A planetary drill bit

Abstract

The present invention discloses a planetary drill bit, including a main drill, wherein the main drill is provided with at least one stirring device along the axial direction, wherein the stirring device includes at least one secondary drill and a planetary transmission mechanism for connecting the main drill and the secondary drill, wherein the secondary drill is driven by the planetary transmission mechanism to rotate and revolve around the main drill at the same time. In the planetary drill bit provided by the present invention, the main drill and each secondary drill are driven by the planetary transmission mechanism to rotate and at the same time drive all the secondary drills to revolve around the main drill. With such a structural design, the area that cannot be stirred by the rotation of the secondary drill and the main drill is fully stirred by the secondary drill revolving around the main drill, thereby eliminating the stirring blind area in the drilling construction area, and helping to improve the uniformity of stirring to ensure the overall structural strength of the cement soil mixing pile.

Description

Technical Field

[0001] The invention relates to the field of pile foundation drill bits, and in particular to a planetary drill bit. Background Art

[0002] Deep cement mixing pile is a kind of pile that uses cement as a curing agent. Through the deep mixing pile machine, soft soil or sand and the curing agent sprayed into the soil are forcibly mixed in the foundation, so that the curing agent and the soil undergo a series of physical and chemical reactions, and the soft soil is hardened into a high-strength and high-quality foundation with integrity, water stability and a certain strength. Therefore, it is suitable for the treatment of soft foundations such as silt, sand, silty soil, peat soil and silt, and the effect is significant. After treatment, it can be made into piles, walls, etc. Cement mixing piles are divided into single-axis, double-axis and multi-axis mixing piles according to the main construction methods used and the number of drill rods of the deep mixing pile machine.

[0003] As a kind of multi-axis mixing pile, the prior art discloses a drill rod assembly frame, comprising: a main frame rod penetrating in the length direction and at least one connecting member group arranged along the length direction of the main frame rod; wherein the connecting member group comprises more than one connecting rod arranged at intervals and respectively hinged to the outer wall of the main frame rod at the proximal end, each connecting rod is respectively hinged to a block at the distal end, and the circular holes of each support block are axially aligned; at least one connecting rod is hinged to one end of a telescopic rod, and the other end of the telescopic rod is hinged to the outer wall of the main frame rod. The top of the secondary drill rod is equipped with a power head.

[0004] Since the top of each drill rod needs to have its own power head to provide power for drilling and mixing, it consumes a lot of energy, and during the drilling process it needs to sink below the surface with the drill rod. When the curing agent undergoes a series of physical and chemical reactions with the soil, it will generate heat, affecting the service life of the power head.

[0005] For example, the prior art also discloses a cement-soil mixing pile driver, the drill rod transmission structure of the cement-soil mixing pile driver includes a driving box with an inner cavity, at least one driving gear connected to the main drill rod is provided in the driving box, the driving gear is connected to a driving structure that can drive the driving gear to rotate, wherein at least two driven gears connected to the auxiliary drill rod are provided on the circumferential outer side of the driving gear, and a gear transmission structure is provided between the driving gear and the driven gear, which can make at least one driven gear rotate in the opposite direction relative to the driving gear when the driving gear rotates and can make the remaining driven gears rotate in the same direction relative to the driving gear.

[0006] The driven gear includes a plurality of first driven gears and second driven gears arranged on the circumferential outer side of the driving gear, wherein the first driven gears and the second driven gears are arranged alternately one by one and are circumferentially distributed with the driving gear as the center and form an annular structure with different diameters; the gear transmission structure includes a first transmission component connected to the driving gear and capable of driving the first driven gear to rotate in the opposite direction relative to the driving gear when the driving gear rotates circumferentially, and a second transmission component arranged between the driving gear and the second driven gear and capable of causing the second driven gear to rotate in the same direction relative to the driving gear when the driving gear rotates.

[0007] Since the drilling depth requirement of cement-soil mixing pile driver is relatively high, during the drilling process, the mixing pile mainly plays the role of mixing and cannot achieve the effect of soil discharge. As the drilling depth increases, the drive box will sink below the surface along with the main drill rod. Since the cross-sectional area of ​​the drive box is too large, the soil squeezing area is too large, and the fluidity of the mixture (including fine granular crushed bodies and fluid) in the drilling area is greatly weakened. During the drilling or withdrawal process of the drill rod, it will cause serious axial extrusion of the mixture, so the pile foundation construction is difficult and the construction efficiency is low.

[0008] In the above-mentioned prior art, the relative position relationship of each drill rod remains unchanged, so there will be a mixing blind area, which causes the curing agent and soil in the mixing blind area to fail to fully react physically and chemically, resulting in a decrease in the quality of the pile. Summary of the invention

[0009] The purpose of the invention is to solve the problem that the existing multi-axis mixing piles have a mixing blind area during the drilling process, resulting in uneven mixing.

