Straightening clamp for keyway broach

Abstract

The straightening clamp for the key groove broach comprises a bottom plate and a pressing plate, two rows of positioning strips parallel to the length direction of the bottom plate are arranged on the bottom plate, the distance between the two rows of positioning strips is equal to the width of the broach, the height of the positioning strips is smaller than that of the broach, and the pressing plate is arranged on the bottom plate. A plurality of screws are further arranged on the periphery of the bottom plate, the pressing plate is connected to the screws in a penetrating mode through through holes in the pressing plate, and nuts used for pressing the pressing plate on the top face of the broach are arranged on the screws. When the broach is straightened, the quenched broach is positioned through the positioning strip, then the pressing plate is pressed on the broach through the screw and the nut, the broach is fixed and straightened in a large range, and finally the broach is locally straightened through the locking mechanism, so that martensite phase transformation of supercooled austenite is induced due to plastic deformation of the broach in the cooling process, and the broach is straightened. Therefore, the broach is straightened, soft spots are not generated, and the bending strength of a pressed part is not reduced.

Description

Technical Field

[0001] The utility model relates to the field of tooling fixtures, in particular to a straightening fixture for a keyway broach. Background Art

[0002] Straightening eliminates workpiece shape defects during machining, ensuring that the workpiece's shape meets acceptable standards. Workpieces can bend and deform during heat treatment or subsequent processing and transportation. Straightening eliminates these defects through the application of external forces, ensuring that the workpiece's shape and dimensions meet quality standards. Currently, the most commonly used straightening methods are flame straightening and percussion straightening.

[0003] When using the flame straightening method, the heating temperature must be controlled. The bent part of the broach must be heated with an acetylene flame, and then the bent part must be quickly cooled with compressed air to achieve the straightening effect. However, soft spots are easily formed. When using the tapping straightening method, a chisel is used to repeatedly tap the grooves of the concave surface of the broach. Each tap compresses the metal at the tapped point and expands it to the surrounding area, gradually achieving the straightening effect. However, the bending strength and impact toughness of the tapped part will decrease. When using a hand press, the pressure head of the press must be aligned with the raised part of the broach. The broach must be pressed to 0.5 to 1 times its original deformation. After static pressing for 5 to 10 minutes, the deformation must be checked and the operation must be repeated until the deformation of the broach is minimized, thus completing the straightening. However, the bending strength of the pressed part will decrease. Utility Model Content

[0004] In order to overcome the above-mentioned deficiencies of the existing broach straightening method, the technical problem to be solved by the present invention is to provide a straightening fixture for keyway broaches which has a simple structure and is convenient for straightening.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] The straightening fixture for keyway broaches includes a base plate and a pressure plate, the base plate is provided with two rows of positioning strips parallel to the length direction of the base plate, the distance between the two rows of positioning strips is equivalent to the width of the broach, and the height of the positioning strips is less than the height of the broach, and a plurality of screws are provided around the base plate, the pressure plate is connected to the screws through the through holes thereon, and a nut is provided on the screw, and the nut is used to press the pressure plate on the top surface of the broach placed between the two rows of positioning strips; it also includes at least one locking mechanism, the locking mechanism includes a clamping arm and a locking bolt, the clamping arm is a C-shaped structure, and is mounted on the pressure plate and the base plate from top to bottom, the two ends of the clamping arm are clamped with the two sides of the base plate by hooks, and a threaded hole is provided in the middle of the clamping arm. The locking bolt passes through the threaded hole and abuts against the pressure plate to lock the pressure plate and the base plate together.

[0007] Furthermore, each row of positioning strips includes at least two positioning blocks arranged at intervals, and the positioning blocks are detachably mounted on the bottom plate via pins.

[0008] Furthermore, the screws include at least six and are symmetrically arranged on both sides of the bottom plate in the width direction, and the screws on both sides are evenly spaced.

[0009] Furthermore, a sleeve coaxial with the through hole on the pressing plate is provided at the bottom of the pressing plate, and the inner diameters of the sleeve and the through hole are both larger than the outer diameter of the screw.

[0010] Furthermore, a pressure block is rotatably provided on one end of the locking bolt that abuts against the pressure plate.

[0011] The beneficial effects of the present utility model are as follows: the quenched broach is first positioned by the positioning strip on the bottom plate, and then the pressure plate is pressed against the broach by means of screws and nuts to fix the broach and straighten it over a large area, and finally the locking mechanism is used to locally straighten the broach, so that during the cooling process of the broach, the plastic deformation induces the supercooled austenite to undergo martensitic phase transformation, during the phase transformation, the plasticity of the high-speed steel will be improved, and a phase transformation superplasticity phenomenon will occur, thereby straightening the broach without producing soft spots and causing the bending strength of the pressed parts to decrease. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the utility model;

[0013] Figure 2 It is a side view of the utility model after being locked.

