Torque control modules for power tools

Abstract

The present invention is a torque-fixing module for a power tool, comprising a transmission ring, two buffer units, an inner shaft, and an outer shaft; the transmission ring comprises a main body, a coupling portion, a spindle, two chambers, and two detents; the two buffer units are respectively located in portions of the two chambers, leaving a receiving space in each chamber; the inner shaft comprises an inner disc, two inner protrusions extending into the two receiving spaces, an axial groove for the spindle to extend into, a shaft rod, and a clamping portion; the outer shaft comprises an outer disc, two outer protrusions, a shaft tube, a detent, an axial hole, and a clamping groove for the clamping portion of the inner shaft to extend into. Thus, the torque-fixing module can provide different torque outputs during forward and reverse rotation, and has high rotation speed, excellent working efficiency, and reduced manufacturing costs.

Description

Technical Field

[0001] The present invention relates to a power tool, and in particular to a torque-fixing module for a power tool. Background Art

[0002] Power tools include pneumatic tools, electric tools, or hydraulically driven tools. These power tools typically use a rotating shaft connected to a tool head to turn parts such as bolts or nuts. When the shaft rotates in the reverse direction to loosen the nut or bolt, the power tool must provide as much torque as possible to smoothly unscrew the nut or bolt. However, when tightening the nut or bolt, the user must control the torque of the shaft's forward rotation within an appropriate range to avoid overtightening, which may damage the bolt or nut, or make it difficult to remove later. Furthermore, in many applications, such as when installing tire frames, the torque of multiple nuts must be consistent. Otherwise, uneven stress may cause some nuts to loosen easily after prolonged vibration.

[0003] Currently, pneumatic tools utilize hydraulic principles or planetary gear reduction mechanisms to control output shaft torque. However, these structures require high machining precision, resulting in high costs, and their low speeds lead to poor operating efficiency. Therefore, how to control the output torque at high speeds while simplifying machining and reducing manufacturing costs has become a pressing technical challenge for the industry. Summary of the Invention

[0004] One object of the present invention is to provide a torque-fixing module for a power tool that can provide different torque outputs during forward and reverse rotation. Another object of the present invention is to provide a torque-fixing module for a power tool that has a high rotation speed, good working efficiency, and can reduce manufacturing costs.

[0005] The cam is connected with the drive shaft by the linking mechanism, and the cam is connected with the drive shaft by the linking mechanism, and the cam is connected with the drive shaft by the linking mechanism. The locking portion is located at one end of the shaft rod; the outer shaft member includes an outer disc body, two outer protrusions extending from the outer disc body toward the main body of the transmission ring and located at the outside of the inner disc body, a shaft tube extending from the side of the outer disc body opposite to the two outer protrusions, a detent portion is provided at one end of the shaft tube, an axial hole extending from the outer disc body to the interior of the shaft tube for the shaft rod of the inner shaft member to extend therein, and a locking groove located at an inner end of the axial hole for the locking portion of the inner shaft member to extend therein; wherein, the inner disc body is located between the outer disc body and the main body of the transmission ring, when the transmission ring rotates in a first direction, the two detent blocks hit the two outer protrusions to transmit the rotational force to the outer shaft member, and when the transmission ring rotates in a second direction opposite to the first direction, the two buffer units hit the two inner protrusions to transmit the rotational force to the inner shaft member, and then transmit the rotational force to the outer shaft member through the locking portion and the locking groove.

[0006] Thus, the fixed torque module can provide different torque outputs during forward rotation (second direction) and reverse rotation (first direction), and has high rotation speed, good working efficiency, and can reduce manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A perspective view of a power tool having a torque-fixing module according to a first preferred embodiment of the present invention;

[0008] Figure 2 for Figure 1 Cross-sectional view along direction 2-2;

[0009] Figures 3-4 This is an exploded view of a torque-fixing module for a power tool according to a first preferred embodiment of the present invention;

[0010] Figure 5 A side view of the outer shaft of the torque-fixing module according to the first preferred embodiment of the present invention;

[0011] Figure 6A perspective view of a torque-fixing module for a power tool according to a first preferred embodiment of the present invention;

[0012] Figure 7a ~b is a schematic diagram of the fixed torque module in the reverse state according to the first preferred embodiment of the present invention;

[0013] Figure 8a ~b is a schematic diagram of the fixed torque module in the first preferred embodiment of the present invention in the forward rotation state;

[0014] Figure 9 A perspective view of a torque-fixing module for a power tool according to a second preferred embodiment of the present invention;

[0015] Figure 10 This is a perspective view of a torque-fixing module for a power tool according to a third preferred embodiment of the present invention.