[0010] To achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0011] A planetary drill bit comprises a main drill, wherein the main drill is provided with at least one stirring device along the axial direction, wherein the stirring device comprises at least one secondary drill and a planetary transmission mechanism for connecting the main drill and the secondary drill, wherein the secondary drill is driven by the planetary transmission mechanism to rotate on its own while performing an orbital motion around the main drill.

[0012] Furthermore, the above-mentioned planetary drill bit also has the following characteristics: the planetary transmission mechanism includes: a fixed-axis gear coaxially arranged on the main drill, planetary gears of the same number as the secondary drills on the same stirring device and meshing with the fixed-axis gear, and a retaining frame installed on the main drill to keep the planetary gears and the fixed-axis gears correctly meshed, the secondary drills pass through the retaining frame and are connected and fixed to the corresponding planetary gears, and the secondary drills and the retaining frame are rotationally matched.

[0013] Furthermore, the planetary drill bit has the following features:

[0014] The retaining frame is connected and fixed to the main drill;

[0015] Alternatively, the retainer is rotatably connected to the main drill, and a limiting mechanism is provided on the main drill to prevent the retainer from axial movement. The retainer is connected to the main drill via at least one main drill bearing assembly, and a guillotine is detachably mounted on the outer peripheral wall of the retainer for preventing the retainer from rotating when drilling in and out.

[0016] Preferably, the distance from the outer end of the guillotine to the center of the main drill is greater than the drilling range radius of the main drill, and the drilling range radius of the main drill is greater than or equal to the maximum stirring radius of the stirring device.

[0017] Furthermore, the planetary drill bit has the following characteristics: the main drill bearing assembly includes a bearing seat fixed on the retaining frame and sealed with the retaining frame, and a bearing installed in the bearing seat, and the bearing is installed in cooperation with the main drill.

[0018] Furthermore, the planetary drill bit has the following features: the retainer includes a bottom plate, the fixed axis gear and the planetary gear are both located on the bottom plate, and the bottom plate forms a radial recess between two adjacent planetary gears;

[0019] Preferably, the retaining frame further comprises a cover shell fixed on the bottom plate, the fixed axis gear and the planetary gear are both mounted in a cavity formed by the cover shell and the bottom plate, and the cross-sectional outer contour of the cover shell matches the cross-sectional outer contour of the bottom plate;

[0020] The upper end surface and / or the lower end surface of the retaining frame decreases in area along the axial direction to form an outwardly convex conical structure.

[0021] Furthermore, the above-mentioned planetary drill bit also has the following characteristics: the planetary transmission mechanism also includes: a plurality of secondary drill bearing assemblies fixedly mounted on the retaining frame, and each of the secondary drills is rotatably connected to the retaining frame through at least one of the secondary drill bearing assemblies.

[0022] Furthermore, the above-mentioned planetary drill bit also has the following characteristics: the stirring device also includes at least one sealing assembly, the sealing assembly includes a sealing sleeve sleeved on the main drill and at least one seal installed between the main drill and the sealing sleeve, and the sealing sleeve is sealed and connected to the retaining frame or the main drill bearing assembly.

[0023] Furthermore, the planetary drill bit has the following features: a plurality of central stirring blades are arranged at intervals on the outer peripheral wall of the main drill, and a plurality of peripheral stirring blades are arranged at intervals on the outer peripheral wall of the secondary drill. During the rotation process, the central stirring blade on the main drill does not interfere with each secondary drill and the peripheral stirring blades on each secondary drill, and the peripheral stirring blades on the secondary drill do not interfere with the main drill, the adjacent secondary drill and the peripheral stirring blades on the adjacent secondary drill;

[0024] Preferably, the central stirring blade is provided with a lower cutting edge for the tangential rotation direction when drilling in and / or an upper cutting edge for the tangential rotation direction when drilling out along the rotation direction; the peripheral stirring blade is provided with a lower cutting edge for the tangential rotation direction when drilling in and / or an upper cutting edge for the tangential rotation direction when drilling out along the rotation direction.

[0025] Furthermore, the planetary drill bit has the following features: the lower end of the primary drill and the upper end and / or lower end of the secondary drill are respectively provided with a cutting portion, and the cutting portion includes a drill tip;

[0026] The cutting portion at the lower end of the main drill further comprises: a main cutting edge formed on the drill tip, and at least one spiral wing arranged on the outer peripheral surface of the main drill and close to the drill tip; the spiral wing is formed with a continuous cutting edge at the end facing the object to be cut;

[0027] Preferably, the spiral wing has a plurality of shovel teeth arranged on a radial end surface close to the drill tip.

