Gear box of electric drill and electric drill

Abstract

The electric drill comprises a motor and an output shaft, the gearbox comprises a gearbox shell and a transmission mechanism, the transmission mechanism is used for transmitting power of the motor to the output shaft, the gearbox shell comprises a front shell, a rear shell and a connecting piece connecting the front shell and the rear shell, the front shell and the rear shell form a space, and the transmission mechanism is contained in the space. The transmission mechanism comprises a gear reduction mechanism and an impact mechanism, the gear reduction mechanism is configured to provide torque for the output shaft, the impact mechanism is configured to provide impact force for the output shaft, the gear reduction mechanism comprises a plurality of reduction gear sets, so that the output torque of the output shaft is not smaller than 100 N.M, the axial size of the gear box is 68-72 mm, the radial size of the gear box is 52-55 mm, and the output torque of the gear box is not smaller than 100 N.M. The axial direction is parallel to the axis of the output shaft and the radial direction is perpendicular to the axis of the output shaft. The gear box has the small axial size and radial size, miniaturization of electric drill products is facilitated, and the gear box can be used in a narrow space conveniently.

Description

Technical Field

[0001] The utility model relates to the field of electric tools, in particular to a gear box of an electric drill and the electric drill. Background Art

[0002] An electric drill is a multifunctional tool that can be used for drilling holes and tightening screws. An electric drill generally includes a housing, a motor housed in the housing, a gearbox, an output shaft, and other structures. For applications in narrow spaces, the axial size of the electric drill is required to be reduced. In addition, the operating comfort angle also requires a reduction in size. The axial size of the motor is mainly determined by the motor and the gearbox. Replacing a brushed motor with a brushless motor can achieve a significant size reduction. In addition, reducing the size of the gearbox is also very necessary, especially for electric drills with large output torque. The reduction ratio is relatively large, the number of stages of the reduction gear set is more, and the space occupied also increases accordingly. Utility Model Content

[0003] The purpose of this application is to overcome the deficiencies in the prior art and to provide a small-sized gear box for an electric drill and an electric drill.

[0004] The present application provides a gearbox for an electric drill, the electric drill comprising a motor and an output shaft, the gearbox comprising a gearbox housing and a transmission mechanism, the transmission mechanism being used to transmit the power of the motor to the output shaft, the gearbox housing comprising a front housing, a rear housing and a connector connecting the front housing and the rear housing, the front housing and the rear housing forming a space, the transmission mechanism being accommodated in the space, the transmission mechanism comprising a gear reduction mechanism and an impact mechanism, the gear reduction mechanism being configured to provide torque to the output shaft, the impact mechanism being configured to provide impact force to the output shaft, the impact mechanism comprising a first ratchet, a second ratchet and a function switching bracket, the first ratchet being coupled to the output shaft, the first ratchet comprising a first tooth facing the second ratchet, the second ratchet comprising a second tooth and a plurality of supports surrounding the second tooth part and a gap formed between adjacent support parts, multiple support parts are arranged along the circumference of the second tooth, the function switching bracket includes a convex part, the first ratchet has a first position and a second position, when the first ratchet is in the first position, the convex part is aligned with the support part and supported by the support part; when the first ratchet is in the second position, the convex part is aligned with the gap, so that the convex part can enter the gap to realize the engagement of the first tooth and the second tooth; the gear reduction mechanism includes a plurality of reduction gear sets, so that the output torque of the output shaft is not less than 100N.M, the axial dimension of the gear box is 68~72mm, and the radial dimension of the gear box is 52~55mm, the axial direction is parallel to the axis of the output shaft, and the radial direction is perpendicular to the axis of the output shaft.

[0005] Furthermore, the front shell includes a plurality of first holes, the rear shell includes a plurality of second holes corresponding one-to-one to the first holes, and the connecting member is passed through the first holes and the second holes to connect the front shell and the rear shell; the plurality of first holes are arranged along the circumference of the front shell, and each first hole protrudes inward toward the transmission mechanism.

[0006] Furthermore, the rear shell includes a first end surface close to the front shell and a second end surface away from the front shell. The rear shell has a recessed portion recessed from the second end surface toward the first end surface. The second hole passes through the recessed portion and the first end surface.

[0007] Furthermore, the connecting member is a threaded member, the threaded member includes a head for receiving driving force, and the head of the threaded member is located in the recess.

