Linear drive
Patent Information
- Application Number
- PCT/DE2026/100186
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-22
- Filing Date
- 2026-02-17
- Publication Date
- 2026-08-27
Smart Images
Figure DE2026100186_27082026_PF_FP_ABST
Abstract
Description
[0001] Attorney file: 525002-PCT
[0002] Applicant: Framo Morat GmbH & Co KG
[0003] Franz-Morat-Straße 6
[0004] 79871 Eisenbach
[0005] Title: Linear actuator
[0006] DESCRIPTION
[0007] The invention is based on a linear drive which converts a rotational movement into a linear movement.
[0008] Linear drives of this type generate translational motion from a torque, for example, from a motor. They typically incorporate components such as a threaded spindle, a rack, a connecting rod, or a cam. To change the input speed, torque, or direction of rotation, linear drives are equipped with a suitable gearbox. This gearbox can be, for example, a worm gear or a bevel gear. Worm gears consist of a helical worm and a worm wheel with spur teeth, where at least one thread of the worm engages with the spur teeth of the worm wheel. Worm gears have the disadvantage of a relatively large center distance, which essentially corresponds to the sum of the outer radius of the worm wheel and the outer radius of the worm. This center distance results in a large overall size.
[0009] In principle, worm gears are virtually unlimited in terms of geometry and load-carrying capacity in terms of their gear ratio, so that theoretically ratios of up to 100 or more are possible. However, at high ratios, the efficiency drops considerably due to increasing sliding forces, meaning that high ratios require a relatively high input power. Bevel gears consist of a frustoconical worm and a similarly beveled gear. Although they have a smaller center distance than worm gears, they require precise positioning of the worm and gear, resulting in complex assembly. They are susceptible to positional deviations of the worm and gear. Loss of inertia, increased noise, jamming, or increased backlash can result.
[0010] The invention is based on the objective of providing a linear drive which is equipped with an additional gear stage for changing an incoming direction of rotation and / or an incoming speed, which has a small size with simultaneously high efficiency, low weight, low noise generation and low susceptibility to positional deviations and in which assembly is simplified.
[0011] This problem is solved by a linear drive with the features of claim 1. The drive is characterized by being equipped with a gear stage comprising a cylindrical worm and a worm gear. The worm has at least one thread on its circumferential surface. It is driven to rotate about a geometric worm axis. The worm gear has a helical toothing on its face. This is also referred to as arc toothing. The worm engages with the worm gear such that its at least one thread meshes with the toothing of the worm gear, and the worm thereby drives the worm gear to rotate about a geometric worm gear axis.The worm and the worm gear are aligned such that the geometric axis of the worm and the geometric axis of the worm gear are skew geometric lines whose distance d is smaller than the outer radius of the worm gear. The distance here is meant in an immature sense: the distance d is the shortest connection between these geometric lines.
[0012] A first gear element is rotationally connected to the worm gear or integrally formed with it. A second gear element is directly or indirectly coupled to the first gear element such that the first gear element, rotating together with the worm gear, imparts a linear motion to the second gear element. This linear motion occurs along a geometric linear axis. Examples of combinations of a first gear element and a second gear element include spindle drives with a threaded spindle and a spindle nut, a rack with a spur gear, a crank with a connecting rod, a cam, or a cam disc with a spring-loaded rod.
[0013] The worm gear can be coupled directly or indirectly to a drive, such as a motor, so that the drive's torque is transmitted to the worm gear. A manual drive can also be used instead of a motor. In the case of an indirect coupling, additional gear stages are provided between the worm gear and the drive. The drive's torque is then transmitted from the worm gear to the cross-worm wheel.
[0014] The combination of worm and cross worm gear changes the direction of rotation. The number of teeth on the cross worm gear and the minimum one thread on the worm determine the gear ratio between the input and output speeds.
[0015] Since the worm gear does not engage the gear circumferentially, but rather on its flat surface, the distance between the geometric axis of the worm gear and the geometric axis of the cross worm gear is smaller than the outer radius of the cross worm gear and therefore also smaller than in worm drives known from the prior art. This results in a smaller overall size. It also allows for space-saving integration of the linear drive at its point of use.
