Method for ensuring accurate stroke of magnetic core tube

Abstract

The method for guaranteeing the stroke accuracy of the magnetic core tube comprises the following steps that S1, a magnetism isolating sheet and an armature which are independently machined are sequentially placed into a guide set hole; s2, a push rod is placed in an armature hole; s3, the assembled magnetic core tube is placed on a standard base used for guaranteeing the stroke, a standard hole with the standard depth is formed in the standard base, the lower end of the push rod is supported on the bottom face of the standard hole, and the end face of the guide set is supported on the end face, around the standard hole, of the standard base; s4, a riveting head used for riveting and fixing the push rod is placed on the end face of the armature; riveting by a press; and the stroke tolerance of the obtained magnetic core tube is within + / -0.02 mm. According to the method, the stroke tolerance of the electromagnet can be accurately controlled within + / -0.01 mm, the problem in electromagnet production is solved, and it is guaranteed that the stroke of the electromagnet cannot be changed in subsequent use.

Description

Technical Field

[0001] The invention relates to the production and manufacturing of electromagnets, in particular to a method for ensuring accurate stroke of a magnetic core tube during the production and manufacturing of electromagnets, and belongs to the technical field of electromagnet production and manufacturing. Background Art

[0002] The stroke of the proportional electromagnet used in hydraulic control is a very important attribute of the core tube (electromagnet). In terms of its characteristics, the smaller the tolerance, the better in manufacturing. In this way, the stroke consistency is good. Good stroke consistency means that the opening position of the valve core is accurate and consistent, and the pressure or flow characteristics controlled by the valve body are also consistent. Therefore, the accuracy and consistency of the electromagnet's stroke directly reflects the control accuracy of the hydraulic valve. In precision control, the performance requirements of the electromagnet are very high, requiring the stroke accuracy of the electromagnetic magnet to reach more than ±0.02mm. Correspondingly, the added value of the production and manufacturing of this type of electromagnet is also high. The stroke of the core tube (electromagnet) is assembled by three parts: the armature assembly, the magnetic isolation plate and the guide group (also called the guide sleeve). In the traditional manufacturing method, in order to obtain a consistent and high-precision stroke, the accuracy and consistency of the above three components must be guaranteed; this will bring difficulty in processing and control costs to the previous components; in actual production, even if the size control of the previous components is improved, the final stroke is the cumulative tolerance of the three components, so the final stroke is not very consistent. The existing process can control the electromagnet stroke tolerance within ±0.10mm, and it cannot reach within ±0.02mm at all. It is necessary to pick electromagnets with good consistency after production to meet the requirements of precise control, which will lead to an increase in production costs. In addition to ensuring the accuracy of the core tube stroke in the production and manufacturing process, it is also necessary to consider the use of the electromagnet. During use, how to maintain the precise stroke? The stroke cannot be guaranteed during the use of the electromagnet, which is mainly reflected in two aspects. One is that a fault occurs in the hydraulic control and the pressure is too large, which will cause the riveting between the push rod and the armature to loosen, resulting in the subsequent use of the electromagnet's stroke accuracy being affected. The other is that in the existing electromagnet, the push rod and the armature are riveted into one body to form an armature assembly, and the magnetic isolation plate and the magnetic core tube are installed in the guide group to form a magnetic core tube. Obviously, the reliability of the riveting of the push rod and the armature will affect the accuracy of the electromagnet's stroke during use. In order to ensure the reliability of the riveting, the existing production will rivet the push rod and the armature to form the armature assembly and then apply a set destructive force (the destructive force varies according to the specifications of the magnetic core tube, both within 1 50N or more) is used to test the reliability of the riveted parts (also called pull-out force test). Those that pass the pull-out force test are considered qualified. In this production process, although qualified products have been tested, the push rod will also be subjected to a large force during the inspection process. Although this large force does not destroy the fixed connection structure formed by riveting, it has a negative impact on the reliability of the fixed connection between the push rod and the armature. For example, if the riveting of the push rod and the armature can be destroyed by a force of 150N, but the set force applied during the inspection is 150N, although the riveting is not destroyed, the force of 150N will obviously have a negative effect on the reliability of the riveting point. In this way, the riveting point is easy to loosen in subsequent use, resulting in inaccurate stroke of the electromagnet and inability to meet the requirements of precision control.Therefore, how to ensure that the range of the stroke tolerance of the electromagnet when it leaves the factory can meet the needs of precision control and its stability in later use is a difficult problem in electromagnet manufacturing and has not been solved in the industry for many years. Summary of the Invention

[0003] The purpose of the present invention is to overcome the problem that it is difficult to ensure the stroke accuracy during the manufacture and use of existing electromagnets, and to provide a method for ensuring the stroke accuracy of a magnetic core tube.

