Broach device for simultaneously machining multiple arc grooves in outer surface of workpiece

Abstract

A broach device for simultaneously machining a plurality of arc grooves in the outer surface of a workpiece comprises a tool apron which is of a disc-shaped structure, and a cylindrical mounting hole used for containing and positioning a tool is formed in the center of the tool apron; the broaching tools are evenly distributed in the circumferential direction of the tool apron, and each broaching tool comprises a tool body used for installation and positioning; the shape of the tooth part is composed of a section of arc and two oblique lines tangent to the arc, and the radius of the arc is smaller than that of the outer circle of the workpiece; and the plurality of screws are used for fixing the broaching tool in the positioning groove of the tool apron through the screw holes in the tool body.

Description

Technical field

[0001] The utility model relates to the technical field of mechanical processing, in particular to a broaching device for simultaneously processing a plurality of circular arc grooves on the outer surface of a workpiece. [Background Technology]

[0002] In the field of mechanical machining, it is often necessary to machine multiple, evenly spaced arc grooves on the outer circumference of a cylindrical workpiece. Existing techniques typically use a hob for this purpose, but this method can only machine one groove at a time, requiring multiple passes to complete the machining of all the grooves. For example, a workpiece requiring six evenly spaced arc grooves would require six passes to complete the machining.

[0003] This traditional processing method has the following technical problems:

[0004] 1. Low processing efficiency, requiring multiple clamping and cutting;

[0005] 2. There is indexing error, which affects the processing accuracy;

[0006] 3. Multiple clamping results in inconsistent positioning datums, affecting the uniform distribution of grooves;

[0007] 4. The processing cycle is long and the production cost is high. [Utility Model Content]

[0008] The purpose of the utility model is to overcome the above problems existing in the prior art and to provide a broaching device capable of simultaneously processing a plurality of circular arc grooves on the outer surface of a workpiece, so as to improve the processing efficiency and precision.

[0009] The technical problem to be solved by the utility model is how to realize simultaneous machining of multiple arc grooves on the outer surface of a workpiece and ensure machining accuracy.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is to provide a broaching device for simultaneously processing multiple arc grooves on the outer surface of a workpiece, comprising:

[0011] The tool holder is a disc-shaped structure with a cylindrical mounting hole in the center for placing and positioning the workpiece;

[0012] At least two broaches are evenly distributed around the circumference of the tool holder, each of the broaches comprising:

[0013] a cutter body, for mounting and positioning; and

[0014] The tooth portion is formed by an arc and two oblique lines tangent to the arc, wherein the radius of the arc is smaller than the outer radius of the workpiece; and

[0015] A plurality of screws are used to fix the broach in the positioning groove of the tool holder through the screw holes on the tool body.

[0016] Furthermore, the broach is made of high-speed tool steel with an overall hardness of not less than HRC 60. This material selection and hardness requirement ensure that the broach has good wear resistance and service life.

[0017] Furthermore, the tool holder is provided with a plurality of positioning grooves, and the depth of each positioning groove is 50%-70% of the thickness of the broach. This structural design can ensure the stability of the broach without affecting its strength.

[0018] The at least two broaches are preferably six in number, and are distributed at equal angles of 60 degrees in the circumference of the tool holder. This distribution method can ensure uniformity and balance in processing.

[0019] The screw holes on the cutter body are countersunk holes with a taper angle of 80-90 degrees. This design can provide a better fixing effect.

[0020] The radius of the tooth arc is 85%-95% of the outer radius of the workpiece. This size relationship can ensure that the machined groove has a suitable depth.

[0021] A plurality of straight grooves for positioning are provided on the inner wall of the cylindrical mounting hole of the tool holder, and these straight grooves can improve the positioning accuracy of the workpiece.

[0022] The angle between the side wall of the positioning groove and the radial direction of the tool holder is 3-5 degrees. This angle design can prevent the broach from loosening during use.

