Sealing structure for electric hammer

Abstract

A sealing structure for an electric hammer includes a head shell and a rotating sleeve. An insert is fixedly connected to the head shell. The insert removes material at one time to form a stepped through hole with multiple steps of diameter ranging from large to small. The rotating sleeve is located in the stepped through hole. A rolling element and a sealing ring are provided between the insert and the rotating sleeve. The rolling element and the sealing ring are respectively located on adjacent steps in the stepped through hole. The diameter of the step where the sealing ring is located is larger than the diameter of the step where the rolling element is located. Since the outer peripheral surface of the insert and the stepped through hole are completed at one time, the adverse effects of the sealing ring's sealing performance due to coaxiality differences are eliminated. Since needle rollers are used instead of ball bearings, the damage to the sealing ring's sealing performance by the distance sleeve is eliminated. At the same time, a rolling element is used for centering between the insert and the rotating sleeve, eliminating the factor that reduces the sealing performance of the sealing ring due to unstable internal and external spacing. Based on the above elimination of the three major factors affecting the sealing performance of the sealing ring, the oil leakage problem of the electric hammer is fundamentally solved.

Description

Technical Field

[0001] The present invention relates to an electric tool, and more particularly to a sealing structure for an electric hammer. Background Art

[0002] Currently commonly used electric hammers are generally multifunctional electric hammers that can switch between drill gear, hammer gear, hammer drill gear, and conversion gear. Many parts in the electric hammer have relative rotation or movement, such as the swivel sleeve, piston, rocker bearing, hammer rod, gear shaft, etc. Grease is required between the various parts in the electric hammer. Therefore, the channel between the electric hammer and the outside world needs to be sealed with a sealing structure to prevent grease leakage.

[0003] At present, electric hammers produced by power tool manufacturers, including large multinational companies with strong foreign technical strength, usually directly install a sealing ring between the head shell and the rotating sleeve to seal. During the use of the electric hammer, there is relative motion between the rotating sleeve and the rotating part sleeved therein, and the large amount of heat generated by the friction causes the temperature of the head shell to rise. When the temperature of the head shell rises to a certain level, the plastic head shell will gradually soften and produce plastic deformation, causing the sealing ring and the head shell to lose their sealing function and leak oil. Therefore, after a period of continuous use, the existing electric hammer needs to be suspended to allow the head shell to dissipate heat before the head shell softens and deforms, and then resume use when the head shell temperature returns to normal. Intermittent use of the electric hammer will affect work efficiency and work progress. In addition, due to the gap between the rotating parts sleeved therein, plus the accumulation and difficulty in ensuring coaxiality, the electric hammer transmission parts will inevitably experience unexpected radial vibration, which affects the sealing performance of the sealing ring. After long-term use, oil leakage is inevitable, so the sealing ring needs to be replaced frequently, which is not only time-consuming and labor-intensive, but also increases the cost of using the electric hammer.

[0004] In response to the above defects, our company submitted an invention patent application named "Electric Hammer" to the State Intellectual Property Office on October 8, 2011. The patent application was authorized and announced on August 5, 2015, with the announcement number CN102501223B. The technical solution disclosed in this patent is: an electric hammer, including a head shell and a rotating sleeve, a through hole is provided on the head shell, the rotating sleeve is located in the through hole, a ball bearing and a sealing ring are respectively provided between the head shell and the rotating sleeve, the sealing ring is located on one side of the ball bearing, and the rotating sleeve is rotatable relative to the head shell, the outer ring of the ball bearing extends to one side of the sealing ring and forms a support ring, the width of the support ring is greater than the width of the inner ring of the ball bearing, the outer circumferential surface of the sealing ring abuts against the inner circumferential surface of the support ring, the inner circumferential surface of the sealing ring abuts against the outer circumferential surface of the rotating sleeve, the support ring is fixedly connected to the inner wall of the through hole of the head shell, the support ring is injection molded as one piece with the inner wall of the through hole of the head shell during the injection molding process of the head shell, the outer circumferential surface diameter of one end of the support ring and the sealing ring on the same side is smaller than the outer circumferential surface diameter of the other end of the support ring on the same side of the ball bearing to form an outer step; the inner circumferential surface diameter of one end of the support ring and the sealing ring on the same side is smaller than the inner circumferential surface diameter of the other end of the support ring on the same side of the ball bearing to form an inner step. This technical solution has made great progress in solving the oil leakage problem of electric hammers. However, since the bearing in this technical solution and the inner circumference of the support ring extending from the outer ring of the bearing for installing the sealing ring are not processed at one time, it is difficult to ensure the coaxiality of the bearing and the support ring, so that the sealing performance cannot reach the ideal state; and since the distance sleeve in this technical solution continuously impacts the inner ring of the ball bearing during the movement of the rotating sleeve, it is easy to cause the ball bearing to fall apart over time, resulting in instability in the inner and outer spacing of the installed sealing ring, thereby making the sealing performance of the sealing ring invalid. Summary of the Invention

