Small-aperture intermittent deep hole machining tool set

Abstract

A small-aperture intermittent deep hole machining tool set comprises a first tool, a second tool, a third tool, a fourth tool and a fifth tool. Through reasonable arrangement of component structures, a front section hole is a guide hole, a multi-blade supporting structure plays a supporting and guiding role in the front section hole through a first multi-blade supporting shaft and a second multi-blade supporting shaft in the machining process, the overall machining rigidity and stability are enhanced, cutter breakage is avoided, the whole cutter composition cost is low, and the machining efficiency is improved. And the machining of small-aperture intermittent deep holes can be efficiently and reliably completed.

Description

Technical Field

[0001] This utility model belongs to the field of cutting tool technology, specifically relating to a tool set for machining small-diameter discontinuous deep holes. Background Technology

[0002] With the increasing variety of gearbox types, the related lubrication circuits on housing parts are becoming more complex. Agricultural AT hydraulic gearboxes, such as those used in cotton harvesters, are increasingly featuring small-diameter, discontinuous, deep oil passages with a depth greater than 50 times the diameter (D7 or less). Furthermore, these oil passages often intersect eccentrically with bearing holes, and the discontinuous hole openings have large slopes, making machining extremely difficult. Due to the excessively long tool overhang and weak rigidity, ordinary deep-hole drilling tools experience severe vibration and are prone to breakage, resulting in low machining efficiency and high tool costs.

[0003] Agricultural gearbox housings, in particular, have large external dimensions, resulting in numerous deep cavities and holes. Generally, deep hole machining of oil passages employs a pilot tool + gun drill or a pilot tool + solid alloy deep hole drill. However, both of these methods result in a very high rate of tool breakage in the later stages of machining small-diameter, discontinuous deep holes.

[0004] like Figure 1 The image shows a small-diameter oil hole on our company's AT gearbox. It intersects eccentrically with the bearing hole, dividing the oil hole into two discontinuous sections: a front section and a rear section. The hole diameter is 6 ≤ D ≤ 7 mm, with relatively loose tolerances, the upper tolerance being b = 0.12 mm. The hole depth L is generally over 350 mm, with a length-to-diameter ratio L / D ≥ 50. The axial length L4 of the inclined surface at the rear hole opening is > 1.2 * D, and the slope is greater than 50°. When machining the inclined surface at the rear hole opening using a standard alloy deep-hole drill or gun drill, the drill bit is only subjected to radial force on one side, making it impossible to center, resulting in poor cutting stability and tool tip vibration. Furthermore, because the tool's rear end lacks support in the front hole, the drill bit is prone to deflection and breakage, making the machining of the rear hole extremely difficult. When the hole depth L exceeds the standard alloy bar length of 330 mm, a custom-made non-standard bar is required for the solid alloy deep-hole drill, resulting in extremely high tool costs. Additionally, the excessive tool overhang leads to poor machining rigidity, necessitating reduced cutting parameters and limiting machining efficiency. How to effectively reduce the problems of oscillation and tool breakage in the subsequent hole machining, and efficiently and reliably complete the machining of small-diameter intermittent deep holes with lower tool costs, is a key issue that urgently needs to be solved. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this utility model is to provide a tool set for machining small-diameter intermittent deep holes, solving the problems of vibration and tool breakage in the later stages of hole machining with existing tools.

[0006] To achieve the above objectives, the technical solution adopted by this utility model includes:

[0007] A tool set for machining small-diameter discontinuous deep holes includes:

[0008] The first cutter is a first guide drill, comprising a first cutter head;

[0009] The second cutter comprises a second cutter head, a length of a groove of the second cutter head l21>L1, a diameter of the second cutter head d2<d1, and a drill tip angle of the second cutter head a2< a1.

[0010] The third cutter comprises a third cutter head and a first multi-blade support shaft coaxially arranged from front to back, the third cutter head and the first multi-blade support shaft have the same diameter, and satisfy l31>L3 and (L1+L3+L4)-(l31+l32)≤(25%-30%)*L1; wherein, l31 represents a length of the third cutter head, L3 represents a distance between two adjacent ends of the front section hole and the rear section hole, L4 represents a hole length of a tapped hole mouth inclined surface of the rear section hole, and l32 represents a length of the first multi-blade support shaft.

