Electromagnet
By designing the armature, the guide sleeve and the push rod in the electromagnet, and using the guide sleeve and the accommodating hole gap, the problem of the armature stuck in the magnetic isolation sleeve is solved, and the reliability of the electromagnet is improved.
Patent Information
- Application Number
- CN202411915468.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-02-28
AI Technical Summary
Among the existing electromagnets, the armature is prone to stagnation during the movement of the magnetic separator, resulting in a decrease in the reliability of the electromagnet.
An electromagnet is designed, with the armature, guide sleeve and push rod connected as one, and the guide sleeve and the receiving hole gap are matched. The outer diameter of the armature is smaller than the outer diameter of the guide sleeve, so as to avoid contact between the armature and the inner wall of the receiving hole.
Through the guiding effect of the guide sleeve and the appropriate size design of the armature, the armature is avoided to stagnate during the absorption and movement, and the reliable attachment between the armature and the front yoke is achieved, and the reliability of the electromagnet is improved.
Smart Images
Figure CN119541989A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electromagnets, and in particular to an electromagnet. Background Art
[0002] An electromagnet is an electrical actuator that converts electrical energy into mechanical energy to complete command actions. Compared with mechanical devices or hydraulic devices, electromagnets have the advantages of fast response time, strong electromagnetic attraction, small size and light weight. They are widely used in the field of industrial automation.
[0003] In the existing electromagnet, a receiving hole is provided in the magnetic isolation sleeve in the magnetic core tube assembly, and the front yoke and the armature are both installed in the receiving hole. When the coil of the electromagnet is energized, a magnetic field is generated, and the front yoke and the armature are attracted to each other. The armature moves toward the front yoke along the axial direction of the magnetic isolation sleeve in the receiving hole, and the armature drives the push rod to move synchronously, so that the push rod extends out of the front yoke and triggers the switch of the external actuator. Since the armature rubs against the inner wall of the receiving hole during movement, the armature is prone to get stuck in the magnetic isolation sleeve, which reduces the reliability of the electromagnet. Summary of the invention
[0004] The object of the present invention is to provide an electromagnet to prevent the armature from getting stuck in the magnetic isolation sleeve and to improve the reliability of the electromagnet.
[0005] To achieve this purpose, the technical solution adopted by the present invention is:
[0006] The electromagnet comprises a magnetic core tube assembly, a coil, a front yoke, an armature, a guide sleeve and a push rod, wherein the magnetic core tube assembly comprises a magnetic isolation sleeve, the coil is sleeved on the magnetic isolation sleeve, a receiving hole is provided in the magnetic isolation sleeve, and the front yoke is sealed at the opening of the receiving hole;
[0007] The armature and the guide sleeve are both axially slidably arranged in the accommodating hole along the magnetic isolation sleeve, the guide sleeve and the accommodating hole are clearance-matched, the outer diameter of the armature is smaller than the outer diameter of the guide sleeve; the push rod movably passes through the front yoke and is fixedly connected to the armature and the guide sleeve respectively, and one end of the push rod passes through the front yoke.
[0008] As an optional solution for the electromagnet, the armature is provided with a first mounting hole along the axial direction, the guide sleeve is provided with a second mounting hole along the axial direction, and one end of the push rod is fixedly passed through the first mounting hole and the second mounting hole in sequence.
[0009] As an optional solution for the electromagnet, the push rod is provided with two installation grooves spaced apart along the axial direction, and the inner wall of the first installation hole and the inner wall of the second installation hole are respectively riveted and pressed with the corresponding installation grooves.
[0010] As an optional solution for the electromagnet, one axial end of the armature fits with one axial end of the guide sleeve.
[0011] As an optional solution for the electromagnet, the armature is further provided with a first oil hole along the axial direction, and the guide sleeve is further provided with a second oil hole along the axial direction, and the armature and the guide sleeve separate the accommodating hole into a first cavity and a second cavity, wherein the first cavity is located between the armature and the front yoke, and the second cavity is located on a side of the guide sleeve away from the armature;
[0012] The push rod is axially penetrated to form a through hole communicating with the second cavity, and the first cavity is connected with the second cavity through the first oil hole and the second oil hole.