[0005] In order to overcome the above defects, the technical problem to be solved by the present invention is: to provide a sealing structure for an electric hammer, to eliminate the factors causing oil leakage between the rotary sleeve and the head shell in the prior art, and to fundamentally solve the oil leakage problem.

[0006] The technical solution of the present invention to solve the problems existing in the prior art is: a sealing structure for an electric hammer, which includes a hollow head shell and a rotating sleeve, the rotating sleeve is located in the head shell, the rotating sleeve is rotatable relative to the head shell, an insert is fixedly connected to the inner wall of the head shell, the axial center of the insert removes material from one end to the other end at one time to form a stepped through hole with multiple steps of diameter from large to small, the rotating sleeve is located in the stepped through hole, a rolling element and a sealing ring are respectively provided between the insert and the rotating sleeve, the rolling element and the sealing ring are respectively located on adjacent steps in the stepped through hole, and the diameter of the step where the sealing ring is located is larger than the diameter of the step where the rolling element is located. It can be seen from the distinguishing technical features that material is removed from one end to the other end of the axial center of the insert at one time to form a stepped through hole with multiple steps of diameter from large to small that the processing process of the insert is as follows: first, the outer cylindrical surface of the insert is processed, and then the outer cylindrical surface of the insert is used as a positioning reference to process the multiple steps of the stepped through hole at one time, so that the coaxiality of the outer cylindrical surface of the insert and the multiple steps of the stepped through hole can be effectively guaranteed, eliminating the adverse effects of the sealing performance of the sealing ring due to the coaxiality difference; from the distinguishing technical features that rolling elements and sealing rings are respectively provided between the insert and the rotating sleeve, and the rolling elements and sealing rings are located on adjacent steps in the stepped through hole, it can be seen that rolling elements are used instead of ball bearings, the inner ring of the bearing is omitted, and the damage to the sealing performance of the sealing ring by the distance sleeve is eliminated; at the same time, a rolling element made of metal material is used for centering between the insert and the rotating sleeve, so that the internal and external spacing of the installed sealing ring is stable, effectively ensuring that the sealing performance of the sealing ring can be maintained for a long time, thereby eliminating the factor that the sealing performance of the sealing ring is reduced due to the unstable internal and external spacing in the installation environment. Based on the above, the three major factors that affect the sealing performance of the sealing ring are eliminated, thereby fundamentally solving the oil leakage problem of the electric hammer.

[0007] Preferably, the stepped through hole has four steps, and the rolling element and sealing ring are located on the two middle steps of the stepped through hole. Setting the stepped through hole to four steps and placing the rolling element and sealing ring on the two middle steps not only increases the length of the insert, effectively increasing the fixed connection area between the insert and the head shell to achieve greater fixing force, thereby effectively improving the stability of the sealing ring installation environment, but also ensures that the operation of the rolling element and sealing ring is not affected by other components, which is conducive to the stability of the sealing ring's sealing performance.

[0008] Preferably, the outer circumference of the insert is provided with a stopper capable of limiting the axial movement of the insert relative to the head shell, and the inner circumference of the head shell matches the outer circumference of the insert, thereby increasing the axial fixing force between the insert and the head shell.

[0009] Preferably, the stopper is an annular groove. The stopper can be a convex body, a concave pit, a convex strip, or a strip groove. Considering that the head shell is a plastic part and the inlay is a metal part, the stopper of the present invention adopts an annular groove.

[0010] Preferably, the rolling element is a needle roller. The rolling element can be a ball roller, a roller, or a needle roller. Considering that the ball roller is in point contact, while the roller and the needle roller are in line contact, but the contact line of the needle roller is larger than that of the roller, the rolling element of the present invention is a needle roller, which can effectively improve the force conditions between the needle roller, the insert, and the rotating sleeve.

[0011] Preferably, the stepped through hole is provided with a groove at a position close to the sealing ring where the step with a diameter greater than that of the sealing ring is located. A retaining ring for the hole can be engaged in the groove to limit the position of the sealing ring, thereby ensuring the correct installation position of the sealing ring and facilitating the stable sealing performance of the sealing ring.

