Electric cylinder with external displacement sensor

Abstract

The utility model provides an electric cylinder with an external displacement sensor, which comprises a cylinder body and a displacement sensor, and the displacement sensor comprises a linear displacement ruler and a reading head; a piston rod is movably arranged in the cylinder body; the linear displacement ruler is fixedly arranged outside the cylinder body, and the length extension direction of the linear displacement ruler is the same as the linear motion direction of the piston rod; the reading head is located above the linear displacement ruler, and a gap exists between the reading head and the linear displacement ruler. The reading head is connected with the portion, located on the outer side of the cylinder body, of the piston rod, and the piston rod drives the reading head to move relative to the linear displacement ruler when moving so as to obtain the stroke amount of movement of the piston rod. The electric cylinder is simple in structure, small in occupied space and reliable in measurement result, the cylinder body structure does not need to be damaged, and the reliability of the overall structure and precision of the electric cylinder is guaranteed.

Description

Technical Field

[0001] This application relates to the field of electric cylinder technology, and more specifically, to an electric cylinder with an external displacement sensor. Background Technology

[0002] An electric cylinder is a modular product that integrates a servo motor and a lead screw, converting the rotary motion of the servo motor into linear motion. To meet different needs and improve control performance, an external magnetic scale is required to control the precision of the electric cylinder's reciprocating motion.

[0003] In related technologies, electric cylinders with external magnetic scales typically have a long, narrow opening cut into the cylinder body. A reading head or magnetic scale is connected to a lead screw and nut inside the electric cylinder via mechanical parts at this opening, allowing the reading head or magnetic scale to move with the lead screw and nut, thus measuring the stroke of the piston rod inside the electric cylinder. This structural design significantly reduces the service life of the electric cylinder.

[0004] In view of the above, this application is hereby submitted. Utility Model Content

[0005] This application is made in view of the above problems. According to one aspect of this application, an electric cylinder with an external displacement sensor is provided, comprising: a cylinder body and a displacement sensor, the displacement sensor including a linear displacement ruler and a reading head;

[0006] A piston rod is movably disposed inside the cylinder; a linear displacement gauge is fixedly disposed outside the cylinder, and the length extension direction of the linear displacement gauge is the same as the linear movement direction of the piston rod.

[0007] The reading head is located above the linear displacement ruler and there is a gap between the reading head and the linear displacement ruler; the reading head is connected to the part of the piston rod located outside the cylinder body, and when the piston rod moves, it drives the reading head to move relative to the linear displacement ruler in order to obtain the stroke of the piston rod.

[0008] For example, the electric cylinder also includes a pull rod and a linkage plate; the pull rod is parallel to the piston rod; one end of the pull rod is connected to the reading head, and the other end is connected to the portion of the piston rod located outside the cylinder body through the linkage plate.

[0009] For example, the electric cylinder also includes a connector; the pull rod is connected to the reading head via the connector.

[0010] For example, a slide rail is fixedly provided on the outer side of the cylinder body; the length extension direction of the slide rail is the same as the linear movement direction of the piston rod; a slider is provided on the slide rail; one side of the connector is connected to the top of the reading head, and the other side is connected to the top of the slider.

[0011] For example, the cylinder body is provided with a front limiting post, which is located in front of the slider along the slider moving direction, and when the piston rod moves forward to the maximum stroke, the front side of the slider contacts the front limiting post.

[0012] For example, the cylinder body is provided with a rear limiting post, which is located behind the slider along the slider moving direction, and when the piston rod moves backward to the maximum stroke, the rear side of the slider contacts the rear limiting post.

[0013] For example, the connector includes a first connecting plate, a second connecting plate, and a third connecting plate; the first connecting plate is vertically arranged, and the second connecting plate and the third connecting plate are respectively fixed on both sides of the first connecting plate; the second connecting plate is connected to the top of the reading head, and the third connecting plate is connected to the top of the slider.

