Cutter bar mechanism and self-tapping screw tightening equipment

Abstract

The utility model relates to a cutter bar mechanism and self-tapping screw tightening equipment. The cutter bar mechanism comprises a connecting shaft, a limiting sleeve and a bit, the first end of the connecting shaft is connected with the driving device, and the driving device can drive the connecting shaft to rotate and axially move. The limiting sleeve is arranged on the outer side of the connecting shaft in a sleeving mode, and the connecting shaft can rotate in the limiting sleeve. The screwdriver head is connected to the second end of the connecting shaft and used for being connected with a to-be-connected screw, and the screwdriver head and the connecting shaft act synchronously. The limiting sleeve is arranged on the outer side of the connecting shaft in a sleeving mode, the effect of improving the structural strength of the connecting shaft is achieved, and the situation that the connecting shaft is broken due to huge twisting force when the screw is screwed is avoided. And meanwhile, the connecting shaft is limited and guided by arranging the limiting sleeve, so that the connecting shaft does not swing in the radial direction during high-speed rotation, and the rotation stability of the connecting shaft is improved.

Description

Technical Field

[0001] The present application relates to the technical field of self-tapping screw tightening, and in particular to a tool bar mechanism and a self-tapping screw tightening device. Background Art

[0002] With the increasing demand for lightweight in the automotive and other fields, typical high-strength materials such as aluminum alloys, titanium alloys and composite materials are being used more and more widely. Therefore, some advanced connection technologies have emerged for the connection of workpieces made of the above materials, such as FDS flow drill screw connection, also known as self-tapping screw connection or hot melt self-tapping connection. FDS flow drill screw connection requires special self-tapping screw tightening equipment.

[0003] In the related technology, the self-tapping screw tightening equipment transmits the high-speed rotational motion of the servo motor to the screw through the arbor mechanism, which acts on the plate to be connected, generates frictional heat, and causes the material to undergo plastic deformation under the action of huge axial pressure. A cylindrical through hole is formed under the extrusion of the screw, and the screw tip pierces and screws into the plate to be connected, finally forming a fully engaged threaded connection between the plate and the screw.

[0004] However, the tool rod mechanism is subject to great torsional force and requires high structural strength. During the process of twisting and squeezing the screw, the tool rod mechanism is very likely to break, resulting in high maintenance and replacement costs. Utility Model Content

[0005] Based on this, it is necessary to provide a tool bar mechanism and a self-tapping screw tightening device to address the problem that the tool bar mechanism is easy to break.

[0006] A knife bar mechanism, comprising:

[0007] A connecting shaft, wherein a first end of the connecting shaft is connected to a driving device, and the driving device can drive the connecting shaft to rotate and move axially;

[0008] A limiting sleeve, wherein the limiting sleeve is arranged on the outer side of the connecting shaft, and the connecting shaft can rotate in the limiting sleeve;

[0009] A screwdriver bit is connected to the second end of the connecting shaft, and the screwdriver bit is used to connect with the screw to be connected, and the screwdriver bit and the connecting shaft move synchronously.

[0010] In one embodiment, the connecting shaft includes a connecting portion and a guiding portion, the connecting portion and the guiding portion are an integrated structure, the guiding portion is arranged inside the limiting sleeve, the connecting portion is located outside the limiting sleeve, and the end of the connecting portion away from the guiding portion is used to connect to the driving device.

[0011] In one embodiment, the outer diameter of the connecting portion is greater than the outer diameter of the guiding portion.

[0012] In one embodiment, the outer diameter of the connecting portion is the same as the outer diameter of the limiting sleeve.

[0013] In one of the embodiments, a guide groove is provided at one end of the bit facing the connecting shaft, and the portion of the bit provided with the guide groove is inserted into the limiting sleeve and can rotate in the limiting sleeve.

[0014] In one embodiment, the outer diameter of the portion of the bit not provided with the guide groove is the same as the outer diameter of the limiting sleeve.

[0015] In one embodiment, the bit is connected to the connecting shaft through threaded engagement.

[0016] In one of the embodiments, a bearing is provided between the connecting shaft and the limiting sleeve.

[0017] In one embodiment, the bearing includes a first bearing and a second bearing, and the first bearing and the second bearing are respectively arranged at two axial ends of the limiting sleeve.