[0011] The fourth cutter is a second guide drill, comprising a fourth cutter head, a cutter rod and a second multi-blade support shaft coaxially arranged from front to back, the fourth cutter head, the cutter rod and the second multi-blade support shaft have the same diameter, and satisfy l41>L3 and (L1+L3+L4+1.5D)-(l41+l42)≤(25%-30%)*L1; wherein, l41 represents a length of the fourth cutter head and the cutter rod after being connected, and l42 represents a length of the second multi-blade support shaft.

[0012] The fifth cutter comprises a fifth cutter head, and the fifth cutter head is provided with a chip removal groove from a front end thereof to a rear end, and a length of the chip removal groove l51>L1+L3+L2.

[0013] Preferably, the diameter d1 of the first cutter head is The drill tip angle a1 of the first cutter head is 140°, and a drill depth l11 is 1.5D-2D; wherein, D represents a diameter of a hole to be machined.

[0014] Preferably, the blade of the second cutter head comprises a double-blade and a single-blade coaxially arranged from front to back, and a length of the double-blade l22 is 6D-7D.

[0015] Preferably, the diameter d2 of the second cutter head is The drill tip angle a2 of the second cutter head is 136°.

[0016] Preferably, the third cutter head is a 2-tooth flat bottom cutter head, a length of a cutting edge of the third cutter head l33≥2.5*L4, and a diameter of the third cutter head d3 is d2-d3=0.005-0.025; an included angle a3 of the first multi-blade support shaft is 90°, a blade width β3 is 1.5, and a helix angle a31 is 20-25°.

[0017] Preferably, a diameter of a single side necking of the third cutter head is 0.05-0.1mm.

[0018] Preferably, the first multi-blade support shaft is a 6-blade support shaft.

[0019] Preferably, the drill tip angle of the fourth tool head is 140°, the fourth tool head blade length l43=4D, the drill depth is 1.5D~2D, and the fourth tool head diameter d4 is 4D~5D.

[0020] Preferably, the diameter of the tool bar is single-sided necked by 0.05~0.1mm.

[0021] Preferably, the fifth tool head diameter d5 is 4D~5D. The drill tip angle of the fifth tool head is 120°.

[0022] Compared with the prior art, the utility model has the advantages that:

[0023] (1) The small hole diameter intermittent deep hole machining tool set of the utility model, through the reasonable setting of the part structure, the previous section hole is a guide hole, the multi-blade support structure in the previous section hole plays a supporting and guiding role in the machining through the first multi-blade support shaft and the second multi-blade support shaft, the overall machining rigidity and stability are enhanced, the tool breakage is avoided, and the whole tool set is low in cost and can efficiently and reliably complete the machining of the small hole diameter intermittent deep hole.

[0024] (2) The small hole diameter intermittent deep hole machining tool set of the utility model, the first tool and the second tool are previous section hole machining tools, the first tool is a previous section hole machining guide drill, and the second tool is a previous section hole machining deep hole drill, the separate machining of the previous section hole can shorten the tool overhang, the tool rigidity is maximally improved, the whole hard alloy with an inner cooling hole can be used, higher cutting parameters can be used to improve the machining efficiency, the machining precision and hole wall smoothness of the previous section hole are guaranteed, and the foundation for the machining of the latter section hole is laid.

[0025] (3) The small hole diameter intermittent deep hole machining tool set of the utility model, the third tool, the fourth tool and the fifth tool are latter section hole machining tools, the third tool is used for machining the latter section hole and is used for tapping the inclined surface part of the hole mouth, the first support shaft plays a supporting and guiding role in the previous section hole in the tapping of the inclined surface part of the latter section hole mouth, the first support shaft is simple and easy to implement in tool manufacturing and good in precision, the inclined surface part of the latter section hole mouth is tapped into a plane by using the third tool, the fourth tool can be well centered when the drill tip of the fourth tool drills, and the tool breakage is avoided; the fourth tool is a latter section hole machining guide drill, and the design of the second multi-blade support shaft guarantees the effective support in the machining; the guide hole of the tool is drilled by using the tool, the drill tip of the tool is guided and directed, the tool 5 is stably drilled, and the whole deep hole machining is completed. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application and explain the principles of the present application together with the specific embodiments below, but do not constitute a limitation on the present application. In the drawings:

[0027] Figure 1 It is a schematic diagram of a small-diameter oil hole on an AT gearbox;

[0028] Figure 2 It is a schematic diagram of the structure of the small-diameter intermittent deep hole machining tool set of the present application. Each reference numeral in the figure is:

[0029] 1 first tool, 1-1 first tool bit;

[0030] 2 second tool, 2-1 second tool bit, 2-12 double-edged belt, 2-11 single-edged belt;

[0031] 3 third tool, 3-1 third tool bit, 3-2 first multi-blade support shaft, 3-10 tool body;

[0032] 4 fourth tool, 4-1 fourth tool bit, 4-2 tool rod, 4-21 second multi-blade support shaft;

[0033] 5 fifth tool, 5-1 fifth tool bit, 5-10 chip removal groove. DETAILED DESCRIPTION

[0034] The present application is not limited to the following specific embodiments, and any equivalent variations made on the basis of the technical solutions of the present application fall within the protection scope of the present application.