[0013] As an optional solution for the electromagnet, the magnetic core tube assembly further includes a shell, the magnetic isolation sleeve is installed in the shell, and the coil extends into the shell and is sleeved on the magnetic isolation sleeve.
[0014] As an optional solution for the electromagnet, a first inner hole, a second inner hole and a third inner hole which are connected in sequence are provided in the shell along the axial direction;
[0015] The magnetic isolation sleeve includes a first sleeve and a second sleeve that are connected to each other. The second sleeve is provided with the accommodating hole in the axial direction. The end of the accommodating hole away from the first sleeve is closed, and the end of the accommodating hole close to the first sleeve is blocked with the front yoke. The first sleeve is inserted into the first inner hole, and the first sleeve is clearance-fitted with the first inner hole. The second sleeve is sequentially inserted into the second inner hole and the third inner hole, and the second sleeve is interference-fitted with the second inner hole. The coil extends into the third inner hole and is sleeved on the second sleeve.
[0016] As an optional solution for the electromagnet, a first step surface is provided between the first inner hole and the second inner hole, a second step surface is provided between the first sleeve and the second sleeve, and the first step surface and the second step surface are in limiting contact with each other.
[0017] As an optional solution for the electromagnet, a sealing groove is provided on the outer circumference of the first sleeve, a sealing ring is installed in the sealing groove, and the sealing ring is clamped between the outer circumference of the first sleeve and the inner side wall of the first inner hole.
[0018] As an optional solution for the electromagnet, the electromagnet also includes a retaining ring and an elastic member, the retaining ring is sleeved on the push rod, the push rod moves through the retaining ring and cooperates with the retaining ring gap, and the elastic member is compressed and installed between the retaining ring and the armature to press the retaining ring against one end of the front yoke close to the armature.
[0019] The beneficial effects of the present invention are:
[0020] The electromagnet proposed by the present invention has an armature, a guide sleeve and a push rod connected as a whole. When the coil is energized to generate a magnetic field, the armature drives the guide sleeve and the push rod to move along the axial direction of the magnetic isolation sleeve toward the front yoke under the action of the magnetic field force, so as to achieve the attraction of the armature and the front yoke. Since the guide sleeve and the receiving hole are matched with each other, the guide sleeve plays a guiding role in the attraction and movement of the armature, and the outer diameter of the armature is smaller than the outer diameter of the guide sleeve, so that the armature will not contact the inner side wall of the receiving hole during the attraction and movement, so as to avoid the armature from being stuck in the magnetic isolation sleeve, thereby ensuring the smooth attraction and movement of the armature, achieving the reliable attraction of the armature and the front yoke, and improving the reliability of the electromagnet. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is a cross-sectional view of an electromagnet provided by an embodiment of the present invention;
[0022] Figure 2 is a cross-sectional view of an electromagnet with a coil removed provided by an embodiment of the present invention;
[0023] Figure 3 It is a schematic diagram of the structural decomposition of the housing and the magnetic isolation sleeve provided in an embodiment of the present invention;
[0024] Figure 4 It is a schematic diagram of the structural decomposition of the armature, the guide sleeve and the push rod provided in an embodiment of the present invention.
[0025] The names and numbers of the components in the figure are as follows:
[0026] 1. Magnetic isolation sleeve; 11. First sleeve; 111. Sealing groove; 12. Second sleeve; 121. Accommodating hole; 1211. First cavity; 1212. Second cavity; 13. Second step surface; 2. Coil; 3. Front yoke; 31. Inner ring; 4. Armature; 41. First mounting hole; 42. First oil hole; 5. Guide sleeve; 51. Second mounting hole; 52. Second oil hole; 6. Push rod; 61. Mounting groove; 62. Through hole; 7. Shell; 71. First inner hole; 72. Second inner hole; 73. Third inner hole; 74. First step surface; 8. Sealing ring; 9. Retaining ring; 10. Elastic member. DETAILED DESCRIPTION
[0027] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, not all.