[0023] The surface of the teeth is coated with a friction-reducing coating, and the arc section of the teeth is provided with multiple evenly distributed chip-breaking grooves, each with a depth of 0.2-0.5 mm and a width of 0.5-1.0 mm. These designs can improve cutting conditions and enhance processing quality.

[0024] The toolholder is equipped with an annular coolant channel on its periphery, which is connected to a plurality of radially distributed nozzles, the outlets of which are directed towards the teeth of each broach. This cooling system design can effectively reduce the processing temperature and extend the tool life.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Able to process multiple arc grooves at the same time, greatly improving processing efficiency;

[0027] 2. The structure of evenly distributed multiple broaches eliminates indexing errors and improves machining accuracy;

[0028] 3. All processing can be completed in one clamping, ensuring the uniformity of processing benchmarks;

[0029] 4. Equipped with chip breaker and cooling system, it improves cutting conditions and processing quality;

[0030] 5. Reasonable structural design, easy installation and reliable use.

Brief Description of the Drawings

[0031] Figure 1 This is a schematic structural diagram of the broaching device of the present utility model;

[0032] Figure 2 This is a schematic diagram of the cross-sectional structure of the broaching device of the present utility model.

[0033] The components in the figure are marked as follows:

[0034] 1-Broach; 2-Workpiece; 3-Tool holder; 4-Screw; 5-Tooth (cutting part), 6-Tool body (installation and positioning part). [Specific implementation method]

[0035] The present invention will be described in further detail below with reference to the accompanying drawings.

[0036] Example 1

[0037] like Figure 1-2 As shown, the broaching device provided by the present invention includes a tool holder 3, six broaches 1 and a plurality of screws 4. The specific parameters are as follows:

[0038] 1. Tool holder parameters:

[0039] Material: 45# steel quenching treatment, hardness HRC38-42

[0040] Dimensions: diameter 300mm, thickness 50mm

[0041] Center mounting hole: diameter 52H7mm (suitable for processing workpieces with a diameter of 50f7mm)

[0042] Positioning straight groove: width 8mm, depth 5mm, axial length 40mm, a total of 6 evenly distributed positioning grooves: width 32h7mm, depth 12mm (60% of the broach thickness 20mm), length 160mm Annular coolant channel: inner diameter 100mm, rectangular cross section, width 12mm, depth mm

[0043] Nozzle: outlet diameter 2mm, 12 evenly distributed, 60° spray angle, working pressure 0.3MPa

[0044] 2.Broach parameters:

[0045] Material: M2 high speed tool steel, overall heat treatment hardness HRC64

[0046] Blade body 6 size: length 180mm, width 30mm, thickness 20mm

[0047] Total length of tooth 5: 80mm

[0048] Tooth arc: radius 45mm (90% of workpiece radius 25mm)

[0049] Tooth oblique line: tangent to the arc, inclination angle °

[0050] Screw hole: M10 countersunk hole, taper angle 85°, depth mm, 1 per broach

[0051] Anti-friction coating: TiAlN, PVD process, thickness 2.5μm, microhardness 3000HV0.025

[0052] Chip breaker groove: 0.3mm deep, 0.8mm wide, groove bottom arc R0.2mm, 8 evenly distributed, surface roughness Ra0.4μm

[0053] 3. Connectors:

[0054] Screw 4: M10×30, 12.9 grade high strength hexagon socket countersunk screw, 12 pieces

[0055] Positioning surface accuracy: the surface roughness of the broach positioning surface and the tool holder positioning groove is Ra0.8μm

[0056] 4. Processing parameters:

[0057] Workpiece material: 45# steel quenched and tempered (HB180-220)

[0058] Workpiece size: outer diameter 50f7mm, length 100mm

[0059] Arc groove requirements: depth 4mm, arc R45mm, six evenly spaced

[0060] Broaching speed: 4m / min

[0061] Coolant: 6% microemulsion, flow rate 20L / min

[0062] Single cutting amount: rough drawing 0.8mm, fine drawing 0.2mm

[0063] 5. Processing effect:

