Electric cylinder

Abstract

An electric cylinder comprises an outer cylinder, a sliding unit and a screw, at least one guide groove extending in the longitudinal direction is formed in the inner wall of the outer cylinder, the sliding unit comprises a nut, a rotation limiting piece and an output shaft, the rotation limiting piece is combined with the first end of the nut and provided with at least one guide block used for being combined in the guide groove of the outer cylinder, and the output shaft is connected with the screw. One end of the force output shaft is combined with the second end of the nut, the screw and the nut are combined in a relative movement mode, when the screw rotates, the nut, the rotation limiting piece and the force output shaft can move relative to the screw in the longitudinal direction, and the guide block can move in the guide groove in the longitudinal direction. Therefore, the nut and the output shaft are prevented from rotating relative to the outer cylinder. Therefore, the sliding seat and the nut of the sliding unit are integrated to simplify the structure of the electric cylinder, the assembly is convenient, the combination tolerance is reduced, and the operation precision of the electric cylinder is improved. Further, a rotation restrictor of the electric cylinder is designed to effectively prevent rotation of the sliding unit during movement, and to facilitate assembly of the rotation restrictor and an outer cylinder.

Description

Technical Field

[0001] This invention relates to an electric cylinder, and more particularly to a sliding unit for an electric cylinder. Background Technology

[0002] Electric cylinders or slides, widely used on industrial machines, utilize motors as power sources and are driven by screws to enable linear movement of the load end. Figure 1 and Figure 2 A conventional electric cylinder is disclosed, comprising an outer cylinder 10, a sliding unit 12 housed within the outer cylinder 10, and a screw 14. The inner wall of the outer cylinder 10 has two opposing guide grooves 16. The sliding unit 12 includes a slide block 18, a nut 20, and an output shaft 22. The slide block 18 has a first end 24 and a second end 26 separated along a longitudinal direction, and has a through hole 28 extending along the longitudinal direction internally. The nut 20 is fixed to the first end 24 of the slide block 18 by a screw 30, and one end of the output shaft 22 is coupled to the second end 26 of the slide block 18, such that the slide block 18, the nut 20, and the output shaft 22 can move together within the outer cylinder 10 along the longitudinal direction. The inner wall of the nut 20 has a helical inner groove 32. The outer section of the screw 14 passes through the interior of the nut 20 and the through hole 28 of the slide 18. The outer periphery of the screw 14 has a spiral outer groove 34. Ball bearings 36 are located between the outer groove 34 and the inner groove 32 of the nut, so that when the screw 14 rotates, the nut 20 is driven to move relative to the screw 14 along the longitudinal direction. In this embodiment, the inner section of the screw 14 is attached to a mounting base 38, which can be connected to a motor (not shown), and the screw 14 can be connected to the motor's shaft (not shown), allowing the screw 14 to be driven by the motor. Furthermore, the outer periphery of the slide 18 is provided with two opposing guide blocks 40, which are respectively located within the two guide grooves 16 of the outer cylinder 10, preventing rotation of the slide 18 and the output shaft 22 when they move within the outer cylinder 10.

[0003] However, the sliding unit 12 has many components, making assembly time-consuming. Furthermore, the combination of these components is prone to tolerances, reducing the accuracy of the linear motion of the sliding unit 12 and negatively impacting the operating accuracy of the electric cylinder. Moreover, the connection of the two guide blocks 40 to the slide block 18 using screws 42 complicates the structure of the sliding unit 12. Additionally, screw tightening is prone to deviations, hindering the smooth placement of the guide blocks 40 into the guide groove 16 and introducing assembly tolerances. This can cause the slide block 18 to move unevenly or wobble, thus affecting the stability of the linear motion of the sliding unit 12. Summary of the Invention

[0004] The purpose of this invention is to provide an electric cylinder that integrates the sliding unit's slide block and nut into one unit to simplify the electric cylinder's structure, facilitate assembly, reduce assembly tolerances, and improve the electric cylinder's operating accuracy. Furthermore, the rotation limiting component of this electric cylinder is designed to effectively prevent the sliding unit from rotating during movement and facilitates the assembly of the rotation limiting component with the outer cylinder.