[0035] It should be noted that the directional terms mentioned in this paper are consistent with the specific directions on the paper or the corresponding directions in the drawings shown in the drawings; all components and devices in the present application, such as without special instructions, all use the components and devices known in the prior art.

[0036] The hole diameter to be machined in the present embodiment is D, 6≤D≤7mm, and the hole diameter tolerance requirement is b=0.12. The hole depth L to be machined is greater than 350mm, and the length-diameter ratio L / D is greater than 50; the axial length L4 of the rear hole orifice bevel is greater than 1.2*D, and the slope is greater than 50°.

[0037] EMBODIMENT

[0038] The present embodiment discloses a small-diameter intermittent deep hole machining tool set, comprising:

[0039] The first tool 1 is a first guide drill, comprising a first tool bit 1-1;

[0040] The second cutter 2 comprises a second cutter head 2-1, the length l21 of the flute of the second cutter head 2-1 is greater than the length L1 of the front hole, the diameter d2 of the second cutter head 2-1 is less than the diameter d1 of the first cutter head 1-1, and the drill tip angle a2 of the second cutter head 2-1 is less than the drill tip angle a1 of the first cutter head 1-1;

[0041] The third cutter 3 comprises a third cutter head 3-1 and a first support shaft 3-2 coaxially connected from front to back, the third cutter head 3-1 and the first multi-blade support shaft 3-2 are equal in diameter, and satisfy l31>L3 and (L1+L3+L4)-(l31+l32)≤(25%-30%)*L1; wherein, l31 is the length of the third cutter head 3-1, L3 is the distance between the two adjacent ends of the front hole and the rear hole, L4 is the length of the hole of the counterbore hole mouth inclined surface, and l32 represents the length of the first multi-blade support shaft 3-2;

[0042] The fourth cutter 4 is a second guide drill, comprising a fourth cutter head 4-1, a cutter bar 4-2 and a second multi-blade support shaft 4-21 coaxially connected from front to back, the fourth cutter head 4-1, the cutter bar 4-2 and the second multi-blade support shaft 4-21 are equal in diameter, and satisfy l41>L3 and (L1+L3+L4+1.5D)-(l41+l42)≤(25%-30%)*L1; wherein, l41 represents the length of the fourth cutter head 4-1 and the cutter bar 4-2 after connection, and l42 represents the length of the second multi-blade support shaft 4-21;

[0043] The fifth cutter 5 comprises a fifth cutter head 5-1, the fifth cutter head 5-1 is provided with a chip flute 5-10 from the front end thereof to the rear, and the length l51 of the chip flute 5-10 is greater than L1+L3+L2;

[0044] The functions are as follows: the first cutter 1 and the second cutter 2 are both front-hole machining cutters, the first cutter 1 is a front-hole machining guide drill, and the second cutter 2 is a front-hole machining deep hole drill; the separate machining of the front hole can shorten the cutter overhang, maximally improve the rigidity of the cutter, use the whole hard alloy with inner cooling holes, use higher cutting parameters to improve the machining efficiency, and ensure the machining precision and hole wall smoothness of the front hole, thereby laying a good foundation for the machining of the rear hole. The third cutter 3, the fourth cutter 4 and the fifth cutter 5 are rear-hole machining cutters, the third cutter 3 is used for machining the rear-hole flatted hole mouth inclined surface part, the first support shaft 3-2 plays a supporting and guiding role in the front hole when the rear-hole flatted hole mouth inclined surface part is flatted, the first support shaft 3-2 is simple and easy to manufacture and has good precision, the rear-hole flatted hole mouth inclined surface part is flatted by using the third cutter 3, the fourth cutter 4 can be well centered when the drill tip is drilled, and the cutter breakage is avoided; the fourth cutter 4 is a rear-hole machining guide drill, the design of the second multi-blade support shaft 4-21 ensures that the multi-blade support structure always effectively supports in the machining; the guide hole of the rear hole is drilled by using the cutter 4, the drill tip of the cutter 5 is guided and directed, the cutter 5 is stably drilled, and the whole deep hole machining is completed.