[0064] Processing time: 3 minutes per piece (including clamping and unloading time)

[0065] Dimensional accuracy: groove depth 4±0.02mm

[0066] Position accuracy: adjacent groove angle error ≤ 0.1°

[0067] Surface quality: roughness Ra1.6μm

[0068] Arc profile: 0.02mm

[0069] Batch life: After continuous processing of 3000 pieces, the main cutting edge wear VB≤0.2mm

[0070] This embodiment has been applied in a manufacturing enterprise, not only improving processing efficiency by 300%, but also achieving a product qualification rate of over 99.5%, achieving significant economic benefits. Compared with the traditional single-groove processing method, this embodiment shows obvious advantages in the following aspects:

[0071] Improved processing time: from 12 minutes / piece to 3 minutes / piece

[0072] Reduced labor costs: the number of operators was reduced from 2 to 1

[0073] Improved machining accuracy: Groove uniformity error increased from 0.3° to 0.1°

[0074] Surface quality improved: roughness increased from Ra3.2μm to Ra1.6μm

[0075] Reduced processing costs: Comprehensive processing costs reduced by 45%

[0076] The broach 1 comprises a tool body 6 and a tooth portion 5. The tool body 6 is made of high-speed tool steel with an overall hardness of HRC64 and is provided with a countersunk screw hole with a taper angle of 85 degrees. The shape of the tooth portion 5 consists of a circular arc and two oblique lines tangent to the circular arc. Taking the processing of a workpiece with an outer diameter of 50 mm as an example, the radius of the tooth arc is 45 mm (i.e., 90% of the outer radius of the workpiece). The surface of the tooth portion 5 is coated with a TiAlN anti-friction coating using a physical vapor deposition (PVD) process. The coating thickness is 2-3 μm and the microhardness reaches 3000 HV0.025. Eight chip breaker grooves are evenly arranged along the axial direction on the circular arc segment of the tooth portion. The chip breaker grooves are 0.3 mm deep and 0.8 mm wide. The arc transition radius of the groove bottom is 0.2 mm and the surface roughness Ra≤0.4 μm.

[0077] Screws 4, grade 12.9 high-strength screws, secure the broach 1 to the locating groove of the tool holder 3 through the screw holes. To ensure machining accuracy, all locating surfaces of the broach 1 and the locating grooves of the tool holder 3 are precision ground to a surface roughness of Ra ≤ 0.8 μm. The sidewalls of the locating grooves form an angle of 3-5 degrees with the radial direction of the tool holder.

[0078] Example 2

[0079] Based on Example 1, for a workpiece with a diameter of 80 mm, the radius of the tooth arc was adjusted to 72 mm. Accordingly, the number of chip breakers was increased to 12, while other parameters remained unchanged. Actual machining tests showed that this solution also achieved ideal machining results.

[0080] Example 3

[0081] Based on Example 1, the number of broaches 1 was increased to four, distributed at 90-degree angles around the circumference of the tool holder 3. This approach is suitable for machining workpieces requiring four evenly spaced circular grooves. In this case, the number of positioning grooves and straight grooves 12 on the tool holder 3 was adjusted to four, and the number of nozzles in the annular coolant channel was adjusted to eight. Experiments have shown that this solution also achieves efficient and stable machining.

[0082] The working process of this utility model is as follows:

[0083] 1. Install the workpiece 4 in the center mounting hole of the tool holder 3 and position it through the straight groove 12;

[0084] 2. Check whether the broach 1 is firmly installed in the positioning groove and tighten the screw 4 if necessary;

[0085] 3. Start the cooling system, supplying cutting fluid to the tooth 5 through the annular coolant channel and nozzle. The annular coolant channel has an inner diameter of 100 mm and a rectangular cross-section with a width of 12 mm and a depth of mm. The nozzle has an outlet diameter of 2 mm and is directed at a 60° spray angle toward the broach tooth. The operating pressure is 0.3 MPa. The cutting fluid is a 6% microemulsion at a flow rate of 20 L / min.