[0018] A self-tapping screw tightening device comprises a driving device and a knife bar mechanism as described above, wherein the driving device is used to clamp and drive the knife bar mechanism to move axially, and the driving end of the driving device is connected to the connecting shaft to drive the connecting shaft to rotate.

[0019] The above-mentioned knife bar mechanism, by setting a limit sleeve on the outer side of the connecting shaft, plays a role in increasing the structural strength of the connecting shaft, which is beneficial to prevent the connecting shaft from breaking due to the huge torsional force when the screw is turned. At the same time, by setting the limit sleeve to limit and guide the connecting shaft, the connecting shaft will not swing radially when rotating at high speed, thereby improving the rotation stability of the connecting shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a schematic diagram of a partial cross-sectional structure of a knife bar mechanism in one embodiment of the present application.

[0021] FIG. 2 is a schematic diagram of the structure of a limit sleeve in one embodiment of the present application.

[0022] FIG. 3 is a schematic diagram of the structure of a connecting shaft in one embodiment of the present application.

[0023] FIG. 4 is a schematic diagram of the structure of a screwdriver bit in one embodiment of the present application.

[0024] Description of reference numerals:

[0025] 1. Connecting shaft; 101. First end; 102. Second end; 11. Connecting portion; 12. Guide portion; 2. Limit sleeve; 21. Through hole; 3. Bit; 31. Guide groove; 32. Threaded hole; 33. Clamping hole; 4. First bearing; 5. Second bearing. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0027] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0028] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0030] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0032] FDS (Flow Drill Screw) usually refers to a flow drill screw, and FDS is also used to represent the flow drill screw tightening process, which is also called self-tapping screw connection or hot-melt self-tapping connection. In this embodiment, a self-tapping screw tightening device is proposed for self-tapping screw connection. Specifically, the self-tapping screw tightening device includes a driving device and a tool bar mechanism. The driving device is used to clamp the tool bar mechanism and drive the tool bar mechanism to rotate at high speed and move axially. The tool bar mechanism transmits the high-speed rotational motion to the screw. The high-speed rotating screw acts on the plate to be connected, generating frictional heat, and plastically deforms the plate material under the action of huge axial pressure. A cylindrical through hole is formed under the extrusion of the self-tapping screw, and the screw tip pierces and screws into the plate to be connected, so that drilling, tapping, and tightening are completed at one time on the self-tapping screw tightening device, and finally a fully meshed threaded connection is formed between the plate and the screw. In this application, the tool bar mechanism is mainly improved. For the driving device, the existing conventional structure can be adopted, and no detailed description is given here.

[0033] Refer to Figure 1, which shows a partial cross-sectional structural schematic diagram of the tool bar mechanism in an embodiment of the present application. The tool bar mechanism includes a connecting shaft 1, a limiting sleeve 2 and a bit 3. The first end 101 of the connecting shaft 1 is connected to a driving device, and the driving device can drive the connecting shaft 1 to rotate and move axially. The limiting sleeve 2 is sleeved on the outer side of the connecting shaft 1, and the connecting shaft 1 can rotate inside the limiting sleeve 2. The bit 3 is connected to the second end 102 of the connecting shaft 1, and the bit 3 is used to connect with the screw to be connected, and the bit 3 moves synchronously with the connecting shaft 1. When the tool bar mechanism is used in a self-tapping screw tightening device, the driving device clamps the limiting sleeve 2, and the driving end of the driving device is connected to the first end 101 of the connecting shaft 1. Specifically, as shown in Figure 2, a through hole 21 is axially arranged on the limit sleeve 2, and the inner diameter of the through hole 21 is equal to or slightly larger than the outer diameter of the connecting shaft 1, so that the connecting shaft 1 can rotate smoothly in the through hole 21, while avoiding a large range of shaking of the connecting shaft 1 in the through hole 21, thereby ensuring the limiting effect of the limit sleeve 2 on the connecting shaft 1.

[0034] When the driving device drives the connecting shaft 1 to rotate, the limiting sleeve 2 is clamped and kept stationary. When the driving device drives the connecting shaft 1 to move axially, the limiting sleeve 2 is synchronously driven to move axially with the connecting shaft 1, ensuring that the limiting sleeve 2 and the connecting shaft 1 maintain an unchanged axial position.