[0005] To achieve the above objectives, the present invention discloses an electric cylinder, characterized by comprising:

[0006] An outer cylinder has an interior containing a longitudinally extending storage hole, the wall of which is provided with at least one guide groove extending along the longitudinal direction.

[0007] A sliding unit includes a nut, a rotation limiting member, and an output shaft. The nut has a through hole extending longitudinally inside and has a first end and a second end separated along the longitudinal direction. The rotation limiting member is attached to the first end of the nut and includes an annular body with a through hole inside. At least one guide block is provided around the outer periphery of the body for engaging with a guide groove in an outer cylinder. One end of the output shaft is attached to the second end of the nut.

[0008] A screw and a nut are connected in a movable relationship. The screw has an inner section and an outer section separated along a longitudinal direction. The inner section of the screw is connected to a drive member to drive the screw to rotate. The outer section of the screw extends through the through hole of the rotation limiter and the through hole of the nut. When the screw rotates, the nut, the rotation limiter and the output shaft move relative to the screw along the longitudinal direction. The rotation limiter guide block moves along the longitudinal direction in the corresponding guide groove to limit the nut and the output shaft from rotating relative to the outer cylinder.

[0009] The nut has a spiral inner groove in the wall of the perforation, and the screw has a spiral outer groove around its outer periphery. There are balls between the outer groove and the inner groove of the nut, so that when the screw rotates, the nut will be driven to move relative to the screw along the longitudinal direction. The perforation at the first end of the nut has an opening with an enlarged diameter, and the opening accommodates a stop ring.

[0010] The nut has at least one engagement groove around its outer periphery, and the body is contained in a first side and a second side facing each other in the longitudinal direction. The first side has at least one engagement portion for engaging with the engagement groove of the nut.

[0011] The connecting groove is an annular groove adjacent to the first end of the nut. The first surface of the body has multiple connecting portions separated along the circumferential direction. Each connecting portion extends along the longitudinal direction and has a hook to engage with the connecting groove.

[0012] The storage hole has multiple guide grooves separated along the circumferential direction on its wall, and the outer circumference of the main body has multiple guide blocks separated along the circumferential direction. Each guide block is engaged in a corresponding guide groove of the outer cylinder.

[0013] The guide block extends along the longitudinal direction and has two ends separated along the longitudinal direction, each end having a notch and two guide arms separated by the notch.

[0014] The guide block has a first width at its end in a width direction, and the guide groove has a second width, wherein the first width is equal to or greater than the second width.

[0015] The guide block has an arc-shaped recess in the middle of its side surface.

[0016] The second surface has multiple positioning portions spaced along the circumferential direction, each positioning portion extending along the longitudinal direction. The sliding unit further includes a ring-shaped magnet disposed on the second surface of the body and positioned between the multiple positioning portions and the multiple guide blocks.

[0017] Therefore, the present invention can achieve the following technical effects through the above structure:

[0018] 1. Simple structure, easy operation, and convenient maintenance.

[0019] 2. The sliding unit has relatively few components, which can effectively simplify the structure of the electric cylinder, facilitate the assembly of the electric cylinder, and reduce assembly tolerances.

[0020] 3. The rotation limiting component of the electric cylinder can be easily assembled with the nut and the outer cylinder, and can ensure the smooth sliding of the sliding unit in the outer cylinder and effectively prevent rotation, thereby improving the working accuracy of the electric cylinder.

[0021] 4. The stop ring can effectively prevent the ball from falling out, and the arc-shaped concave part can reduce the friction between the guide block and the groove wall of the guide groove, thereby ensuring the smooth sliding of the guide block in the guide groove. The rotation limiter can also continue to function without rotating relative to the outer cylinder after long-term use, which can effectively prevent the sliding unit from rotating during movement and facilitate the assembly of the rotation limiter and the outer cylinder.