[0016] Due to the cylindrical worm and the cross worm gear, there is one degree of freedom during assembly in the direction of the geometric worm axis. Compared to bevel gears, the robustness against deviations in the worm's orientation relative to the cross worm gear is increased in the direction of the geometric worm axis. This simplifies assembly of the gearbox. Furthermore, the gearbox is less susceptible to positional deviations than a bevel gear gearbox.
[0017] The cylindrical worm and the cross-worm gear have a high contact ratio. Several turns of the worm are always engaged with the helical teeth of the cross-worm gear. This results in a high power density during torque transmission. Furthermore, the combination of a cylindrical worm and a cross-worm gear with helical teeth offers improved torque transmission and kinematically favorable sliding characteristics.
[0018] Efficiency losses due to friction and wear are minimized. Furthermore, the transmission according to the invention is quiet.
[0019] The combination of worm and cross worm gear offers the advantage that the torque, direction of rotation, and speed of a motor or manual drive can be adapted to the requirements, and power can be transmitted from the cross worm gear to the rod, thus initiating the translational movement of the rod necessary for the respective application of the linear drive. Possible applications of the linear drive include, for example, adjustment devices or applications where cyclic linear motion is required, such as in valve controls. According to a further advantageous embodiment of the invention, the linear drive is equipped with a linear drive base on which the worm and the cross worm gear are at least indirectly rotatably mounted. The linear drive base can form a housing or housing part, or be connected to a housing.The linear drive base serves as a structural element that securely and precisely positions the worm, the worm gear, the rod, and any other mechanical components. The rotatable mounting of the worm and worm gear on the linear drive base ensures low-friction and efficient transmission of the rotational motion. The linear drive base can be manufactured from various materials, selected according to the application to meet specific requirements for load-bearing capacity, rigidity, weight, and temperature and humidity resistance. Integrating the worm, worm gear, and rod into a single linear drive base simplifies assembly, as the linear drive is mounted as a pre-assembled unit at the point of use. The installation of individual parts on the final product is avoided or at least reduced.The positioning of the components relative to each other is determined by the linear drive base. This leads to a reduction in manufacturing costs and an increase in production speed. The linear drive base can also be equipped with additional mounting points, enabling simple and secure integration into various applications.
[0020] According to a further advantageous embodiment of the invention, the worm gear is rotatably mounted at a first end relative to the linear drive base. The first end of the worm gear can, for example, be connected directly or indirectly to a motor or a manual drive. The first end of the worm gear is designed to couple to a motor shaft or a manually driven shaft, thereby transmitting the drive torque to the worm gear. One or more gear stages can be provided between the drive and the worm gear. These gear stages can be referred to as upstream gear stages. The worm gear is mounted on a threadless section of the worm shaft or on a worm shaft. The worm shaft can be identical to the worm shaft. Alternatively, the worm shaft can be connected to the worm shaft.The worm gear can also be rotatably mounted in a motor or in the motor housing of a motor.
[0021] According to a further advantageous embodiment of the invention, a second end of the screw, opposite the first end, is a free end. The single-sided bearing ensures that the screw is held stably and precisely in its position, guaranteeing reliable transmission of the rotational motion to the cross worm gear. The single-sided bearing of the screw simplifies the gearbox, as fewer bearing components are required, leading to a reduction in manufacturing costs and a simplification of the assembly process. Furthermore, the single-sided bearing of the screw can reduce the space requirement, which is particularly important in applications where available space is limited. Finally, the single-sided bearing of the screw can improve ease of maintenance, as access to the screw and its bearing components is facilitated.