[0028] Furthermore, the planetary drill bit has the following features: a plurality of nozzles are installed at intervals along the axial direction on the side wall of the main drill, and a number of delivery channels that are equal to and corresponding to the nozzles are arranged inside the main drill along the axial direction, each of the delivery channels can be used to transport different media and all pass through to the top of the main drill, and a flared nozzle is arranged at the bottom of each nozzle; the bottom of the nozzle is unobstructed, and the spray range of the nozzle covers the center of the main drill to the edge of the drilling area of ​​the main drill;

[0029] Preferably, the number of the nozzles is two, which are respectively distributed at the upper and lower ends of the main drill; and the stirring device is located between the two nozzles.

[0030] The planetary drill bit provided by the present invention is driven by a planetary transmission mechanism between the main drill and each secondary drill. The rotation of the main drill drives each secondary drill to rotate through the planetary transmission mechanism, and at the same time drives all the secondary drills to make an orbital motion around the main drill. Such a structural design allows the secondary drills to make an orbital motion around the main drill to fully stir the area that cannot be stirred by the rotation of the secondary drill and the main drill, thereby eliminating the mixing blind area in the drilling construction area, helping to improve the uniformity of mixing, and ensuring the overall structural strength of the cement soil mixing pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0032] Figure 1 is a stereoscopic diagram of a planetary drill bit using a single stirring device in the first embodiment;

[0033] Figure 2 is a three-dimensional diagram of a planetary drill bit using multiple stirring devices in Example 1;

[0034] Figure 3 is a stereoscopic diagram of a planetary drill bit using multiple identical stirring devices and sharing a secondary drill in the first embodiment;

[0035] Figure 4 is an exploded view of the stirring device in Example 1;

[0036] Figure 5 is a three-dimensional diagram of the main drill in the first embodiment;

[0037] Figure 6 is a stereogram of the secondary drill in the first embodiment;

[0038] Figure 7 is a three-dimensional diagram of the cutting portion of the main drill in the first embodiment;

[0039] Figure 8 is a three-dimensional diagram of the planetary drill bit in the second embodiment;

[0040] Fig. 9 is an exploded view of the stirring device in Example 2;

[0041] Fig.10 This is a schematic diagram of the stirring device after assembly in Example 2;

[0042] Fig.11 is an exploded view of the secondary drill bearing assembly in Example 3;

[0043] Fig.12 is a schematic structural diagram of a retainer in Embodiment 4;

[0044] Fig.13 is a schematic diagram of a half-section structure of the main drill in the fifth embodiment;

[0045] Fig.14 is a schematic diagram of a half-section structure of the nozzle in the fifth embodiment;

[0046] Fig.15Schematic diagram of the working state of the main drill bottom spraying and upper air supply in the fifth embodiment;

[0047] Fig.16 This is a schematic diagram of the working state of the main drill bottom air supply and upper part spraying in the fifth embodiment;

[0048] Fig.17 is a schematic diagram of a stirring device using a secondary drill in the sixth embodiment;

[0049] Fig.18 , 19 is a schematic diagram of the stirring device using two secondary drills in the sixth embodiment;

[0050] Fig. 20 is a schematic diagram of the stirring device using three secondary drills in the sixth embodiment;

[0051] Fig.21 It is a schematic diagram of the stirring device in the sixth embodiment using five secondary drills.

[0052] In the attached figure:

[0053] 1. Main drill; 11. Central stirring blade; 12. Nozzle; 121. Nozzle; 13. Delivery channel;

[0054] 2, secondary drill; 21, peripheral stirring blade; 1a, 2a, lower cutting edge; 1b, 2b, upper cutting edge;

[0055] 3. Planetary transmission mechanism; 31. Fixed axis gear; 32. Planetary gear; 33. Cage; 331. Bottom plate; 332. Cover; 333. Guillotine;

[0056] 4. Main drill bearing assembly; 41. Bearing seat; 42. Bearing; 43. O-ring;

[0057] 5. Sealing assembly; 51. Sealing sleeve; 52. Sealing ring;

[0058] 6. cutting part; 61. drill tip; 62. main cutting edge; 63. spiral wing; 64. shovel tooth;

[0059] 7. Secondary drill bearing assembly; 71. Bearing base; 72. Roller bearing;

[0060] 8. conveying device; 81. rotating core; 811. pipeline; 82. housing; 821. input port; 83. ring groove;

[0061] 9. Circlip. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0063] <Example 1>

[0064] like Figure 1 and Figure 2 As shown, the planetary drill bit provided in this embodiment is used for pile foundation construction in the case of cement soil mixing piles. The planetary drill bit includes a main drill, and the main drill 1 is axially mounted with at least one stirring device, and the stirring device includes at least one secondary drill 2 and a planetary transmission mechanism 3 that is transmission-connected between the main drill 1 and the secondary drill 2. The secondary drill 2 is driven by the planetary transmission mechanism 3 to rotate while orbiting around the main drill 1. During operation, the top of the main drill 1 is connected to a power device, and the power device drives the main drill 1 to rotate.