[0022] Other objects, advantages and features of the present invention can be understood from the following detailed description of preferred embodiments and with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is an exploded view of some components of a conventional electric cylinder.

[0024] Figure 2 for Figure 1 A combined sectional view.

[0025] Figure 3 This is a perspective view of the electric cylinder of the present invention.

[0026] Figure 4 for Figure 3 An exploded view of most of the components of an electric cylinder.

[0027] Figure 5 for Figure 3 A longitudinal sectional view of an electric cylinder.

[0028] Figure 6 for Figure 3 A cross-sectional view of an electric cylinder.

[0029] Figure 7 for Figure 5 A schematic diagram showing the sliding unit moving outward relative to the screw.

[0030] Figure 8 for Figure 4 Component exploded view of the sliding unit.

[0031] Figure 9 show Figure 4 A schematic diagram showing the screw passing through the nut of the sliding unit and the rotation limiter.

[0032] Figure 10 This is a schematic diagram showing the assembly of the guide block of the rotation limiter being engaged with the guide groove of the outer cylinder. Detailed Implementation

[0033] This invention can have many different structural embodiments. A specific embodiment, which is merely an example and not intended to be limiting, will now be described with reference to the accompanying drawings, highlighting a preferred structural aspect of the invention:

[0034] like Figures 3 to 10 The diagram shows an electric cylinder 50 according to an embodiment of the present invention. The electric cylinder 50 includes an outer cylinder 52, a sliding unit 54 housed within the outer cylinder 52, and a screw 56. The screw 56 is driven by a drive member, such as a motor 58, to cause the sliding unit 54 to move linearly within the outer cylinder 52. The motor 58 may be, for example, a servo motor or a step motor, and includes a rotating shaft 60. In this embodiment, the screw 56 is, for example, a ball screw, having an inner section 61 and an outer section 62 separated along a longitudinal direction, and a helical outer groove 63 around the outer periphery of the screw 56. The inner section 61 of the screw 56 is coupled to a mounting base 64 and connected to the rotating shaft 60 of the motor 58, such that the screw 56 can be driven to rotate by the motor 58. The mounting base 64 connects the motor 58 and the outer cylinder 52. The outer cylinder 52 has an internal receiving hole 66 for accommodating the sliding unit 54 and the screw 56 (see...). Figure 5The wall of the receiving hole 66 (the inner wall of the outer cylinder 52) is provided with a plurality of guide grooves 68 spaced along the circumferential direction (see...). Figure 6 The guide groove 68 extends along the longitudinal direction. In this embodiment, the inner wall of the outer cylinder 52 is provided with four guide grooves 68.

[0035] The technical feature of this invention lies in the sliding unit 54, which includes a nut 70, a rotation limiting member 72, and a force output shaft 74 (see...). Figure 8 and Figure 9 The nut 70 is generally cylindrical and has an internal perforation 76 extending along the longitudinal direction. The nut 70 further has a first end 78 and a second end 80 separated along the longitudinal direction. The wall of the perforation 76 of the nut 70 has a spiral internal groove 82 (see...). Figure 5 The outer section 62 of the screw 56 extends through the through hole 76 of the nut 70. A ball bearing 84 is present between the inner groove 82 and the outer groove 63 of the screw 56, such that when the screw 56 rotates, the nut 70 is driven to move relative to the screw 56 along the longitudinal direction. Furthermore, at least one engagement groove 86 is provided around the outer periphery of the nut 70 to provide engagement with the rotation restraint 72 (see...). Figure 9 In this embodiment, the engaging groove 86 is an annular groove adjacent to the first end 78 of the nut 70. The second end 80 of the nut 70 is provided with external threads 88 to provide engagement with the output shaft 74. Furthermore, the through hole 76 at the first end 78 of the nut 70 is provided with an enlarged opening 90, which accommodates a stop ring 92 to prevent the ball bearing 84 from disengaging (see...). Figure 5 ).

