Boring tool for machining high-precision holes
By setting multiple support components on the tool holder, the problem of insufficient support range caused by the fixed position of the guide bar is solved, achieving stable support throughout the hole depth and improving machining accuracy and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- PGI AUTO COMPONENTS KUNSHAN CO LTD
- Filing Date
- 2025-08-08
- Publication Date
- 2026-07-21
AI Technical Summary
The existing guide bar is only fixed at a certain point on the tool holder, resulting in a limited support range that cannot cover the entire hole depth. Especially in deep holes or long overhang conditions, the area of the tool holder far from the guide bar lacks support, affecting machining accuracy and stability.
Multiple support components are set on the tool holder, including a front support unit, a middle support unit, and a tail support unit, all of which are in contact with the hole wall to form multi-point support, covering the entire hole depth range and providing stable radial support.
It achieves stable support in shallow and deep hole sections, reduces tool runout, improves machining accuracy and production efficiency, reduces defect rate, and is suitable for long overhang and high cutting load conditions.
Smart Images
Figure CN224526020U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of boring tool technology, and in particular to a boring tool for machining high-precision holes. Background Technology
[0002] With the development of the times, parts processing is also moving towards precision, especially for automotive engine parts, many of which have high precision requirements. In the process of machining deep holes, in order to improve the stability of deep hole machining and the accuracy of deep hole boring, it is usually necessary to set a guide mechanism on the tool holder to provide guide support.
[0003] For example, patent CN202221494766.6 discloses a high-precision guiding mechanism for deep boring tools. This patent uses a guide sleeve coaxially sleeved with a cylindrical ring in the middle of an extension rod. Guide bars are arranged in an array on the outer circumference of the guide sleeve. When boring is required for deep holes, the guide sleeve and guide bars can be used to position the inner hole of the workpiece when the tool holder is connected to the boring tool through the extension rod. This can reduce the vibration caused by the excessive length of the tool holder, thereby reducing the possible defective products and the wear of the tool itself.
[0004] However, the applicant discovered that in the comparative patent, the guide bar is only fixed at a certain position on the extension rod, so that the guide bar can only contact the hole wall at that position. This results in a limited support range, which cannot cover the entire hole depth. Furthermore, for deep holes (such as depth > 5 times the hole diameter) or long overhang conditions, the area of the tool bar far from the guide bar will still deflect due to lack of support, thereby affecting the machining accuracy, resulting in a large number of defective parts and reducing economic benefits. Utility Model Content
[0005] In view of this, the purpose of this utility model is to propose a boring tool for machining high-precision holes, so as to solve the problem that the existing guide bar is usually fixed at a certain position of the tool bar, so that the guide bar can only contact the hole wall at a certain axial position, resulting in a limited support range, which cannot cover the full hole depth. Furthermore, for deep holes (such as depth > 5 times the hole diameter) or long overhang conditions, the area of the tool bar far from the guide bar will still deflect due to lack of support, resulting in poor machining accuracy.
[0006] To achieve the above objectives, this utility model provides a boring tool for machining high-precision holes, including a cutting tool and a tool holder, and a tool shank connected between the cutting tool and the tool holder. The tool shank is characterized by having multiple support components, including a front support unit, a middle support unit, and a tail support unit. The front support unit, the middle support unit, and the tail support unit all contact the inner wall of the machined hole to form a stable radial support point.
[0007] The multi-point support of the multi-segment support assembly can cover the entire depth range of the machined hole, so as to provide stable support in both shallow and deep hole sections.
[0008] Preferably, the front support unit includes a front support ring, the middle support unit includes a middle support ring, and the tail support unit includes a tail support ring. The front support ring, the middle support ring, and the tail support ring are all fixedly sleeved on the tool holder, and the middle support ring is located between the front support ring and the tail support ring.
[0009] Preferably, the front support ring, the middle support ring, and the tail support ring are each provided with multiple placement slots, and guide strips can be detachably installed in the placement slots.
[0010] Preferably, the guide bar is composed of an arc-shaped block and a wedge-shaped block, and the arc-shaped block is installed in the placement groove by screws.
[0011] Preferably, the diameter of the guide bar is slightly smaller than the inner diameter of the machined hole.
[0012] Preferably, the wedge-shaped block has marking lines on its side for observing wear.
[0013] The beneficial effects of this utility model are as follows: by setting up the front support unit, the middle support unit and the tail support unit, the front support unit, the middle support unit and the tail support unit are all in contact with the inner wall of the machined hole during the cutting process of the tool, forming a stable radial support point.
[0014] The multi-point support formed by the three support units can cover the entire depth range of the hole, providing stable support in different sections such as shallow and deep holes, avoiding the problem of insufficient support range of a single guide bar. In addition, multiple support points evenly distribute the force on the tool body, further reducing the risk of local deformation, making it especially suitable for working conditions with long overhang and high cutting load.