[0012] Preferably, the insert is integrally molded with the head shell during the injection molding process, which is not only beneficial to the coaxiality of the insert and the head shell, but also beneficial to the firmness of the fixed connection between the insert and the head shell.

[0013] The beneficial effects of the present invention are as follows: because the outer peripheral surface of the insert and the stepped through-holes of the four steps are completed at one time and are injection-molded into one piece with the head shell, the coaxiality of the insert structure is ensured, eliminating the adverse effects of coaxiality differences on the sealing performance of the sealing ring; because needle rollers are used instead of ball bearings, the inner ring of the bearing is omitted, eliminating the damage to the sealing performance of the sealing ring caused by the distance sleeve; at the same time, the centering of the insert and the rotating sleeve by a rolling element ensures the stability of the inner and outer spacing of the installed sealing ring, eliminating the factor that reduces the sealing performance of the sealing ring due to unstable inner and outer spacing. Based on the above, the three major factors affecting the sealing performance of the sealing ring are eliminated, thereby fundamentally solving the oil leakage problem of the electric hammer. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic cross-sectional view of the structure of the electric hammer of the present invention.

[0015] Figure 2 yes Figure 1 Enlarged schematic diagram of the R part in .

[0016] In the figure: head shell 1, rotating sleeve 2, insert 3, needle roller 4, sealing ring 5, hole retaining ring 6, groove 7, stepped through hole 8, annular groove 9. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0018] Example: A sealing structure for an electric hammer, such as Figure 1 As shown, it includes a hollow head shell 1 and a rotating sleeve 2, as shown in FIG. Figure 2 As shown, the rotating sleeve 2 is located in the head shell 1, and the rotating sleeve 2 is rotatable relative to the head shell 1. An insert 3 is embedded in the inner wall of the head shell 1 by injection molding. Before injection molding, the outer cylindrical surface of the insert 3 is first processed, and then three annular grooves 9 that can limit the axial movement of the insert 3 relative to the head shell 1 are equidistantly processed in the middle part of the outer cylindrical surface of the insert 3. The outer cylindrical surface of the insert 3 is used as the positioning reference, and the insert 3 is processed into four steps arranged in order from large to small diameter from one end to the other end of the axial center at one time. Out, thereby forming a stepped through hole 8, the rotating sleeve 2 is located in the stepped through hole 8, and matching needle rollers 4 and sealing rings 5 ​​are respectively provided between the insert 3 and the rotating sleeve 2. The needle rollers 4 and sealing rings 5 ​​are respectively located on two adjacent steps in the middle of the stepped through hole 8, and the diameter of the step where the sealing ring 5 is located is larger than the diameter of the step where the needle roller 4 is located. The stepped through hole 8 is provided with a groove 7 at a position close to the sealing ring 5 where the step with a diameter larger than that of the sealing ring 5 is located, and a matching hole retaining ring 6 is clamped in the groove 7.

[0019] The embodiment described above is only a preferred solution of the present invention and does not limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solution described in the claims.

[0020] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A sealing structure for an electric hammer, comprising a hollow head shell and a rotating sleeve, wherein the rotating sleeve is located in the head shell and is rotatable relative to the head shell, characterized in that: An insert is fixedly connected to the inner wall of the head shell, and material is removed at one time from one end to the other end of the axial center of the insert to form a stepped through hole with four steps of diameter from large to small. The rotating sleeve is located in the stepped through hole, and a rolling member and a sealing ring are respectively provided between the insert and the rotating sleeve. The rolling member and the sealing ring are respectively located on the two middle steps of the stepped through hole. The diameter of the step where the sealing ring is located is larger than the diameter of the step where the rolling member is located, and the rolling member is a needle roller.

2. The sealing structure for an electric hammer according to claim 1, characterized in that: The outer circumferential surface of the insert is provided with a stopper capable of limiting the axial movement of the insert relative to the head shell, and the inner circumferential surface of the head shell matches the outer circumferential surface of the insert.

3. The sealing structure for an electric hammer according to claim 2, characterized in that: The stopping body is an annular groove.

4. The sealing structure for an electric hammer according to claim 1, characterized in that: The stepped through hole is provided with a groove at a position where the step having a diameter greater than that of the sealing ring is close to the sealing ring.

5. The sealing structure for an electric hammer according to any one of claims 1 to 3, characterized in that: The insert is integrally molded with the head shell during the injection molding process of the head shell.

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