[0036] like Figure 8 and Figure 9 As shown, the rotation limiting member 72 is attached to the first end 78 of the nut 70 and includes an annular body 94. The body 94 has a through hole 95 through which the screw 56 can pass. The body 94 includes a first surface 96 and a second surface 98 that are opposite each other in the longitudinal direction. The first surface 96 has at least one engaging portion 100 for engaging in the engaging groove 86 of the nut 70. In this embodiment, the first surface 96 of the body 94 has a plurality of engaging portions 100 spaced along the circumferential direction. Each engaging portion 100 extends along the longitudinal direction and has a hook portion 102 for engaging in the engaging groove 86. The second surface 98 has a plurality of positioning portions 104 spaced along the circumferential direction. Each positioning portion 104 extends along the longitudinal direction and has a hook portion 105. Furthermore, at least one guide block 106 is provided around the outer periphery of the main body 94 for engaging within the guide groove 68 of the outer cylinder 52. In this embodiment, four guide blocks 106 are provided around the outer periphery of the main body 94, spaced along the circumferential direction, and each guide block 106 engages within a corresponding guide groove 68 of the outer cylinder 52 (see...). Figure 6When the nut 70 moves relative to the screw 56 along the longitudinal direction, the guide block 106 moves along the longitudinal direction within the corresponding guide groove 68. In this embodiment, the guide block 106 extends along the longitudinal direction and has two ends 108 separated along the longitudinal direction. Each end 108 has a notch 110 and two guide arms 112 separated by the notch 110 (see...). Figure 10 In this embodiment, the notch 110 forms an enlarged opening at the end face of the end 108, resulting in a V-shaped cross-section. The end 108 of the guide block 106 has a first width (w1) in a width direction, and the guide groove 68 has a second width (w2). The first width (w1) is equal to or slightly larger than the second width (w2), such that after compressing the two guide arms 112 of the end 108, the guide block 106 can be fitted into the guide groove 68 and contact the groove wall of the guide groove 68. Therefore, when the nut 70 moves relative to the screw 56 along the longitudinal direction, it can be ensured that the nut 70 and the rotation restraint 72 will not rotate relative to the outer cylinder 52. Furthermore, an arc-shaped recess 116 is provided in the middle of the side surface 114 of the guide block 106 to reduce the friction between the guide block 106 and the groove wall of the guide groove 68, thereby ensuring that the guide block 106 can slide smoothly in the guide groove 68, and that the rotation limiting member 72 can continue to not rotate relative to the outer cylinder 52 even after long-term use. In this embodiment, the rotation limiting member 72 is made of a wear-resistant material.

[0037] like Figure 7 and Figure 8 As shown, the output shaft 74 is a cylindrical hollow rod, with its inner end 118 engaging with the second end 80 of the nut 70, so that when the screw 56 rotates, the output shaft 74 and the nut 70 move together along the longitudinal direction. In this embodiment, the inner end 118 of the output shaft 74 is provided with an internal thread 120 that can be screwed into the external thread 88 of the nut 70. The outer section 62 of the screw 56 passes through the through hole 76 of the nut 70 and is located inside the output shaft 74. In this embodiment, the outer end 122 of the output shaft 74 is connected to a connector 124 for connecting the object driven by the electric cylinder 50.

[0038] In this embodiment, the sliding unit 54 further includes a ring-shaped magnet 126 and a shock-absorbing ring 128. The magnet 126 is disposed on the second surface 98 of the body 94 and is located between the plurality of positioning portions 104 and the plurality of guide blocks 106, and the magnet 126 is fixed by the hook portion 105 of the positioning portion 104 (see...). Figure 9 The magnet 126 can be used in conjunction with a sensor (not shown) to sense the movement position of the nut 70. In one embodiment, the sensor is, for example, a reed switch and is located on the outer cylinder 52.

[0039] In operation, when the motor 58 rotates forward and backward, the screw 56 is driven to extend or retract the nut 70 and the output shaft 74 along the longitudinal direction within the outer cylinder 52. At this time, the movement of the guide block 106 of the rotation limiting member 72 within the guide groove 68 of the outer cylinder 52 prevents the nut 70 and the output shaft 74 from rotating relative to the outer cylinder 52 during the movement.