[0022] According to a further advantageous embodiment of the invention, a second end of the screw, opposite the first end, is rotatably mounted, for example, on the linear drive base. The screw is mounted on the screw shaft or the screw shank. Mounting at both ends of the screw absorbs resulting gear forces, particularly radial forces, reduces screw deflection under the influence of these forces, and thus prevents bending fracture. Furthermore, the two-sided mounting of the screw enables more stable and uniform rotation around the geometric axis of the screw, leading to a reduction in vibration and noise during operation. The additional mounting also contributes to the longevity of the components by reducing wear on the screw and the bearings.This is particularly important in applications where the linear actuator is operated frequently and under varying loads. The even distribution of forces across the bearings prevents uneven loading, which extends the service life of the bearings and the worm gear.
[0023] According to a further advantageous embodiment of the invention, the gearing of the worm gear has an elliptically rounded tooth root. This means that the base of the teeth of the worm gear has an elliptical shape, resulting in a rounding. This reduces stresses in the tooth root. This, in turn, increases the load-bearing capacity and reduces the risk of tooth breakage.
[0024] According to a further advantageous embodiment of the invention, the teeth of the cross worm gear feature a chamfered end chamfer. This means that the edges of the teeth are chamfered in the head region. This reduces the risk of edge bearing and thus the risk of local stress concentrations, which increases the service life and reliability of the cross worm gear. By avoiding local stress concentrations, the likelihood of a reduction in load-carrying capacity is reduced, which is particularly important in applications with high loads and torques. In addition, the chamfered end chamfer contributes to improved running characteristics and smooth operation of the cross worm gear, leading to a reduction in vibration and noise during operation. Furthermore, the chamfered end chamfer can facilitate the assembly and installation of the cross worm gear, as the chamfered edges are less susceptible to damage during handling.
[0025] According to a further advantageous embodiment of the invention, the toothing of the worm gear has a continuous run-out on one or both sides without tooth edges. The absence of tooth edges means that the teeth do not extend to the outer or inner circumferential side of the worm gear. With a continuous run-out on both sides, the teeth do not extend to either the outer or inner circumferential side of the worm gear. With a continuous run-out on one side, the teeth extend to the inner circumferential side but not to the outer circumferential side, or vice versa. Due to the lateral connection of the tooth, it is more stable with respect to the forces acting upon it. Local stress concentrations at the tooth edges are avoided, thus increasing the load-bearing capacity against tooth edge breakage on the gear.Furthermore, the load-bearing capacity of the worm is increased in the area of the avoided tooth face edges. The lubricating film is also improved by avoiding a lubricating wedge formed by the tooth face edge. In this case, the worm must be designed and positioned relative to the cross worm gear such that the engagement of the worm with at least one turn in the cross worm gear's teeth is located within the area of the fully formed tooth profiles of the cross worm gear. Outside of the fully formed tooth profiles, a collision between the worm and the cross worm gear must be avoided.
[0026] According to a further advantageous embodiment of the invention, the width of each tooth of the worm gear decreases from an inner tooth end, which faces the geometric axis of the worm gear, to an outer tooth end facing away from the inner tooth end. This tooth shape is also referred to as a comma-shaped tooth head. It improves the engagement of the worm with the worm gear and ensures better force distribution during engagement.
[0027] According to a further advantageous embodiment of the invention, the worm gear has at least one bearing raceway or bearing seat. According to a further advantageous embodiment of the invention, the at least one thread of the worm engages with the teeth of the worm gear at at least three contact points. If the worm has several threads, these threads engage with the teeth of the worm gear at a total of at least three contact points.
[0028] According to a further advantageous embodiment of the invention, the first gear part is designed as a threaded spindle and the second gear part as a spindle nut that engages with the threaded spindle. The linear drive thus comprises a spindle drive.
[0029] According to a further advantageous embodiment of the invention, the threaded spindle is rotatably mounted on the linear drive base and connected to the worm gear in a rotationally fixed manner, while the spindle nut is mounted on the linear drive base in a rotationally fixed and linearly displaceable manner. The rotatable mounting of the threaded spindle on the linear drive base ensures that the threaded spindle can rotate freely while simultaneously being rigidly connected to the worm gear to guarantee synchronous movement. The spindle nut is mounted on the linear drive base in a linearly displaceable manner and secured against rotation, thus enabling smooth and controlled linear movement.
