Surface broaching machine and broaching method

Abstract

This invention provides a surface broaching machine and a broaching method that can perform high-precision machining while taking into account the condition of the surface broach. [Solution] The surface broaching machine 100 according to the present invention comprises a surface broach 102 having multiple cutting blades 102a arranged vertically and horizontally, a broach holder 116 that holds the surface broach, and a workpiece fixing jig 118 that holds and moves a workpiece 104 relative to the surface broach. The workpiece fixing jig comprises a base 120 facing the broach holder, a clamp receiver 122 fixed to the base and in contact with the side surface 104a of the workpiece and the back surface 104b on the base side, a clamp 124 that presses the workpiece toward the clamp receiver, a plurality of wedge-shaped tapered liners 128 inserted between the clamp receiver and the base and arranged along the longitudinal direction of the workpiece, and an adjustment screw 132 for individually adjusting the insertion amount of the plurality of tapered liners.

Description

Technical Field

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[0001] The present invention relates to a surface broaching machine for processing a workpiece by a surface broach and a broaching method.

Background Art

[0002] A surface broaching machine includes, for example, a surface broach having a plurality of cutting edges arranged vertically and horizontally, and may process a rack (rack gear) on a long workpiece by the surface broach. The surface broach is detachably fixed to the broach holder by a plurality of fastening parts while being in contact with the broach fixing surface of the broach holder.

[0003] Patent Document 1 describes a grinding machine that processes a workpiece by a rotating cup grinding wheel instead of a surface broach. This grinding machine includes a height adjustment fixture for adjusting and holding the workpiece in the height direction. The height adjustment fixture has a plurality of stages supported at the upper ends of a plurality of stage shafts and a plurality of wedge-shaped blocks arranged on a base.

[0004] The plurality of stages respectively support the workpiece to be processed at a plurality of parts. A pad is fixed to the lower end of the stage shaft. The wedge-shaped block is arranged below the pad and supports the pad.

[0005] In this height adjustment fixture, for any number of stages, by individually moving the independent wedge-shaped blocks in the width direction (horizontal direction) of the base, it is possible to adjust the height of each stage, the inclination of the workpiece, and the mutual adjustment of each stage, that is, the adjustment of middle convexity and middle concavity.

Prior Art Documents

Patent Documents

[0006] <病気の名前>

Patent Document 1

Summary of the Invention

[0007] In surface broaching machines, prolonged surface broaching causes wear on the cutting edge of the surface broach. This changes the distance between the cutting edge of the surface broach and the workpiece, increasing the OPD (Over Pin Diameter) dimensional error. Additionally, when replacing broaches, the OPD dimensional error may increase due to individual differences in the broaches. Furthermore, repeated broach replacements can lead to wear and scratches on the broach mounting surface, which can also increase the OPD dimensional error.

[0008] Therefore, with surface broaching machines, the OPD (Original Printed Distance) dimensional error is corrected by disassembling the workpiece fixing jig that holds the workpiece and changing or adding shims such as spacers, and then the OPD dimensional error is confirmed by test machining the workpiece. This is time-consuming because it involves disassembling the workpiece fixing jig, and furthermore, defective workpieces are produced during the test machining.

[0009] When the height adjustment jig from Patent Document 1 is applied to a surface broaching machine, although the workpiece can be adjusted in the height direction, it does not take into account the condition of the surface broach due to wear and scratches, making high-precision machining difficult.

[0010] The present invention aims to provide a surface broaching machine and a broaching method that can perform high-precision machining while taking into account the state of the surface broach. [Means for solving the problem]

[0011] To solve the above problems, a typical configuration of the surface broaching machine according to the present invention is a surface broaching machine for machining racks on long workpieces, comprising a surface broach with multiple cutting edges arranged vertically and horizontally, a broach holder for holding the surface broach, and a workpiece fixing jig for holding and moving the workpiece relative to the surface broach. The workpiece fixing jig comprises a base facing the broach holder, a clamp receiver fixed to the base and in contact with the side surface of the workpiece and the base side, a clamp for pressing the workpiece toward the clamp receiver, a plurality of wedge-shaped tapered liners inserted between the clamp receiver and the base and arranged along the longitudinal direction of the workpiece, and an adjustment mechanism for individually adjusting the insertion amount of the plurality of tapered liners.