[0045] The machining difficulty of the small-diameter intermittent deep hole disclosed in the scheme mainly lies in the machining of the rear hole; in order to solve the problem of cutter breakage, the front hole is used as a guide hole, the first multi-blade support shaft 3-2 and the second multi-blade support shaft 4-21 play a supporting and guiding role in the front hole in the machining, the overall machining rigidity and stability are enhanced, and the problems of cutter breakage, high cutter cost and low machining efficiency are effectively solved.

[0046] The first cutter disclosed in the embodiment adopts hard alloy, the diameter d1 of the first cutter head 1-1 is The drill tip angle a1 of the first cutter head 1-1 is 140°, and the drill depth l11 is 1.5D-2D; the composite hole mouth chamfer improves the efficiency, increases the diameter of the shank, and improves the rigidity.

[0047] The second cutter disclosed in the embodiment adopts hard alloy, the blade belt of the second cutter head 2-1 includes coaxially connected double-blade belts 2-12 and single-blade belts 2-11 from front to back, and the length l22 of the double-blade belt 2-12 is 6D-7D. The drill tip angle a2 of the second cutter 2 is 136°.

[0048] The third tool material disclosed in the embodiment is powder metallurgy high speed steel, which has better toughness than the cemented carbide tool and is not easy to break, and the cost is lower than that of the alloy tool. The third tool head 3-1 is a 2-tooth flat bottom tool head. The flat bottom tool head is only subjected to axial force in machining, avoiding the problem that the drill cannot be centered due to uneven radial force on the inclined surface. The design of 2 teeth can ensure sufficient chip space. The cutting edge length l33 of the third tool head 3-1 is greater than or equal to 2.5*L4, and the diameter d3 of the third tool head 3-1 is d2-d3=0.005~0.025; the rake angle a3 of the first multi-blade support shaft 3-2 is 90°, the blade width b3 is 1.5, and the helix angle a31 is 20~25°. The diameter of the tool body 3-10 of the third tool head 3-1 disclosed in the embodiment is single-sidedly necked by 0.05~0.1mm, avoiding jamming in the hole. The first multi-blade support shaft 3-2 is a 6-blade support shaft.

[0049] The drill tip angle a4 of the fourth tool head 4-1 disclosed in the embodiment is 140°, the blade length l43 of the fourth tool head 4-1 is 4D, the drill depth is 1.5D~2D, and the diameter d4 of the fourth tool head 4-1 is The diameter of the tool bar 4-2 is single-sidedly necked by 0.05~0.1, avoiding jamming in the hole. The fourth tool head 4-1 selects a cemented carbide tool bar 4-2, which selects a powder metallurgy high speed steel, and the two are sleeved and welded to increase the contact area and the welding strength. At the same time, the welded structure greatly reduces the tool cost compared with the overall cemented carbide drill, and the cemented carbide tool head also ensures sufficient tool life and machining efficiency. At the same time, the rake angle, the blade width, and the helix angle of the second multi-blade support shaft 4-21 are the same as those of the first multi-blade support shaft 3-2.

[0050] The diameter d5 of the fifth tool head 5-1 disclosed in the embodiment is The drill tip angle a5 of the fifth tool head 5-1 is 120°. The brazed cemented carbide head gun drill is used, which has low cost and good toughness compared with the overall cemented carbide drill, and is not easy to break. The tool with internal cooling can effectively remove chips, and the cemented carbide tool head has a guide strip structure, which can always drill stably after entering the guide hole.

[0051] The working process of the tool set of the embodiment is as follows:

[0052] (1) The first tool 1 is used to drill the guide hole and chamfer the hole mouth of the front section hole, and the drilling depth is (1.5~2)*D;

[0053] (2) The second tool 2 is used to drill the through front section hole, and the drilling depth is L1+(4~6)mm;

[0054] (3) The third tool 3 is used to chamfer the inclined surface part of the rear section hole to a plane, and the machining depth is L1+L3+L4;

[0055] (4) using the fourth cutter 4 to drill the pilot hole of the rear section hole, the machining depth is L1+L3+L4+1.5D;

[0056] (5) using the fifth cutter 5 to drill the rear section hole to the required depth in the drawing, the machining depth is L1+L3+L2, and the processing of the small-diameter intermittent deep hole is completed. Figure 1

[0057] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept range of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection range of the present disclosure.

