A method for machining inclined grooves in arc-extinguishing chamber contact seats

Abstract

The present invention discloses a method for processing an arc extinguishing chamber contact seat bevel groove, which determines the slot thickness H and radius R of the contact seat and the center angle β of the bevel groove in the axial direction of the contact seat, calculates the chord length L=2Rsin(β / 2) of the start end and the root end of the bevel groove in the axial direction of the contact seat, calculates the bevel groove cutting angle α by inverse trigonometric function, and adjusts the tool cutting angle to α on the processing equipment to process the bevel groove; the method can determine the contact seat specifications in advance according to the arc extinguishing chamber specifications, and determine the bevel groove cutting angle according to the thickness of the contact seat. Moreover, the method can determine the cutting angle for different thicknesses and the size of the center angle of the bevel groove without the help of an empirical parameter table, further improving the contact processing efficiency and reducing the trial and error rate.

Description

Technical Field

[0001] The invention relates to the field of machining, and in particular to a method for machining an oblique groove of an arc extinguishing chamber contact seat. Background Art

[0002] As an important part of the arc extinguishing chamber, the contact seat of the vacuum arc extinguishing chamber plays a key role in the current switching. The switching effect is achieved through the contact and disconnection of the moving and static contacts. When it disconnects a certain value of current, the moving and static contacts are separated at the moment of separation, and the current shrinks to the point where the contacts are just separated, resulting in a sharp increase in resistance between the electrodes and a rapid increase in temperature until the electrode metal evaporates, and at the same time, an extremely high electric field strength is formed, resulting in extremely strong emission and gap breakdown, and generating a vacuum arc. In order to prevent the current from shrinking to one point of the contact, an inclined slot is opened on the contact seat. According to Ampere's law, when the current passes through the conductor between the two inclined slots on the contact seat, a longitudinal magnetic field and a transverse magnetic field are generated. In the process of breaking, the vacuum arc is mainly controlled by the magnetic field generated by the contact structure. Among them, the longitudinal magnetic field helps to keep the vacuum arc stable and diffuse under large currents. To increase the longitudinal magnetic field, the current must travel a longer distance along the circumference of the contact seat, so a longer bevel slot needs to be opened. Generally, the center angle of the bevel slot (the center angle of the bevel slot on the axial projection of the contact seat) is between 90° and 180°. The larger the center angle, the greater the longitudinal magnetic field. In order to reduce the transverse magnetic field, the thickness of the contact seat should be reduced as much as possible. However, in the prior art, when processing the bevel slot of the contact seat, the cutting angle is usually determined first, and then the thickness of the contact seat is determined according to the cutting angle for milling. The specifications are basically determined and processed through data comparison tables obtained through experience or experiments. It is difficult to meet the requirements when processing contact seats of some special thicknesses. Therefore, for arc extinguishing chambers that need to be miniaturized, it is difficult to select the bevel cutting angle when selecting a contact seat with a smaller thickness. Summary of the invention

[0003] In order to solve the deficiencies in the prior art, a contact seat bevel groove processing method is provided, which can determine the contact seat thickness according to the specifications of the arc extinguishing chamber and can provide a reasonable bevel groove cutting angle for different contact seat thicknesses. The technical solution adopted by the present invention is:

[0004] A method for processing the inclined groove of an arc extinguishing chamber contact seat, determining the groove thickness H and radius R of the contact seat and the center angle β of the orthographic projection of the inclined groove on the axial direction of the contact seat, and calculating the chord length of the orthographic projection of the starting end and the root end of the inclined groove on the axial direction of the contact seat The bevel groove cutting angle α is calculated by inverse trigonometric function, and the tool cutting angle is adjusted to α on the processing equipment to perform bevel groove processing.

[0005] Furthermore, when α is the angle between the tool and the end face of the contact seat or

[0006] Furthermore, when α is the axial angle between the tool and the contact seat or

[0007] Furthermore, during cutting, the cutter is inserted from the middle of the inclined groove and cuts along the radial direction of the contact seat.

[0008] Furthermore, during cutting, the knife is inserted from the starting end of the inclined groove and fed along the direction of the inclined groove.

[0009] Furthermore, during cutting, the knife is inserted from the starting end of the inclined groove to make the contact seat rotate along an axis passing through the center of the contact and parallel to the axis direction of the tool.

[0010] This method can determine the specifications of the contact seat in advance according to the specifications of the arc extinguishing chamber, and determine the angle of the bevel cutting according to the thickness of the contact seat. In addition, this method can determine the cutting angle for different thicknesses and the size of the bevel center angle without the help of an empirical parameter table, further improving the contact processing efficiency and reducing the trial and error rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the contact seat structure;

[0012] Figure 2 Calculate the corresponding parameters for the cutting angle, a is a schematic diagram of the side view of the contact base, and b is a schematic diagram of the top view of the contact base;

[0013] Figure 3 Schematic diagram of the tool cutting method, A is cutting from the center of the inclined slot; B is cutting from the starting end of the inclined slot and the tool feeds in a straight line; C is cutting from the starting end of the inclined slot and the contact seat rotates to feed;

[0014] Among them: 1. Contact seat; 2. Bevel groove; 3. Cutting tool. DETAILED DESCRIPTION

[0015] In order to better understand the technical solution of the present invention, the technical solution of the present invention is further described in detail below with reference to the accompanying drawings.