[0040] The sliding unit 54 according to the present invention has relatively few components (including a nut 70, a rotation limiting member 72, and a power output shaft 74), which can effectively simplify the structure of the electric cylinder 50, facilitate the assembly of the electric cylinder 50, and reduce assembly tolerances. Furthermore, the rotation limiting member 72 of the electric cylinder 50 can be easily assembled with the nut 70 and the outer cylinder 52, and can ensure smooth sliding of the sliding unit 54 within the outer cylinder 52 while effectively preventing rotation, thereby improving the operating accuracy of the electric cylinder.

[0041] The foregoing description is based on a specific embodiment of the present invention, and it is understood that various changes or modifications can be made according to the design features of the present invention. Therefore, obvious substitutions and modifications that can be made by those skilled in the art are still included within the scope of the patent claimed by the present invention.

Claims

1. An electric cylinder, characterized in that... include: An outer cylinder has an interior containing a longitudinally extending storage hole, the wall of which is provided with at least one guide groove extending along the longitudinal direction. A sliding unit includes a nut, a rotation limiting member, and an output shaft. The nut has a through hole extending longitudinally inside and has a first end and a second end separated along the longitudinal direction. The rotation limiting member is attached to the first end of the nut and includes an annular body with a through hole inside. At least one guide block is provided around the outer periphery of the body for engaging with a guide groove in an outer cylinder. One end of the output shaft is attached to the second end of the nut. A screw and a nut are connected in a movable relationship. The screw has an inner section and an outer section separated along a longitudinal direction. The inner section of the screw is connected to a drive member to drive the screw to rotate. The outer section of the screw extends through the through hole of the rotation limiter and the through hole of the nut. When the screw rotates, the nut, the rotation limiter and the output shaft move relative to the screw along the longitudinal direction. The rotation limiter guide block moves along the longitudinal direction in the corresponding guide groove to limit the nut and the output shaft from rotating relative to the outer cylinder.

2. The electric cylinder as described in claim 1, characterized in that, The nut has a spiral inner groove in the perforation wall and a spiral outer groove around the outer periphery of the screw. There are balls between the outer groove and the inner groove of the nut, so that when the screw rotates, the nut will be driven to move relative to the screw along the longitudinal direction. The perforation at the first end of the nut has an enlarged opening, which accommodates a stop ring.

3. The electric cylinder as described in claim 1, characterized in that, The nut has at least one engagement groove around its outer periphery. The body is contained in a first side and a second side facing each other in the longitudinal direction. The first side has at least one engagement portion for engaging in the engagement groove of the nut.

4. The electric cylinder as described in claim 3, characterized in that, The connecting groove is an annular groove adjacent to the first end of the nut. The first surface of the body has multiple connecting portions separated along the circumferential direction. Each connecting portion extends along the longitudinal direction and has a hook to engage with the connecting groove.

5. The electric cylinder as described in claim 1, characterized in that, The storage hole has multiple guide grooves separated along the circumferential direction on its wall, and multiple guide blocks separated along the circumferential direction are provided around the outer periphery of the main body. Each guide block is engaged in a corresponding guide groove of the outer cylinder.

6. The electric cylinder as described in claim 5, characterized in that, The guide block extends along the longitudinal direction and has two ends separated along the longitudinal direction, each end having a notch and two guide arms separated by the notch.

7. The electric cylinder as described in claim 5, characterized in that, The end of the guide block has a first width in a width direction, and the guide groove has a second width, the first width being equal to or greater than the second width.

8. The electric cylinder as described in claim 5, characterized in that, The guide block has an arc-shaped recess in the middle of its side.

9. The electric cylinder as described in claim 3, characterized in that, The second surface has a plurality of positioning portions spaced along the circumferential direction, each positioning portion extending along the longitudinal direction. The sliding unit further includes a ring-shaped magnet disposed on the second surface of the body and positioned between the plurality of positioning portions and the plurality of guide blocks.

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