[0035] The knife bar mechanism proposed in this embodiment increases the structural strength of the connecting shaft 1 by setting a limit sleeve 2 on the outer side of the connecting shaft 1, which is beneficial to prevent the connecting shaft 1 from breaking due to the huge torsional force when the screw is turned. At the same time, by setting the limit sleeve 2 to limit and guide the connecting shaft 1, the connecting shaft 1 will not swing radially when rotating at high speed, thereby improving the rotation stability of the connecting shaft 1.

[0036] In the related art, the connecting shaft 1 is set as a split structure, including two parts connected by threads, one part is connected to the driving end of the driving device, and the other part is connected to the screwdriver bit 3, so as to transmit the high-speed rotation of the driving device to the screwdriver bit 3. There is a stress concentration point at the connection of the two parts of the connecting shaft 1, which has a greater risk of fracture.

[0037] In order to solve the above problems, the structure of the connecting shaft 1 is improved in this embodiment. Specifically, as shown in Figure 3, the connecting shaft 1 includes a connecting portion 11 and a guide portion 12. The connecting portion 11 and the guide portion 12 are an integrated structure. The guide portion 12 is arranged inside the limiting sleeve 2, and the connecting portion 11 is located outside the limiting sleeve 2. The end of the connecting portion 11 away from the guide portion 12 is used to connect with the driving device. By setting the connecting shaft 1 as an integrated structure, the stress concentration at the connection between the connecting portion 11 and the guide portion 12 can be significantly reduced, the structural strength of the connecting shaft 1 is further improved, and the risk of fracture of the connecting shaft 1 is reduced. Furthermore, the connecting shaft 1 can be formed by turning a bar stock, and the processing is faster. During assembly, the assembly steps of the connecting portion 11 and the guide portion 12 are also omitted, which is conducive to improving assembly efficiency.

[0038] There is also a stress concentration point at the connection between the connecting shaft 1 and the bit 3, which has a greater risk of fracture. In order to reduce the risk of fracture at the connection between the guide portion 12 and the bit 3, as shown in FIG4 , a guide groove 31 is provided at one end of the bit 3 facing the guide portion 12, and the portion of the bit 3 provided with the guide groove 31 is inserted into the limiting sleeve 2 and can rotate in the limiting sleeve 2. By rotating one end of the bit 3 in the limiting sleeve 2, the limiting sleeve 2 limits and guides the bit 3, preventing the bit 3 from radially swinging during high-speed rotation, which is beneficial to improving the structural strength of the bit 3, thereby reducing the risk of fracture at the connection between the guide portion 12 and the bit 3.

[0039] A clamping hole 33 is provided on the end face of the screwdriver bit 2 away from the connecting shaft 1. The specific shape of the clamping hole 33 matches the shape of the screw head of the screw to be connected, so that the screw head is clamped into the clamping hole 33 for clamping fit, so that the screw can be driven to rotate by the screwdriver bit 2. Generally, the clamping hole 33 is set to be a hexagonal inner hole.

[0040] Optionally, the outer diameter of the portion of the bit 3 not provided with the guide groove 31 is the same as the outer diameter of the limit sleeve 2, so that the outer surfaces of the bit 3 and the limit sleeve 2 are on the same surface, the surface is relatively smooth, which is conducive to the installation and use of the tool rod mechanism in the application space.

[0041] Furthermore, the screwdriver bit 3 is connected to the connecting shaft 1 through threaded matching. As shown in FIG3 and FIG4, a threaded hole 32 is provided at the end of the screwdriver bit 3, and an external thread is correspondingly provided on the connecting shaft 1, so that the end of the connecting shaft 1 provided with the external thread is screwed into the threaded hole 32 for connection. Specifically, the threaded hole 32 is provided as a blind hole, and the connecting shaft 1 is connected in place when it is screwed until it abuts against the bottom of the blind hole.

[0042] Optionally, as shown in Figure 3, the connecting shaft 1 is arranged to be stepped, and the outer diameter of the connecting part 11 is larger than the outer diameter of the guide part 12, so as to facilitate the insertion of the connecting part 11 into the limiting sleeve 2 and make the connecting part 11 located outside the limiting sleeve 2. The connecting part 11 acts as a limiting step to limit the axial installation position of the connecting shaft 1 in the limiting sleeve 2.

[0043] Specifically, the outer diameter of the connection part 11 is the same as the outer diameter of the limiting sleeve 2. The outer surfaces of the connection part 11 and the limiting sleeve 2 are on the same surface, and the surface is relatively smooth, which is conducive to the installation and use of the tool bar mechanism in the application space. In this way, the outer surfaces of the screwdriver bit 3, the limiting sleeve 2 and the connection part 11 are all on the same surface, making the surface of the overall structure of the tool bar mechanism relatively flat.

