Combination impact method and power tool

Abstract

The present application relates to the technical field of power tools, in particular to a combined impact method and a power tool. The combined impact method comprises alternating axial impact and radial impact. During the working process, the convex part is located in the impact groove, when the resistance increases, the convex part is separated from the impact groove and contacts with the impact surface of the impact boss, which drives the output shaft to move forward, forming an axial impact. During the working process, the impact wing is located in the impact groove, when the external resistance increases, the impact seat gradually moves axially downward to separate the impact wing from the impact groove, the upper end surface of the impact block is higher than the lower end surface of the impact wing, under the resetting action of the reset spring, the impact seat is quickly reset, the impact block knocks the impact wing, forming a radial impact. The above combined impact method changes the traditional single axial impact or radial impact form, greatly improves the working efficiency of the power tool, and expands the application range of the power tool.

Description

Technical Field

[0001] This invention relates to the field of power tool technology, specifically to a combined impact method and power tool. Background Technology

[0002] Power tools, generally referring to electric wrenches or drills, have a linear power output. In some applications, when the resistance encountered by the electric wrench or drill is too great, the linear power output is insufficient to meet the demand. Therefore, power tools with impact functions have emerged. As the drilling depth of screws, drill bits, etc., increases, and external resistance increases, an impact force is generated through the impact structure, thus broadening the application range of electric wrenches and drills.

[0003] Common impact power tools are only equipped with axial or radial impact structures; that is, existing impact power tools can only achieve radial or axial impact. Compared to non-impact power tools, their performance is significantly improved and their application range is wider. However, power tools with only radial or axial impact capabilities still have room for performance improvement. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a combined impact method with both axial and radial impact functions, and a power tool that applies the combined impact scheme, so as to further improve the performance and applicability of impact power tools.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a combined impact method applied to a power tool, the power tool including at least an output shaft and a transmission shaft, the output shaft being configured to perform rotational and axial movements, the transmission shaft being configured to perform rotational movements, and the upper end face of the transmission shaft contacting and engaging with the lower end face of the output shaft; the combined impact method includes the following steps:

[0006] Step A: Axial impact;

[0007] At least two protrusions are evenly distributed along the circumferential direction on the lower end face of the output shaft, and impact grooves and impact bosses are spaced apart along the circumferential direction on the upper end face of the transmission shaft.

[0008] During operation, the protrusion is located in the impact groove. When the resistance increases, the protrusion comes out of the impact groove and contacts the impact surface of the impact boss, driving the output shaft to move forward and forming an axial impact.

[0009] Step B: Radial impact;

[0010] A pair of symmetrically arranged impact wings are provided radially outward from the position adjacent to the lower end of the output shaft. An impact seat that can move axially relative to the transmission shaft is sleeved on the outer side of the transmission shaft. A pair of impact blocks are symmetrically arranged on the end face of the impact seat facing the output shaft. An impact groove for accommodating the impact wings is provided between adjacent impact blocks. A return spring is provided on the side of the impact seat away from the output shaft.

[0011] During operation, the impact wing is located in the impact groove. The impact block acts on the impact wing, driving the output shaft to rotate. As the external resistance increases, the impact seat gradually moves downward in an axial direction until the impact wing is dislodged from the impact groove. The upper end face of the impact block passes over the lower end face of the impact wing. Under the reset action of the reset spring, the impact seat quickly resets, and the impact block strikes the impact wing, forming a radial impact.

[0012] The axial impact in step A and the radial impact in step B are performed alternately.

[0013] In a preferred embodiment, in step B, as the upper end face of the impact block passes over the lower end face of the impact wing, the protrusion disengages from the impact groove and contacts the impact surface of the impact boss, driving the output shaft to move forward, thus forming the axial impact described in step A.

[0014] In a preferred embodiment, the number of impact grooves and impact protrusions are both integer multiples of the number of protrusions.

[0015] In a preferred embodiment, the axial movement space of the impact seat is greater than the axial depth of the impact groove.

[0016] In a preferred embodiment, the protrusion is integrally formed on the lower end face of the output shaft; or, the protrusion is a steel ball, and the lower end face of the output shaft is provided with a receiving groove for accommodating the steel ball, the steel ball being able to roll within the receiving groove.