[0014] For example, the connector further includes a fourth connecting plate; the fourth connecting plate is fixed to the first connecting plate and the fourth connecting plate and the second connecting plate are located on the same side of the first connecting plate;

[0015] The reading head is connected to a cable, and a cable chain is provided on the outside of the cable; one side of the cable chain is fixed to the fourth connecting plate, and the other side of the cable chain is fixed to the cylinder body.

[0016] For example, a fixing plate is installed on the top of the cylinder; a cover is provided on the fixing plate;

[0017] The linear displacement gauge is fixed on the fixed plate, and both the linear displacement gauge and the reading head are located within the working space formed by the cover and the fixed plate.

[0018] For example, the electric cylinder also includes a drive motor and a transmission component; the drive motor is connected to the piston rod via the transmission component.

[0019] Compared with existing technologies, in this application, a gap exists between the reading head and the linear displacement ruler. This non-contact arrangement prevents direct contact between the reading head and the linear displacement ruler, thus avoiding frictional wear and extending the service life of both. Furthermore, this design eliminates the need for an external frame for the linear displacement ruler, simplifying the structure, reducing space requirements, and facilitating structural design and layout. Additionally, the reading head is directly connected to the piston rod located on the outer side of the cylinder. This connection method avoids damaging the cylinder structure, preserving its strength and rigidity, and ensuring a relatively enclosed internal environment, thereby extending the lifespan of the electric cylinder. Moreover, this connection allows for direct sampling of the piston rod with high accuracy, avoiding the impact of intermediate component deformation on sampling precision, thus providing more precise data for the feedback control of the electric cylinder. In summary, the electric cylinder of this application has a simple structure, occupies less space, provides reliable measurement results, and does not damage the cylinder structure, ensuring the overall structural and accuracy reliability of the electric cylinder.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of an electric cylinder with an external displacement sensor according to an embodiment of this application;

[0023] Figure 2 for Figure 1 A schematic diagram of the internal structure of the electric cylinder shown.

[0024] Figure 3 for Figure 2 Top view of the structure shown;

[0025] Figure 4 for Figure 2 Right view of the structure shown;

[0026] Figure 5 for Figure 2 Left view of the structure shown;

[0027] Figure 6 This is a schematic diagram of the connection relationship of the connectors according to an embodiment of this application.

[0028] In the diagram: 1. Drive motor; 2. Cylinder body; 3. Piston rod; 4. Linkage plate; 5. Tie rod; 6. Cover; 7. Transmission component; 8. Slide rail; 9. Linear displacement gauge; 10. Cable chain; 11. Front limit post; 12. Cable; 13. Reading head; 14. Connector; 1401. First connecting plate; 1402. Second connecting plate; 1403. Third connecting plate; 1404. Fourth connecting plate; 15. Slider; 16. Rear limit post; 17. Fixing plate. Detailed Implementation

[0029] In the following description, numerous details are provided to enable a thorough understanding of the present invention. However, those skilled in the art will appreciate that the following description pertains only to preferred embodiments of the present invention, which may be practiced without one or more of these details. Furthermore, to avoid confusion with the present invention, some technical features well-known in the art have not been described.

