Linearantrieb

Abstract

Linear actuator, consisting of: • a long shaft section (20) which extends in the axial direction (X) and is designed with a roller conveyor (22), • a displacement module (30) which is mounted on the long shaft part (20) in an axial direction (X) in a pendulum-like manner and is provided with a groove (31) complementary to the roller conveyor (22), wherein the roller conveyor (22) forms a load path with the groove (31), • a roller unit (40) which is arranged in the load path and comprises several roller parts (41) and several spacers (42), wherein a spacer (42) is inserted between all two roller parts (41), • a return assembly (50) which is arranged on the displacement module (30) or connected to the load path and comprises a first return pipe (51), a second return pipe (52) connected to the first return pipe (51), and a return channel (53) passing through the first return pipe (51) and the second return pipe (52), wherein the return channel (53) serves for the circulation of the roller unit (40), wherein the first return pipe (51) has a first connection side (512) and the second return pipe (52) has a second connection side (522), and the first connection side (512) of the first return pipe (51) presses against the second connection side (522) of the second return pipe (52), • at least one detection assembly (60) which is attached to the displacement module (30) and to the connection point between the first connection side (512) of the first return pipe (51) and the second connection side (522) of the second return pipe (52) and to an outer surface of the first return pipe (51) and the second return pipe (52), and which can detect the changes in distance of the individual roller parts (41) and then output a corresponding signal when the roller unit (40) rotates in the return channel (53), and • a data interception unit (80) which is signal-connected to at least one acquisition unit (60) in order to receive signals from the acquisition unit (60).

Description

[0001] The invention relates to a linear drive, in particular a ball screw, in which the changes in distance of the individual rolling parts can be diagnosed in real time.

[0002] In Fig. 1A is a linear roller bearing as described in U.S. Patent No. US7178981B2, which is provided with a guide frame 1. The guide frame 1 can be mounted on a guide rail 2 via bearing balls (not shown) and is provided with at least one roller track (not shown) for the bearing ball, which comprises a support track (not shown) for the bearing ball and a deflection track (not shown) connected to the support track. The deflection track is integrated into the end assembly 3 of the guide frame 1, whereby the bearing balls are somewhat slowed down in the direction of rotation as they roll in the roller track. The end assembly 3 contains a sensor 4, which detects any anomaly due to rolling resistance when the bearing balls impact the cover plate.However, installing such a sensor 4 requires increasing the length of the guide frame 1, which leads to a complicated design, a longer operating path, or increased costs.

[0003] In Fig. Figure 1B describes a ball screw with a sensing device according to Japanese Patent Publication No. JP2007225024, wherein the sensing device 6 (capacitive or optical) is installed in a hole of the nut 5 to detect displacement states of the bearing balls 7 and subsequently evaluate the load on the nut 5. However, installing such a sensing device 6 requires increasing the dimension or diameter of the nut 5, which results in a longer operating travel of the nut 5.

[0004] Furthermore, Japanese patent disclosure no. JP3936519 describes an embodiment in which a vibration sensor for detecting the operating conditions of the bearing balls is attached to a bend in an outer rotating part of the ball screw. However, with this design, the nut must be machined with a special bore to accommodate the vibration sensor, a process that is complex and time-consuming. Moreover, the vibration sensor attached to a bend in an outer rotating part of the ball screw can only detect the change in stress when the bearing balls impact the wall surface of the bend in the outer rotating part and subsequently assess the smooth running of the bearing balls (e.g., stiffness of the bearing balls due to insufficient lubrication). However, it is impossible to detect changes in the distance between the bearing balls.This makes it impossible to determine whether a bearing ball is clogged or jammed.

[0005] Japanese patent disclosure No. JP2014114944A discloses a ball screw spindle with a detection device for detecting a defective condition of the balls in the circulation path of the ball screw spindle.

[0006] German patent application DE102010050175A1 shows a ball screw nut with a base body and a ball return device which extends at least partially over an outer circumference of the base body.

[0007] The Japanese patent disclosures No. JP2014114944A, JPA2014159847 and No. JPA2013200032, as well as the German patent application DE102010050175A1, also exhibit the aforementioned disadvantages. In this context, the known linear actuators need to be improved.