[0086] 4. Start the machine tool, drive the tool holder 3 to move axially, and use the teeth 5 of the broach 1 to cut the workpiece 4 at the same time;

[0087] 5. After processing, the chip breaker can effectively cut off the chips, and the anti-friction coating reduces the cutting resistance and ensures the quality of the processed surface.

[0088] Actual application effect:

[0089] The broaching device of the utility model is used to process a certain type of valve body (outer diameter 50mm, 6 evenly distributed arc grooves need to be processed), and the following effects are obtained:

[0090] 1. Processing efficiency: Single-piece processing time is shortened from 12 minutes to 3 minutes;

[0091] 2. Processing accuracy: The arc profile of the groove is controlled within 0.02mm, and the angular error of adjacent grooves is less than 0.1 degrees;

[0092] 3. Surface quality: Processed surface roughness Ra≤1.6μm, no obvious tool marks;

[0093] 4. Tool life: Under normal cutting parameters, the broach can continuously process more than 3,000 workpieces, and the overall cost is significantly reduced.

[0094] This utility model has a simple structure, is easy to manufacture, reliable in use, and has good industrial applicability. The broaching device of this utility model can complete a processing step that previously required six steps in one step, significantly improving production efficiency and reducing production costs. Furthermore, the various technical features of this utility model work synergistically to ensure processing accuracy and quality, meeting the needs of industrial production.

Claims

1. A broaching device for simultaneously machining multiple arc grooves on the outer surface of a workpiece, characterized in that: include: The tool holder is a disc-shaped structure with a cylindrical mounting hole in the center for placing and positioning the workpiece; At least two broaches are evenly distributed around the circumference of the tool holder, each of the broaches comprising: a cutter body, for mounting and positioning; and The tooth portion is shaped like a circular arc and two oblique lines tangent to the circular arc, wherein the radius of the circular arc is smaller than the outer radius of the workpiece; and A plurality of screws are used to fix the broach in the positioning groove of the tool holder through the screw holes on the tool body.

2. The broaching device according to claim 1, characterized in that: The broach is made of high-speed tool steel, and its overall hardness is not less than HRC60.

3. The broaching device according to claim 1, characterized in that: The tool holder is provided with a plurality of positioning grooves, and the depth of each positioning groove is 50%-70% of the thickness of the broach.

4. The broaching device according to claim 1, characterized in that: The number of the broaches is six, and they are distributed at equal angles of 60 degrees on the circumference of the tool holder.

5. The broaching device according to claim 1, characterized in that: The screw hole on the cutter body is a countersunk hole with a taper angle of 80-90 degrees.

6. The broaching device according to claim 1, characterized in that: The radius of the tooth arc is 85%-95% of the outer radius of the workpiece.

7. The broaching device according to claim 1, characterized in that: A plurality of straight grooves for positioning are provided on the inner wall of the cylindrical mounting hole of the knife seat.

8. The broaching device according to claim 3, characterized in that: The angle between the side wall of the positioning groove and the radial direction of the tool holder is 3-5 degrees.

9. The broaching device according to claim 1, characterized in that: The surface of the tooth portion is provided with a friction-reducing coating, and a plurality of evenly distributed chip-breaking grooves are provided on the circular arc section of the tooth portion. The depth of the chip-breaking grooves is 0.2-0.5 mm and the width is 0.5-1.0 mm.

10. The broaching device according to claim 1, characterized in that: An annular coolant channel is provided on the outer periphery of the tool holder, and the channel is communicated with a plurality of radially distributed nozzles, wherein the outlets of the nozzles face toward the teeth of each broach.

Images