[0030] An electric cylinder is a modular product that integrates a servo motor and a lead screw. It comprises a cylinder body, a lead screw, a lead screw nut, and a piston rod. The lead screw nut is connected to the piston rod and is mounted on the lead screw. External power drives the lead screw to rotate, causing the lead screw nut to move back and forth along the lead screw, which in turn moves the piston rod back and forth. As described above, adding a magnetic scale to the electric cylinder in related technologies reduces its lifespan. Specifically, the opening in the cylinder body reduces its strength and rigidity, increases its stress deformation, and consequently reduces the cylinder's precision. The opening also allows direct contact between the cylinder's interior and air, making it easier for foreign objects to fall in and affect its operation; furthermore, the direct contact between the lubricating grease and air reduces its lifespan. All these factors ultimately lead to a reduced lifespan for the electric cylinder. Furthermore, as described above, in related technologies, the sampling point of an electric cylinder with an external magnetic scale is the lead screw nut connected to the piston rod. This means that the sampling point is not the final part to be measured (i.e., the piston rod), but rather an intermediate transmission component. Therefore, the stroke measured by the reading head is the stroke of the lead screw nut, not the stroke of the piston rod. Since the intermediate transmission component may deform during movement, there may be a difference between the stroke of the lead screw nut and the stroke of the piston rod, resulting in poor measurement accuracy. Additionally, electric cylinders with external magnetic scales in related technologies typically use a framed magnetic scale, with the reading head slidably mounted on the frame. This structure results in a large space occupation by the magnetic scale, and the reading head may wear against the frame during movement relative to the magnetic scale, potentially causing damage to the reading head. To at least solve some of the above technical problems, this application provides an electric cylinder with an external displacement sensor. This electric cylinder has a simple structure, occupies less space, provides reliable measurement results, and does not require damage to the cylinder structure, ensuring the overall structural and accuracy reliability of the electric cylinder. The specific structure and working principle of this electric cylinder are described in detail below.

[0031] To more clearly illustrate the technical solutions in this application, the following description is provided in the form of specific embodiments.

[0032] Example

[0033] See also Figure 1-6This embodiment provides an electric cylinder with an external displacement sensor. The electric cylinder includes a cylinder body 2 and a displacement sensor, which includes a linear displacement ruler 9 and a reading head 13. A piston rod 3 is movably disposed inside the cylinder body 2. The linear displacement ruler 9 is fixedly disposed outside the cylinder body 2, and the length extension direction of the linear displacement ruler 9 is the same as the linear movement direction of the piston rod 3. The reading head 13 is located above the linear displacement ruler 9, and there is a gap between the reading head 13 and the linear displacement ruler 9. The reading head 13 is connected to the portion of the piston rod 3 located outside the cylinder body 2. When the piston rod 3 moves, it drives the reading head 13 to move relative to the linear displacement ruler 9 to obtain the stroke amount of the piston rod 3.

[0034] Optionally, the linear displacement ruler 9 can be directly fixed to the outside of the cylinder body 2, or indirectly fixed to the outside of the cylinder body 2, for example, by fixing it to the outside of the cylinder body 2 through the fixing plate 17 described below, which will not be elaborated further.

[0035] In this document, the linear displacement ruler can be an optical grating ruler, a magnetic grating ruler, or other existing or future linear displacement sensing elements. In one specific embodiment, the linear displacement ruler can be a magnetic grating ruler.

[0036] In this embodiment, when the piston rod 3 moves, it can drive the reading head 13 to move relative to the linear displacement ruler 9. During this movement, the reading head 13 can emit a feedback signal, through which the stroke and speed of the piston rod 3 can be obtained. This feedback signal provides precise information for the feedback control of the electric cylinder, contributing to accurate feedback and control.

[0037] In this embodiment, a gap exists between the reading head 13 and the linear displacement ruler 9. This non-contact arrangement prevents direct contact between the reading head 13 and the linear displacement ruler 9, thus avoiding frictional wear and extending the service life of both. Furthermore, this design eliminates the need for an external frame for the linear displacement ruler 9, simplifying the structure, reducing space requirements, and facilitating structural design and layout. Additionally, the reading head 13 is directly connected to the portion of the piston rod 3 located outside the cylinder body 2. This connection method avoids damaging the structure of the cylinder body 2, preserving its strength and rigidity, and maintaining a relatively enclosed internal environment, thereby extending the lifespan of the electric cylinder. Moreover, this connection method allows for direct sampling of the piston rod 3 with high accuracy, avoiding the impact of intermediate component deformation on sampling precision, thus providing more precise data for the feedback control of the electric cylinder. In summary, the electric cylinder in this embodiment has a simple structure, occupies less space, provides reliable measurement results, and does not damage the structure of the cylinder body 2, ensuring the overall structural and accuracy reliability of the electric cylinder.