[0016] like Figure 1 The contact seat shown is provided with a group of bevel grooves along the circumference, and the conductor between two adjacent bevel grooves is used for current to pass through. In this way, when the current passes through the conductor between each bevel groove, longitudinal and transverse magnetic fields will be generated. The longitudinal magnetic field can help the vacuum arc to spread evenly on the contact, which is helpful for arc extinguishing. The bevel groove processing industry usually adopts saw blade milling cutter to obtain it by milling along the bevel groove direction. However, the cutting angle directly affects the length of the bevel groove. The smaller the cutting angle (the angle between the milling cutter and the end face of the contact seat) of the contact seat with the same thickness, the longer the bevel groove cut. However, the traditional practice is to determine the cutting angle based on experience, and select the contact thickness according to the angle. If the contact thickness changes, the cutting angle needs to be adjusted to meet the cutting length, such as Figure 1As shown, there is an end plate at the bottom of the contact seat. Generally, the root of the inclined groove cannot cut through the end plate. Therefore, when the central angle of the inclined groove (the central angle of the two points of the starting end and the root end of the inclined groove on the axial projection of the contact seat) remains unchanged, the smaller the thickness of the contact seat, the smaller the cutting angle must be. It is difficult to give a reasonable cutting angle based on the thickness through traditional experience.

[0017] Therefore, in order to design a reasonable cutting angle according to the specifications (thickness and radius) of the contact seat, the method adopted by the present invention is:

[0018] like Figure 2 As shown, first determine the contact seat slot thickness H (the height from the end of the inclined slot to the root, generally a distance of 1-2 mm is reserved between the root of the inclined slot and the end plate of the contact seat, so after the thickness of the contact seat is determined, the slot thickness is the thickness of the contact seat minus the reserved distance) and the radius R and the central angle β of the orthographic projection of the inclined slot on the axial direction of the contact seat; calculate the chord length of the orthographic projection of the starting end and the root end of the slot on the axial direction of the contact seat by the chord length formula Then the bevel cutting angle α is calculated by inverse trigonometric function.

[0019] Since different processing equipment or tooling refer to different cutting angles α when adjusting the tool 3, if α is the angle between the cutting tool and the end face of the contact seat, it is represented by a1, then or When α is the axial angle between the cutting tool and the contact seat, it is represented by a2. or Alternatively, it can be obtained by subtracting α1 from 90°.

[0020] Then, the angle between the tool and the contact is adjusted on the milling machine so that the cutting angle is equal to α to perform the bevel groove processing.

[0021] When machining the bevel groove, the tool can be Figure 3 Cut as shown below:

[0022] 1) Insert the tool at the center of the groove and machine the groove radially.

[0023] 2) Enter the tool from the starting end of the inclined groove and feed along the direction of the inclined groove.

[0024] 3) Insert the tool from the starting end of the inclined slot to rotate the contact seat along an axis passing through the center of the contact seat and parallel to the axis direction of the tool.

[0025] For the remaining grooves, the contact holder is rotated through the specified angles in sequence according to the pitch circle and then the above-mentioned cutting process is performed.

Claims

1. A method for processing an arc extinguishing chamber contact seat bevel groove, characterized in that: Determine the slot thickness H and radius R of the contact seat and the central angle β of the slant slot on the axial direction of the contact seat, and calculate the chord length of the slant slot starting end and root end on the axial direction of the contact seat. The bevel groove cutting angle α is calculated by inverse trigonometric function, and the tool cutting angle is adjusted to α on the processing equipment to perform bevel groove processing.

2. The arc extinguishing chamber contact seat inclined groove processing method according to claim 1, characterized in that: When α is the angle between the tool and the end face of the contact seat or When α is the included angle between the tool and the end face of the contact seat, it is represented by a1.

3. The arc extinguishing chamber contact seat inclined groove processing method according to claim 1, characterized in that: When α is the axial angle between the tool and the contact seat or When α is the axial angle between the tool and the contact seat, it is represented by a2.

4. The arc extinguishing chamber contact seat inclined groove processing method according to claim 1, characterized in that: When cutting, the tool is inserted from the middle of the inclined groove and cuts along the radial direction of the contact seat.

5. The arc extinguishing chamber contact seat inclined groove processing method according to claim 1, characterized in that: When cutting, the knife enters from the starting end of the bevel and moves along the direction of the bevel.

6. The arc extinguishing chamber contact seat inclined groove processing method according to claim 1, characterized in that: When cutting, the knife is inserted from the starting end of the inclined groove to make the contact seat rotate along an axis passing through the center of the contact and parallel to the axis direction of the tool.

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