[0008] Furthermore, the gear reduction mechanism includes a fixed gear ring, which is made of metal and includes an ear located in the recess, the ear having a third hole coaxial with and connected to the second hole, and the connecting member passes through the third hole, the second hole and the first hole in sequence.

[0009] Furthermore, in the radial and axial directions of the gearbox, the fixed gear ring is completely located within the area of the rear housing; in the axial direction of the gearbox, the fixed gear ring protrudes into the rear housing, so that the internal teeth are exposed in the space.

[0010] Furthermore, the second ratchet includes a bottom wall and a side wall, the second tooth is formed on the bottom wall, and the support portion is formed on the side wall; the bottom wall and the side wall form an accommodating cavity, and when the first tooth is engaged with the second tooth, the first ratchet is completely located in the accommodating cavity.

[0011] Furthermore, the gearbox includes a movable ring gear and a shift fork driving the movable ring gear. When the shift fork is driven, it drives the movable ring gear to move axially, so that the gear reduction mechanism outputs different transmission ratios; the gearbox also includes a positioning ring, which is located between the movable ring gear and the rear housing. The positioning ring is used to stop the movable ring gear to limit the extreme position of the movable ring gear; the positioning ring includes a flat plate portion arranged on a side away from the movable ring gear.

[0012] Furthermore, the gearbox includes an oil seal structure, the gearbox shell includes a through hole, the oil seal structure includes a pin and a seal sleeved on the pin, the pin passes through the through hole and presses against the transmission mechanism, and the seal seals the gap between the pin and the through hole.

[0013] The present application also provides an electric drill, comprising a housing, a motor disposed in the housing, an output shaft and the gearbox as described above, wherein the motor transmits power to the output shaft through the transmission mechanism.

[0014] The present application provides a high-torque electric drill, whose gear box has smaller axial and radial dimensions, which is conducive to the miniaturization of the electric drill product and is convenient for use in narrow spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a three-dimensional diagram of an electric drill according to an embodiment of the present application.

[0016] Figure 2 for Figure 1 An angled perspective view of the gearbox of the electric drill is shown.

[0017] Figure 3 for Figure 2 Another perspective view of the gearbox is shown.

[0018] Figure 4 for Figure 2 Schematic diagram of the rear view of the gearbox shown.

[0019] Figure 5 for Figure 2 Exploded view of the gearbox shown.

[0020] Figure 6 yes Figure 2 A schematic cross-sectional view of the gearbox is shown.

[0021] Figure 7 yes Figure 2 A three-dimensional schematic diagram of the rear shell of the gearbox is shown.

[0022] Figure 8 yes Figure 2 A three-dimensional schematic diagram of the fixed gear ring of the gearbox is shown. DETAILED DESCRIPTION

[0023] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different drawings represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with this application.

[0024] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should have the usual meaning understood by people with ordinary skills in the field to which this utility model belongs. The "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one" or "one" and other similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. "Multiple" or "several" means two or more. Unless otherwise indicated, "front", "rear", "lower" and / or "upper" and other similar words are only for ease of description and are not limited to one position or one spatial orientation.

[0025] "Include" or "comprising" and other similar words mean that the elements or objects appearing before "include" or "comprising" include the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. "Connected" or "connected" and other similar words are not limited to physical or mechanical connections, and can include electrical connections, whether direct or indirect. The singular forms "a", "said" and "the" used in this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0026] Combine Figures 1 to 3 The present application provides a high-torque electric drill comprising a housing 1, a motor (not shown) housed therein, a gearbox 3, and an output shaft 4. The gearbox 3 comprises a gearbox housing 31 and a transmission mechanism 32. The output shaft 4 is power-connected to the transmission mechanism 32. The transmission mechanism 32 is configured to transmit power from the motor to the output shaft 4, providing the desired speed and torque. Optionally, the motor is a brushless motor, and the electric drill is powered by a removable battery pack.