[0038] For example, in conjunction with reference Figure 2 and Figure 3 The electric cylinder also includes a pull rod 5 and a linkage plate 4; the pull rod 5 is parallel to the piston rod 3; one end of the pull rod 5 is connected to the reading head 13, and the other end is connected to the part of the piston rod 3 located outside the cylinder body 2 through the linkage plate 4.

[0039] In such Figure 2 In the described embodiment, the linkage plate 4 has two openings, one of which is adapted to the pull rod 5, and the other is adapted to the piston rod 3. During installation, the piston rod 3 and the pull rod 5 can be connected through the openings on the linkage plate 4, and the linkage plate 4 can be fixed to the piston rod 3 and the pull rod 5 with nuts.

[0040] The above technical solution has a simple structure. The connection structure composed of the pull rod 5 and the linkage plate 4 can ensure that the reading head 13 moves with the piston rod 3, thereby helping to ensure the accuracy of the stroke measured by the reading head 13.

[0041] For example, such as Figure 2 As shown, the electric cylinder also includes a connector 14; the pull rod 5 is connected to the reading head 13 via the connector 14. This connection method can improve the overall structural strength and allows for some positional adjustment between the pull rod 5 and the reading head 13 to adapt to different installation requirements.

[0042] For example, in conjunction with reference Figure 2 and Figure 3 A slide rail 8 is fixedly installed on the outside of the cylinder body 2; the length extension direction of the slide rail 8 is the same as the linear movement direction of the piston rod 3; a slider 15 is installed on the slide rail 8; one side of the connector 14 is connected to the top of the reading head 13, and the other side is connected to the top of the slider 15.

[0043] In this example, when the piston rod 3 drives the reading head 13 to move relative to the linear displacement ruler 9, the slider 15 can move together with the reading head 13 via the connecting piece 14. The structure consisting of the slider 15 and the slide rail 8 can support and limit the reading head 13, ensuring that the relative position of the reading head 13 and the linear displacement ruler 9 is precisely fixed. This helps to improve the stability of the reading head 13 during its movement relative to the linear displacement ruler 9, ensuring that the reading head 13 always moves relative to the linear displacement ruler 9 in a non-contact manner.

[0044] For example, in conjunction with reference Figure 2 , Figure 3 and Figure 5 The cylinder body 2 is provided with a front limit post 11. The front limit post 11 is located in front of the slider 15 along the moving direction of the slider 15, and when the piston rod 3 moves forward to the maximum stroke, the front side of the slider 15 contacts the front limit post 11.

[0045] In this example, when the piston rod 3 moves forward to its limit position (i.e., when the piston rod 3 moves forward to its maximum stroke), the front side of the slider 15 contacts the front limit post 11. This limits the range of motion of the slider 15, preventing it from exceeding its designed trajectory in extreme cases, thereby avoiding damage to the mechanical structure.

[0046] For example, in conjunction with reference Figure 2 , Figure 3 and Figure 5 The cylinder body 2 is provided with a rear limit post 16. The rear limit post 16 is located behind the slider 15 along the moving direction of the slider 15, and when the piston rod 3 moves backward to the maximum stroke, the rear side of the slider 15 contacts the rear limit post 16.

[0047] In this example, when the piston rod 3 moves backward to its limit position (i.e., when the piston rod 3 moves backward to its maximum stroke), the rear side of the slider 15 contacts the front limit post 11. This limits the range of motion of the slider 15, preventing it from exceeding its designed trajectory in extreme cases, thereby avoiding damage to the mechanical structure.