[0028] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0029] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0030] In the description of this embodiment, the terms "upper", "lower", "right", "left" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0031] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.
[0032] In the existing electromagnet, the coil generates a magnetic field after being energized, the front yoke and the armature are attracted, the armature moves in the receiving hole of the magnetic isolation sleeve along the axial direction of the magnetic isolation sleeve toward the front yoke, and the armature drives the push rod to move synchronously, so that the push rod extends out of the front yoke and triggers the switch of the external actuator. Since the armature rubs against the inner wall of the receiving hole during the movement, the armature is prone to get stuck in the magnetic isolation sleeve, which reduces the reliability of the electromagnet.
[0033] To solve the above problems, Figure 1 and Figure 2As shown, this embodiment proposes an electromagnet, which includes a magnetic core tube assembly, a coil 2, a front yoke 3, an armature 4, a guide sleeve 5 and a push rod 6. The magnetic core tube assembly includes a magnetic isolation sleeve 1, the coil 2 is sleeved on the magnetic isolation sleeve 1, and a receiving hole 121 is opened in the magnetic isolation sleeve 1. The front yoke 3 blocks the opening of the receiving hole 121. The armature 4 and the guide sleeve 5 are both axially slidably arranged in the receiving hole 121 along the magnetic isolation sleeve 1. The guide sleeve 5 and the receiving hole 121 are clearance-matched, and the outer diameter of the armature 4 is smaller than the outer diameter of the guide sleeve 5. The push rod 6 movably passes through the front yoke 3 and is fixedly connected to the armature 4 and the guide sleeve 5 respectively, and one end of the push rod 6 passes through the front yoke 3. The armature 4, the guide sleeve 5 and the push rod 6 are connected as a whole. When the coil 2 is energized to generate a magnetic field, the armature 4 drives the guide sleeve 5 and the push rod 6 to move toward the front yoke 3 (from right to left) along the axial direction of the magnetic isolation sleeve 1 under the action of the magnetic field force, so as to realize the attraction of the armature 4 and the front yoke 3. Due to the clearance fit between the guide sleeve 5 and the accommodating hole 121, the guide sleeve 5 plays a guiding role during the attraction and movement of the armature 4, and the outer diameter of the armature 4 is smaller than the outer diameter of the guide sleeve 5, so that the armature 4 will not contact the inner wall of the accommodating hole 121 during the attraction and movement, so as to avoid the armature 4 from getting stuck in the magnetic isolation sleeve 1, thereby ensuring the smooth attraction and movement of the armature 4, realizing the reliable attraction of the armature 4 and the front yoke 3, and improving the reliability of the electromagnet.
[0034] like Figure 1 and Figure 2 As shown, the magnetic core tube assembly also includes a shell 7, the magnetic isolation sleeve 1 is installed in the shell 7, and the coil 2 extends into the shell 7 and is sleeved on the magnetic isolation sleeve 1. By arranging the magnetic core tube assembly as a split structure, the processing and manufacturing of the magnetic isolation sleeve 1 and the shell 7 are facilitated, the processing difficulty of the magnetic isolation sleeve 1 and the shell 7 is reduced, and the magnetic isolation sleeve 1 is easy to detect to ensure the processing accuracy of the magnetic isolation sleeve 1.
