Turning tool special for ball nut threads

Abstract

The invention discloses a special turning tool for ball nut threads, which is characterized in that the special turning tool comprises a tool main body (1), the tool main body (1) is in an equilateral triangle sheet shape and comprises an upper end face (2), a lower end face (3) and three side faces (4), tool bits (5) are arranged at the three vertexes of the tool main body (1), the thickness of the tool main body (1) is 3-6mm, the side length of the tool main body (1) is 15-25mm, and the thickness of the tool main body (1) is 3-6mm. The front angle of the tool bit (5) is a positive front angle gamma 0, the value range of gamma 0 is 6-10 degrees, a first rear angle alpha 0 and a second rear angle alpha '0 are arranged on the tool bit (5), the value range of the first rear angle alpha 0 is 5-8 degrees, the value range of the second rear angle alpha' 0 is 15-20 degrees, and a mounting hole (6) is formed in the centroid of the tool body (1).

Description

Technical Field

[0001] The invention relates to the field of machining, in particular to a special turning tool for ball nut threads. Background Art

[0002] The ball nut is the core part of the ball screw pair. During the working process, the rolling body of the ball nut keeps rolling in the closed raceway formed by the ball nut, the screw and the return gear. The mainstream processing process of the thread raceway is: turning the thread raceway (reservation) - quenching and other heat treatment - grinding the thread raceway finished product.

[0003] This process takes a long time to process and has relatively low efficiency. If metal cutting is used to process the thread raceway, the above problems can be effectively solved. However, the internal space of the ball nut is limited. In order to minimize the amount of thread grinding, CNC program interpolation turning is now mostly used to complete the rough machining of the knife, but it is difficult to ensure the machining accuracy of the thread tooth shape after processing.

[0004] Therefore, a method or device capable of solving the above problems is now needed. Summary of the invention

[0005] The present invention aims to solve the above-mentioned deficiencies in the prior art and proposes a special turning tool for ball nut threads which has a simple structure, ingenious design, reasonable layout, high adaptability, good machining accuracy and can effectively improve machining efficiency.

[0006] The technical solution of the present invention is: a special turning tool for ball nut thread, characterized in that: the special turning tool comprises a tool body 1, the tool body 1 is in the shape of an equilateral triangle, it includes an upper end face 2, a lower end face 3 and three side faces 4, a tool head 5 is arranged at the three vertices of the tool body 1, the thickness of the tool body 1 is 3-6mm, and the side length is 15-25mm, The rake angle of the cutter head 5 is a positive rake angle γ0, and the value range of γ0 is 6°-10°. The cutter head 5 is provided with a first back angle α0 and a second back angle α'0, wherein the first back angle α0 is in the range of 5°-8°, and the second back angle α'0 is in the range of 15°-20°. The tool body 1 has a mounting hole 6 at its centroid. The projection of the cutter head 5 in the horizontal direction is an axisymmetric figure, which is composed of two symmetrically distributed curves L. The curve L is composed of a straight line segment L1, a first transition curve L2, a second transition curve L3 and a third curve L4 connected in sequence. The third curve L4 of the curve L follows the Gothic channel design of the screw.

[0007] The main body of the cutter head 5 follows the design of a double-arc Gothic shape with equal radius and eccentricity, and the radius of the above arc is R. Within the double-arc Gothic shape of the main body of the cutter head 5, the circle inscribed in the above two arcs is circle A, and the diameter of circle A is d. The size of d is equal to the rolling element diameter of the ball screw pair, R=0.55d. The forming turning contact angle of the cutter head 5 is θ, and the value range of θ is 45°±1°.

[0008] Compared with the prior art, the present invention has the following advantages: The ball nut thread turning tool of this structural form has a simple structure, ingenious design and reasonable layout. Aiming at the problems existing in the internal thread processing process of the traditional ball nut, a special equilateral triangle structure tool is designed. A tool head is respectively arranged at the three vertices of the equilateral triangle. The projection curve of the tool head on the horizontal plane follows the Gothic design. At the same time, the angles of the positive rake angle, the first clearance angle and the second clearance angle are specially designed. The cutting edge body of the tool head adopts a double arc structure design, which can meet the channel requirements of the processed nut while having high tool rigidity, small cutting resistance, low cutting vibration and good cutting surface quality.

[0009] The main structure of the tool is an equilateral triangle, and the Figure 7 , Figure 8 The connection method can realize thread turning in a narrow space. It can realize front installation and front cutting. Compared with the traditional cutting process in which there is a certain cutting angle between the tool and the XY plane of the lathe, this front cutting method can optimize the force condition of the tool and extend its service life; it can improve the cutting quality of the machined surface, reduce the cutting profit borne by the workpiece, and reduce the deformation that may be caused in the subsequent heat treatment process; and three cutter heads are integrated on one tool, which can reduce the overall cost of the tool.

[0010] Moreover, the manufacturing process of this turning tool is simple and the manufacturing cost is low, so it can be said that it has multiple advantages and is particularly suitable for promotion and application in this field, and its market prospect is very broad. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the three-dimensional structure of an embodiment of the present invention (direction one).

[0012] Figure 2 It is a schematic diagram of the three-dimensional structure of an embodiment of the present invention (direction two).

[0013] Figure 3 It is a front view of an embodiment of the present invention.

[0014] Figure 4 2 is a top view of an embodiment of the present invention.

[0015] Figure 5 yes Figure 4 A partial enlarged view of the .