[0017] In a preferred embodiment, the impact boss is provided with an impact surface having a certain arc length, and the arc length of the impact groove is greater than the arc length of the impact boss.

[0018] In a preferred embodiment, the impact seat is provided with an inner hole for accommodating the drive shaft, and a transmission structure is provided between the inner hole and the drive shaft. The transmission structure includes a pair of transmission grooves symmetrically arranged on the inner wall of the inner hole and extending axially, and a pair of transmission parts arranged on the outer wall of the drive shaft and adapted to the transmission grooves.

[0019] In a preferred embodiment, the transmission part is a steel ball, and the outer wall of the transmission shaft is provided with a receiving groove to accommodate the steel ball.

[0020] In a preferred embodiment, the impact seat has a spring receiving cavity extending axially from its end face on the side away from the output shaft.

[0021] This embodiment provides a power tool that applies the combined impact method described above. The output shaft is provided with a first pin hole extending inward from the center of the lower end face, and the transmission shaft is provided with a second pin hole extending inward from the center of the upper end face. It also includes a connecting pin that is adapted to and connected to the first pin hole and the second pin hole respectively. The connecting pin is at least clearance-fitted with the first pin hole or the second pin hole.

[0022] The combined impact method and power tool of this embodiment have the following advantages compared with the prior art:

[0023] In this embodiment, the power tool, during operation, alternates between the axial impact in step A and the radial impact in step B as the external resistance increases, forming a combined impact. This changes the traditional single axial or radial impact form, greatly improving the working efficiency of the power tool and expanding its application range. Attached Figure Description

[0024] Figure 1 This is a partial structural diagram of a power tool with a combined impact structure in this embodiment;

[0025] Figure 2 This is a schematic diagram of the radial impact structure in its explosive state in this embodiment;

[0026] Figure 3 This is a schematic diagram of the axial impact structure in the exploded state in this embodiment;

[0027] Figure 4 A partial structural diagram of a power tool containing an axial impact structure in the prior art;

[0028] Figure 5 for Figure 4 The diagram shows the explosive state structure of the axial impact structure in the power tool. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] like Figures 1-3 As shown, a combined impact structure used in a power tool according to this embodiment includes a coaxially arranged drive shaft 40 and output shaft 10, with the upper end face of the drive shaft 40 contacting and engaging with the lower end face of the output shaft 10. The drive shaft 40 is driven by a power source and can rotate, while the output shaft 10 has a certain axial movement space and can perform both rotational and axial movements. It should be noted that the connection between the drive shaft and the power source, as well as the power transmission between the drive shaft and the output shaft, are not the inventive point of this application and will not be described in detail here.

[0033] In this embodiment, the output shaft 10 is provided with a first pin hole 11 extending inward from the center of its lower end face, and the transmission shaft 40 is provided with a second pin hole 44 extending inward from the center of its upper end face. A connecting pin 50 is adapted to and connected to the first pin hole 11 and the second pin hole 44, respectively. Furthermore, the connecting pin 50 has a clearance fit with at least one of the first or second pin holes, thereby allowing the output shaft 10 to move both axially and rotationally.

[0034] In this embodiment, the axial impact structure is as follows: Figure 1-3 As shown, at least two protrusions are evenly distributed along the circumferential direction on the lower end surface of the output shaft 10, and impact grooves 41 and impact bosses 42 are spaced apart along the circumferential direction on the upper end surface of the transmission shaft 40.

[0035] The impact protrusion 42 is provided with an impact surface having a certain arc length. Preferably, the arc length of the impact groove is greater than the arc length of the impact protrusion. Furthermore, the number of impact grooves 41 and impact protrusions 42 are both integer multiples of the number of protrusions.

[0036] Preferably, in this embodiment, the protrusion is a rolling element, preferably a steel ball 60, and there are two of them. Correspondingly, in this embodiment, the number of impact grooves 41 and impact protrusions 42 are four each, which is twice the number of steel balls.

[0037] In this embodiment, the lower end face of the output shaft 10 is provided with two receiving grooves 12 for accommodating the steel ball 60, and the steel ball 60 can roll within the receiving grooves 12.