[0035] like Figure 2 and Figure 3As shown, the housing 7 has a first inner hole 71, a second inner hole 72 and a third inner hole 73 which are connected in sequence along the axial direction. The magnetic isolation sleeve 1 includes a first sleeve 11 and a second sleeve 12 which are connected to each other. The second sleeve 12 has an accommodating hole 121 which is axially provided in the second sleeve 12. The end of the accommodating hole 121 which is far from the first sleeve 11 is closed, and the end of the accommodating hole 121 which is close to the first sleeve 11 is blocked with a front yoke 3. The first sleeve 11 is inserted into the first inner hole 71, and the first sleeve 11 and the first inner hole 71 are clearance-fitted. The second sleeve 12 is inserted into the second inner hole 72 and the third inner hole 73 in sequence, and the second sleeve 12 and the second inner hole 72 are interference-fitted. The coil 2 extends into the third inner hole 73 and is sleeved on the second sleeve 12. Through the interference fit between the second sleeve 12 and the second inner hole 72, the magnetic isolation sleeve 1 and the housing 7 are stably assembled, and there is no need to weld the two, thereby improving the assembly efficiency of the magnetic isolation sleeve 1 and the housing 7. A space for accommodating the coil 2 is formed between the second sleeve 12 and the third inner hole 73, so that the coil 2 and the magnetic core tube assembly can be compactly installed, making the structure of the electromagnet more compact.
[0036] Furthermore, a first step surface 74 is provided between the first inner hole 71 and the second inner hole 72, a second step surface 13 is provided between the first sleeve 11 and the second sleeve 12, and the first step surface 74 is limitedly abutted against the second step surface 13. When the first step surface 74 is fitted and abutted against the second step surface 13, the magnetic isolation sleeve 1 is assembled in place with the housing 7, so that the magnetic isolation sleeve 1 is assembled in axial positioning to ensure the coaxiality of the second sleeve 12 and the second inner hole 72, thereby improving the assembly accuracy and the stability of the assembly structure.
[0037] like Figure 2 and Figure 3 As shown, a sealing groove 111 is provided on the outer circumference of the first sleeve 11, and a sealing ring 8 is installed in the sealing groove 111. The sealing ring 8 is sandwiched between the outer circumference of the first sleeve 11 and the inner wall of the first inner hole 71. Since the first sleeve 11 and the first inner hole 71 are clearance-matched, the sealing ring 8 is provided to achieve the sealed assembly of the magnetic isolation sleeve 1 and the housing 7, thereby preventing the hydraulic oil in the receiving hole 121 from leaking.
[0038] like Figure 2 and Figure 4 As shown, the armature 4 is provided with a first mounting hole 41 in the axial direction, the guide sleeve 5 is provided with a second mounting hole 51 in the axial direction, and one end of the push rod 6 is fixedly passed through the first mounting hole 41 and the second mounting hole 51 in sequence. The armature 4 and the guide sleeve 5 of this embodiment are both cylindrical and coaxially mounted on the push rod 6. When the armature 4 is attracted to the front yoke 3, the armature 4, the guide sleeve 5 and the push rod 6 move synchronously toward the front yoke 3. The front yoke 3 and the guide sleeve 5 jointly support the push rod 6, and the armature 4 with a smaller outer diameter will not contact the inner side wall of the accommodating hole 121, thereby preventing the armature 4 from getting stuck when it is attracted and moved.
[0039] Specifically, Figure 4 As shown, the push rod 6 is provided with two installation grooves 61 spaced apart in the axial direction, and the inner wall of the first installation hole 41 and the inner wall of the second installation hole 51 are respectively riveted to the corresponding installation grooves 61. The armature 4 and the guide sleeve 5 are respectively riveted and assembled with the push rod 6, which improves the connection strength of the armature 4, the guide sleeve 5 and the push rod 6 and realizes the synchronous movement of the three. The armature 4 and the guide sleeve 5 are riveted into the corresponding installation grooves 61 by riveting equipment such as a riveting press, which improves the assembly efficiency of the armature 4 and the guide sleeve 5. Since the riveting assembly is a prior art, the riveting process of the armature 4, the guide sleeve 5 and the push rod 6 will not be described in detail.
[0040] Furthermore, one axial end of the armature 4 is fitted with one axial end of the guide sleeve 5. After the armature 4 and the push rod 6 are assembled by riveting, the guide sleeve 5 is sleeved on the push rod 6 and abuts against one axial end of the armature 4 to limit the position of the guide sleeve 5 during riveting, thereby improving the riveting accuracy of the guide sleeve 5. At the same time, the armature 4 and the guide sleeve 5 are fitted together, which is conducive to shortening the length of the push rod 6, thereby reducing the axial size of the magnetic isolation sleeve 1, and is conducive to miniaturization of the electromagnet.