[0012] The adjustment mechanism described above is preferably an adjustment screw having a threaded portion that is screwed into a clamp receiver and a head that is combined with a tapered liner.

[0013] Preferably, the above adjustment mechanism further includes a motor that rotates the adjustment screw.

[0014] To solve the above problems, a typical configuration of the broaching method according to the present invention is a broaching method using the surface broaching machine described above, in which the inclination of the surface broach and the inclination of the workpiece are measured with respect to the workpiece fixing jig, and the insertion amount of the tapered liner of the workpiece fixing jig is adjusted to incline the workpiece in order to absorb the relative inclination between the surface broach and the workpiece. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a surface broaching machine and a broaching method that can perform high-precision machining while taking into account the state of the surface broach. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing an overview of the configuration of a surface broaching machine in an embodiment of the present invention. [Figure 2] It is a diagram showing the work fixing jig of FIG. 1. [Figure 3] It is a diagram showing the positional relationship between the surface broach of FIG. 1 and the work after processing. [Figure 4] It is a diagram showing a procedure for measuring the relative inclination between the inclined surface broach of FIG. 3(b) and the work before processing. [Figure 5] It is a diagram showing a procedure for correcting the OPD dimensional error by inclining the work. [Figure 6] It is a diagram showing a modified example of the work fixing jig of FIG. 2.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit duplicate description, and elements not directly related to the present invention are not shown.

[0018] FIG. 1 is a perspective view showing an overview of the configuration of a surface broaching machine 100 in an embodiment of the present invention. The surface broaching machine 100 includes a surface broach 102 shown in FIG. 1(a), and broaches a rack on long cylindrical workpieces 104 and 106 (see FIG. 2(a)).

[0019] The surface broaching machine 100 includes an installation base 108 installed on the floor of a factory or the like, a rail 110, a moving base 112, a support base 114, and a broach holder 116. The surface broach 102 is a cutting tool in which a plurality of cutting edges 102a (see FIG. 3) for cutting the workpieces 104 and 106 are arranged vertically and horizontally. The surface broach 102 is arranged along the cutting direction indicated by arrow A for cutting the workpieces 104 and 106.

[0020] The rail 110 is supported by the installation base 108 and extends along the cutting direction. The moving table 112 is assembled to the rail 110 and is movable along the rail 110 in the cutting direction by a drive mechanism (not shown). The support base 114 is attached to the installation base 108 and supports the broach holder 116. The broach holder 116 holds the surface broach 102.

[0021] Furthermore, the surface broaching machine 100 includes a work fixing jig 118 shown in Fig. 1(b). The work fixing jig 118 is attached to the mounting surface 112a of the moving table 112 and faces the broach holder 116 shown in Fig. 1(a). The work fixing jig 118 is a jig for holding the workpieces 104 and 106 as shown in Fig. 2(a).

[0022] Therefore, when the moving table 112 moves in the cutting direction, the work fixing jig 118 can move the workpieces 104 and 106 in a state of being held with respect to the surface broach 102 held by the broach holder 116 shown in Fig. 1(a). In this way, in the surface broaching machine 100, by the work fixing jig 118 moving together with the moving table 112, the surface broach 102 processes a rack on the long workpieces 104 and 106.

[0023] Fig. 2 is a view showing the work fixing jig 118 of Fig. 1. Fig. 2(a) shows the overall configuration of the work fixing jig 118. Fig. 2(b) shows the main part of the work fixing jig 118. The work fixing jig 118 has a base 120, a clamp receiver 122, a pair of clamps 124 and 126, a pair of taper liners 128 and 130, and an adjustment screw 132 as shown in Fig. 2(a). In Fig. 2(a), the clamp 124 is partially omitted from the illustration to show the adjustment screw 132.