[0044] Furthermore, in order to make the connecting shaft 1 rotate more smoothly in the limiting sleeve 2, a bearing is provided between the connecting shaft 1 and the limiting sleeve 2. By providing the bearing, the connecting shaft 1 is supported, the friction coefficient between the connecting shaft 1 and the limiting sleeve 2 is reduced, and the rotation accuracy of the connecting shaft 1 is ensured, and the smoothness of the relative rotation between the connecting shaft 1 and the limiting sleeve 2 is improved, so as to avoid the situation where the connecting shaft 1 is stuck and cannot rotate relative to each other, thereby further reducing the risk of the connecting shaft 1 being twisted off.

[0045] Please refer back to Figure 1. In order to ensure that the connecting shaft 1 has a better rotation effect, the bearing includes a first bearing 4 and a second bearing 5. The first bearing 4 and the second bearing 5 are respectively arranged at the axial ends of the limiting sleeve 2. Specifically, the first bearing 4 is arranged at the end of the guide part 12 connected to the bit 3, and the first bearing 4 can be a needle bearing. The second bearing 5 is arranged at the end of the guide part 12 connected to the connecting part 11, and the second bearing 5 can be a thrust bearing. By arranging bearings at the two stress concentration points of the connecting shaft 1, the support and friction reduction effects of the bearings on the connecting shaft 1 are further improved, thereby further improving the rotation smoothness of the connecting shaft 1.

[0046] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A knife bar mechanism, characterized in that: include: A connecting shaft (1), wherein a first end (101) of the connecting shaft (1) is connected to a driving device, and the driving device is capable of driving the connecting shaft (1) to rotate and move axially; A limiting sleeve (2), wherein the limiting sleeve (2) is sleeved on the outer side of the connecting shaft (1), and the connecting shaft (1) is capable of rotating inside the limiting sleeve (2); A screwdriver bit (3) is connected to the second end (102) of the connecting shaft (1), the screwdriver bit (3) being used to be connected to a screw to be connected, and the screwdriver bit (3) and the connecting shaft (1) move synchronously.

2. The knife bar mechanism according to claim 1, characterized in that: The connecting shaft (1) comprises a connecting portion (11) and a guiding portion (12); the connecting portion (11) and the guiding portion (12) are an integrated structure; the guiding portion (12) is arranged inside the limiting sleeve (2); the connecting portion (11) is located outside the limiting sleeve (2); and an end of the connecting portion (11) away from the guiding portion (12) is used for connecting to the driving device.

3. The knife bar mechanism according to claim 2, characterized in that: The outer diameter of the connecting portion (11) is greater than the outer diameter of the guiding portion (12).

4. The knife bar mechanism according to claim 3, characterized in that: The outer diameter of the connecting portion (11) is the same as the outer diameter of the limiting sleeve (2).

5. The knife bar mechanism according to claim 1, characterized in that: A guide groove (31) is provided at one end of the screwdriver bit (3) facing the connecting shaft (1); the portion of the screwdriver bit (3) provided with the guide groove (31) is inserted into the limiting sleeve (2) and is capable of rotating within the limiting sleeve (2).

6. The knife bar mechanism according to claim 5, characterized in that: The outer diameter of the portion of the screwdriver bit (3) not provided with the guide groove (31) is the same as the outer diameter of the limiting sleeve (2).

7. The knife bar mechanism according to any one of claims 1 to 6, characterized in that: The screwdriver bit (3) is connected to the connecting shaft (1) through threaded engagement.

8. The knife bar mechanism according to any one of claims 1 to 6, characterized in that: A bearing is provided between the connecting shaft (1) and the limiting sleeve (2).

9. The knife bar mechanism according to claim 8, characterized in that: The bearing comprises a first bearing (4) and a second bearing (5), and the first bearing (4) and the second bearing (5) are respectively arranged at two axial ends of the limiting sleeve (2).

10. A self-tapping screw tightening device, comprising a driving device, characterized in that: It also comprises a knife bar mechanism according to any one of claims 1 to 9, wherein the driving device is used to clamp and drive the knife bar mechanism to move axially, and the driving end of the driving device is connected to the connecting shaft (1) to drive the connecting shaft (1) to rotate.

Images