[0065] In this embodiment, there are four secondary drills 2 and each secondary drill 2 is parallel to the main drill 1 and evenly distributed around the central axis of the main drill 1 .

[0066] Specifically, when two or more stirring devices are used, the number of secondary drills 2 on each stirring device can be the same or different; when stirring devices with the same number of secondary drills 2 are used, the coaxial secondary drills 2 installation positions between adjacent stirring devices can share the same secondary drill 2, such as Figure 3 shown.

[0067] like Figure 4 As shown, as the key technical content of the present invention, the planetary transmission mechanism 3 provided in this embodiment includes: a fixed axis gear 31 coaxially arranged on the main drill 1, a planetary gear 32 having the same number as the secondary drills 2 on the same stirring device and meshing with the fixed axis gear 31, and a retaining frame 33 installed on the main drill 1 to keep the planetary gear 32 and the fixed axis gear 31 correctly meshed, the secondary drill 2 passes through the retaining frame 33 and is connected and fixed with the corresponding planetary gear 32, and the secondary drill 2 and the retaining frame 33 are rotationally matched.

[0068] Specifically, the secondary drill 2 can be connected to the corresponding planetary gear 32 in a whole section or in sections. The connection methods include one-piece connection and detachable connection. The detachable connection is preferred to facilitate later replacement and maintenance and reduce replacement costs. The detachable connection method includes one or a combination of flange connection, key connection, and fastener fixation.

[0069] Specifically, the retainer 33 is connected and fixed to the main drill 1. The connection and fixing method can be a detachable fixed connection such as a fastener, and the connection is sealed by a sealing structure such as a sealing ring, or a non-detachable fixed connection such as welding. When the retainer 33 is connected and fixed to the main drill 1, the rotation of the main drill 1 will inevitably drive the retainer 33 to rotate, and then drive the secondary drill 2 to perform an orbital motion around the main drill 1.

[0070] Furthermore, the retaining frame 33 includes a base plate 331, and the fixed axis gear 31 and the planetary gear 32 are both located on the base plate 331, and the base plate 331 forms a radial recess between two adjacent planetary gears 32; the retaining frame 33 also includes a cover shell 332 fixed on the base plate 331, and the fixed axis gear 31 and the planetary gear 32 are both installed in a cavity formed by the cover shell 332 and the base plate 331, and the cross-sectional outer contour of the cover shell 332 matches the cross-sectional outer contour of the base plate 331. In this embodiment, the retaining frame 33 is radially arranged along the circumference of the "petals" similar in shape to the planetary gears 32, and unnecessary area occupation is reduced by the principle of similar cross-sectional shapes. Conventional planetary gear transmission mechanisms usually adopt an outer ring gear arranged on the outside of the planetary gear to keep the planetary gear and the center gear engaged. Since the shape of the outer ring gear is circular, the shell must be a corresponding circular structure, which occupies a large area. During the drilling process, the soil squeezing area is large. In this embodiment, the base plate 331 adopts a plum blossom structure design. There are as many "petals" as there are planetary gears. Through the principle of similar shapes, the unnecessary area occupation is reduced as much as possible to achieve the effect of reducing the soil squeezing area, which is beneficial to the flow of the stirred object in the construction area and ensures the smoothness of the planetary drill bit in drilling and retracting.

[0071] like Figure 5 and Figure 6 As shown, in this embodiment, a plurality of central stirring blades 11 are arranged at intervals on the outer peripheral wall of the main drill 1, and a plurality of peripheral stirring blades 21 are arranged at intervals on the outer peripheral wall of the secondary drill 2. The central stirring blades 11 and the peripheral stirring blades 21 can be respectively installed on the main drill 1 and the secondary drill 2 in a detachable manner, or can be installed on the main drill 1 and the secondary drill 2 in a non-detachable manner.

[0072] During the rotation process, the central stirring blade 11 on the main drill 1 does not interfere with each secondary drill 2 and the circumferential stirring blades 21 on each secondary drill 2, and the circumferential stirring blades 21 on the secondary drill 2 do not interfere with the main drill 1, the adjacent secondary drill 2 and the circumferential stirring blades 21 on the adjacent secondary drill 2; specifically, the length of the central stirring blade 11 of the main drill 1 in the common section area and the non-common section area with the secondary drill 2 can be adjusted to prevent interference. Of course, the central stirring blade 11 may not be set in the common section area of ​​the main drill 1 with the secondary drill 2.