[0014] Marked in the figure are, 1-base plate, 2-pressure plate, 3-positioning bar, 4-broach, 5-locking mechanism, 11-screw, 12-nut, 21-sleeve, 31-positioning block, 51-clamping arm, 52-locking bolt, 53-hook, 54-threaded hole, 55-pressure block. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] It should be noted that if directional terms are used in this utility model, such as "up," "down," "left," "right," "front," and "back," these are intended to facilitate the description of the relative positions of components and are not intended to specify the absolute positions of the related components or the positional relationships between them. They are only used to explain the relative positional relationships and movement of the components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. If terms related to quantity are used in this utility model, such as "multiple," "a plurality," and "several," these specifically refer to two or more.

[0017] like Figure 1 、 Figure 2 As shown, the utility model provides a straightening fixture for keyway broaches, comprising a base plate 1 and a pressure plate 2, wherein the base plate 1 is provided with two rows of positioning strips 3 parallel to the length direction of the base plate 1, the distance between the two rows of positioning strips 3 is equivalent to the width of the broach 4, the height of the positioning strips 3 is less than the height of the broach 4, and a plurality of screws 11 are provided around the base plate 1, the pressure plate 2 is connected to the screws 11 through the through holes thereon, and the screws 11 are provided with nuts 12, and the nuts 12 are used to fix the pressure plate 2 It is pressed on the top surface of the broach 4 placed between the two rows of positioning strips 3; it also includes at least one locking mechanism 5, which includes a clamping arm 51 and a locking bolt 52. The clamping arm 51 is a C-shaped structure and is mounted on the pressure plate 2 and the base plate 1 from top to bottom. The two ends of the clamping arm 51 are clamped with the two sides of the base plate 1 through hooks 53. A threaded hole 54 is provided in the middle of the clamping arm 51. The locking bolt 52 passes through the threaded hole 54 and abuts against the pressure plate 2 to lock the pressure plate 2 and the base plate 1 together.

[0018] The straightening principle of the present invention is as follows: the broach is generally made of high-speed steel, which will have more austenite after quenching treatment at about 260°C. During the cooling process, the austenite will gradually transform into martensite. During the phase transformation, the plasticity of the high-speed steel will increase, and a phase transformation superplasticity phenomenon will occur, which is conducive to straightening. The broach can be straightened by applying pressure. As the broach continues to cool to below 160°C, the plasticity will become smaller and smaller, and the broach will maintain its shape after cooling, thereby achieving straightening of the broach.

[0019] The use process of the present utility model is: quickly place the broach 4 that has been quenched at about 260°C between two rows of positioning strips 3, position the broach 4, and then connect the pressure plate 2 to the screw 11, slowly move it down until it contacts the top of the broach 4, and then install the nut 12 on the screw 11, and press the pressure plate 2 downward. Because the screws 11 are arranged at intervals, if the deformation area of ​​the broach 4 is located between the two screws 11, it may not have a sufficient straightening effect. Therefore, the present utility model adds a locking mechanism 5, sets the locking mechanism 5 on the pressure plate 2 and the base plate 1, and moves it to the part of the broach 4 where the deformation is larger, and then presses the pressure plate 2 and the base plate 1 together by rotating the locking bolt 52, thereby achieving precise straightening of the broach 4. The structure after locking is as shown below. Figure 2 As shown. This process must be completed before the broach 4 cools to 160°C to reduce the clamping force and facilitate plastic deformation of the broach 4. Typically, after 30 minutes, the broach 4 will cool to room temperature, completing the straightening process. Furthermore, the entire straightening fixture is ideally constructed of metal. The surface of the broach 4 is in contact with a metal plate with good thermal conductivity, which improves the efficiency of heat dissipation. The cold shrinkage stress generated within the broach 4 aids in straightening the broach 4.

[0020] Regarding the positioning strips 3, in order to improve positioning accuracy and reduce material consumption, the present invention utilizes positioning blocks 31 arranged at intervals to form the positioning strips 3. Each row of positioning strips 3 must include at least two positioning blocks 31. In addition, the positioning blocks 31 are preferably detachably mounted on the base plate 1 via pins. This allows only one side of the positioning blocks 31 to be installed before straightening. When the broach 4 is placed on the base plate 1 during the straightening process, one side of the broach 4 can be brought into contact with the positioning block 31 before the positioning block 31 on the other side of the broach is installed. This improves the positioning efficiency of the broach 4. Because the bending of the broach 4 generally occurs on the blade side, and its two sides generally do not bend, the positioning blocks 31 can be used to position the broach 4.