[0027] Please combine Figures 2 to 5The gearbox housing 31 includes a front housing 311, a rear housing 312, and a connector 313 connecting the front and rear housings. The front housing 311 and rear housing 312 form a space within which the transmission mechanism 32 is housed, with the output shaft 4 protruding from the space. The front housing 311 includes a plurality of first holes 3111, and the rear housing 312 includes a plurality of second holes 3121 corresponding one-to-one to the first holes 3111. The connector 33 passes through the first and second holes 3111, 3121, to connect the front and rear housings 311 and 312. The plurality of first holes 3111 are arranged along the circumference of the front housing 311, and each first hole 3111 protrudes inward toward the transmission mechanism. This allows the first holes 3111 to utilize the small space between the transmission mechanism 32 and the gearbox housing 31, thereby reducing the radial dimension D of the gearbox from the current 58 mm to 54-55 mm. The radial dimension here is defined by the first hole 3111 located on the outside. Although the front housing has multiple more prominent protrusions 3112, these protrusions are directly exposed and are located at the same radial position as the housing outside the gearbox. Therefore, these protrusions are not included in the radial dimension of the gearbox. The axial direction is the direction perpendicular to the radial direction and is parallel to the axis of the output shaft 4.

[0028] Please combine Figure 7 The rear shell 312 includes a first end face 3122 close to the front shell 311 and a second end face 3123 away from the front shell. The rear shell 312 has a recessed portion 3124 that is recessed from the second end face 3123 toward the first end face 3122. The second hole 3121 passes through the recessed portion 3124 and the first end face 3122. That is, the second hole 3121 is a sinking hole. This can prevent the connecting member 313 from protruding from the second end face, thereby further reducing the axial size of the gearbox. Specifically, the radial dimension L of the gearbox can be reduced from 75mm to 71-72mm. Optionally, the connecting member 33 is a threaded member (such as a screw), and the threaded member includes a head 331 that receives the driving force. The head 331 of the threaded member is located in the recessed portion 3124.

[0029] The transmission mechanism 32 includes a gear reduction mechanism and an impact mechanism. The gear reduction mechanism is configured to provide torque to the output shaft 4, and the impact mechanism is configured to provide impact force to the output shaft. Specifically, the gear reduction mechanism includes a first-stage gear set 321, a second-stage gear set 322, a third-stage gear set 323 and a shaft lock structure 324. The gear set mainly includes an inner ring gear, a planetary carrier and planetary gears. The shaft lock structure 324 receives power from the third-stage gear set 323 and cooperates with the output shaft to achieve torque transmission. When the torque is too large, the output shaft 4 is disengaged from the shaft lock structure 324, thereby protecting the motor. The three gear sets are used to convert the high speed and low torque of the motor into low speed and high torque. Generally speaking, the more gear sets there are, the greater the reduction ratio and torque obtained, but this will inevitably lead to an increase in the size of the entire machine. The output torque in this embodiment is not less than 100N.M.

[0030] Please combine Figure 8 The first-stage gear set 321 (gear reduction mechanism) includes a fixed gear ring 3211, which is made of metal and includes an ear portion 3212 located in the recess. The ear portion 32112 has a third hole 3213 that is coaxial with and connected to the second hole. The connecting member 33 passes through the third hole 3213, the second hole 3121 and the first hole 3111 in sequence. The ear portion 3212 also serves as a gasket, which helps to improve the fastening strength of the connecting member without increasing the axial dimension. Optionally, in the radial and axial directions of the gearbox 32, the fixed gear ring 3211 is completely located in the area of the rear shell, so that the fixed gear ring 3211 does not increase the radial dimension of the gearbox; in the axial direction of the gearbox, the inner gear ring protrudes from the rear shell, so that the inner teeth are exposed in the space.

[0031] Please combine Figure 5 The gear reduction mechanism also includes a movable ring gear 3221 (the inner ring gear of the secondary gear set 322) and a shift fork 3223 that drives the movable ring gear. When the shift fork 3223 is driven by the speed regulating bracket 11, it drives the movable ring gear to move axially, so that the gear reduction mechanism outputs different transmission ratios; the gear box also includes a positioning ring 3225, which is located between the movable ring gear 3221 and the rear shell 312. The positioning ring 3225 is used to cooperate with the movable ring gear to stop the movable ring gear 3221 to limit the extreme position of the movable ring gear 3221; the positioning ring 3225 includes a flat plate portion arranged on the side away from the movable ring gear, which can also serve as a gasket. Compared with the separate arrangement of the positioning ring and gasket, the axial size of the gear box can be further reduced to 69-70 mm.