[0073] Preferably, the central stirring blade 11 is provided with a lower cutting edge 1a for tangential rotation direction when drilling in and / or an upper cutting edge 1b for tangential rotation direction when drilling out along the rotation direction; the peripheral stirring blade 21 is provided with a lower cutting edge 2a for tangential rotation direction when drilling in and / or an upper cutting edge 2b for tangential rotation direction when drilling out along the rotation direction. In the embodiment, the stirring blades of the primary drill and the secondary drill can be arranged in a group of 2 to 5 stirring blades at intervals along the axial direction of the drill rod, or can be arranged in a spiral at intervals.

[0074] Specifically, the central stirring blade 11 and the peripheral stirring blade 21 are both inclined. Due to the external meshing transmission of the fixed axis gear 31 and the planetary gear 32, the rotation direction of each secondary drill 2 is opposite to the rotation direction of the main drill 1, so the inclination direction of the central stirring blade 11 and the peripheral stirring blade 21 is also opposite.

[0075] When drilling forward, the lower cutting edges (1a, 2a) on the central stirring blade 11 and the peripheral stirring blades 21 first cut into the mixture; when drilling backward, the main drill 1 rotates in the opposite direction and is lifted by the pile driver, and the upper cutting edges (1b, 2b) on the central stirring blade 11 and the peripheral stirring blades 21 first cut into the mixture to reduce the travel resistance.

[0076] Furthermore, if Figures 1 to 4 As shown, the lower end of the main drill 1 and the upper and lower ends of the secondary drill 2 are respectively provided with a cutting portion 6, and the cutting portion 6 can be installed on the main drill 1 or the secondary drill 2 in a detachable manner, or can be installed on the main drill 1 or the secondary drill 2 in a non-detachable manner. Specifically, the cutting portion 6 includes: a drill tip 61. As a preferred technical solution, in this embodiment, the drill tip 61 is configured with at least two spiral cutting edges with a helical angle of 5° to 85° that are spaced around the central axis, and the drill tip 61 and the corresponding main drill 1 or secondary drill 2 are fixed by welding, or screwed and fixed by fasteners not shown in the figure, or integrally formed during the production and manufacturing process of the main drill 1 and the secondary drill 2.

[0077] Among them, Figure 7 As shown, the cutting portion 6 at the lower end of the main drill 1 further comprises: a main cutting edge 62 formed on a drill tip 61, and at least one spiral wing 63 disposed on the outer peripheral surface of the main drill 1 and close to the drill tip 61; the spiral wing 63 is formed with a continuous cutting edge at the end facing the object to be cut;

[0078] In addition, a plurality of shovel teeth 64 are arranged on the radial end surface of the spiral wing 63 near the drill tip, thereby improving the rock breaking and cutting capability of the planetary drill bit.

[0079] <Example 2>

[0080] In this embodiment, the same parts as those in the first embodiment are given the same figure marks, and the same text descriptions are omitted.

[0081] like Figure 8 and Fig. 9 As shown, compared with the first embodiment, the planetary drill bit provided in this embodiment has the following different structural designs:

[0082] The fixed connection between the retainer 33 and the main drill 1 in the first embodiment is replaced by a rotational connection between the retainer 33 and the main drill 1, and a limiting mechanism is provided on the main drill 1 to prevent the retainer 33 from axial movement. Specifically, the limiting mechanism can be a retaining spring 9 installed on the main drill 1 slot, or a flange (not shown in the figure) integrally formed or fixedly installed on the main drill 1 to achieve axial limiting, and is of course not limited to the above limiting methods.

[0083] In this embodiment, in order to prevent the secondary drill 2 from performing a revolution during the drilling process, a guillotine 333 for preventing the holder 33 from rotating during the drilling process can be detachably mounted on the outer peripheral wall of the holder 33. Preferably, the distance from the outer end of the guillotine 333 to the center of the main drill 1 is greater than the drilling range radius of the main drill 1, and the drilling range radius of the main drill 1 is greater than or equal to the maximum stirring radius of the stirring device. During the drilling process, the secondary drill 2 rotates under the meshing action of the gears, and the guillotine 333 enters the undrilled soil. Due to the resistance of the soil, the holder 33 maintains a relative position unchanged during the drilling process, so that the relative position relationship between each secondary drill 2 and the main drill 1 remains unchanged for drilling.

[0084] Furthermore, to ensure the sealing performance during the rotation process, a sealing assembly 5 is provided at the connection between the main drill 1 and each secondary drill 2 and the retainer 33. The sealing assembly 5 includes a sealing sleeve 51 sleeved on the main drill 1 or the secondary drill 2 and at least one sealing member 52 sleeved on the main drill 1 or the secondary drill 2. The sealing sleeve 51 and the main drill 1 or the secondary drill 2 are sealed by the sealing member 52. The sealing sleeve 51 is fixedly connected to the retainer 33 and a sealing gasket is provided at the connection for sealing. In this embodiment, the sealing member 52 can be at least one sealing ring, an oil seal, etc. or a combination of several.

