the operation of the internal gear in a preferred embodiment of the present invention.

Fig. 5(D) is a diagram showing the action of the internal gear in the preferred embodiment of the present invention (4).

Fig. 5(E) is a diagram showing the action of the internal gear unit (5) according to a preferred embodiment of the present invention.

Figure 6 is a schematic diagram of torque adjustment in accordance with a preferred embodiment of the present invention.

The seventh figure is a schematic diagram of the lock of the electric screwdriver of the present invention actually applied to the dynamic torque measuring machine.

The eighth figure is a schematic diagram of the lock of a general electric screwdriver actually applied to a dynamic torque tester.

The electric screwdriver (1) is of a charging type and has a set of matching housings (10) on the outside, and the form of the housing (10) is not limited, such as an upright type, a gun type, etc., and the present embodiment is a gun type. For example, the housing (10) is provided with at least a motor group (20), an internal clutch group (30), a driver head group (40), a plate unit (50), and a control group (60).

The motor unit (20) further includes: a motor (21), an accelerator/supercharger (22), and the motor (21) preferably uses a brushless motor, but not limited thereto. And the power output shaft (211) is provided with an accelerator/supercharger (22), which comprises one or more bearings (or sleeves) of a certain proportion of weight and made of metal; the accelerator is implemented/ The supercharger (22) is disposed at the position of the power output shaft (211) of the motor (21) to achieve the effect of slow start and running acceleration, thereby multiplying the horsepower of the motor, but the power consumption is a little, thereby enabling the lock to be paid The screw time is shortened, increasing work efficiency.

The clutch set (30) further includes: an internal clutch (31), a lower clutch (32), an adapter shaft (33), a torsion cylinder (34), a torsion spring (35), and a torsion sheath (36); As shown in the fifth figure, the internal tooth clutch (31) is a star gear type formed by combining a gear (311) and a toothed disc (312) on one side, and is coupled with the rotating shaft of the motor (21) and driven to operate, and the other side is driven. In order to provide a set of interlaced (inner and outer ring) planetary orbits, and a cam surface (37) having a misaligned convex portion (371) on the planetary orbit, a steel ball (372) is disposed on the set of planetary orbits, The lower clutch (32) is in engagement with the cam surface of the internal tooth clutch (31), and the adapter shaft (33) is disposed through the lower clutch (32) and has one end coupled to the star gear of the internal tooth clutch (31). The power transmission and shifting action of the motor (21), the other end of the adapter shaft (33) is sleeved with a torsion cylinder (34), and the torsion cylinder (34) is sheathed with a torsion spring (35), and then Covered by a torsion sheath (36), which can set the required torque value, and also provides the user with the ability to adjust the torque value to a large or small value after the torque sheath (36) is removed. Further torsion spring (35) of the replacement, attachment screws serve to enhance the accuracy and quality.

The cam surface (37) of the internal tooth clutch (31) is as shown in the fifth figure. The cam surface (37) has inner and outer ring planet tracks, and is disposed on the inner and outer ring rails: two ridges The convex portions (371) correspond to the edges of the inner or outer ring planet orbits, respectively. The two convex portions (371) are divided into different shapes, and two steel balls (372) are respectively operated on the inner and outer ring planetary orbits with a three hundred and sixty degree circular motion and do not affect each other.

a screwdriver head set (40) having a connecting shaft (41) disposed in the driver head set (40) and coaxially coupled to the adapter shaft (33) rod in the clutch pack (30); the connecting shaft (41) There is mainly a coupling groove (411) for providing various types of screwdriver heads (42), and the shape of the groove of the coupling groove (411) can be any geometric shape to match the joint end of the conventional common screwdriver head. The shape of the head, such as any one of a circular shape, a square shape and a polygonal shape, is not limited herein, and three steel balls (412) for positioning the clamp are provided in the groove to synchronously and stably clamp the screwdriver head (42).

The plate unit (50) is used to provide the operation start control of the electric screwdriver (1) and has the function of preventing the button from being reset.