[0004] To achieve the purpose of the present invention, the following technical solution is adopted: a method for ensuring the accurate travel of a magnetic core tube, comprising the following steps: S1: Place the separately processed magnetic isolation plate and armature into the guide group hole in sequence; S2: Place the push rod into the armature hole; S3: placing the assembled magnetic core tube on a standard base for ensuring the stroke, wherein the standard base is provided with a standard hole of a standard depth, the lower end of the push rod is supported on the bottom surface of the standard hole, and the end surface of the guide group is supported on the end surface around the standard hole of the standard base; S4: Place the riveting head for riveting and fixing the push rod on the end face of the armature; perform riveting with a press; The stroke tolerance of the obtained magnetic core tube is within ±0.02mm.

[0005] Furthermore, the clearance between the rivet head and the armature hole is between 2 and 5 wires.

[0006] Furthermore, the stroke tolerance of the obtained magnetic core tube is within ±0.01 mm.

[0007] Further, the method further comprises the following steps: S5: Remove the riveted armature assembly from the guide assembly. The armature assembly refers to the assembly formed by riveting the push rod and the armature together. S6: Place the armature assembly on a special fixture for drilling. The special fixture includes a base, and a V-shaped block for positioning the armature is fixedly connected or integrally provided on the base. The front end of the V-shaped block has a stop surface. When the front end face of the armature on the guide V-shaped block is against the stop surface, the push rod does not interfere with the stop surface. A sleeve is fixedly provided on the base behind the V-shaped block. The rear part of the sliding shaft with a through hole is slidably installed in the sleeve part. An internal thread is machined on the rear inner wall of the sleeve part, and a screw sleeve is screwed on the internal thread. The front end of the through hole has a shaft shoulder, and a T-shaped step shaft rotated 90 degrees clockwise is slidably installed in the through hole. The small diameter end of the step shaft faces forward and can pass through the shaft shoulder, and the large diameter end of the step shaft cannot pass through the shaft shoulder. A spring is installed in the hole, and a thread is also processed on the hole wall at the rear of the through hole, and an adjusting screw is screwed on the thread; a previously extended tightening head is integrally arranged or fixedly connected at the front end of the sliding shaft, and the tightening head has an upper open groove. After the armature is placed on the V-shaped block, the push rod is located in the upper open groove and corresponds to the front and back of the step shaft; a screw nut is fixedly installed in front of the V-shaped block, and a screw is screwed in the screw nut, and the screw corresponds to the front and back of the push rod; the armature assembly is placed on the V-shaped block, and the screw sleeve drives the sliding shaft forward to press the front and rear end faces of the armature against the stop surface and the tightening head respectively, at this time, the spring presses the step shaft against the rear end of the push rod, and after the screw is rotated to make the screw contact the front end of the push rod, the riveting point is subjected to the pressure of the spring, and a pin hole is drilled along the radial direction of the armature to pass through the push rod; S7: An open cylindrical pin is installed in the pin hole, and there is an interference fit between the cylindrical pin and the pin hole; S8: Install the armature assembly obtained in step S7 into the original guide group.

[0008] Furthermore, the pressure of the spring on the push rod is no more than 50N.

[0009] Furthermore, the interference fit between the cylindrical pin and the pin hole is from 10 to 10 threads.

[0010] Furthermore, no pull-out force test is performed during the manufacture of the magnetic core tube and during the manufacture of the electromagnet using the magnetic core tube.

[0011] The positive and beneficial technical effect of the present invention is that the method can accurately control the stroke of the electromagnet within a stroke tolerance of ±0.01mm, solves the problem in electromagnet production, and ensures that the stroke of the electromagnet will not change in subsequent use. It is described in detail in conjunction with the specific implementation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the assembly of the magnetic core tube of the present invention.

[0013] Figure 2 This is a schematic diagram of a special fixture.

[0014] Figure 3 It is a schematic diagram of the front and rear directions of the tightening head.

[0015] Figure 4 It is a cross-sectional diagram of a cotter pin. DETAILED DESCRIPTION

[0016] In order to more fully explain the implementation of the present invention, implementation examples of the present invention are provided. These implementation examples are merely elaborations of the present invention and do not limit the scope of the present invention.

[0017] .The marks in the accompanying drawings are: 1: base; 2: V-block; 3: stop surface; 4: sleeve; 5: sliding shaft; 6: screw sleeve; 7: adjusting screw; 8: step shaft; 9: tightening head; 901: upper open groove; 10: spring; 11: handle; 12: screw nut; 13: screw; 14: push rod; 15: armature; 16: pin hole; 17: open cylindrical pin; 18: standard base; 19: rivet head.