[0030] According to a further advantageous embodiment of the invention, the first gear part is designed as a spindle nut and the second gear part as a threaded spindle. The spindle nut is arranged in a rotationally fixed position on the worm gear or is an integral part of the worm gear. The threaded spindle is mounted in a rotationally fixed position and is linearly displaceable on the linear drive base. This combination of worm gear and spindle nut ensures that the rotary motion of the worm gear is transmitted directly and without backlash to the spindle nut. According to a further advantageous embodiment of the invention, the worm gear is simultaneously designed as a spindle nut. This means that the worm gear not only fulfills the function of a gear that is set in rotation by the worm, but also assumes the function of a spindle nut that runs on a threaded spindle.While the helical teeth are located on the face of the worm gear, a central through-hole, running coaxially through the gear's geometric axis, can be designed as a threaded bore that functions as the spindle nut. The threaded spindle is guided within this bore and engages with the threads of the worm gear's bore. This dual functionality of the worm gear as a spindle nut reduces the number of components required, simplifying the design and lowering manufacturing costs. Furthermore, the linear actuator's footprint is reduced because two functions are integrated into a single component.
[0031] According to a further advantageous embodiment of the invention, the first transmission part is designed as a linear drive gear and the second transmission part as a rack. The worm gear is equipped with a linear drive gear that engages with the rack. The rack is an elongated component that can be moved along a linear geometric axis, while the linear drive gear is a rotating component that engages with the rack and enables its linear movement. The linear drive gear is driven either directly or indirectly by the worm gear. For this purpose, the linear drive gear can, for example, be arranged at a rotational angle to the worm gear or be formed integrally with the worm gear. The interaction between the rack and the linear drive gear is achieved through gearing, in which the teeth of the linear drive gear engage with the teeth of the rack.According to a further advantageous embodiment of the invention, the linear drive gear is integrally formed with the worm gear. It advantageously forms an integral part of the worm gear.
[0032] According to a further advantageous embodiment of the invention, the linear drive gear and the worm gear are arranged on a common shaft. The common shaft optimizes the mechanical connection between the linear drive gear and the worm gear.
[0033] According to a further advantageous embodiment of the invention, the first transmission part is designed as a crank, which is arranged eccentrically on the worm gear with respect to the geometric axis of the worm gear. An elongated connecting rod has a first connecting rod head at one end and a second connecting rod head at the opposite end. The connecting rod with the first connecting rod head is rotatably connected to the crank. The second connecting rod head is designed as a second transmission part, which is moved along a geometric linear axis when the worm gear and the crank rotate.
[0034] According to a further advantageous embodiment of the invention, the linear drive base is equipped with a linear guide by which the second connecting rod head is guided linearly. The linear guide additionally ensures that the translational movement of the second connecting rod head takes place along a predetermined and defined geometric linear axis.
[0035] According to a further advantageous embodiment of the invention, the first gear part is designed as a cam and the second gear part as a rod, which is spring-loaded and linearly displaceable on the linear drive base such that a spring presses the rod against the cam, and the rod transmits the movement resulting from the cam's rotation at the cam's edge. The cam and the rod are thus not rigidly connected. Rather, one end of the rod rests loosely against the cam. The spring ensures that the rod remains in constant contact with the cam and thus follows the cam's movement.
[0036] According to a further advantageous embodiment of the invention, the cam is formed by a cylinder which is arranged eccentrically on the worm gear with respect to the axis of the worm gear.
[0037] According to a further advantageous embodiment of the invention, the cam is formed by a cam disk.
[0038] According to a further advantageous embodiment of the invention, the first gear part is designed as a pin which is arranged eccentrically on the worm gear with respect to the geometric axis of the worm gear and projects axially beyond the flat surface of the worm gear facing away from the toothing. The second gear part is designed as a linearly movable slide which rests loosely against the pin and which is deflected by the pin rotating together with the worm gear.