[0085] <Example 3>

[0086] In this embodiment, the same parts as those in the first embodiment are given the same figure marks, and the same text descriptions are omitted.

[0087] like Figures 9 to 11 As shown, compared with the second embodiment, the planetary drill bit provided in this embodiment has the following different structural designs:

[0088] The retainer 33 is also connected to the main drill 1 through at least one main drill bearing assembly 4. Preferably, two main drill bearing assemblies 4 are used, which are respectively distributed above and below the retainer 33, so that the main drill 1 and the retainer 33 can rotate relative to each other more smoothly. Specifically, the main drill bearing assembly 4 includes a bearing seat 41 fixed on the retainer 33 and sealed with the retainer 33 through an O-ring 43, and a bearing 42 installed in the bearing seat 41, and the bearing 42 is installed in cooperation with the main drill 1. Correspondingly, the sealing assembly 5 on the main drill 1 is installed on the bearing seat 41, and the sealing sleeve 51 is fixedly connected to the bearing seat 41, and a sealing gasket is provided at the connection for sealing.

[0089] Furthermore, each of the secondary drills 2 and the retainer 33 is rotatably connected to the retainer 33 through at least one secondary drill bearing assembly 7 to ensure smooth rotation between the secondary drill 2 and the retainer 33. Specifically, the secondary drill bearing assembly 7 includes a bearing base 71 and a roller bearing 72 installed in the bearing base 71 and installed in cooperation with the corresponding secondary drill 2. The bearing base 71 is fixed on the retainer 33 and a sealing gasket is provided at the connection for sealing. Correspondingly, the sealing assembly 5 on the secondary drill 2 is installed on the bearing base 71, and the sealing sleeve 51 is fixedly connected to the bearing base 71 and a sealing gasket is provided at the connection for sealing. In this embodiment, the inner ring of the bearing base 71 can be fixedly connected to the secondary drill 2 through a fastener not shown in the figure, and a sealing structure such as a sealing ring is provided between the inner ring of the bearing base 71 and the secondary drill 2 for sealing. The outer ends of the bearing base 71 are all provided with end plates for sealing to prevent mud and the like from entering the interior, thereby reducing the use of the sealing assembly 5 on the secondary drill 2.

[0090] <Example 4>

[0091] In this embodiment, the same parts as those in Embodiments 1 to 3 are given the same figure marks, and the same text descriptions are omitted.

[0092] like Fig.12 As shown, the stirring device with three secondary drill bits 2 is used as an example for explanation. Compared with the first to third embodiments, the planetary drill bit provided in this embodiment has the following different structural designs:

[0093] The upper end face and / or the lower end face of the retainer 33 decrease in area along the axial direction to form a convex conical structure. Whether drilling in or out, the retainer 33 is first subjected to force by the cone tip, and the mixture can flow along the surface of the protective cover 34 instead of accumulating on the surface of the retainer 33, which helps to reduce the resistance during drilling in and out, and reduces the difficulty of pile foundation construction. In this embodiment, the cross section of the retainer 33 decreases continuously to form a smooth curved surface, and of course it can also decrease step by step to form a stepped surface.

[0094] <Example 5>

[0095] In this embodiment, the same parts as those in Embodiments 1 to 4 are given the same figure marks, and the same text descriptions are omitted.

[0096] like Figures 1 to 3 as well as Figure 5 , Figure 8 , Fig.13 and Fig.14 As shown, compared with the first to fourth embodiments, the planetary drill bit provided in this embodiment has the following different structural designs:

[0097] A plurality of nozzles 12 are installed at intervals along the axial direction on the side wall of the main drill 1, and a number of delivery channels 13 that are in correspondence with and connected to the nozzles 11 are arranged inside the main drill 1 along the axial direction, each of the delivery channels 13 passes through to the top of the main drill 1, and a flared nozzle 121 is arranged at the bottom of each nozzle 12;

[0098] Preferably, the bottom of the nozzle 121 is unobstructed, and the nozzle 121 is in an elongated strip shape, and its spray range covers the center of the main drill 1 to the edge of the drilling area of ​​the main drill 1. The outer end of the nozzle 12 is set to a cutting bevel, so that the nozzle 12 can also achieve a cutting effect.

[0099] As a preferred technical solution, in this embodiment, the number of the nozzles 12 is two, respectively distributed at the upper and lower ends of the main drill 1; the stirring device is located between the two nozzles 12. Correspondingly, the number of the conveying channels 13 is also two, for conveying gas and slurry.