[0008] The object of the invention is to provide a linear drive in which the change in distance of the individual roller parts can be diagnosed in real time in order to determine whether any spacer between the individual roller parts is jammed, and to prevent a resulting defect of the linear drive from leading to the shutdown of the entire system.

[0009] To solve the problem, a linear drive in the form of a ball screw according to claim 1 is provided, consisting of: • a long shaft section which extends in the axial direction (X) and is designed with a roller conveyor, • a displacement module which is mounted on the long shaft part in an axial direction (X) in a pendulum-like manner and is provided with a groove complementary to the roller conveyor, wherein the roller conveyor and the groove form a load path, • a roller unit which is arranged in the load path and comprises several roller parts and several spacers, wherein a spacer is inserted between all two roller parts, • a return assembly which is arranged on the displacement module or connected to the load path and comprises a first return pipe, a second return pipe connected to the first return pipe and a return channel passing through the first return pipe and the second return pipe, wherein the return channel serves for the circulation of the roller unit, wherein the first return pipe has a first connection side and the second return pipe has a second connection side, and the first connection side of the first return pipe presses against the second connection side of the second return pipe, • at least one detection assembly, which is attached to the displacement module and to the connection point between the first connection side of the first return pipe and the second connection side of the second return pipe and to an outer surface of the first return pipe and the second return pipe, and which can detect the changes in distance of the individual roller parts and then output a corresponding signal when the roller unit rotates in the return channel, and • a data interception unit which is signal-connected to at least one acquisition module in order to receive signals from the acquisition module.

[0010] Preferably, the linear drive designed as a ball screw is provided with a cover which is attached to the outer surface of the displacement module to cover the return assembly and at least one detection assembly and is provided with a receiving groove for receiving the return assembly and at least one detection assembly, the wall surface of which is formed with at least one receiving slot for receiving at least one detection assembly.

[0011] Preferably, the signal transmission between the acquisition unit and the data interception unit is wireless.

[0012] Preferably, the detection assembly is electrically inductive or optical.

[0013] Preferably, the first return pipe has a first connection side and a first through-side, while the second return pipe has a second connection side and a second through-side. The return channel extends through the first connection side and the first through-side of the first return pipe and the second connection side and the second through-side of the second return pipe. The first connection side of the first return pipe is complementary to the second connection side of the second return pipe. The first through-side of the first return pipe and the second through-side of the second return pipe are connected to respective ends of the load path. The at least one detection assembly is mounted on the first connection side of the first return pipe and the second connection side of the second return pipe.

[0014] In some embodiments, the first connection side of the first return pipe is preferably 0.1 mm to 0.2 mm away from the second connection side of the second return pipe.

[0015] In some embodiments, the part of the return channel passing through the first connection side and the second connection side is formed in the form of a straight line.

[0016] Preferably, the return assembly is made of a plastic.

[0017] As mentioned above, the linear drive according to the invention consists of a long-shaft section, a displacement module, a roller unit, a return assembly, a sensing assembly, and a data acquisition unit. Such a linear drive has a simple design, and the sensing assemblies are arranged at the junction of the first return tube and the second return tube of the return assembly. The sensing assembly can diagnose the changes in distance between the individual rollers in real time. In a critical situation (for example, a breakdown), the sensing assembly will output a corresponding signal, which a control unit will use to shut down the machine in a timely manner. The control unit will then determine the status of the workpieces in relation to the machine table to prevent further operation from damaging the machine table and / or the workpieces.Furthermore, the acquisition unit can serve as a medium for data transmission, which further simplifies maintenance. Fig. 1A View of the linear roller bearing according to U.S. Patent Disclosure No. US7178981B2 Fig. 1B View of the ball screw with a detection device according to Japanese patent disclosure no. JP2007225024 Fig. 2 Perspective view of the first embodiment according to the invention, wherein the linear drive is designed as a ball screw. Fig. 3A Exploded view I of the first embodiment according to the invention. Fig. 3B Exploded view II of the first embodiment according to the invention. Fig. 4 Sectional view I of the first embodiment according to the invention. Fig. 5 Sectional view II of the first embodiment according to the invention. Fig. 6 Perspective view of the second embodiment according to the invention, wherein the signal transmission between the detection assembly and the data interception unit is wireless.