[0039] The slide can be spring-loaded and linearly displaceable on the linear drive base. Alternatively, the slide can be equipped with an elongated recess into which the pin engages, similar to a cam track.
[0040] According to a further advantageous embodiment of the invention, the linear drive is equipped with at least one further gear stage, which is positioned upstream of the worm gear.
[0041] According to a further advantageous embodiment of the invention, the worm and / or the cross worm gear are made of plastic. This material has the advantage of being lightweight. Furthermore, the components can be manufactured cost-effectively in large quantities. Plastic also exhibits high corrosion resistance, which increases the durability and reliability of the components, particularly in humid or corrosive environments. Another advantage of plastic is its noise-dampening property. By using plastic for the worm and / or the cross worm gear, the operating noise of the drive is reduced. In addition, plastic offers a good balance between strength and flexibility. Shocks and vibrations can be absorbed.
[0042] According to a further advantageous embodiment of the invention, the worm and / or the cross worm gear are made of a thermoplastic or thermoset. Besides the advantages in manufacturing, the material of the worm and the cross worm gear influences the friction properties between the worm and the cross worm gear. These, in turn, affect the efficiency and service life of the linear drive.
[0043] According to a further advantageous embodiment of the invention, the worm and / or the cross worm gear are manufactured by plastic injection molding. This represents a cost-effective manufacturing process, particularly for large production runs, with which complex geometries can be produced with high precision and repeatability.
[0044] According to a further advantageous embodiment of the invention, the cross worm gear is manufactured by hot stamping. In this manufacturing process, the material of the cross worm gear is brought into the desired shape under the influence of heat and pressure. This method enables a precise and uniform shaping of the helical teeth on the face of the gear.
[0045] In a further advantageous embodiment, the worm gear is manufactured by injection molding and comprises a metallic or ceramic insert, or a plastic insert. Metallic inserts offer high strength and wear resistance, while ceramic inserts exhibit high temperature resistance and hardness. A plastic insert can be designed with or without reinforcement, for example, fiber reinforcement. A fiber-reinforced plastic insert combines the advantages of lightweight construction and increased strength through the embedding of fibers, such as glass or carbon fibers, in the plastic matrix. These inserts improve the structural integrity of the worm gear and contribute to the reduction of deformation and material fatigue. The integration of such inserts into the worm gear leads to improved performance and durability of the gearbox, particularly under demanding operating conditions.
[0046] According to a further advantageous embodiment of the invention, the worm gear is made of a metallic or ceramic material and is sintered, at least in the area of the teeth. Metallic materials offer high strength and durability, which is particularly important for withstanding high mechanical loads. Ceramic materials, on the other hand, are characterized by their high wear resistance and temperature resistance, which is especially advantageous in applications involving high temperatures and friction. Sintering in the area of the teeth further improves the material properties by creating a denser and more homogeneous structure, which increases the service life and reliability of the worm gear. Sintering also increases the surface hardness in the area of the teeth, which improves wear resistance and the ability to withstand high loads.This results in a longer service life for the worm gear and reduces the need for maintenance and replacement.
[0047] According to a further advantageous embodiment of the invention, the worm gear is made of sintered metal powder, at least in the area of the teeth. In another advantageous embodiment, the worm gear made of sintered metal powder is impregnated with a lubricant, a plastic, or a metallic impregnating agent. Impregnating the worm gear with a lubricant such as oil provides the following properties: (Emergency) lubrication, as the lubricant-filled pores act as a lubricant reservoir. This also increases wear resistance and provides a degree of corrosion protection. Impregnation with plastics such as resins or wax can close the pores in the material, thus achieving a seal or a degree of corrosion protection.Furthermore, impregnation with plastics is a fundamental requirement as a pretreatment for further coating processes such as electroplating. Impregnation with metallic impregnating agents, usually with low-melting alloys, can be used to densify the worm gear or to increase its mechanical strength.
[0048] According to a further advantageous embodiment of the invention, the worm gear is made of metal and is manufactured by investment casting.