[0016]

Explanation of symbols

[0017] 1,1a,1b fixed torque module

[0018] 2 Power tool 3 Air motor 4 Output unit

[0019] 5 Output shaft F front B rear

[0020] 10, 10a, 10b transmission ring 11 body 12, 12a, 12b coupling part

[0021] 121, 121a shaft column 122 impact block

[0022] 13b embedded hole 14 spindle

[0023] 16 chamber 161 gap

[0024] 17 Accommodation space 18 Detent block

[0025] D1 first direction D2 second direction

[0026] 20 buffer unit 22 elastic body 221 convex side

[0027] 222 concave side 24 shrapnel

[0028] 26 pads

[0029] 30 inner shaft 31 inner disc 32 inner protrusion

[0030] 34 axis slot 35 axis rod

[0031] 36 end 37 middle

[0032] 38 clamping portion 39 cut surface

[0033] 40 outer shaft 41 outer disc 42 outer protrusion

[0034] 44 shaft tube 45 end

[0035] 46 detent portion 47 shaft hole

[0036] 48 inner end 49 card slot

[0037] 491 flat surface DETAILED DESCRIPTION

[0038] The following three preferred embodiments are combined with the accompanying drawings to explain in detail the technical content and features of the present invention. Figures 1 to 4 As shown, a torque module 1 for a power tool provided by the first preferred embodiment of the present invention is provided. The torque module 1 is built into a power tool 2. The power source of the power tool 2 is not limited, for example, it can be electric, pneumatic or hydraulic driven. This embodiment takes a pneumatic tool as an example.

[0039] The power tool 2 is driven by an air motor 3 and an impact group, and the impact group transmits the rotational power of the air motor 3 forward. For the sake of convenience, the front of this article is Figure 2 The direction of arrow F is indicated in the front, and the direction of arrow B is indicated in the rear. The impact assembly is the output portion 4 of the power tool 2, which is used to output the rotational power of the air motor 3. The structure of the power tool, its air motor, and the impact assembly is not a feature of this invention and will not be described in detail here. In other embodiments, the impact assembly may not be provided, and the output portion 4 may be formed by the output shaft 5 of the air motor 3 or other components.

[0040] The torque-fixing module 1 includes a transmission ring 10 , two buffer units 20 , an inner shaft 30 , and an outer shaft 40 .

[0041] The transmission ring 10 is machined from metal and includes a short cylindrical body 11; a coupling portion 12 extending rearward from the body 11 for coupling with the output unit 4; a spindle 14 extending forward from the body 11 opposite the coupling portion 12; two chambers 16 disposed within the body 11, one on each side of the spindle 14; and two detent blocks 18 extending forward from the body 11, further away from the spindle 14 than the two chambers 16. The coupling portion 12 includes a shaft 121 and two impact blocks 122 extending from the shaft 121 to receive the intermittent impact force of the impact assembly. The structure of the coupling portion 12 can be modified to match the output unit 4, as long as the outer peripheral cross-section of the shaft 121 is non-circular to receive the rotational force of the output unit 4. The spindle 14 is located at the rotation center of the body 11. The two chambers 16 have the same shape and are symmetrical to the spindle 14. The detent block 18 is approximately located outside the two chambers 16, symmetrical to the spindle 14, and is in an arc-shaped strip. However, the shapes of the chambers 16 and the detent block 18 can be changed as needed.

[0042] The two buffer units 20 are respectively arranged in the parts of the two chambers 16, so that the two chambers 16 respectively leave an accommodating space 17; wherein each of the buffer units 20 includes an arc-shaped elastic body 22, two arc-shaped spring pieces 24 and a pad 26, the material of the elastic body 22 is a natural or artificial polymer material, such as rubber or silicone, which can be elastically deformed and has the effect of buffering and shock absorption, and the two spring pieces 24 are made of metal material, arranged in parallel and abutting against a convex side 221 of the elastic body 22. Since a gap 161 is left between a concave side 222 of the elastic body 22 and the inner wall of the chamber 16, as shown in FIG. Figure 7b As shown, the elastic body 22 can be deformed to a greater extent to provide more buffer space, and the two springs 24 can also provide a better buffering effect due to the support of the elastic body 22. The pad 26 is made of metal material and has a considerable thickness, and has better impact resistance to protect these springs 24 from being damaged by continuous impact.