[0018] Further objectives, advantages, features and application possibilities of the present invention will become apparent from the following description of the exemplary embodiments with reference to the drawing.

[0019] In Fig. 2 to Fig. Figure 5 shows the preferred embodiments of the linear drive according to the invention, wherein the linear drive is designed, for example, as a ball screw, consisting of: a long shaft part 20 which extends in the axial direction X (wherein in the present embodiment the long shaft part 20 is designed as a worm and comprises a worm circular surface 21 as well as a roller carriage 22 spirally recessed in the worm circular surface 21), a displacement module 30, which is mounted on the long shaft part 20 in an axial direction X in a pendulum-like manner, can move relative to the long shaft part 20 and is provided with a groove 31 complementary to the roller carriage 22, wherein the roller carriage 22 forms a load path with the groove 31 (where in the present embodiment the displacement module 30 is a nut), A roller unit 40, which is installed in the load path and comprises several roller parts 41 and several spacers 42, wherein a spacer 42 is inserted between each pair of roller parts 41. In the present embodiment, the roller part 41 is a bearing ball. In other embodiments, the roller part 41 can be designed as a needle roller. The spacers 42 are each designed as a cylinder, both sides of which are formed with a groove for receiving a portion of the roller part 41.

[0020] The two return assemblies 50 are each made of a plastic material and are attached to the displacement module 30 or connected to the load path. In the present embodiment, each return assembly 50 is arranged on the displacement module 30 and comprises a first return pipe 51, a second return pipe 52 connected to the first return pipe 51, and a return channel 53 passing through the first return pipe 51 and the second return pipe 52, the return channel 53 serving for the circulation of the roller unit 40.

[0021] In the present embodiment, the two return assemblies 50 are structurally identical. Therefore, one return assembly 50 is described as follows. The first return pipe 51 has a first connection side 512 and a first through-side 514. The second return pipe 52 has a second connection side 522 and a second through-side 524. The return channel 53 extends through the first connection side 512 and the first through-side 514 of the first return pipe 51 and the second connection side 522 and the second through-side 524 of the second return pipe 52. The portion of the return channel 53 passing through the first connection side 512 and the second connection side 522 is in the form of a straight line. The first connection side 512 of the first return pipe 51 is complementary to the second connection side 522 of the second return pipe 52.The first through side 514 of the first return pipe 51 and the second through side 524 of the second return pipe 52 are connected to a respective end of the load path.

[0022] In another embodiment, the linear drive can be provided with only one return assembly 50.

[0023] The designs, compositions and operating methods of the long shaft part (worm gear), the displacement module (nut), the two return assemblies and the roller unit are not described in detail here, as they are already well known.

[0024] Four detection modules 60 are provided, two of which are attached to the outer surfaces complementary to the two sides of each return assembly 50, while the other two detection modules 60 are arranged at the connection point of the first return pipe 51 with the second return pipe 52 of each return assembly 50. This means that these two detection modules 60 are each attached to the first connection side 512 of the first return pipe 51 and the second connection side 522 of the second return pipe 52. However, the embodiment according to the invention is not limited to this. In the version consisting of Fig. In the embodiment shown in Figure 3B, a detection assembly 60 is attached to the first connection side 512 of the first return pipe 51 and the second connection side 522 of the second return pipe 52, providing the same performance. When the roller unit 40 rotates in the return channel 53 in this configuration, each detection assembly 60 can detect changes in the distance between the individual roller parts 41 and then output a corresponding signal, which is used to assess whether any spacer 42 between all roller parts 41 is damaged or displaced.Furthermore, because the portion of the return channel 53 passing through the first connection side 512 and the second connection side 522 is formed in the form of a straight line, each roller element 41 and each spacer 42 can be inserted into the section of the return channel 53 passing through the first connection side 512 and the second connection side 522 in an approximately linearly sliding manner, so that each detection assembly 60 can output an accurate signal. In the present embodiment, each detection assembly 60 is, for example, electrically inductive, but can also be optically inductive.The electrical induction device is a device that performs measurements based on coil self-induction or mutual induction of coils. It offers advantages such as low construction costs, customizable dimensions, higher output power, strong interference immunity, low operating environment requirements, high resolution, and good stability. The optical induction device utilizes various properties of light to detect the presence of an object or changes in surface conditions. It offers advantages such as a long detection range, fewer limitations on the object being measured, and non-contact detection with higher resolution.If a spacer 42 between the two roller parts 41 is displaced, such that the distance between the two roller parts 41 exceeds a limit value (2 mm in the present embodiment; this value may change in other embodiments), the roller unit 40 located in the return channel 53 and the load path may become jammed, leading to the shutdown of the system. Based on the present design of the detection assemblies 60, any anomaly of the linear drive can now be diagnosed in real time. In the event of a critical situation, a control unit can shut down the machine in time and then determine the status of the workpieces with respect to the machine table in order to prevent further operation from damaging the machine table and / or the workpieces.