[0049] According to a further advantageous embodiment of the invention, the worm gear is made of a metallic material and is manufactured by means of cold extrusion.
[0050] According to a further advantageous embodiment of the invention, the worm gear is made of a metallic material and is manufactured by forging.
[0051] According to a further advantageous embodiment of the invention, the worm gear is manufactured by an additive manufacturing process. Examples include powder bed fusion (SLS, SLM) and binder jetting processes, which involve plastics and metals, as well as stereolithography (SLA, MSLA), which involves plastics, and fused deposition modeling (FDM).
[0052] According to a further advantageous embodiment of the invention, the worm gear is at least partially manufactured by machining.
[0053] According to a further advantageous embodiment of the invention, the linear drive is equipped with grease or oil lubrication.
[0054] Further advantages and advantageous embodiments of the invention can be seen in the following description, the drawing and the claims.
[0055] drawing
[0056] The drawing shows exemplary embodiments of the invention. It shows:
[0057] Figure 1 shows a first embodiment of a linear drive in a side view.
[0058] Figure 2 Linear drive according to Figure 1 in sectional view, section along H - H in Figure 1 ,
[0059] Figure 3 Linear actuator according to Figure 1 in a view from above,
[0060] Figure 3a Linear drive according to Figure 1 with additional linear guide in a first position of the worm gear, Figure 3b Linear drive according to Figure 3a in a second position of the worm gear,
[0061] Figure 4 Linear drive according to Figure 1 in sectional view, section along G - G in Figure 3,
[0062] Figure 5 Linear drive according to Figure 1 in perspective view from above,
[0063] Figure 6 Linear drive according to Figure 1 in perspective view from below,
[0064] Figure 7: Cross-worm gear and crank of the linear drive according to Figure 1 in side view.
[0065] Figure 8: Planing worm gear and crank of the linear drive according to Figure 1 in perspective view.
[0066] Figure 9 Gear stage with worm and cross worm gear for a linear drive according to Figure 1 in a top view,
[0067] Figure 10 Worm and worm gear according to Figure 9 in sectional view with section along the plane marked A - A in Figure 9,
[0068] Figure 11 is a section of Figure 10 concerning the area marked B in Figure 10.
[0069] Figure 12 Worm and section of the cross worm gear of the gear stage according to Figure 9,
[0070] Figure 13 Gear stage according to Figure 9 with motor in perspective view, Figure 14 Gear stage according to Figure 9 with additional gear stage in front of the worm gear,
[0071] Figure 15 shows gear stages according to Figure 14 in perspective view.
[0072] Figure 16 shows a second embodiment of a worm gear.
[0073] Figure 17 Gear stage with worm supported on both sides in a top view,
[0074] Figure 18 Gear stage according to Figure 17 in sectional view with section along the plane marked D - D,
[0075] Figure 19 Gear stage according to Figure 17 in perspective view,
[0076] Figure 20 Gear stage according to Figure 17 in perspective view, rotated relative to the representation in Figure 19,
[0077] Figure 21 Gear stage according to Figure 17 in sectional view with section along the plane marked E - E,
[0078] Figure 22 shows a third embodiment of a worm gear in a perspective view from above.
[0079] Figure 23: Planing worm gear according to Figure 22 in a top view.
[0080] Figure 24 Excerpt from the illustration according to Figure 23,
[0081] Figure 25 Section through the cross-worm gear according to Figure 22 along the plane A - A, Figure 26 fourth embodiment of a cross-worm gear in perspective view from above,
[0082] Figure 27 shows the fifth embodiment of a worm gear in a perspective view from above.
[0083] Figure 28 sixth embodiment of a cross-winding worm gear in a top view,
[0084] Figure 29 Planing worm gear according to Figure 28 in a sectional view with a section along the plane marked A - A in Figure 20,
[0085] Figure 30: Planing worm gear according to Figure 28 in a perspective view from above.
[0086] Figure 31 shows a second embodiment of a linear drive in perspective view.