[0048] For example, such as Figure 6 As shown, the connector 14 includes a first connecting plate 1401, a second connecting plate 1402, and a third connecting plate 1403. The first connecting plate 1401 is vertically arranged, and the second connecting plate 1402 and the third connecting plate 1403 are respectively fixed on both sides of the first connecting plate 1401. The second connecting plate 1402 is connected to the top of the reading head 13, and the third connecting plate 1403 is connected to the top of the slider 15. This structural design can improve the connection stability between the reading head 13 and the slider 15, thereby ensuring that the slider 15 can always move with the reading head 13.

[0049] For example, such as Figure 6 As shown, the connector 14 also includes a fourth connecting plate 1404; the fourth connecting plate 1404 is fixed on the first connecting plate 1401 and the fourth connecting plate 1404 and the second connecting plate 1402 are located on the same side of the first connecting plate 1401; the reading head 13 is connected to a cable 12, and a cable chain 10 is provided on the outside of the cable 12; one side of the cable chain 10 is fixed to the fourth connecting plate 1404, and the other side of the cable chain 10 is fixed to the cylinder 2. This solution, by providing a cable chain 10 on the outside of the cable 12, can protect and guide the cable 12, ensuring that it is not damaged during the movement of the reading head 13.

[0050] For example, such as Figure 1 As shown, a fixing plate 17 is installed on the top of the cylinder body 2; a cover 6 is installed on the fixing plate 17; a linear displacement ruler 9 is fixed on the fixing plate 17, and the linear displacement ruler 9 and the reading head 13 are both located in the working space formed by the cover 6 and the fixing plate 17.

[0051] In such Figure 2 In the illustrated embodiment, the slide rail 8, the front limit post 11, and the rear limit post 16 are all fixed to the fixing plate 17, and the other side of the cable chain 10 is fixed to the cylinder body 2 via the fixing plate 17. Furthermore, the slide rail 8, the front limit post 11, the rear limit post 16, the cable chain 10, and other structures are all located within the working space formed by the cover 6 and the fixing plate 17. One end of the pull rod 5 extends through the cover 6 and connects to the linkage plate 4.

[0052] The above solution, by setting the fixing plate 17 and the cover 6, can reduce the impact on the cylinder 2 (only the fixing plate 17 needs to be installed on the cylinder 2), and can provide a relatively enclosed working space for the reading head 13 and the linear displacement ruler 9, preventing foreign objects from falling onto the slide rail 8 or the linear displacement ruler 9 and affecting the operation of the reading head 13. This helps to ensure the accuracy of the results obtained by the reading head 13 and improve the service life of components such as the reading head 13 and the linear displacement ruler 9.

[0053] For example, such as Figure 1-2 As shown, the electric cylinder also includes a drive motor 1 and a transmission component 7; the drive motor 1 is connected to the piston rod 3 via the transmission component 7.

[0054] In some embodiments, a lead screw and a lead screw nut are provided inside the cylinder body 2. One end of the lead screw extends out of the cylinder body 2 and is connected to the transmission component 7. The lead screw nut is mounted on the lead screw and is connected to the piston rod 3. Rotation of the lead screw drives the lead screw nut to move back and forth, thereby driving the piston rod 3 to move back and forth. In this embodiment, the transmission component 7 may include a meshing driving gear and a driven gear. The driving gear is mounted on the drive shaft of the drive motor 1, and the driven gear is mounted on the lead screw. Of course, in addition to gear transmission, the transmission component 7 may also be designed using belt transmission, chain transmission, etc., which will not be elaborated further. The overall structure of the electric cylinder in this solution is simple and can stably drive the piston rod 3.