[0018] As shown in the accompanying drawings, the method for ensuring the accurate travel of the magnetic core tube includes the following steps: S1: Place the separately processed magnetic isolation plate and armature into the guide group hole in sequence; S2: Place the push rod into the armature hole; S3: Place the assembled magnetic core tube on a standard base 18 for ensuring the stroke. The standard base is provided with a standard hole of a standard depth, and the lower end of the push rod is supported on the bottom surface of the standard hole. In this embodiment, the upper and lower end surfaces of the standard base are parallel planes, and the standard hole is a through hole that penetrates the two planes. The height of the standard base is equal to the depth of the standard hole. When riveting, the standard base is located on a supporting plane. S4: Place the rivet head 19 for riveting and fixing the push rod on the end face of the armature; the clearance between the rivet head and the armature hole is 2 to 5 threads, and perform press riveting; The stroke tolerance of the obtained magnetic core tube is within ±0.01mm As a further optimization of the present invention, in order to ensure the accurate travel of the electromagnet during use, S5: Remove the riveted armature assembly from the guide assembly. The armature assembly refers to the assembly formed by riveting the push rod and the armature together. S6: Place the armature assembly on a special fixture for drilling. The special fixture includes a base 1, on which a V-shaped block 2 for positioning the armature is fixedly connected or integrally provided. The front end of the V-shaped block 2 has a stop surface 3. When the front end face of the armature on the guide V-shaped block is pressed against the stop surface 3, the push rod does not interfere with the stop surface. A sleeve member 4 is fixedly provided on the base behind the V-shaped block. The rear part of the sliding shaft 5 with a through hole is slidably installed in the sleeve member, and the sliding shaft cannot rotate in the sleeve member. There are many ways to achieve non-rotation, such as the sliding shaft and the sleeve can be matched in a non-rotating shape, or the sliding shaft can be restricted from rotating by setting front and rear guide keys and matching keyways on the inner walls of the sliding shaft and the sleeve. An internal thread is processed on the rear inner wall of the sleeve, and a threaded sleeve 6 is screwed on the internal thread. The front end of the through hole has a shaft shoulder, and a T-shaped stepped shaft 8 that rotates 90 degrees clockwise is slidably installed in the through hole. The small diameter end of the stepped shaft 8 faces forward and can pass through the shaft shoulder, and the large diameter end of the stepped shaft cannot pass through At the shoulder of the shaft, a spring 10 is installed in the through hole, and a thread is also processed on the wall of the rear part of the through hole. An adjusting screw 10 is screwed on the thread. The two ends of the spring are respectively pressed on the step shaft and the adjusting screw. By rotating the adjusting screw, the size of the pushing force of the step shaft on the push rod can be adjusted. A previously extended tightening head 9 is integrally provided or fixedly connected at the front end of the sliding shaft. The tightening head has an upper open groove 901. After the armature is placed on the V-block, the push rod 14 is located in the upper open groove 901 and corresponds to the step shaft 8 front and back; A lead screw nut 12 is fixedly installed in the front of the push rod, and a lead screw is screwed into the lead screw nut 12. The lead screw 13 corresponds to the front and rear ends of the push rod; the armature assembly is placed on the V-shaped block, and the screw sleeve 6 is rotated to drive the slide shaft to move forward so that the front and rear end faces of the armature are respectively pressed against the stop surface and the tightening head. At this time, the spring presses against the step shaft against the rear end of the push rod. The pressure of the spring on the push rod is not more than 50N. After the lead screw is rotated so that the lead screw contacts the front end of the push rod, the riveting point is subjected to the pressure of the spring, and a pin hole 16 is drilled along the radial direction of the armature to pass through the push rod; S7: Install the open cylindrical pin 17 in the pin hole, with an interference fit between the cylindrical pin 17 and the pin hole 16; the interference fit between the cylindrical pin and the pin hole is 5 to 10 threads.

[0019] S8: Install the armature assembly obtained in step S7 into the original guide group.

[0020] .In this application, no pull-out force test is performed during the manufacture of the magnetic core tube and the process of using the magnetic core tube to manufacture the electromagnet.

[0021] In the present invention, after the magnetic isolation plate and the armature assembly are installed into the hole of the guide group, the lower end of the push rod falls freely to the bottom surface of the standard hole to provide support. The length of the push rod extending out of the guide group is only related to the depth of the standard hole. Therefore, by controlling the depth of the standard block, a magnetic core tube with very good stroke tolerance can be obtained. Taking a certain model as an example, the depth of the standard hole is controlled within 9.3±0.005mm, and the stroke tolerance of the obtained magnetic core tube can meet the requirement of 9.3±0.01mm. In order to prevent the negative impact of the pull-out force test on the riveting point, a special clamp is used to fix the armature after riveting. After machining the pin hole on the assembly, a cotter pin is driven in to fit the component, making the connection between the push rod and the armature more secure. The force applied to the riveting point by the special fixture is very small, and it can ensure that the relative position of the push rod and the armature will not change even if the riveting point loosens. The stroke will not change after the cotter pin is driven in. Because the push rod and the armature can withstand greater axial forces than riveting through the cotter pin and the pin hole, the pull-out force test for the riveting process in the original process can be omitted, thus eliminating the potential negative impact on the stroke accuracy of the electromagnet caused by the pull-out force test. This method has been tested and used effectively in the production of electromagnets.