[0016] Figure 6 It is a partial enlarged view of the cutter head part in the embodiment of the present invention.

[0017] Figure 7 It is a schematic diagram of the connection state between the special turning tool and the turning tool rod according to an embodiment of the present invention.

[0018] Figure 8 Schematic diagram of the working state of an embodiment of the present invention.

[0019] Tool body 1, upper end face 2, lower end face 3, side face 4, tool head 5, mounting hole 6. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention will be described below with reference to the accompanying drawings. Figures 1 to 8 As shown: A special turning tool for ball nut thread, which includes a tool body 1, the tool body 1 is in the shape of an equilateral triangle, and includes an upper end face 2, a lower end face 3 and three side faces 4. A tool head 5 is arranged at the three vertices of the tool body 1. The thickness of the tool body 1 is 3-6 mm, and the side length is 15-25 mm. The rake angle of the cutter head 5 is a positive rake angle γ0, and the value range of γ0 is 6°-10°. The cutter head 5 is provided with a first back angle α0 and a second back angle α'0, wherein the first back angle α0 is in the range of 5°-8°, and the second back angle α'0 is in the range of 15°-20°. The tool body 1 has a mounting hole 6 at its centroid. The projection of the cutter head 5 in the horizontal direction is an axisymmetric figure, which is composed of two symmetrically distributed curves L. The curve L is composed of a straight line segment L1, a first transition curve L2, a second transition curve L3 and a third curve L4 connected in sequence. The third curve L4 of the curve L follows the Gothic channel design of the screw.

[0021] The main body of the cutter head 5 follows the design of a double-arc Gothic shape with equal radius and eccentricity, and the radius of the above arc is R. Within the double-arc Gothic shape of the main body of the cutter head 5, the circle inscribed in the above two arcs is circle A, and the diameter of circle A is d. The size of d is equal to the rolling element diameter of the ball screw pair, R=0.55d. The forming turning contact angle of the cutter head 5 is θ, and the value range of θ is 45°±1°.

[0022] The working process of the ball nut thread turning tool of the embodiment of the present invention is as follows: first, the tool body 1 is installed on the turning tool rod 7, that is, the connection between the tool body 1 and the turning tool rod 7 is realized by using the bolts inserted into the installation hole 6. When the tool body 1 after installation is used for turning processing, since it is in the shape of an equilateral triangle as a whole and the structure of each cutter head 5 is the same, after a cutter head 5 is worn, the tool body 1 can be removed from the turning tool rod 7, rotated 120 degrees and reinstalled, and a new cutter head 5 can be used for processing; this structure can effectively save the use cost of the turning tool; in the process of installing the tool body 1 on the turning tool rod 7, any two of the three side faces 4 and the lower end face 3 of the tool body 1 can be used as reference surfaces for positioning; The value range of the positive rake angle γ0 on each cutter head 5 is 6°-10°. This angle can obtain a sharper cutting edge, effectively reduce the chip force and the heat generated during the cutting process, make the cutting process more labor-saving and light, and also improve the quality of the machined surface; The value range of the first back angle α0 on the cutter head 5 is 5°-8°. Such an angle can improve the quality of the machined surface, reduce vibration during the machining process, and effectively extend the life of the cutter; The value range of the second back angle α'0 on the cutter head 5 is 15°-20°. Such an angle can avoid interference between the turning insert and the thread raceway on the nut being turned, thereby ensuring that the turning operation can proceed normally.

[0023] The forming turning contact angle θ of the cutter head 5 has a value range of 45°±1°. At the same time, the main part of the cutter head 5 follows the design of an eccentric double-arc Gothic shape with equal radius. The radius of the above two arcs is R, where R=0.55d, where d is the diameter of circle A, and circle A is a circle that is inscribed in both arcs of the Gothic double-arc shape in the main body of the cutter head 5. The specific limitations of the above θ and R can more accurately control the machining allowance of the turning raceway to minimize the forming grinding amount after heat treatment and quenching.

Claims

1. A special turning tool for ball nut thread, characterized in that: The special turning tool comprises a tool body (1), the tool body (1) is in the shape of an equilateral triangle, and comprises an upper end face (2), a lower end face (3) and three side faces (4). Tool heads (5) are arranged at the three vertices of the tool body (1). The tool body (1) has a thickness of 3-6 mm and a side length of 15-25 mm. The rake angle of the cutter head (5) is a positive rake angle γ0, and the value range of γ0 is 6°-10°. The cutter head (5) is provided with a first back angle α0 and a second back angle α'0, wherein the first back angle α0 has a value range of 5°-8°, and the second back angle α'0 has a value range of 15°-20°. A mounting hole (6) is provided at the centroid of the tool body (1). The projection of the cutter head (5) in the horizontal direction is an axisymmetric figure, which is composed of two symmetrically distributed curves L, and the curve L is composed of a straight line segment L1, a first transition curve L2, a second transition curve L3 and a third curve L4 connected in sequence, and the third curve L4 of the curve L follows the Gothic channel design of the screw.

2. The ball nut thread turning tool according to claim 1, characterized in that: The main body of the cutter head (5) is designed in a double-arc Gothic shape with equal radius and eccentricity, and the radius of the arc is R. The circle inscribed in the double-arc Gothic shape of the main body of the cutter head (5) and the two arcs is circle A. The diameter of circle A is d, and the size of d is equal to the rolling element diameter of the ball screw pair, R=0.55d. The forming turning contact angle of the cutter head (5) is θ, and the value range of θ is 45°±1°.

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