Nut screw tap with rear guide tooth breakage prevention function

Abstract

A nut screw tap with a rear guide tooth breakage prevention function comprises a screw tap body (5) and a handle part (6) and is characterized in that a cutting tooth part (1), a calibration tooth part (2) and a rear guide part (4) are sequentially arranged on the screw tap body (5), and three or more U-shaped chip groove parts (3) extend from the top end of the cutting tooth part (1) to the tail end of the rear guide part (4) and are distributed around the screw tap body (5) in an equal row mode; the surface of the rear guide part (4) is smooth, the front and rear diameters are consistent, and the excircle diameter is smaller than the diameter of the tail end of the calibration tooth part (2) and the aperture of a workpiece to be machined; a first transition angle alpha is formed between the front end of the rear guide part (4) and the tail end of the calibration tooth part (2), a second transition angle beta is formed between the tail end of the rear guide part (4) and the screw tap body (5), and smooth transition is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of taps, in particular to a nut tap with a rear guide to prevent tooth collapse. Background Art

[0002] A nut tap is a tool used to process the internal threads of fasteners. It has the advantages of long service life and convenient tapping and is widely used in the field of internal thread processing of fasteners, especially in the processing of large quantities of fasteners such as hexagonal nuts, flange nuts, slotted nuts, etc., whose internal threads are generally formed by one-time tapping.

[0003] like Figure 1 As shown, the traditional nut tap is mainly composed of a tap body, a cutting tooth portion, a calibration tooth portion, a chip groove portion, and a shank portion.

[0004] When a traditional nut tap processes threads, the workpiece is first cut by the cutting teeth, then relieved, extruded, polished and calibrated by the calibration teeth, and finally guided to the tap body through the thread of the calibration teeth.

[0005] The calibration teeth of traditional nut taps have a large difference in diameter from the outer diameter of the tap body! Therefore, when the workpiece leaves the tail of the calibration teeth, it shakes violently due to the reduction in the number of teeth in contact between the workpiece and the tap. This causes the processed nut to collide with the teeth of the calibration teeth, resulting in "tooth collapse". If this continues, it will spread to the cutting teeth.

[0006] Therefore, the traditional nut tap will affect its service life and reduce the accuracy and pass rate of the workpiece. Utility Model Content

[0007] The purpose of the utility model is to address the above-mentioned problems in the existing technology and propose a nut tap with a rear guide to prevent tooth breakage, aiming to solve the problems in the existing technology, reduce tooth breakage and improve the product quality of the processed parts.

[0008] In order to solve the above problems, the utility model adopts the following technical solutions:

[0009] A nut tap with a rear guide to prevent tooth chipping, comprising a tap body 5 and a shank 6, characterized in that: a cutting tooth portion 1, a calibration tooth portion 2 and a rear guide portion 4 are sequentially arranged on the tap body 5, three or more U-shaped chip groove portions 3 extend from the top of the cutting tooth portion 1 to the tail end of the rear guide portion 4, and are evenly distributed around the tap body 5; the rear guide portion 4 has a smooth surface, the front and rear diameters are consistent, and the outer diameter is smaller than the tail end diameter of the calibration tooth portion 2 and the aperture of the workpiece to be processed; the rear end of the rear guide portion 4 forms a first transition angle α with the tap body 5, and its tail end forms a second transition angle β with the tail end of the calibration tooth portion 2, both of which are smooth transitions.

[0010] Furthermore, the total length of the rear guide portion 4 is smaller than the diameter of the thread to be processed or is half of the diameter of the thread to be processed.

[0011] Furthermore, the first transition angle α is set to 30°, and the second transition angle β is set between 30° and 45°.

[0012] Furthermore, the outer diameter of the rear guide portion 4 is larger than the outer diameter of the tap body 5 and is arranged in a step-type transition.

[0013] Furthermore, the rear guide portion 4 is a cylindrical segment with no back relief on the surface and does not participate in the cutting process.

[0014] Furthermore, the tap body 5 and the shank 6 have the same diameter, and the shank 6 is configured to be curved.

[0015] The beneficial effects of the utility model are:

[0016] When the workpiece is tapped and passes through the end of the calibration tooth portion, the workpiece is first guided by the calibration tooth portion to the rear guide portion, and the rear guide portion completes the transition of the workpiece from the calibration tooth portion to the rear guide portion, and then the rear guide portion directly guides the workpiece to the tap body.