[0038] Preferably, the depth of the receiving groove 12 is greater than the radius of the steel ball 60, and the diameter of the opening of the receiving groove is smaller than the diameter of the steel ball 60. With this arrangement, the steel ball will not fall out of the receiving groove.

[0039] In the axial impact structure described in this embodiment, during operation, the steel ball 60 is located in the impact groove 41. As the drilling depth of the screw, drill bit, etc. increases and the external resistance increases, the steel ball 60 comes out of the impact groove 41 and contacts the impact surface of the impact boss 42. During this process, the output shaft 10 is driven to move forward, forming an axial impact.

[0040] In this embodiment, the impact boss 42 is provided with an impact surface having a certain arc length, wherein "certain arc length" is relative to... Figure 5 As shown in the prior art, the steel ball can slide a certain distance on the impact surface, so that after the axial impact, it remains under the axial high pressure state formed by the axial impact for a certain period of time. Especially for impact drills, the axial impact effect is better.

[0041] It should be noted that the protrusion described in this embodiment can also be integrally formed on the lower end face of the output shaft 10. In comparison, in the scheme where the protrusion is a rolling element, the rolling element and the impact groove and impact boss experience rolling friction, resulting in less resistance, less power required from the power source, lower cost and energy consumption, less wear, and longer service life.

[0042] Preferably, in this embodiment, guide surfaces 43 are provided at both ends of the impact groove 41 adjacent to the impact boss 42. The purpose of providing guide surfaces 43 is to make it easier for the steel ball to exit from the impact groove. Providing guide surfaces 43 at both ends of the impact groove 41 makes this axial impact structure suitable for power tools that can rotate in both directions. If the guide surface 43 is only provided at one end of the impact groove 41, it is only suitable for power tools that rotate in one direction.

[0043] Figure 4 , Figure 5The diagram shows an axial impact structure in the prior art. The axial impact structure includes a fixedly disposed lower impact seat 30 and an upper impact seat 20 disposed facing the lower impact seat 30. The upper impact seat 20 is fixedly disposed on the output shaft 10, which rotates under the drive of a power source and has a certain range of motion in the axial direction.

[0044] The lower impact seat 30 has a lower impact end face gear ring 31 on its end face facing the upper impact seat 20, and the upper impact seat 20 has an upper impact end face gear ring 21 on its end face facing the lower impact seat 30, which meshes with the lower impact end face gear ring 31. During operation, the output shaft 10 rotates under the action of the power source. As the output shaft 10 rotates, the lower impact end face gear ring 31 and the upper impact end face gear ring 21 repeatedly mesh and disengage, so that the output shaft 10 performs axial reciprocating motion while rotating, thereby achieving axial impact.

[0045] The drawback of the aforementioned axial impact structure is that:

[0046] (1) The lower impact end face gear ring 31 and the upper impact end face gear ring 21 are engaged by gears. During the engagement and disengagement process, the impact frequency is high, resulting in a short duration in the impact state or non-impact state. The effect of the impact needs to be improved.

[0047] (2) Based on the structural characteristics of gears, their meshing and disengagement processes are relatively linear, and the resulting impact force is small.

[0048] (3) When the power tool is in an impact environment for a long time, the teeth of the impact end face gear ring 31 and the upper impact end face gear ring 21 will inevitably wear. After the wear, the impact effect will be affected. The life of this axial impact structure based on gear meshing is relatively short.

[0049] (4) During the process of engagement and disengagement between the lower impact end face gear ring 31 and the upper impact end face gear ring 21, each tooth will generate resistance. There are many resistance points, the overall resistance is large, and the required power source power is large.

[0050] Compared with the existing axial impact structures, the axial impact structure of this embodiment has the following advantages:

[0051] (1) The number of protrusions, impact grooves and impact bosses in the circumferential direction is less, and the frequency of axial impact is much lower than that of gear meshing. However, since the duration of impact or non-impact state is much longer than that of axial impact structure of gear meshing, the impact effect is better.

[0052] (2) Based on the axial drop between the impact groove and the impact boss, the axial impact force generated by the protrusion during the continuous contact and cooperation with the impact groove and the impact boss is more abrupt, resulting in a larger impact force and a better impact effect.