[0024] The base 120 is attached to the mounting surface 112a of the mobile platform 112 shown in Figure 1(b), and faces the broach holder 116. The clamp receiver 122 is fixed to the base 120 by fixing screws 134a and 134b shown in Figure 2(a). Recesses 122a and 122b are formed on the sides of the clamp receiver 122.

[0025] The recesses 122a and 122b of the clamp receiver 122 extend along the long workpieces 104 and 106, respectively, and are in contact with the workpieces 104 and 106. For example, as shown in Figure 2(b), the recess 122a is in contact with the side surface 104a and the back surface 104b on the base 120 side of the workpiece 104.

[0026] As shown by arrow B in Figure 2(a), clamps 124 and 126 press the workpieces 104 and 106 toward the clamp receiver 122, respectively. For example, clamp 124 presses the workpiece 104 toward the clamp receiver 122 as shown in Figure 2(b). As a result, the workpiece 104 is clamped between the recess 122a of the clamp receiver 122 and clamp 124.

[0027] The tapered liners 128 and 130 are wedge-shaped plate materials whose thickness gradually changes. The tapered liners 128 and 130 are inserted between the clamp receiver 122 and the base 120, and multiple tapered liners are arranged along the longitudinal direction of the workpieces 104 and 106, as shown in Figure 2(a). The tapered liners 128 and 130 also have inclined surfaces 128a and 130a that are in contact with the clamp receiver 122. The inclined surfaces 128a and 130a are inclined so that they move closer to the base 120 as they move away from the clamps 124 and 126. As a result, the tapered liners 128 and 130 have a wedge shape that tapers towards the end as they move away from the clamps 124 and 126.

[0028] The adjustment screw 132 has a threaded portion 132a and a head 132b, as shown in Figure 2(b), for example. A screw hole 136 is formed on the side of the clamp receiver 122. The screw hole 136 is located between the recessed portion 122a and the tapered liner 128. The threaded portion 132a of the adjustment screw 132 is screwed into the screw hole 136 of the clamp receiver 122. The head 132b is combined with a groove 138 formed on the inclined surface 128a of the tapered liner 128. Although not shown in the figure, the adjustment screw 132 is also located on the tapered liner 130 side.

[0029] As a result, the tapered liner 128 can be moved away from or closer to the clamp 124 by rotating the head 132b of the adjustment screw 132 with a tool, as shown by arrow C. In other words, the adjustment screw 132 functions as an adjustment mechanism that can individually adjust the insertion amount of multiple tapered liners 128 and 130. When adjusting the insertion amount of the tapered liners 128 and 130 with the adjustment screw 132, the fixing screws 134a and 134b that secure the clamp receiver 122 to the base 120 should be loosened. After adjusting the insertion amount of the tapered liners 128 and 130, the fixing screws 134a and 134b should be tightened to securely fix the clamp receiver 122 to the base 120.

[0030] As a result, in the workpiece fixing jig 118, when the insertion amount of the tapered liner 128 is increased using the adjustment screw 132, the clamp receiver 122, which has a recessed portion 122a that contacts the back surface 104b of the workpiece 104 on the base 120 side, moves away from the base 120 as shown by arrow D, as shown in Figure 2(b). On the other hand, when the insertion amount of the tapered liner 128 is decreased using the adjustment screw 132, the clamp receiver 122 moves closer to the base 120 as shown by arrow D. The same applies to the recessed portion 122b on the opposite side.

[0031] Furthermore, by individually adjusting the insertion amount of the multiple tapered liners 130, the workpieces 104 and 106 can be tilted in the longitudinal direction or deflected into a convex or concave shape in the longitudinal direction.