[0015] In summary, this technology enables high-precision machining of deep holes and large tool overhangs, reducing tool runout during cutting, lowering the defect rate of parts, and improving production efficiency. This increases company profits, facilitates management, and reduces the likelihood of errors made by employees during production. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the structure of this utility model;
[0018] Figure 2 This is a schematic diagram of the front support ring and guide bar of this utility model;
[0019] Figure 3 This utility model Figure 2 A schematic diagram of the explosive structure.
[0020] In the diagram: 1. Cutting tool; 2. Tool holder; 3. Tool shank; 4. Front support unit; 41. Front support ring; 5. Middle support unit; 51. Middle support ring; 6. Tail support unit; 61. Tail support ring; 7. Guide bar; 71. Arc block; 72. Wedge block; 8. Screw; 9. Marking line. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0023] like Figure 1 , Figure 2 , Figure 3 As shown, a boring bar for machining high-precision holes includes a cutting tool 1 and a tool holder 2. The cutting tool 1 has an insert, and a tool shank 3 is connected between the cutting tool 1 and the tool holder 2. The tool shank 3 is provided with multiple support components, including a front support unit 4, a middle support unit 5, and a tail support unit 6. The front support unit 4, the middle support unit 5, and the tail support unit 6 are all in contact with the hole wall to form a stable radial support point.
[0024] The multi-point support (front support, middle support and tail support) of the multi-segment support assembly can cover the entire depth range of the hole, so as to provide stable support in both shallow and deep hole sections.
[0025] Front support: Located near the cutting area of the blade, it directly counteracts the radial force during cutting, avoids the runout of the cutting edge during initial entry, and ensures machining accuracy;
[0026] Mid-section support: Located in the middle of tool holder 3, it is designed to distribute the bending stress of tool holder 3 and prevent machining dimensional deviations caused by tool body deflection in the case of long overhang during deep hole machining.
[0027] Tail section support: Located near tool holder 2, it enhances the overall rigidity of the tool and reduces vibration transmission at the connection between the machine tool spindle and the tool holder, making it particularly suitable for the stability of the tool when it penetrates deep into the hole during the machining of multi-diameter hole systems.
[0028] The three guide bars 7 can correspond to the front, middle and rear areas of the hole respectively, ensuring support throughout the entire depth of the hole and avoiding the problem of "insufficient support range" of a single guide bar 7 in deep hole machining.
[0029] Multiple guide bars 7 form "multi-point support", which can distribute the force on the tool more evenly and further reduce the runout of the cutting edge (in the patent, traditional boring tools are prone to runout because they do not have guide bar support, while multiple guide bars can enhance this improvement effect).
[0030] In a preferred embodiment of the present invention, the front support unit 4 includes a front support ring 41, the middle support unit 5 includes a middle support ring 51, and the tail support unit 6 includes a tail support ring 61. The front support ring 41, the middle support ring 51, and the tail support ring 61 are all fixedly sleeved on the tool holder 3, and the middle support ring 51 is located between the front support ring 41 and the tail support ring 61.
[0031] In another preferred embodiment of the present invention, the front support ring 41, the middle support ring 51 and the tail support ring 61 are each provided with a plurality of placement grooves, and guide strips 7 are detachably installed in the placement grooves.
[0032] The positional distribution of guide strip 7 at various locations (i.e., the distribution of the support rings in the front, middle, and rear sections) is as follows:
[0033] Let the effective length of the tool holder be L (unit: mm): it refers to the axial distance from the connection between the tool holder 2 and the machine tool spindle to the cutting edge of the tool (i.e., the tool overhang).
[0034] Let the maximum depth of the machined hole be H (unit: mm): H ≤ L (the tool must completely cover the hole depth);
[0035] Let the minimum diameter of the machined hole be d (unit: mm): use the minimum hole diameter as the reference for guide bar size adaptation;
[0036] The blade edge position is the origin (0 point): In the axial direction, the blade edge is the starting point, and the direction towards the tool holder is the positive direction (i.e. the direction of the tool holder extension);
[0037] 1. The front guide bar (i.e., the guide bar 7 located on the front support ring 41), near the cutting tool, is used for support in the cutting zone;
[0038] Position formula: A=k1×d
[0039] Meaning: The axial distance A between the front guide bar and the cutting edge of the blade needs to be close to the cutting zone to counteract the instantaneous cutting force;
[0040] Coefficient k1: Take 0.3-0.5 (empirical value) to ensure that the guide bar 7 does not interfere with the cutting tool (avoiding the accumulation of cutting chips) and can respond quickly to changes in cutting force;
[0041] Example: If the minimum aperture d = 80mm, then A = 0.3 × 80 = 24mm (that is, the guide bar 7 located on the front support ring 41 is located 24mm from the blade edge towards the handle);
[0042] 2. The middle section guide bar (i.e., the guide bar 7 located on the middle section support ring 51) is located in the middle section of the tool holder 3 and is used for deep hole support;
[0043] Position formula:
[0044] Meaning: The rear guide bar is located at the midpoint of the machined hole depth, providing support for the middle section of deep holes (H>5d) and dispersing the deflection of the tool holder;
[0045] Constraints: B>A (a “front-middle” stepped support needs to be formed behind the front guide bar (the guide bar located on the front support ring 41), and B≤0.7L (avoid excessive proximity to the tool holder, which could lead to insufficient support in the middle section);
[0046] Example: If the hole depth H = 500mm, then B = 250mm (that is, located 250mm from the cutting edge of the blade towards the handle).