[0025] It should be noted that in this embodiment, the first connection side 512 of the first return pipe 51 presses against the second connection side 522 of the second return pipe 52. In another preferred embodiment, the first connection side 512 of the first return pipe 51 is separated from the second connection side 522 of the second return pipe 52 by 0.1 mm to 0.2 mm, so that the sensing assemblies 60 detect the changes in distance of the individual roller parts 41 in relation to the gap between the first connection side 512 and the second connection side 522, in order to increase the measurement accuracy.

[0026] A cover 70 is provided, which is attached to the outer surface of the sliding module 30 to cover the two return assemblies 50 and four detection assemblies 60 and is provided with a receiving groove 71 for receiving the return assemblies 50, the wall surface of which is formed with four receiving slots 72 for receiving the four detection assemblies 60. In known monitoring methods, the operating state of the ball screw is usually monitored with an adhesively attached accelerometer, whereby the arrangement points and the signal strength of the detection assemblies are often problematic. To eliminate these shortcomings, the wall surface of the receiving groove 71 in the present embodiment is formed with four recessed receiving slots 72 for receiving four detection assemblies 60.This allows the four detection assemblies 60 not only to be fixed with regard to their mounting positions, but also to be positioned closer to both return assemblies 50 in order to effectively reduce signal interference and achieve the desired signal stability. In this context, four detection assemblies 60 can be installed in the original space of the cover 70 in the embodiment according to the invention. This allows not only the conventional dimensions of the long-shaft section 20 to be retained for real-time diagnosis of the changes in distance between the individual roller parts 41 and the avoidance of machine shutdown, but also ensures that the conventional design of the machine table remains unaffected.

[0027] A data interception unit 80 is also provided, which is signal-connected to the four acquisition modules 60 in order to receive signals from the four acquisition modules 60. In the present embodiment, the signal transmission is, for example, via wiring. However, the embodiment according to the invention is not limited to this. As shown in Fig. As can be seen in Figure 6, the signal transmission between the four detection modules 60 and the data interception unit 80 takes place wirelessly via WiFi, Bluetooth, RF, ZigBee, LoRa, WiGig, 4G or 5G. This eliminates the need for complex cabling.

[0028] In the present embodiment, the linear drive according to the invention is, for example, designed as a ball screw. As shown from Fig.As can be seen in Figure 2, the linear drive according to the invention can also be designed as a linear sliding guide, wherein the long shaft part 20 is a sliding guide, while the displacement module 30 is a slide. The two return assemblies 50 are installed in the displacement module 30. If a chain holder 90 breaks, the gap between the individual roller parts 91 increases, which can be detected by the sensing assemblies 60.

[0029] The arrangement of the individual components of the embodiment according to the invention is described in the preceding section. The following section describes the performance of the embodiment according to the invention.