[0043] The inner shaft 30 includes a circular inner disc 31, two inner protrusions 32 extending rearward from the inner disc 31 and into the two accommodating spaces 17, a shaft groove 34 provided on the rear side of the inner disc 31 for the spindle 14 of the transmission ring 10 to extend therethrough, a shaft 35 extending forward from the inner disc 31 on a side opposite the inner protrusions 32, and a locking portion 38 located at one end 36 of the shaft 35. The inner protrusions 32 are arcuate and adjacent to the two spacers 26, such that the spacers 26 are positioned between the springs 24 and the inner protrusions 32. However, in other embodiments, if the springs 24 are thicker, the spacers 26 may be omitted, i.e., the springs 24 are positioned between the inner protrusions 32 and the elastic body 22, with both the elastic body 22 and the springs 24 being arcuate and convex toward the inner protrusions 32. The shaft groove 34 is for the spindle 14 to extend into, ensuring that the inner shaft 30 and the transmission ring 10 maintain concentric rotation. The two ends of the shaft 35 are larger than the middle section 37. The purpose is to allow the thinner middle section 37 to be subjected to force and torsion deformation to absorb part of the rotational torque while maintaining sufficient structural strength to avoid breakage due to understanding the rotational force. The clamping portion 38 has two chamfered surfaces 39, but as long as the cross-section of its outer peripheral edge is non-circular, the rotational force can be transmitted to the outer shaft 40, as described below.

[0044] The outer shaft member 40 includes a circular outer disc 41, two outer protrusions 42 extending from the outer disc 41 toward the body 11 of the transmission ring 10 (i.e., rearward) and located outside the inner disc 31, a shaft tube 44 extending forward from the side of the outer disc 41 opposite to the two outer protrusions 42, a detent 46 provided at an end 45 of the shaft tube 44, an axial hole 47 extending from the outer disc 41 to the interior of the shaft tube 44 and for the shaft 35 of the inner shaft member 30 to extend therein, and a clamping groove 49 located at an inner end 48 of the shaft hole 47 and for the clamping portion 38 of the inner shaft member 30 to extend therein, as shown in FIG. Figure 5 As shown. The two outer protrusions 42 are in the shape of arc strips and are located on the outside of the inner disc body 31 in an interlaced manner with the two detent blocks 18. The shaft tube 44 is sleeved on the outside of the shaft rod 35 of the inner shaft 30 through the shaft hole 47. The detent portion 46 is in the shape of a square column, but can also be changed to other shapes, such as a non-circular cross-section of the outer periphery, or a tubular shape with a non-circular cross-section of the inner periphery, both of which can transmit rotational power. In actual use, the user can connect a suitable tool head (not shown) such as a socket wrench to the detent portion 46 to drive the nut or bolt. Figure 5 As shown, the inner peripheral shape of the engaging groove 49 is complementary to the engaging portion 38 and also has two-cut surfaces 491, so that the outer shaft 40 can be driven to rotate by the inner shaft 30. In other embodiments, the inner peripheral cross-section of the engaging groove 49 is non-circular to receive the rotational force from the inner shaft 30.

[0045] like Figure 2 、 6 As shown, the inner disc 31 is located between the outer disc 41 and the main body 11 of the transmission ring 10. When the user wants to loosen the nut and rotate the output part 4 of the power tool 2 counterclockwise (reverse), the counterclockwise here is based on the perspective of the user of the power tool 2, as shown in FIG. Figure 7a As shown, the transmission ring 10 is driven by the output portion 4 to rotate in a first direction D1 (i.e., counterclockwise). At this time, the two detent blocks 18 hit the two outer protrusions 42, and the rotational force is transmitted from the transmission ring 10 to the outer shaft 40. Since the two detent blocks 18 and the two outer protrusions 42 are farther away from the spindle 14, that is, the force arm is longer, the moment is larger, and a larger rotational torque can be generated; Figure 7b As shown, at this time, there is still a gap between the inner wall of the chamber 16 of the transmission ring 10 and the two inner protrusions 32 , so the rotational force of the transmission ring 10 is not transmitted to the inner shaft 30 .

[0046] On the contrary, when the user wants to tighten the nut and make the output part 4 of the power tool 2 rotate clockwise (forward), Figure 8aAs shown, when the transmission ring 10 rotates in a second direction D2 (i.e., clockwise) opposite to the first direction D1, the two detent blocks 18 move away from the two outer protrusions 42 and do not transmit the rotational force from the transmission ring 10 to the outer shaft 40. Figure 8b As shown, the two buffer units 20 will use the two pads 26 to hit the two inner convex blocks 32 to transmit the rotational force of the transmission ring 10 to the inner shaft 30, and then transmit the rotational force to the outer shaft 40 through the clamping portion 38 and the clamping groove 49. Since the two inner convex blocks 32 are closer to the spindle 14, that is, the force arm is shorter, the moment is smaller, and the generated rotational torque is smaller, and the clamping portion 38 and the clamping groove 49 are also closer to the axis of the spindle 14, so that the transmitted rotational torque is further reduced. In addition, the The elastomer 22 and spring 24 in the buffer unit 20 can both absorb the rotational force of the transmission ring 10. Furthermore, the slender structure of the shaft 35 of the inner shaft 30 can absorb torque due to torsional deformation. These structural designs reduce the final output forward torque. After actual testing, it can be reduced to about one-quarter of the reverse torque. For example, when the reverse torque output is 400 Newton-meters, the forward torque output is approximately 100 Newton-meters. The forward torque value can be adjusted according to customer needs to achieve the purpose of fixed torque output.