[0017] 1. Reduce the vibration of the workpiece relative to the calibration tooth due to the gap between the calibration tooth and the tap body, thereby reducing the risk of the calibration tooth tail being "broken";

[0018] 2. Reduce the drop of the workpiece into the tap body to ensure the integrity, smoothness and precision of the workpiece thread. The structure is simple to manufacture and has good economy and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a traditional nut tap;

[0020] Figure 2 This is a schematic diagram of the structure of a nut tap with a rear guide to prevent tooth breakage according to the utility model;

[0021] In the figure: 1 cutting tooth portion, 2 calibration tooth portion, 3 chip groove portion, 4 rear guide portion, 5 tap body, 6 shank portion, first transition section angle α, second transition section angle β. DETAILED DESCRIPTION

[0022] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0023] Figure 1The structure of a conventional nut tap is shown in FIG. 4 , which comprises a tap body 4 and a handle 5. The tap body 5 is provided with a cutting tooth portion 1 and a calibration tooth portion 2 in sequence. Three or more U-shaped chip grooves 3 extend from the top of the cutting tooth portion 1 to the rear end of the calibration tooth portion 2 and are evenly distributed around the tap body 4. The rear end of the calibration tooth portion 2 forms a transition angle α with the tap body 4. 1 .

[0024] Figure 2 The utility model is shown as a nut tap with a rear guide to prevent tooth breakage, comprising a tap body 5 and a shank 6, characterized in that: the tap body 5 is provided with a cutting tooth portion 1, a calibration tooth portion 2 and a rear guide portion 4 in sequence, three or more U-shaped chip grooves 3 extend from the top of the cutting tooth portion 1 to the tail end of the rear guide portion 4, and are evenly distributed around the tap body 5; the rear guide portion 4 has a smooth surface, the front and rear diameters are consistent, and the outer diameter is smaller than the tail end diameter of the calibration tooth portion 2 and the aperture of the workpiece to be processed; the rear end of the rear guide portion 4 forms a first transition angle α with the tap body 5, and its tail end forms a second transition angle β with the tail end of the calibration tooth portion 2, both of which are smooth transitions.

[0025] When a nut tap with a rear guide to prevent tooth breakage is used to process a workpiece, the workpiece passes through the calibration tooth portion 2 and then is introduced into the guide portion 4 and enters the tap body 5 .

[0026] The shaking of the workpiece caused by the excessive drop when it is directly introduced from the calibration tooth portion 2 into the tap body 5 can be reduced, and the risk of "tooth breakage" of the tail teeth of the calibration tooth portion 2 can be reduced. At the same time, the integrity and smoothness, accuracy and qualified rate of the workpiece thread are guaranteed, and the damage of the workpiece and the tap is reduced.

Claims

1. A nut tap with a back guide to prevent tooth breakage, comprising a tap body (5) and a handle (6), characterized in that: The tap body (5) is provided with a cutting tooth portion (1), a calibration tooth portion (2) and a rear guide portion (4) in sequence; three or more U-shaped chip removal grooves (3) extend from the top of the cutting tooth portion (1) to the rear end of the rear guide portion (4) and are evenly distributed around the tap body (5); the rear guide portion (4) has a smooth surface, the front and rear diameters are consistent, and the outer diameter is smaller than the rear end diameter of the calibration tooth portion (2) and the aperture of the workpiece to be processed; the rear end of the rear guide portion (4) forms a first transition angle α with the tap body (5), and the rear end forms a second transition angle β with the rear end of the calibration tooth portion (2), both of which are smooth transitions.

2. The nut tap with rear guide to prevent tooth collapse according to claim 1, characterized in that: The total length of the rear guide portion (4) is smaller than the hole diameter of the thread to be processed or is half of the hole diameter of the thread to be processed.

3. The nut tap with rear guide to prevent tooth collapse according to claim 1, characterized in that: The first transition angle α is set to 30°, and the second transition angle β is set between 30° and 45°.

4. The nut tap with rear guide to prevent tooth breakage according to claim 2, characterized in that: The outer diameter of the rear guide portion (4) is larger than the outer diameter of the tap body (5) and is arranged in a step-type transition.

5. The nut tap with rear guide to prevent tooth breakage according to claim 2, characterized in that: The rear guide portion (4) is in the shape of a cylindrical segment and has no back relief on the surface, and does not participate in the cutting process.

6. The nut tap with rear guide to prevent tooth collapse according to claim 1, characterized in that: The tap body (5) and the handle (6) have the same diameter, and the handle (6) is arranged in a curved shape.

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