[0032] The impact mechanism includes a first ratchet 324, a second ratchet 325 and a function switching bracket 326, the first ratchet 324 is coupled to the output shaft, the first ratchet 324 includes a first tooth 3241 facing the second ratchet 325, the second ratchet 325 includes a second tooth, a plurality of support portions 3251 surrounding the second tooth and a gap formed between adjacent support portions, the plurality of support portions 3251 are arranged along the circumference of the second tooth, the function switching bracket 326 includes a convex portion 3261, the first ratchet 324 has a first position and a second position, when the first ratchet 324 is in the first position, the convex portion 3261 is aligned with the support portion 3251 and supported by the support portion; when the first ratchet is in the second position, the convex portion 3261 is aligned with the gap, so that the convex portion 3261 can enter the gap, thereby realizing the engagement of the first tooth 3241 and the second tooth.

[0033] The second ratchet 325 includes a bottom wall 3253 and a side wall 3254. The second teeth are formed on the bottom wall 3253, and the support portion 3251 is formed on the side wall 3254. The bottom wall 3253 and the side wall 3254 define a receiving cavity. Preferably, when the first teeth 3241 engage with the second teeth, the first ratchet 324 is completely located within the receiving cavity, thereby reducing the axial dimension of the gearbox to 68-69 mm.

[0034] Please combine Figure 6 The gearbox 3 also includes an oil seal structure 34, which includes a pin 341 that presses against the transmission mechanism (the inner gear ring of the three-stage gear set) and a seal 342 that fits around the pin. The outer periphery of the pin is provided with an annular groove 3411 that positions the seal 342. The front housing 311 is provided with a through-hole 3110, through which the pin 341 passes to press against the transmission mechanism. The seal seals the gap between the pin 341 and the through-hole 3110. The end surface of the pin 341 that presses against the transmission mechanism is spherical. The seal can be made of an elastic material, such as a rubber ring. The other end of the pin presses against a spring 343, which is mounted on a torque adjustment nut 35. The torque adjustment nut 35 is adjusted via the torque adjustment cover 12. By adjusting the torque adjustment cover 13, the deformation of the spring is changed, thereby controlling the maximum output torque of the output shaft. When the maximum torque is exceeded, the motor is protected by tripping.

[0035] The mode switching between drilling and impacting is achieved through the function switching cover 13. Specifically, the function switching cover 13 is manually rotated to drive the function switching bracket 326 to adjust the axial position of the first ratchet 324 relative to the second ratchet 325, so that the first tooth and the second tooth are engaged or disengaged.

[0036] The present application provides a high-torque electric drill, whose gear box has smaller axial and radial dimensions, which is conducive to the miniaturization of the electric drill product and is convenient for use in narrow spaces.

[0037] It should be understood that the drawings illustrate exemplary embodiments in detail, and it should be understood that the present application is not limited to the details or methods set forth in the specification or illustrated in the drawings. It should also be understood that the terminology is for descriptive purposes only and should not be considered as limiting.

[0038] In view of this specification, further modifications and alternative embodiments of various aspects of the present invention will be obvious to those skilled in the art. Therefore, this description should be interpreted as being illustrative only. The configurations and arrangements shown in the various exemplary embodiments are illustrative only. Although only some embodiments are described in detail in this disclosure, many modifications (for example, variations in the size, dimensions, structure, shape and proportion of various elements, the value of parameters, the installation arrangement, the use of materials, colors, orientations, etc.) can be made without substantially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as being integrally formed can be constructed from multiple parts or elements, can be reversed or otherwise changed in the position of the elements, and the nature or number or position of discrete elements can be changed or varied. According to alternative embodiments, the order or sequence of any process, logical algorithm or method steps can be changed or reordered. Other replacements, modifications, changes and omissions can also be made to the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

[0039] Although the present application recites particular combinations of features in the appended claims, various embodiments of the present invention relate to any combination of any of the features described herein, whether or not such combinations are currently claimed, and any such combination of features may be claimed in this application or in a future application. Any feature, element, or component of any exemplary embodiment discussed above may be used alone or in combination with any feature, element, or component of any other embodiment discussed above.

[0040] In various exemplary embodiments, relative dimensions, including angles, lengths, and radii, as shown in the accompanying drawings are drawn to scale. Actual measurements of the accompanying drawings would disclose the relative dimensions, angles, and ratios of the various exemplary embodiments. The various exemplary embodiments extend to various ranges encompassing absolute and relative dimensions, angles, and ratios that can be determined from the accompanying drawings. Various exemplary embodiments include any combination of one or more relative dimensions or angles that can be determined from the accompanying drawings. In addition, actual dimensions not expressly stated in this specification can be determined by combining the ratios of the dimensions measured in the accompanying drawings with the explicit dimensions stated in this specification.