[0032] Figure 3 shows the positional relationship between the surface broach 102 in Figure 1 and the workpiece 104 after processing. As shown in Figure 3(a), the surface broach 102 is in contact with the broach fixing surface 116a of the broach holder 116 and is detachably fixed to the broach holder 116 by a plurality of fastening components (not shown).

[0033] The workpiece 104 has a rack machined into it by the cutting edge 102a of the surface broach 102. When the pin 140, which is a measuring probe, is pressed against the groove 104c of the machined workpiece 104 and the OPD (Over Pin Diameter) is measured, the OPD dimensional error of the workpiece 104 is small, as shown in the graph on the right side of Figure 3(a). In other words, the workpiece 104 is machined with high precision by the surface broach 102.

[0034] However, if the surface broach 102 is used to process the workpiece 104 for a long period of time, the cutting edge 102a of the surface broach 102 will wear down, as shown in Figure 3(b). When the worn surface broach 102 is replaced, the broach fixing surface 116a of the broach holder 116 will wear down or scratches may occur on the broach fixing surface 116a during the replacement process. As a result, the surface broach 102 will tilt, the distance between the cutting edge 102a of the surface broach 102 and the workpiece 104 will change, and the OPD dimensional error will increase, as shown in the graph on the right side of Figure 3(b).

[0035] Therefore, in the surface broaching machine 100, even if the surface broach 102 becomes tilted due to long-term use, the workpiece fixing jig 118 above tilts the workpiece 104 to match the tilt of the surface broach 102, thereby enabling high-precision broaching. The broaching method using the surface broaching machine 100 will be described below.

[0036] Figure 4 shows the procedure for measuring the relative inclination between the inclined surface broach 102 shown in Figure 3(b) and the workpiece 104 before machining. In the broaching method, first, as shown in Figure 4(a), the touch probe 142 is moved and pressed against the workpiece 104 to measure the position of the workpiece 104 relative to the workpiece fixing jig 118. In this way, the position error of the workpiece 104, i.e., the inclination of the workpiece 104, is measured, as shown in graph E on the right side of Figure 4(a).

[0037] Next, as shown in Figure 4(b), the touch probe 142 is moved and pressed against the cutting edge 102a of the surface broach 102 to measure the position of the surface broach 102 relative to the workpiece fixing jig 118. In this way, the positional error of the surface broach 102, i.e., the tilt of the surface broach 102, is measured, as shown in graph F on the right side of Figure 4(b).

[0038] Next, as shown in Figure 4(c), graph E, which shows the inclination of the workpiece 104, and graph F, which shows the inclination of the surface broach 102, are combined. This allows us to calculate the relative inclination between the surface broach 102 and the workpiece 104, as shown in graph G. The relative inclination between the surface broach 102 and the workpiece 104 is the sum of the positional error of the workpiece 104 and the positional error of the surface broach 102.

[0039] Figure 5 shows the procedure for correcting the OPD dimensional error by tilting the workpiece 104. The workpiece fixing jig 118 adjusts the insertion amount of the tapered liner 128 using the adjustment screw 132 shown in Figure 2(b) to absorb the relative tilt (total error) between the surface broach 102 and the workpiece 104 shown in Graph G.

[0040] As a result, the position of the workpiece 104 relative to the base 120 is adjusted in the workpiece fixing jig 118, causing the workpiece 104 to tilt as shown by arrows H and J in Figure 5. This corrects the OPD dimensional error as shown in graph K on the right side of the figure.

[0041] In this way, the surface broaching machine 100 uses the workpiece fixing jig 118 as a reference for the measurement position to measure the inclination of the surface broach 102 and the inclination of the workpieces 104 and 106, and by adjusting the insertion amount of the tapered liners 128 and 130 to tilt the workpieces 104 and 106, the relative inclination between the surface broach 102 and the workpieces 104 and 106 can be absorbed.