[0055] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front", "back", "up", "down", "left", "right", "horizontal", "vertical", "horizontal", "top", and "bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0056] For ease of description, relative terms such as "above," "over," "on the upper surface of," and "above" are used here to describe the regional positional relationship of one or more components or features shown in the figures to other components or features. It should be understood that relative terms include not only the orientation of the component as depicted in the figure but also different orientations during use or operation. For example, if the components in the figures are inverted as a whole, "above" or "above other components or features" will include cases where the component is "below" or "under" other components or features. Thus, the exemplary term "above" can include both "above" and "below." Furthermore, these components or features may also be positioned at other different angles (e.g., rotated 90 degrees or other angles), and this document intends to include all such cases.

[0057] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, components, parts, and / or combinations thereof.

[0058] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0059] This application has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the scope of the described embodiments. Furthermore, those skilled in the art will understand that this application is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of this application, all of which fall within the scope of protection claimed in this application. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. An electric cylinder with an external displacement sensor, characterized in that, include: A cylinder block and a displacement sensor, wherein the displacement sensor includes a linear displacement ruler and a reading head; A piston rod is movably disposed inside the cylinder; a linear displacement gauge is fixedly disposed outside the cylinder, and the length extension direction of the linear displacement gauge is the same as the linear movement direction of the piston rod. The reading head is located above the linear displacement ruler and there is a gap between the reading head and the linear displacement ruler; the reading head is connected to the part of the piston rod located outside the cylinder body, and when the piston rod moves, it drives the reading head to move relative to the linear displacement ruler in order to obtain the stroke of the piston rod.

2. The electric cylinder with an external displacement sensor according to claim 1, characterized in that, It also includes a pull rod and a linkage plate; the pull rod is parallel to the piston rod; one end of the pull rod is connected to the reading head, and the other end is connected to the portion of the piston rod located outside the cylinder body through the linkage plate.

3. The electric cylinder with an external displacement sensor according to claim 2, characterized in that, It also includes a connector; the pull rod is connected to the reading head via the connector.

4. The electric cylinder with an external displacement sensor according to claim 3, characterized in that, A slide rail is fixedly installed on the outside of the cylinder body; the length extension direction of the slide rail is the same as the linear movement direction of the piston rod; a slider is provided on the slide rail; one side of the connector is connected to the top of the reading head, and the other side is connected to the top of the slider.

5. The electric cylinder with an external displacement sensor according to claim 4, characterized in that, The cylinder is provided with a front limiting post, which is located in front of the slider along the slider moving direction, and the front side of the slider contacts the front limiting post when the piston rod moves forward to the maximum stroke.

6. The electric cylinder with an external displacement sensor according to claim 4, characterized in that, The cylinder body is provided with a rear limiting post, which is located behind the slider along the slider moving direction, and when the piston rod moves backward to the maximum stroke, the rear side of the slider contacts the rear limiting post.

7. The electric cylinder with an external displacement sensor according to claim 4, characterized in that, The connector includes a first connecting plate, a second connecting plate, and a third connecting plate; the first connecting plate is vertically arranged, and the second connecting plate and the third connecting plate are respectively fixed on both sides of the first connecting plate; the second connecting plate is connected to the top of the reading head, and the third connecting plate is connected to the top of the slider.

8. The electric cylinder with an external displacement sensor according to claim 7, characterized in that, The connector further includes a fourth connecting plate; the fourth connecting plate is fixed to the first connecting plate and the fourth connecting plate and the second connecting plate are located on the same side of the first connecting plate; The reading head is connected to a cable, and a cable chain is provided on the outside of the cable; one side of the cable chain is fixed to the fourth connecting plate, and the other side of the cable chain is fixed to the cylinder body.

9. The electric cylinder with an external displacement sensor according to any one of claims 1-8, characterized in that, A fixing plate is installed on the top of the cylinder; a cover is provided on the fixing plate. The linear displacement gauge is fixed on the fixed plate, and both the linear displacement gauge and the reading head are located within the working space formed by the cover and the fixed plate.

10. The electric cylinder with an external displacement sensor according to any one of claims 1-8, characterized in that, It also includes a drive motor and a transmission component; the drive motor is connected to the piston rod via the transmission component.

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