The control group (60) has a board (61) of a microcontroller (MCU) and a power source (62) for supplying required power. In this embodiment, a rechargeable battery is used, but this is not limit.

According to the above-described electric screwdriver of the present invention, in operation, when the motor (21) is started up, the internal clutch (31) is rotated to drive the screwdriver head (42) to rotate; the cam surface of the internal clutch (31) The steel ball (372) and its convex part (371) located on the inner ring planet orbit will first trip to generate a torsion force, which is the torque value of the pre-locking function; then continue to rotate, when the inner and outer ring planet orbits After the steel ball (372) and the corresponding convex portion (371) are simultaneously tripped, a maximum torque is generated, so that the screw is locked tighter and reaches the expected standard value; thus, the entire locking effect and quality can be achieved. perfect.

Please refer to the fifth figure (A)~(E) together to show the internal tooth. The cam surface (37) of the clutch (31) and the two steel balls (372) respectively perform movements; wherein the two convex portions (371) respectively disposed on the inner and outer ring planetary orbits have a top dead center and a bottom dead center. The loop travel, the loop stroke includes at least the following stages: as shown in the fifth diagram (A), for the first stroke, providing the control of the electric screwdriver torque, using the outer R angle design, at this time in the outer ring The steel ball (372) has entered the R angle outside the outer ring convex portion (371); as shown in the fifth figure (B), the second stroke provides a pre-locking function, at which time the outer ring of the steel ball (372) has been advanced to The flat stroke, while the inner ring of the steel ball (372) has entered the R angle outside the inner ring convex portion (371), and at this time obtain a torque value; as shown in the fifth figure (C), the third stroke, this When the steel ball (372) of the outer ring goes to the parallel end, the steel ball (371) of the inner ring continues to crawl the inner ring convex portion (371); as shown in the fifth figure (D), it is the fourth stroke, at this time, The outer ring of the steel ball (372) crawls to the highest top dead center of the convex portion (371), at which time a maximum torque value is generated; as shown in the fifth figure (E), the fifth stroke, the outer ring of the steel ball (372) ) quickly fall to the highest At the bottom of the line, while the inner ring of the steel ball (372) is slowly dropped to the highest bottom dead center, the lock is completed.

If different speeds, pre-locking torque or maximum torque are required, the corresponding angles of the two convex portions can be changed. As shown in the fifth figure, the two convex portions (371) on the inner and outer ring planetary orbits are at the same diameter. On the line, if the convex portion (371) of the inner ring is offset by an angle in a clockwise direction, the angle between the convex portion (371) and the convex portion (371) of the outer ring becomes smaller, and the rotation speed becomes slower; if the inner ring is counterclockwise When the convex portion (372) is offset by an angle, the angle between the convex portion (371) and the convex portion (371) of the outer ring becomes larger, and the rotational speed becomes faster; thereby satisfying a more diverse need for the use of the lock.

Referring to FIG. 6 again, regarding the torque adjustment mode of the electric screwdriver of the present invention, the operation process is as follows: the torsion sheath (36) is loosened and then removed, and then the torque is adjusted. The wrench (70) is gently pushed in. The torque adjustment wrench (70) rotates clockwise and the torque becomes larger, and the counterclockwise torque becomes smaller. According to the demand, after the adjustment is completed, the torque adjustment wrench (70) is taken out, and finally the torque sheath ( 36) Rotate back and confirm the correct position.

In view of the above, the electric screwdriver of the present invention is an externally-adjusted torque, and the torsion adjustment method is extremely convenient in operation, and has high advancement and good torque accuracy compared to the known internal adjustment type torsion.

In addition, since the clutch set and the internal tooth clutch of the electric screwdriver of the present invention are designed, the gear unit and the clutch group of the same unit of the conventional electric screwdriver are less, so that the relative energy can be manufactured. The cost is reduced and the assembly is fast. At the same time, when the electric screwdriver is used, the motor can easily drive the screwdriver to operate, and the power saving effect is achieved.