[0022] After describing the embodiments of the present invention in detail, people familiar with the technology can clearly understand that various changes and modifications can be made without departing from the scope and spirit of the above-mentioned patent application. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention, and the present invention is not limited to the embodiments of the examples given in the specification.

[0023] After describing the embodiments of the present invention in detail, people familiar with the technology can clearly understand that various changes and modifications can be made without departing from the scope and spirit of the above-mentioned patent application. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention, and the present invention is not limited to the embodiments of the examples given in the specification.

Claims

1. A method for ensuring accurate travel of the magnetic core tube, characterized in that The following steps are involved: S1: Place the separately processed magnetic isolation plate and armature into the guide group hole in sequence; S2: Place the push rod into the armature hole; S3: placing the assembled magnetic core tube on a standard base for ensuring the stroke, wherein the standard base is provided with a standard hole of a standard depth, the lower end of the push rod is supported on the bottom surface of the standard hole, and the end surface of the guide group is supported on the end surface around the standard hole of the standard base; S4: Place the riveting head for riveting and fixing the push rod on the end face of the armature; perform riveting with a press; The stroke tolerance of the obtained magnetic core tube is within ±0.02mm.

2. The method for ensuring accurate travel of a magnetic core tube according to claim 1, characterized in that: The matching clearance between the rivet head and the armature hole is 20 to 50 mm.

3. The method for ensuring accurate travel of a magnetic core tube according to claim 1, characterized in that: The stroke tolerance of the obtained magnetic core tube is within ±0.01mm.

4. The method for ensuring accurate travel of a magnetic core tube according to claim 1, characterized in that The following steps are also included: S5: Remove the riveted armature assembly from the guide assembly. The armature assembly refers to the assembly formed by riveting the push rod and the armature together. S6: Place the armature assembly on a special fixture for drilling. The special fixture includes a base, and a V-shaped block for positioning the armature is fixedly connected or integrally provided on the base. The front end of the V-shaped block has a stop surface. When the front end face of the armature on the guide V-shaped block is against the stop surface, the push rod does not interfere with the stop surface. A sleeve is fixedly provided on the base behind the V-shaped block. The rear part of the sliding shaft with a through hole is slidably installed in the sleeve part. An internal thread is machined on the rear inner wall of the sleeve part, and a screw sleeve is screwed on the internal thread. The front end of the through hole has a shaft shoulder, and a T-shaped step shaft rotated 90 degrees clockwise is slidably installed in the through hole. The small diameter end of the step shaft faces forward and can pass through the shaft shoulder, and the large diameter end of the step shaft cannot pass through the shaft shoulder. A spring is installed inside, and a thread is also processed on the rear wall of the through hole, and an adjusting screw is screwed on the thread; a previously extended tightening head is integrally arranged or fixedly connected at the front end of the sliding shaft, and the tightening head has an upper open groove. After the armature is placed on the V-shaped block, the push rod is located in the upper open groove and corresponds to the front and back of the step shaft; a screw nut is fixedly installed in front of the V-shaped block, and a screw is screwed in the screw nut, and the screw corresponds to the front and back of the push rod; the armature assembly is placed on the V-shaped block, and the screw sleeve drives the sliding shaft forward to press the front and rear end faces of the armature against the stop surface and the tightening head respectively, at this time, the spring presses the step shaft against the rear end of the push rod, and after the screw is rotated to make the screw contact the front end of the push rod, the riveting point is subjected to the pressure of the spring, and a pin hole is drilled along the radial direction of the armature to pass through the push rod; S7: An open cylindrical pin is installed in the pin hole, and there is an interference fit between the cylindrical pin and the pin hole; S8: Install the armature assembly obtained in step S7 into the original guide group.

5. The method for ensuring accurate travel of a magnetic core tube according to claim 4, characterized in that: The interference fit between the cylindrical pin and the pin hole is 20 to 50 threads.

6. The method for ensuring accurate travel of a magnetic core tube according to claim 4, characterized in that: The pressure of the spring on the push rod is not greater than 50N.

7. The method for ensuring accurate travel of a magnetic core tube according to claim 3, characterized in that: No pull-out force test is performed during the manufacture of magnetic core tubes or the process of using magnetic core tubes to manufacture electromagnets.

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