[0053] (3) When power tools are in an impact environment for a long time, compared with the meshing and disengagement between gear rings, the wear between the protrusion and the impact groove and impact boss in this embodiment is less, the service life is longer, the structure is simpler, and the production cost is lower.

[0054] (4) During the continuous disengagement and contact of the protrusion with the impact groove and impact boss, there are fewer resistance points, the overall resistance is smaller, and the required power source power is smaller, which can save energy and reduce costs.

[0055] (5) The structure is simple and can be used independently in power tools with axial impact. Since the axial impact structure is set between the end faces of the transmission shaft and the output shaft, it does not occupy additional space. It can also be used in combination with the radial impact structure in the prior art without affecting the installation and use of the existing radial impact structure, forming a combined impact power tool that can perform both radial and axial impact.

[0056] As a special feature of this embodiment, in addition to the aforementioned axial impact structure, the combined impact structure of this embodiment also includes a radial impact structure. For example... Figure 1 , Figure 2 As shown, the radial impact structure includes a pair of impact wings 13 symmetrically arranged on the output shaft 10 and an impact seat 70 sleeved on the outside of the transmission shaft 40 and capable of axial movement relative to the transmission shaft.

[0057] The impact wing 13 extends radially outward from the position adjacent to the lower end of the output shaft. A pair of impact blocks 72 are symmetrically arranged on the end face of the impact seat 70 facing the output shaft 10. An impact groove 73 for accommodating the impact wing 13 is provided between adjacent impact blocks 72.

[0058] In this embodiment, the impact seat 70 is installed in the cavity 110 inside the housing 100, and the axial movement space of the impact seat 70 in the cavity 110 is greater than the axial depth of the impact groove 73.

[0059] In this embodiment, a return spring 90 is also installed within the cavity 110. Preferably, a spring receiving cavity 75 extending axially from the end face is provided on the side of the impact seat 70 away from the output shaft, and one end of the return spring 90 is installed within the spring receiving cavity 75. By providing the spring receiving cavity 75, the axial length of the return spring can be increased, and a longer return spring can provide greater elastic force.

[0060] In this embodiment, the impact seat 70 is provided with an inner hole 71 for accommodating the drive shaft 40, and a transmission structure is provided between the inner hole 71 and the drive shaft 40. Specifically, in this embodiment, the transmission structure includes a pair of transmission grooves 74 symmetrically arranged on the inner wall of the inner hole and extending axially, and a pair of transmission parts arranged on the outer wall of the drive shaft 40 and adapted to the transmission grooves 74. Preferably, in this embodiment, the transmission part is a steel ball 80, and the outer wall of the drive shaft 40 is provided with a receiving groove 45 for accommodating the steel ball.

[0061] In this embodiment, the striking surface 76 of the impact block 72 adjacent to the impact groove 73 is configured as a guide surface so that the impact wing can be smoothly dislodged from the impact groove. Alternatively, the guide surface can also be provided on the side of the impact wing.

[0062] The combined impact structure and power tool of this embodiment uses a combined impact method that includes alternating axial and radial impacts, specifically comprising the following steps:

[0063] Step A: During operation, the protrusion is located within the impact groove. As the drilling depth of the screw, drill bit, etc., increases, the external resistance experienced by the power tool increases. The protrusion then disengages from the impact groove and contacts the impact surface of the impact boss, driving the output shaft forward and generating an axial impact. Specifically, in this embodiment, the protrusion is a steel ball 60.

[0064] Step B: During operation, when the external resistance is relatively small, the drive shaft 40 drives the impact seat 70 to rotate through the transmission structure. The impact wing 13 is located in the impact groove 73, and the impact block 72 acts on the impact wing 13, driving the output shaft 10 to rotate without generating radial or axial impact. As the drilling depth of screws, drill bits, etc., increases, the external resistance experienced by the power tool increases, and the impact seat 70 gradually undergoes axial displacement downward, compressing the return spring 90. The impact seat 70 continues to move downward until the impact wing 13 disengages from the impact groove 73, and the upper end face of the impact block 72 passes over the lower end face of the impact wing 13. Under the reset action of the return spring 90, the impact seat 70 quickly resets, and the impact block 72 strikes the impact wing 13, achieving a radial impact.