[0041] like Figure 2 to Figure 4 As shown, the armature 4 is further provided with a first oil hole 42 along the axial direction, and the guide sleeve 5 is further provided with a second oil hole 52 along the axial direction. The armature 4 and the guide sleeve 5 divide the accommodating hole 121 into a first cavity 1211 and a second cavity 1212. The first cavity 1211 is located between the armature 4 and the front yoke 3, and the second cavity 1212 is located on the side of the guide sleeve 5 away from the armature 4. The push rod 6 is provided with a through hole 62 in the axial direction and communicated with the second cavity 1212. The first cavity 1211 is communicated with the second cavity 1212 through the first oil hole 42 and the second oil hole 52.
[0042] The housing 7 of the electromagnet of this embodiment is sealed and assembled with the interface of the actuator to prevent oil leakage. The switch part of the actuator extends into the magnetic isolation sleeve 1. The oil circuit of the actuator is connected with the through hole 62 of the push rod 6, so that the oil enters the second chamber 1212 through the through hole 62, and enters the first chamber 1211 through the second oil hole 52 and the first oil hole 42, so that the first chamber 1211 on the left side of the armature 4 is connected with the second chamber 1212 on the right side of the guide sleeve 5 and is filled with oil. When the coil 2 is energized to generate a magnetic field, the armature 4 is attracted to the front yoke 3, and the armature 4 is guided by the guide sleeve 5 along the axial direction ( Figure 2The armature 2 moves from right to left toward the front yoke 3 (in the left-right direction), and the push rod 6 passes through the inner ring 31 of the front yoke 3 and triggers the switch of the actuator to control the actuator to open. At this time, the oil in the first chamber 1211 is squeezed by the armature 4 and enters the second chamber 1212 through the first oil hole 42 and the second oil hole 52. When the coil 2 is powered off, the oil in the second chamber 1212 enters the first chamber 1211 through the second oil hole 52 and the first oil hole 42. The armature 4 moves from left to right along the axial direction of the magnetic isolation sleeve 1 under the action of the oil pressure in the first chamber 1211 to reset, and the push rod 6 is disconnected from the switch of the actuator, and the switch of the actuator is reset and controls the actuator to close.
[0043] like Figure 1 and Figure 2 As shown, the electromagnet also includes a retaining ring 9 and an elastic member 10. The retaining ring 9 is sleeved on the push rod 6. The push rod 6 moves through the retaining ring 9 and is in clearance with the retaining ring 9. The elastic member 10 is compressed and installed between the retaining ring 9 and the armature 4 to press the retaining ring 9 against the end of the front yoke 3 close to the armature 4. Since the push rod 6 and the inner ring 31 of the front yoke 3 are in clearance, the retaining ring 9 is sleeved on the push rod 6, so that the retaining ring 9 can block the gap between the push rod 6 and the inner ring 31 of the front yoke 3, reduce oil leakage, and have a good interception effect. The elastic member 10 of this embodiment is a compression spring, which is compressed and installed between the armature 4 and the retaining ring 9, so that the compression spring always has an elastic restoring force to press the retaining ring 9 against the right end of the front yoke 3 to ensure the reliable fit of the retaining ring 9 and the front yoke 3.
[0044] The above embodiments are only to illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and modifications, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.
Claims
1. An electromagnet, characterized in that The invention comprises a magnetic core tube assembly, a coil (2), a front yoke (3), an armature (4), a guide sleeve (5) and a push rod (6); the magnetic core tube assembly comprises a magnetic isolation sleeve (1); the coil (2) is sleeved on the magnetic isolation sleeve (1); a receiving hole (121) is provided in the magnetic isolation sleeve (1); and the front yoke (3) blocks an opening of the receiving hole (121); The armature (4) and the guide sleeve (5) are both axially slidably arranged in the accommodating hole (121) along the magnetic isolation sleeve (1); the guide sleeve (5) and the accommodating hole (121) are clearance-matched; the outer diameter of the armature (4) is smaller than the outer diameter of the guide sleeve (5); the push rod (6) movably passes through the front yoke (3) and is fixedly connected to the armature (4) and the guide sleeve (5) respectively; one end of the push rod (6) passes through the front yoke (3).