[0100] During operation, a conveying device 8 for conveying gas and slurry is installed on the drilling rig, such as Fig.15 and Fig.16 As shown, a rotating core 81 is provided inside, and the rotating core 81 is fixedly connected to the top of the main drill 1. A shell 82 is provided outside, and the shell 82 is fixed on the drilling rig. The rotating core 81 and the shell 82 are sealed and rotatably connected. Two parallel and non-communicating annular grooves 83 are provided on the rotating core 81, and a pipeline 811 penetrating to the bottom is provided at each annular groove 83 of the rotating core 81. The two pipelines 811 are respectively connected to the two conveying channels 13 on the top of the main drill 1. An input port 821 communicating with the corresponding annular groove 83 is provided on the shell 82. Each input port 821 is connected to the output port of the three-way valve through a conveying pipe. The two input ports of the three-way valve are connected to the air source and the slurry source through an air pump and a mortar pump respectively. By controlling the switching of the three-way valve and the switching of the air pump and the mortar pump, the purpose of controlling the required nozzle 12 to spray gas or slurry is achieved.

[0101] During the drilling process, the lower nozzle 12 is controlled to deliver slurry and the upper nozzle 12 is controlled to deliver gas. Fig.15During the drilling process, the lower nozzle 12 is controlled to deliver gas, while the upper nozzle 12 delivers slurry, such as Fig.16 As shown, the purpose of conveying gas is to facilitate mixing and stirring, while preventing the nozzles 121 from being blocked. By controlling the nozzle 12 to switch and convey different media under different working conditions, the uniformity of the pile foundation as a whole can be ensured, avoiding the problem of inconsistent uniformity caused by conveying slurry at the same time.

[0102] <Example 6>

[0103] In this embodiment, the same parts as those in the first embodiment are given the same figure marks, and the same text descriptions are omitted.

[0104] Compared with the above embodiment, each stirring device on the planetary drill bit provided in this embodiment may include a secondary drill 2 arranged at intervals around the central axis of the main drill 1, such as Fig.17 As shown;

[0105] Or, if Fig.18 and 19 As shown, it includes two secondary drills 2 arranged at intervals around the central axis of the main drill 1; of course, the stirring device provided in this embodiment can also include three (such as Fig. 20 as shown), five (as shown Fig.21 The secondary drills 2 are arranged at intervals around the central axis of the main drill 1 as shown in the figure, that is, the secondary drills 2 and the main drill 1 are arranged in a star shape (triangular star, quadrangular star, pentagonal star, etc.).

[0106] In this embodiment, when the number of the secondary drills 2 changes, the planetary transmission mechanism 3 also undergoes a corresponding structural change.

[0107] In the above-mentioned embodiments 1 to 6, preferably, the transmission ratio of the fixed axis gear 31 and the planetary gear 32 is greater than 1, so that the rotation speed of the secondary drill 2 is greater than the rotation speed of the main drill 1, and the stirring effect is improved. Of course, the transmission ratio of the fixed axis gear 31 and the planetary gear 32 can also be ≤1. During the working process, as the drilling depth increases, the top of the main drill 1 is superimposed with a connecting shaft with the same structure as the top of the main drill 1 to meet the requirements of pile foundation construction. Some technical implementation methods of embodiments 1 to 6 can be combined or replaced.

[0108] The technical principle of the present invention is described above in combination with specific embodiments, but it should be noted that the above descriptions are only for explaining the principle of the present invention and cannot be interpreted as a specific limitation on the protection scope of the present invention in any way. Based on the explanation here, technicians in this field can think of other specific embodiments or equivalent replacements of the present invention without paying creative work, which will fall within the protection scope of the present invention.

Claims

1. A planetary drill bit, comprising a main drill (1), characterized in that: The main drill (1) is provided with at least one stirring device along the axial direction, the stirring device comprising at least one secondary drill (2) and a planetary transmission mechanism (3) for transmission connection between the main drill (1) and the secondary drill (2), the secondary drill (2) being driven by the planetary transmission mechanism (3) to rotate while orbiting around the main drill (1), the top of the main drill (1) being connected to a power device, the power device driving the main drill (1) to rotate; The retaining frame (33) in the planetary transmission mechanism (3) is detachably fixedly connected to the main drill (1), or the retaining frame (33) is rotatably connected to the main drill (1), and a guillotine (333) is detachably mounted on the outer peripheral wall of the retaining frame (33) for preventing the retaining frame (33) from rotating when drilling forward or backward.

2. The planetary drill bit according to claim 1, characterized in that: The planetary transmission mechanism (3) comprises: a fixed-axis gear (31) coaxially arranged on the main drill (1), planetary gears (32) of the same number as the secondary drills (2) on the same stirring device and meshing with the fixed-axis gear (31), and a retaining frame (33) mounted on the main drill (1) to keep the planetary gears (32) and the fixed-axis gear (31) correctly meshed, the secondary drills (2) passing through the retaining frame (33) being connected and fixed to the corresponding planetary gears (32), and the secondary drills (2) and the retaining frame (33) being rotationally matched.