[0065] It should be noted that the axial impact in step A occurs as the upper end face of the impact block 72 passes over the lower end face of the impact wing 13. As the drive shaft rotates continuously at high speed, the steel ball 60 is dislodged from the impact groove 41 and contacts the impact surface of the impact boss 42. During this process, the output shaft 10 is driven to move forward, forming an axial impact.

[0066] In summary, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combined impact method applied to a power tool, the power tool comprising at least an output shaft and a drive shaft, the output shaft being configured to perform rotational and axial motion, the drive shaft being configured to perform rotational motion, and the upper end face of the drive shaft engaging with the lower end face of the output shaft; characterized in that, The combined impact method includes the following steps: Step A: Axial impact; At least two protrusions are evenly distributed along the circumferential direction on the lower end face of the output shaft, and impact grooves and impact bosses are spaced apart along the circumferential direction on the upper end face of the transmission shaft. During operation, the protrusion is located in the impact groove. When the resistance increases, the protrusion comes out of the impact groove and contacts the impact surface of the impact boss, driving the output shaft to move forward and forming an axial impact. Step B: Radial impact; A pair of symmetrically arranged impact wings are provided radially outward from the position adjacent to the lower end of the output shaft. An impact seat that can move axially relative to the transmission shaft is sleeved on the outer side of the transmission shaft. A pair of impact blocks are symmetrically arranged on the end face of the impact seat facing the output shaft. An impact groove for accommodating the impact wings is provided between adjacent impact blocks. A return spring is provided on the side of the impact seat away from the output shaft. During operation, the impact wing is located in the impact groove. The impact block acts on the impact wing, driving the output shaft to rotate. As the external resistance increases, the impact seat gradually moves downward in an axial direction until the impact wing is dislodged from the impact groove. The upper end face of the impact block passes over the lower end face of the impact wing. Under the reset action of the reset spring, the impact seat quickly resets, and the impact block strikes the impact wing, forming a radial impact. The axial impact in step A and the radial impact in step B are performed alternately.

2. The combined impact method according to claim 1, characterized in that, In step B, as the upper end face of the impact block passes over the lower end face of the impact wing, the protrusion disengages from the impact groove and contacts the impact surface of the impact boss, driving the output shaft to move forward, thus forming the axial impact described in step A.

3. The combined impact method according to claim 1 or 2, characterized in that, The number of impact grooves and impact protrusions are all integer multiples of the number of protrusions.

4. The combined impact method according to claim 1 or 2, characterized in that, The axial movement space of the impact seat is greater than the axial depth of the impact groove.

5. The combined impact method according to claim 1 or 2, characterized in that, The protrusion is integrally formed on the lower end face of the output shaft; or, the protrusion is a steel ball, and the lower end face of the output shaft is provided with a receiving groove for accommodating the steel ball, and the steel ball can roll in the receiving groove.

6. The combined impact method according to claim 5, characterized in that, The impact boss is provided with an impact surface with a certain arc length, and the arc length of the impact groove is greater than the arc length of the impact boss.

7. The combined impact method according to claim 1 or 2, characterized in that, The impact seat is provided with an inner hole for accommodating the drive shaft. A transmission structure is provided between the inner hole and the drive shaft. The transmission structure includes a pair of transmission grooves symmetrically arranged on the inner wall of the inner hole and extending axially, and a pair of transmission parts arranged on the outer wall of the drive shaft and adapted to the transmission grooves.

8. The combined impact method according to claim 7, characterized in that, The transmission part is a steel ball, and the outer wall of the transmission shaft is provided with a receiving groove to accommodate the steel ball.

9. The combined impact method according to claim 1 or 2, characterized in that, The impact seat has a spring receiving cavity that extends axially from its end face on the side away from the output shaft.

10. A power tool, characterized in that, The combined impact method according to any one of claims 1-9 is provided with a first pin hole extending inward from the center of the lower end face, and a second pin hole extending inward from the center of the upper end face. It also includes a connecting pin adapted to and connected to the first pin hole and the second pin hole respectively, and the connecting pin is at least clearance-fitted with the first pin hole or the second pin hole.

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