2. The electromagnet according to claim 1, characterized in that The armature (4) is provided with a first mounting hole (41) along the axial direction, the guide sleeve (5) is provided with a second mounting hole (51) along the axial direction, and one end of the push rod (6) is fixedly passed through the first mounting hole (41) and the second mounting hole (51) in sequence.
3. The electromagnet according to claim 2, characterized in that The push rod (6) is provided with two installation grooves (61) spaced apart in the axial direction, and the inner wall of the first installation hole (41) and the inner wall of the second installation hole (51) are respectively riveted and pressed into the corresponding installation grooves (61).
4. The electromagnet according to claim 3, characterized in that One axial end of the armature (4) fits into one axial end of the guide sleeve (5).
5. The electromagnet according to claim 2, characterized in that The armature (4) is also provided with a first oil hole (42) along the axial direction, and the guide sleeve (5) is also provided with a second oil hole (52) along the axial direction. The armature (4) and the guide sleeve (5) separate the accommodating hole (121) into a first cavity (1211) and a second cavity (1212), wherein the first cavity (1211) is located between the armature (4) and the front yoke (3), and the second cavity (1212) is located on a side of the guide sleeve (5) away from the armature (4); The push rod (6) is provided with a through hole (62) extending axially therethrough and communicating with the second chamber (1212); the first chamber (1211) is connected to the second chamber (1212) via the first oil hole (42) and the second oil hole (52).
6. The electromagnet according to any one of claims 1 to 5, characterized in that: The magnetic core tube assembly also includes a shell (7), the magnetic isolation sleeve (1) is installed in the shell (7), and the coil (2) extends into the shell (7) and is sleeved on the magnetic isolation sleeve (1).
7. The electromagnet according to claim 6, characterized in that The housing (7) is provided with a first inner hole (71), a second inner hole (72) and a third inner hole (73) which are connected in sequence along the axial direction; The magnetic isolation sleeve (1) comprises a first sleeve (11) and a second sleeve (12) connected to each other, the second sleeve (12) is provided with a receiving hole (121) in the axial direction, the receiving hole (121) is closed at one end away from the first sleeve (11), and the front yoke (3) is blocked at one end of the receiving hole (121) close to the first sleeve (11); the first sleeve (11) is inserted into the first inner hole (71), and the first sleeve (11) and the first inner hole (71) are clearance-fitted; the second sleeve (12) is successively inserted into the second inner hole (72) and the third inner hole (73), and the second sleeve (12) and the second inner hole (72) are interference-fitted, and the coil (2) extends into the third inner hole (73) and is sleeved on the second sleeve (12).
8. The electromagnet according to claim 7, characterized in that A first step surface (74) is provided between the first inner hole (71) and the second inner hole (72), a second step surface (13) is provided between the first shaft sleeve (11) and the second shaft sleeve (12), and the first step surface (74) and the second step surface (13) are in limited contact with each other.
9. The electromagnet according to claim 8, characterized in that The outer circumferential surface of the first shaft sleeve (11) is provided with a sealing groove (111), a sealing ring (8) is installed in the sealing groove (111), and the sealing ring (8) is sandwiched between the outer circumferential surface of the first shaft sleeve (11) and the inner side wall of the first inner hole (71).
10. The electromagnet according to any one of claims 1 to 5, characterized in that: The electromagnet also includes a retaining ring (10) and an elastic member (10), wherein the retaining ring (10) is sleeved on the push rod (6), the push rod (6) moves through the retaining ring (10) and is loosely fitted with the retaining ring (10), and the elastic member (10) is compressed and installed between the retaining ring (10) and the armature (4) to press the retaining ring (10) against one end of the front yoke (3) close to the armature (4).