Finally, please refer to the seventh and eighth figures together. The eighth picture shows the general electric screwdriver locking process in the state dynamic torque testing machine. It can be clearly seen that the locking process is very simple and always locked. The seventh figure is the second-stage locking electric screwdriver of the present invention. It can be clearly seen from the figure that the first-stage locking (so-called pre-locking) and the second-stage locking fixing are completed. It can be seen that the two-stage locking process presented by the dynamic torque tester echoes the so-called perfect lock in Schatz's book.

(1)‧‧‧Electric screwdriver

(10) ‧‧‧Shell

(20)‧‧‧ Motor Group

(21)‧‧‧Motor

(211) ‧‧ ‧ shaft

(22)‧‧‧Accelerator/supercharger

(30)‧‧‧Clutch Set

(31)‧‧‧Internal clutch

(311)‧‧‧ Gears

(312)‧‧‧ toothed disc

(32)‧‧‧ Lower clutch

(33)‧‧‧Transfer shaft

(34)‧‧‧Torque cylinder

(35)‧‧‧Torque spring

(36)‧‧‧Torque sheath

(40) ‧‧‧Starter head group

(41)‧‧‧ Connecting shaft

(42) ‧ ‧ ‧ screwdriver head

(411) ‧‧‧ Combination slot

(412)‧‧‧ Steel Balls

(50) ‧‧‧ board unit

(60) ‧‧‧Control Group

(61)‧‧‧ board

(62) ‧‧‧Power source

Claims (8)

A two-stage locking electric screwdriver has a set of matching housings on the outside, and at least includes a motor group for providing a power source in the housing; a clutch set coupled to the motor and driven to operate The clutch set has power transmission and shifting action, and provides two-stage torque output; a sub-head group, driven by the clutch group, and providing various types of screwdriver head insertion and connection; a board unit for providing an electric screwdriver The operation start control of the motor and has the function of preventing button reset; and a control group having a micro-controller (MCU) board and a power source for supplying required power; wherein the clutch group further includes The inner tooth clutch, the lower clutch, the adapter shaft, the torsion tube, the torsion spring and the torsion sheath; the internal tooth clutch is a star gear type formed by combining a gear and a toothed disc, and is coupled with the rotating shaft of the motor and driven Running on the other side is a set of interlaced (inner and outer ring) planetary orbits, and a cam surface design with misaligned convex portions on the planetary orbits. a steel ball is disposed, the lower clutch is coupled to the cam surface of the internal tooth clutch, the adapter shaft is disposed on the lower clutch and one end is coupled to the star gear of the internal tooth clutch, and the other end of the adapter shaft is provided with a torque cylinder And the torsion tube is sleeved with a torsion spring and covered with a torsion sheath. The two-stage locking electric screwdriver according to claim 1, wherein the motor group further comprises: a motor, an accelerator/supercharger, and the shaft of the motor power output is provided with an accelerator/supercharger. The two-stage locking electric screwdriver according to item 2 of the patent application scope, wherein the motor preferably uses a brushless motor. The two-stage locking electric screwdriver according to claim 2, wherein the accelerator/supercharger comprises one or more bearings (or sleeves) of a certain proportion by weight and made of metal. The two-stage locking electric screwdriver according to claim 1, wherein the screwdriver head group has a connecting shaft and is coaxially connected with the adapter shaft in the clutch group, and the connecting shaft has a variety of screwdrivers. The joint is inserted into the joint groove, and three steel balls for positioning the clip are arranged in the groove. The two-stage locking electric screwdriver according to claim 5, wherein the shape of the groove of the coupling groove can be any geometric shape, such as any one of a circular shape, a square shape and a polygonal shape. The two-stage locking electric screwdriver according to the first aspect of the patent application, wherein the electric source can be a rechargeable battery. The two-stage locking electric screwdriver according to the first aspect of the patent application, wherein the electric screwdriver further comprises a torque adjustment wrench.