[0058] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combination manners. Furthermore, various different embodiments disclosed by the present solution can also be combined in any manner, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as the content invented by the present disclosure.​

Claims

1. A small hole interrupted deep hole machining tool set, characterized by, The application relates to a cutting tool set, which comprises: a first cutter (1) which is a first pilot drill and comprises a first cutter head (1-1); a second cutter (2) which comprises a second cutter head (2-1), the flute length l21 of the second cutter head (2-1) is greater than the hole length L1 of a front section hole, the diameter d2 of the second cutter head (2-1) is less than the diameter d1 of the first cutter head (1-1), and the drill tip angle alpha2 of the second cutter head (2-1) is less than the drill tip angle alpha1 of the first cutter head (1-1); a third cutter (3) which comprises a third cutter head (3-1) and a first multi-blade support shaft (3-2) coaxially arranged from front to back, the third cutter head (3-1) and the first multi-blade support shaft (3-2) have the same diameter, l31>L3 and (L1+L3+L4)-(l31+l32) are less than (25%-30%)*L1 are met; wherein l31 is the length of the third cutter head (3-1), L3 is the distance between the two adjacent ends of the front section hole and the rear section hole, L4 is the hole length of the rear section hole counterbore hole mouth bevel, and l32 represents the length of the first multi-blade support shaft (3-2); a fourth cutter (4) which is a second pilot drill and comprises a fourth cutter head (4-1), a cutter rod (4-2) and a second multi-blade support shaft (4-21) coaxially arranged from front to back, the fourth cutter head (4-1), the cutter rod (4-2) and the second multi-blade support shaft (4-21) have the same diameter, l41>L3 and (L1+L3+L4+1.5D)-(l41+l42) are less than (25%-30%)*L1 are met; wherein l41 represents the length of the fourth cutter head (4-1) and the cutter rod (4-2) after being connected, and l42 represents the length of the second multi-blade support shaft (4-21); a fifth cutter (5) which comprises a fifth cutter head (5-1), the fifth cutter head (5-1) is provided with a chip flute (5-10) from the front end to the back, and the length l51 of the chip flute (5-10) is greater than L1+L3+L2.

2. The small-diameter interrupted deep hole machining tool set according to claim 1, wherein The first tool bit (1-1) has a diameter d1 of The first tool bit (1-1) has a drill tip angle α1 of 140° and a drill depth l11 of 1.5D-2D. Wherein D is the diameter of a hole to be machined.

3. The small diameter interrupted deep hole machining tool set of claim 1, wherein, The blade band of the second cutter head (2-1) comprises a double-blade band (2-12) and a single-blade band (2-11) coaxially arranged from front to back, and the length l22 of the double-blade band (2-12) is 6D-7D.

4. The small diameter interrupted deep hole machining tool set according to claim 3, wherein, The drill bit diameter d2 of the second tool (2) is in the range of The drill tip angle a2 of the second tool (2) is in the range of 136°.

5. The small diameter interrupted deep hole machining tool set of claim 1 wherein, The third tool bit (3-1) is a 2-tooth flat-bottom tool bit, the cutting edge length l33 of the third tool bit (3-1) is greater than or equal to 2.5*L4, and the diameter d3 of the third tool bit (3-1) is d2-d3=0.005~0.025; The rake angle alpha3 of the first multi-blade support shaft (3-2) is 90 degrees, the blade band width beta3 is 1.5, and the helix angle alpha31 is 20-25 degrees.

6. A small diameter interrupted deep hole machining tool set according to claim 5, wherein The diameter of the cutter body (3-10) of the third cutter head (3-1) is single-sidedly necked by 0.05-0.1 mm.

7. A small diameter interrupted deep hole machining tool set according to claim 6, wherein The first multi-blade support shaft (3-2) is a 6-blade support shaft.

8. The small diameter interrupted deep hole machining tool set of claim 1 wherein, The drill tip angle a4 of the fourth tool bit (4-1) is 140°, the blade length l43 of the fourth tool bit (4-1) is 4D, the drill depth is 1.5D-2D, and the diameter d4 of the fourth tool bit (4-1) is 9. A small diameter interrupted deep hole machining tool set according to claim 8, wherein The diameter of the cutter rod (4-2) is single-sidedly necked by 0.05-0.1 mm.

10. The small diameter interrupted deep hole machining tool set of claim 1 wherein, The fifth tool bit (5-1) has a diameter d5 The fifth tool bit (5-1) has a drill tip angle a5 of 120°.

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