[0042] Therefore, with the surface broaching machine 100 and broaching method, even if the surface broach 102 becomes tilted due to long-term use, high-precision broaching can be performed. As a result, there is no need to disassemble the workpiece fixing jig 118 to correct OPD dimensional errors, and furthermore, no defective workpieces are generated due to trial machining.

[0043] Figure 6 shows a modified version of the workpiece fixing jig 118 shown in Figure 2. The modified workpiece fixing jig 118A differs from the workpiece fixing jig 118 in that it has a motor 144 in addition to the adjustment screw 132 as an adjustment mechanism for individually adjusting the insertion amount of the multiple tapered liners 128 and 130 shown in Figure 6(a).

[0044] In the workpiece fixing jig 118A, as shown in Figure 6(b), the motor shaft 144a of the motor 144 and the shaft member 146 attached to the head 132b of the adjustment screw 132 are connected via a coupling 148. This allows the insertion amount of multiple tapered liners 128 and 130 to be individually and automatically adjusted by rotating the adjustment screw 132 with the motor 144.

[0045] Furthermore, in the workpiece fixing jig 118A, when adjusting the insertion amount of the tapered liners 128 and 130 with the adjustment screw 132, it is preferable to automate the loosening and tightening of the clamp receiver 122. Therefore, instead of the fixing screws 134a and 134b, the clamp receiver 122 may be fixed using an electric motor or a hydraulic cylinder.

[0046] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. [Industrial applicability]

[0047] This invention can be used as a surface broaching machine and broaching method for processing a workpiece by surface broaching. [Explanation of Symbols]

[0048] 100…Surface broaching machine, 102…Surface broach, 102a…Cutting edge, 104, 106…Workpiece, 104a…Side of workpiece, 104b…Back of workpiece, 104c…Groove of workpiece, 108…Mounting base, 110…Rail, 112…Mobile base, 112a…Mounting surface of mobile base, 114…Support base, 116…Broach holder, 116a…Broach fixing surface, 118, 118A…Workpiece fixing jig, 120…Base, 122…Clamp receiver, 122a, 12 2b... recess of clamp receiver, 124, 126... clamp, 128, 130... tapered liner, 128a, 130a... inclined surface of tapered liner, 132... adjustment screw, 132a... threaded portion of adjustment screw, 132b... head of adjustment screw, 134a, 134b... fixing screw, 136... screw hole of clamp receiver, 138... groove of tapered liner, 140... pin, 142... touch probe, 144... motor, 144a... motor shaft, 146... shaft member, 148... coupling

Claims

1. In a surface broaching machine that processes racks on long workpieces, A surface broach with multiple cutting edges arranged vertically and horizontally, A broach holder for holding the surface broach, The surface broach is equipped with a workpiece fixing jig that holds and moves the workpiece, The aforementioned workpiece fixing jig is A base facing the broach holder, A clamp receiver fixed to the base and in contact with the side surface of the workpiece and the base side, A clamp that presses the workpiece toward the clamp receiver, A plurality of wedge-shaped tapered liners are inserted between the clamp receiver and the base and arranged along the longitudinal direction of the workpiece, A surface broaching machine characterized by having an adjustment mechanism for individually adjusting the insertion amount of the plurality of tapered liners.

2. The surface broaching machine according to claim 1, characterized in that the adjustment mechanism is an adjustment screw having a threaded portion that is screwed into the clamp receiver and a head that is combined with the tapered liner.

3. The surface broaching machine according to claim 2, characterized in that the adjustment mechanism further comprises a motor for rotating the adjustment screw.

4. A broaching method using a surface broaching machine according to any one of claims 1 to 3, Using the aforementioned workpiece fixing jig as a reference, the inclination of the surface broach and the inclination of the workpiece are measured. A broaching method characterized by tilting the workpiece by adjusting the insertion amount of the tapered liner of the workpiece fixing jig so as to absorb the relative inclination between the surface broach and the workpiece.

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