3. The planetary drill bit according to claim 2, characterized in that: The main drill (1) is provided with a limiting mechanism for preventing the retainer (33) from axial movement. The retainer (33) is connected to the main drill (1) via at least one main drill bearing assembly (4). The distance from the outer end of the guillotine (333) to the center of the main drill (1) is greater than the drilling range radius of the main drill (1), and the drilling range radius of the main drill (1) is greater than or equal to the maximum stirring radius of the stirring device.

4. The planetary drill bit according to claim 3, characterized in that: The main drill bearing assembly (4) comprises a bearing seat (41) fixed on the retaining frame (33) and sealed with the retaining frame (33), and a bearing (42) installed in the bearing seat (41), wherein the bearing (42) is installed in cooperation with the main drill (1).

5. The planetary drill bit according to claim 2, characterized in that: The retaining frame (33) comprises a bottom plate (331), the fixed-axis gear (31) and the planetary gear (32) are both located on the bottom plate (331), and a radial recessed portion is formed on the bottom plate (331) between two adjacent planetary gears (32); The retaining frame (33) further comprises a cover shell (332) fixed on the bottom plate (331); the fixed axis gear (31) and the planetary gear (32) are both mounted in a cavity formed by the cover shell (332) and the bottom plate (331); and the cross-sectional outer contour of the cover shell (332) matches the cross-sectional outer contour of the bottom plate (331); The upper end surface and / or the lower end surface of the retaining frame (33) decreases in area along the axial direction to form an outwardly convex conical structure.

6. The planetary drill bit according to claim 2, characterized in that: The planetary transmission mechanism (3) further comprises: a plurality of secondary drill bearing assemblies (7) fixedly mounted on the retaining frame (33); each secondary drill (2) is rotationally connected to the retaining frame (33) via at least one of the secondary drill bearing assemblies (7).

7. The planetary drill bit according to claim 3, characterized in that: The stirring device further comprises: at least one sealing assembly (5), the sealing assembly (5) comprising a sealing sleeve (51) sleeved on the main drill (1) and at least one sealing member (52) installed between the main drill (1) and the sealing sleeve (51), the sealing sleeve (51) being sealingly connected to the retaining frame (33) or the main drill bearing assembly (4).

8. The planetary drill bit according to claim 1, characterized in that: A plurality of central stirring blades (11) are arranged at intervals on the outer peripheral wall of the main drill (1), and a plurality of peripheral stirring blades (21) are arranged at intervals on the outer peripheral wall of the secondary drill (2). During rotation, the central stirring blade (11) on the main drill (1) does not interfere with each secondary drill (2) and the peripheral stirring blades (21) on each secondary drill (2), and the peripheral stirring blades (21) on the secondary drill (2) do not interfere with the main drill (1), the adjacent secondary drill (2) and the peripheral stirring blades (21) on the adjacent secondary drill (2); The central stirring blade (11) is provided with a lower cutting edge for the tangential rotation direction when drilling in and / or an upper cutting edge for the tangential rotation direction when drilling out along the rotation direction; the peripheral stirring blade (21) is provided with a lower cutting edge for the tangential rotation direction when drilling in and / or an upper cutting edge for the tangential rotation direction when drilling out along the rotation direction.

9. The planetary drill bit according to claim 1, characterized in that: The lower end of the primary drill (1) and the upper end and / or lower end of the secondary drill (2) are respectively provided with a cutting portion (6), and the cutting portion (6) comprises a drill tip (61); The cutting portion (6) at the lower end of the main drill (1) further comprises: a main cutting edge (62) formed on the drill tip (61), and at least one spiral wing (63) arranged on the outer peripheral surface of the main drill (1) and close to the drill tip (61); the spiral wing (63) is formed with a continuous cutting edge at the end facing the object to be cut; The spiral wing (63) is provided with a plurality of shovel teeth (64) arranged on a radial end surface close to the drill tip.

10. The planetary drill bit according to any one of claims 1 to 9, characterized in that: A plurality of nozzles (12) are installed at intervals along the axial direction on the side wall of the main drill (1), and a number of delivery channels (13) that are in corresponding communication with the number of the nozzles (12) are arranged inside the main drill (1) along the axial direction, each of the delivery channels (13) can be used to deliver different media and are all connected to the top of the main drill (1), and a flared nozzle (121) is arranged at the bottom of each nozzle (12); the bottom of the nozzle (121) is unobstructed, and the spraying range of the nozzle (121) covers the center of the main drill (1) to the edge of the drilling area of ​​the main drill (1); There are two nozzles (12), which are respectively distributed at the upper and lower ends of the main drill (1); and the stirring device is located between the two nozzles (12).

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