[0030] Such a linear drive has a simple design, with the detection modules 60 arranged at the junction of the first return tube 51 and the second return tube 52 of each return assembly 50 to diagnose the changes in distance between the individual rollers 41 in real time. In the event of a critical situation with the spacers 42, the detection modules 60 will output a corresponding signal, which a control unit will use to shut down the machine in a timely manner. The control unit will then determine the status of the workpieces in relation to the machine table to prevent further operation from damaging the machine table and / or the workpieces. Furthermore, the detection module 60 can serve as a medium for data transmission, which further simplifies maintenance. Reference symbol list

[0031] [Regarding the conventional designs] 1) Management framework 2) Guide rail 3) Front panel assembly 4) Sensor 5) Mother 6) Recording device 7) Bearing ball

[0032] [Regarding the embodiment according to the invention] X) Axial direction 20) Longwave section 21) Snail circle area 22) Roller walkway 30) Shift module 31) Groove 40) Roll unit 41) Rolling part 42) Spacer 50) Return assembly 51) first return pipe 512) first connection page 514) first passage page 52) second return pipe 522) second connection side 524) second passage side 53) Return channel 60) Data acquisition unit 70) Lid 71) Recording groove 72) Recording slot 80) Data interception unit 90) Chain holder 91) Rolling part

Claims

[1] Linear actuator, consisting of: • a long shaft section (20) which extends in the axial direction (X) and is designed with a roller conveyor (22), • a displacement module (30) which is mounted on the long shaft part (20) in an axial direction (X) in a pendulum-like manner and is provided with a groove (31) complementary to the roller conveyor (22), wherein the roller conveyor (22) forms a load path with the groove (31), • a roller unit (40) which is arranged in the load path and comprises several roller parts (41) and several spacers (42), wherein a spacer (42) is inserted between all two roller parts (41), • a return assembly (50) which is arranged on the displacement module (30) or connected to the load path and comprises a first return pipe (51), a second return pipe (52) connected to the first return pipe (51), and a return channel (53) passing through the first return pipe (51) and the second return pipe (52), wherein the return channel (53) serves for the circulation of the roller unit (40), wherein the first return pipe (51) has a first connection side (512) and the second return pipe (52) has a second connection side (522), and the first connection side (512) of the first return pipe (51) presses against the second connection side (522) of the second return pipe (52), • at least one detection assembly (60) which is attached to the displacement module (30) and to the connection point between the first connection side (512) of the first return pipe (51) and the second connection side (522) of the second return pipe (52) and to an outer surface of the first return pipe (51) and the second return pipe (52), and which can detect the changes in distance of the individual roller parts (41) and then output a corresponding signal when the roller unit (40) rotates in the return channel (53), and • a data interception unit (80) which is signal-connected to at least one acquisition unit (60) in order to receive signals from the acquisition unit (60). [2] Linear drive according to claim 1, characterized by, that the linear drive is designed as a ball screw and is provided with a cover (70) which is attached to the outer surface of the displacement module (30) for covering the return assembly (50) and at least one detection assembly (60) and is provided with a receiving groove (71) for receiving the return assembly (50) and at least one detection assembly (60), the wall surface of which is formed with at least one receiving slot (72) for receiving at least one detection assembly (60). [3] Linear drive according to claim 1, characterized by , that the signal transmission between the acquisition unit (60) and the data interception unit (80) is wireless. [4] Linear drive according to claim 1, characterized by that the detection assembly (60) is electrically inductive. [5] Linear drive according to claim 1, characterized bythat the first return pipe (51) has a first through-side (514), while the second return pipe (52) has a second through-side (524), wherein the return channel (53) extends through the first connection side (512) and the first through-side (514) of the first return pipe (51) and the second connection side (522) and the second through-side (524) of the second return pipe (52), wherein the first connection side (512) of the first return pipe (51) is complementary to the second connection side (522) of the second return pipe (52), wherein the first through-side (514) of the first return pipe (51) and the second through-side (524) of the second return pipe (52) are connected to respective ends of the load path, wherein at least one sensing assembly (60) is located at the first connection side (512) of the first is attached to the return pipe (51) and the second connection side (522) of the second return pipe (52). [6] Linear drive according to claim 5, characterized by , that the first connection side (512) of the first return pipe (51) is 0.1 mm to 0.2 mm away from the second connection side (522) of the second return pipe (52). [7] Linear drive according to claim 6, characterized by , that the part of the return channel (53) passing through the first connection side (512) and the second connection side (522) is formed in the form of a straight line. [8] Linear drive according to claim 1, characterized by , that the return assembly (50) is made of a plastic.

Images