Claims

1. A gearbox for an electric drill, the electric drill comprising a motor and an output shaft, the gearbox comprising a gearbox housing and a transmission mechanism, the transmission mechanism being used to transmit power from the motor to the output shaft, the gearbox housing comprising a front housing, a rear housing, and a connector connecting the front housing and the rear housing, the front housing and the rear housing forming a space, the transmission mechanism being accommodated in the space, the transmission mechanism comprising a gear reduction mechanism and an impact mechanism, the gear reduction mechanism being configured to provide torque to the output shaft, and the impact mechanism being configured to provide impact force to the output shaft, characterized in that: The impact mechanism includes a first ratchet, a second ratchet and a function switching bracket, the first ratchet is coupled to the output shaft, the first ratchet includes a first tooth facing the second ratchet, the second ratchet includes a second tooth, a plurality of support portions surrounding the second tooth and a notch formed between adjacent support portions, the plurality of support portions are arranged along the circumference of the second tooth, the function switching bracket includes a convex portion, the first ratchet has a first position and a second position, when the first ratchet is in the first position, the convex portion is aligned with the support portion and supported by the support portion; when the first ratchet is in the second position, the convex portion is aligned with the notch so that the convex portion can enter the notch to achieve meshing of the first tooth and the second tooth; The gear reduction mechanism includes multiple reduction gear sets, so that the output torque of the output shaft is not less than 100 N.M. The axial dimension of the gear box is 68 to 72 mm, and the radial dimension of the gear box is 52 to 55 mm. The axial direction is parallel to the axis of the output shaft, and the radial direction is perpendicular to the axis of the output shaft.

2. The gear box of the electric drill according to claim 1, characterized in that: The front shell includes a plurality of first holes, the rear shell includes a plurality of second holes corresponding to the first holes, and the connecting member is provided through the first holes and the second holes to connect the front shell and the rear shell; A plurality of first holes are arranged along the circumference of the front shell, and each first hole protrudes inwardly toward the transmission mechanism.

3. The gear box of the electric drill according to claim 2, characterized in that: The rear shell includes a first end surface close to the front shell and a second end surface away from the front shell. The rear shell has a recessed portion recessed from the second end surface toward the first end surface. The second hole passes through the recessed portion and the first end surface.

4. The gear box of the electric drill according to claim 3, characterized in that: The connecting member is a screw member, which includes a head for receiving driving force, and the head of the screw member is located in the recess.

5. The gear box of the electric drill according to claim 3, characterized in that: The gear reduction mechanism includes a fixed gear ring, which is made of metal and includes an ear located in the recess, the ear having a third hole coaxial with and connected to the second hole, and the connecting member passes through the third hole, the second hole and the first hole in sequence.

6. The gear box for an electric drill according to claim 5, characterized in that: In the radial and axial directions of the gearbox, the fixed gear ring is completely located within the area of the rear housing; In the axial direction of the gear box, the fixed gear ring protrudes into the rear housing, so that the internal teeth are exposed in the space.

7. The gear box for an electric drill according to claim 1, characterized in that: The second ratchet comprises a bottom wall and a side wall, the second teeth are formed on the bottom wall, and the support portion is formed on the side wall; The bottom wall and the side wall form an accommodating cavity. When the first tooth is engaged with the second tooth, the first ratchet is completely located in the accommodating cavity.

8. The gear box for an electric drill according to claim 1, characterized in that: The gearbox includes a movable ring gear and a shift fork driving the movable ring gear. When the shift fork is driven, the movable ring gear moves axially, so that the gear reduction mechanism outputs different transmission ratios. The gearbox further includes a positioning ring, which is located between the movable ring gear and the rear housing and is used to stop the movable ring gear to define an extreme position of the movable ring gear; The positioning ring includes a flat plate portion arranged at a side away from the movable gear ring.

9. The gear box of the electric drill according to claim 1, characterized in that: The gearbox includes an oil seal structure, the gearbox housing includes a through hole, the oil seal structure includes a pin and a seal sleeved on the pin, the pin passes through the through hole and presses against the transmission mechanism, and the seal seals the gap between the pin and the through hole.

10. An electric drill comprising a housing, a motor disposed in the housing, an output shaft, and the gear box according to any one of claims 1 to 9, wherein the motor transmits power to the output shaft through the transmission mechanism.

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