[0047] 3. Tail section guide bar (i.e., guide bar 7 located on tail section support ring 61), close to tool holder 2, provides overall rigid support;
[0048] Position formula: C=L-k2×d
[0049] Meaning: The axial distance between the tail section guide bar and the tool holder is k2×d, and it is close to the tool holder to enhance the stability of the connection between the tool holder and the spindle;
[0050] The coefficient k2 is set to 0.3-0.5 (to be symmetrical with the front guide bar and to balance the overall support);
[0051] Constraint: C>B (must be behind the back-end guide bar, forming a full "front-middle-back" range coverage);
[0052] Example: If the effective length of the tool holder L = 600mm and d = 80mm, then C = 600 - 0.3 × 80 = 576mm (that is, located 576mm from the cutting edge of the blade towards the tool holder).
[0053] The guide bar 7 is composed of an arc-shaped block 71 and a wedge-shaped block 72. The end of the guide bar 7 is a wedge-shaped block 72, which can reduce the contact area with the hole wall and reduce friction. The arc-shaped block 71 is installed in the placement groove by screws 8.
[0054] The diameter of guide bar 7 is slightly smaller than the inner diameter of the machined hole.
[0055] The core function of the guide bar is to provide support through contact with the hole wall; therefore, its diameter must be matched to the hole diameter at the corresponding machining location. The formula is:
[0056] The guide bar diameter = the minimum diameter of the corresponding hole section - Δ, where Δ is the gap between the guide bar and the hole wall (usually 0.01-0.03mm), ensuring that the guide bar 7 can fit tightly against the hole wall to provide support, without causing friction jamming or scratching the hole wall due to interference fit.
[0057] The wedge block 72 has marking lines 9 on its side for observing wear. By setting the marking lines 9, the wear of the guide strips 7 on the same support ring can be observed, avoiding different wear levels of the guide strips 7 on the same support ring, which would reduce the support effect.
[0058] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention is limited to these examples; within the framework of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in the details for the sake of brevity.
[0059] The embodiments of this utility model are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A boring bar for machining high-precision holes, comprising a cutting tool (1) and a tool holder (2), and a tool shank (3) connected between the cutting tool (1) and the tool holder (2), characterized in that, The tool holder (3) is provided with multiple support components, including a front support unit (4), a middle support unit (5) and a tail support unit (6). The front support unit (4), the middle support unit (5) and the tail support unit (6) are all in contact with the hole wall to form a stable radial support point. The multi-point support of the multi-segment support assembly can cover the entire depth range of the hole, so as to provide stable support in both shallow and deep hole sections.
2. The boring tool for machining high-precision holes according to claim 1, characterized in that, The front support unit (4) includes a front support ring (41), the middle support unit (5) includes a middle support ring (51), and the tail support unit (6) includes a tail support ring (61). The front support ring (41), the middle support ring (51), and the tail support ring (61) are all fixedly sleeved on the tool holder (3), and the middle support ring (51) is located between the front support ring (41) and the tail support ring (61).
3. A boring tool for machining high-precision holes according to claim 2, characterized in that, The front support ring (41), the middle support ring (51) and the tail support ring (61) are each provided with multiple placement slots, and guide strips (7) can be detachably installed in the placement slots.
4. A boring tool for machining high-precision holes according to claim 3, characterized in that, The guide bar (7) is composed of an arc-shaped block (71) and a wedge-shaped block (72), and the arc-shaped block (71) is installed in the placement groove by screws (8).
5. A boring tool for machining high-precision holes according to claim 4, characterized in that, The diameter of the guide bar (7) is slightly smaller than the inner diameter of the machining hole.
6. A boring tool for machining high-precision holes according to claim 4, characterized in that, The wedge-shaped block (72) has marking lines (9) on its side for observing wear.