[0047] Through the above-mentioned design, the torque-fixing module 1 for a power tool provided by the present invention can provide different torque outputs during forward and reverse rotation. Since the outer shaft 40 rotates synchronously with the output portion 4 of the power tool 2, the output speed is not reduced. The speed can be as high as 8000 to 9000 rpm in both forward and reverse rotation, which has excellent working efficiency. In addition, the parts processing precision requirements are not as high as those of conventional hydraulic mechanisms. The manufacturing cost can be significantly reduced due to the relative ease of processing, which has great market potential.

[0048] Based on the design spirit of the present invention, the structure of the fixed torque module can have other changes, such as Figure 9 FIG. 1 shows a torque module 1a according to a second preferred embodiment of the present invention. The structure of the torque module 1a is substantially the same as that of the first embodiment, with the only difference being that the coupling portion 12a of the transmission ring 10a is a hexagonal shaft 121a configured to match the output portion of different power tools. Figure 10The figure shows a torque-fixing module 1b provided in a third preferred embodiment of the present invention. Its structure is substantially the same as that of the first embodiment, with the only difference being that the coupling portion 12b of the transmission ring 10b is provided with a hexagonal embedding hole 13b for matching the output portion of different power tools. This allows the torque-fixing module 1b to be externally mounted on the square column-shaped output shaft of a commercially available power tool, thereby expanding the application range of the present invention. In fact, the coupling portion of the transmission ring can be a shaft column with a non-circular outer peripheral cross-section, or a embedding hole with a non-circular inner peripheral cross-section. The buffer unit can be replaced with other structures that can absorb the applied force, such as a spring. All such easily conceivable structural changes should be covered by the claims of the present invention.

Claims

1. A torque-fixing module for a power tool, characterized in that: The power tool has an output part, and the torque-fixing module includes: A transmission ring comprising a body, a coupling portion extending from the body and configured to couple with the output portion, a spindle extending from a side of the body opposite to the coupling portion, two chambers disposed in the body and located on opposite sides of the spindle, and two detent blocks extending from the body and further away from the spindle than the two chambers; Two buffer units are respectively provided in parts of the two receiving chambers, so that a receiving space is left in each of the two receiving chambers; An inner shaft member includes an inner disc, two inner protrusions extending from the inner disc and extending into the two accommodating spaces, an axis groove provided in the inner disc for the spindle of the transmission ring to extend therein, a shaft extending from a side of the inner disc opposite to the two inner protrusions, and a clamping portion located at one end of the shaft; as well as an outer shaft member comprising an outer disc, two outer protrusions extending from the outer disc toward the main body of the transmission ring and located outside the inner disc, a shaft tube extending from a side of the outer disc opposite to the two outer protrusions, a detent portion disposed at an end of the shaft tube, an axial hole extending from the outer disc into the interior of the shaft tube for the shaft rod of the inner shaft member to extend therethrough, and a clamping groove located at an inner end of the axial hole for the clamping portion of the inner shaft member to extend therethrough; The inner disk is located between the outer disk and the main body of the transmission ring. When the transmission ring rotates in a first direction, the two detent blocks hit the two outer protrusions and transmit the rotational force to the outer shaft. When the transmission ring rotates in a second direction opposite to the first direction, the two buffer units hit the two inner protrusions and transmit the rotational force to the inner shaft, and then transmit the rotational force to the outer shaft through the clamping portion and the clamping groove.

2. The torque-fixing module for a power tool according to claim 1, characterized in that: The buffer unit includes an elastic body and at least one elastic piece located between the inner protrusion and the elastic body.

3. The torque-fixing module for a power tool according to claim 2, characterized in that: The material of the elastomer is natural or artificial polymer material.

4. The torque-fixing module for a power tool according to claim 2, characterized in that: The buffer unit further includes a pad located between the elastic piece and the inner protrusion.

5. The torque-fixing module for a power tool according to claim 2, characterized in that: The elastic body and the elastic piece are both in an arc shape convex toward the inner convex block.

6. The torque-fixing module for a power tool according to claim 1, characterized in that: The coupling portion of the transmission ring is a shaft column whose outer peripheral cross section is non-circular, or an embedded hole whose inner peripheral cross section is non-circular.

7. The torque-fixing module for a power tool according to claim 1, characterized in that: The two ends of the shaft are larger than the middle section.

8. The torque-fixing module for a power tool according to claim 1, characterized in that: The cross section of the outer periphery of the clamping portion of the inner shaft is non-circular, and the cross section of the inner periphery of the clamping groove of the outer shaft is non-circular.

9. The torque-fixing module for a power tool according to claim 1, characterized in that: The outer peripheral cross section of the detent portion is non-circular or the inner peripheral cross section is non-circular.

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