[0021] There should be at least six screws 11, symmetrically arranged on both sides of the width of the bottom plate 1, and the screws 11 on both sides are evenly spaced. Two are set at each end of the bottom plate 1 and at least two are set in the middle to ensure that the pressure plate 2 is evenly stressed along its length.

[0022] In order to improve the stability of the connection between the pressing plate 2 and the screw 11, a sleeve 21 coaxial with the through hole thereon is provided at the bottom of the pressing plate 2. The inner diameters of the sleeve 21 and the through hole are both larger than the outer diameter of the screw 11. The sleeve 21 is used to increase the contact area between the pressing plate 2 and the screw 11, thereby improving the stability of the connection between the pressing plate 2 and the screw 11. Since the blade surface at the top of the broach 4 is an inclined surface, setting the inner diameter of the sleeve 21 and the through hole slightly larger than the outer diameter of the screw 11 can facilitate the inclined setting of the pressing plate 2 and fit it with the inclined surface at the top of the broach 4, thereby improving the straightening effect. In addition, a soft gasket made of copper plate, wood or rubber can be set at the bottom of the pressing plate 2 to prevent damage to the cutting edge.

[0023] In order to prevent wear between the locking bolt 52 and the pressure plate 2 during the process of locking the pressure plate 2 using the locking mechanism 5, a pressing block 55 can be rotatably provided at the end of the locking bolt 52 that abuts the pressure plate 2. After the pressing block 55 contacts the pressure plate 2, the pressing block 55 will no longer rotate with the locking bolt 52 when the locking bolt 52 is subsequently rotated, thereby reducing wear on the pressure plate 2.

[0024] In summary, the utility model first positions the quenched broach 4 through the positioning strip 3 on the base plate 1, and then uses the screw 11 and the nut 12 to press the pressure plate 2 onto the broach 4 to fix and straighten the broach 4 on a large scale. Finally, the locking mechanism 5 is used to locally straighten the broach 4, so that the broach 4 induces the martensitic phase transformation of the supercooled austenite due to plastic deformation during the cooling process. During the phase transformation, the plasticity of the high-speed steel will be improved, and the phase transformation superplasticity phenomenon will occur, so that the broach is straightened, and no soft spots will be produced, and the pressed parts will not cause a decrease in bending strength. It has good practicality and application value.

Claims

1. A straightening fixture for keyway broaches, characterized by: The invention comprises a bottom plate (1) and a pressing plate (2), wherein the bottom plate (1) is provided with two rows of positioning strips (3) parallel to the length direction of the bottom plate (1), the distance between the two rows of positioning strips (3) is equivalent to the width of the broach (4), and the height of the positioning strips (3) is less than the height of the broach (4), and a plurality of screw rods (11) are provided around the bottom plate (1), and the pressing plate (2) is connected to the screw rods (11) through the through holes thereon, and the screw rods (11) are provided with nuts (12), and the nuts (12) are used to press the pressing plate (2) tightly on the two rows of positioning strips (3). The invention relates to a tool for fixing a plurality of movable parts of the plurality of movable parts, wherein the plurality of movable parts are connected to each other by a plurality of locking means. The tool for fixing a plurality of movable parts is provided with a plurality of locking means. The tool for fixing a plurality of movable parts is provided with a plurality of locking means. The tool for fixing a plurality of movable parts is provided with a plurality of locking means.

2. The straightening fixture for a keyway broach according to claim 1, wherein: Each row of positioning strips (3) comprises at least two positioning blocks (31) arranged at intervals, and the positioning blocks (31) are detachably mounted on the bottom plate (1) via pins.

3. The straightening fixture for a keyway broach according to claim 1, wherein: The screw rods (11) include at least six and are symmetrically arranged on both sides of the base plate (1) in the width direction, and the screw rods (11) on both sides are evenly spaced.

4. The straightening fixture for a keyway broach according to claim 1, wherein: The bottom of the pressing plate (2) is provided with a sleeve (21) coaxial with the through hole thereon, and the inner diameters of the sleeve (21) and the through hole are both larger than the outer diameter of the screw (11).

5. The straightening fixture for a keyway broach according to claim 1, wherein: A pressing block (55) is rotatably provided on one end of the locking bolt (52) that abuts against the pressing plate (2).

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