[0087] Figure 32 Linear drive according to Figure 31 with linear drive base,
[0088] Figure 33 shows a third embodiment of a linear drive in perspective view.
[0089] Figure 34 Linear drive according to Figure 33 in sectional view,
[0090] Figure 35 Linear drive according to Figure 33 with linear drive base,
[0091] Figure 36: Cross-worm gear of the linear drive according to Figure 28.
[0092] Figure 37 fourth embodiment of a linear drive in perspective
[0093] View, Figure 38 Linear drive according to Figure 37 with linear drive base,
[0094] Figure 39 Linear drive according to Figures 37 and 38 in a top view,
[0095] Figure 40 Linear drive according to Figure 37 in sectional view, section along the plane marked A - A in Figure 34,
[0096] Figure 41 Linear drive according to Figure 37 in side view,
[0097] Figure 42 Linear drive according to Figure 37 in sectional view, section along the plane marked B - B in Figure 36,
[0098] Figure 43 Linear drive according to Figure 37 in sectional view, section along the plane marked C - C in Figure 41,
[0099] Figure 44 Cross-worm gear of the linear drive according to Figures 37 to 43,
[0100] Figure 45 shows the fifth embodiment of a linear drive in side view.
[0101] Figure 46 Linear drive according to Figure 45 in a sectional view, section along the plane marked F - F in Figure 45,
[0102] Figure 47 Linear drive according to Figure 45 in a top view,
[0103] Figure 48 Linear drive according to Figure 45 in a sectional view, section along the plane marked E - E in Figure 47,
[0104] Figure 49 Cross-worm gear of the linear drive according to Figures 45 to 48,
[0105] Figure 50: Planing worm wheel according to Figure 49 in perspective view,
[0106] Figure 51 sixth embodiment of a linear drive in side view, Figure 52 linear drive according to Figure 51 in a sectional view, section along the plane marked A - A in Figure 51,
[0107] Figure 53 Cross-worm gear of the linear drive according to Figures 51 and 52,
[0108] Figure 54: Planing worm gear according to Figure 53 in perspective view
[0109] Figure 55 shows the seventh embodiment of a linear drive.
[0110] Description of the exemplary implementations
[0111] Figures 1 to 8 show a first embodiment of a linear drive 200. The linear drive comprises a cylindrical worm 202, which can be rotated about a geometric worm axis 203. For this purpose, a motor shaft, for example of the motor 12 shown in Figure 13, can be connected to a worm shaft of the worm 202. Alternatively, a further gear stage 14 can be provided upstream of the worm 202, as shown in Figures 14 and 15. The worm 202 has a thread 204 with a constant pitch on its circumferential surface. The linear drive 200 also includes a cross-worm gear 205, which has a helical toothing 207 on a face 206 facing the worm 202. This toothing 207 is located on the outer edge of the cross-worm gear 205.The worm 202 is in effective engagement with the cross-cutting worm gear 5, with the thread 204 of the worm 202 engaging the teeth 207 of the cross-cutting worm gear 205. This causes the cross-cutting worm gear 205 to rotate about a geometric cross-cutting worm gear axis 208. The geometric worm axis 203 and the geometric cross-cutting worm gear axis 208 are skew geometric lines with a distance d between them that is smaller than the outer radius R of the cross-cutting worm gear 205. The distance d and the radius R are shown in Figure 9 with respect to the worm 2 and the cross-cutting worm gear 5. The same applies to the worm 202 and the cross-cutting worm gear 205 of the linear drive 200 according to Figures 1 to 8.
[0112] The worm gear 205 is equipped with a crank 210. The crank forms a first gear element, which ensures that the rotational motion is converted into a translational motion. The crank 210 is arranged on the face 211 of the worm gear 205 opposite the toothing. The illustration in Figure 1 shows that the crank 210 is arranged offset from the geometric axis 208 of the worm gear 205.
[0113] Figure 2 shows the linear drive 200 in a section along the plane labeled H-H in Figure 1. Figure 3 shows a detail from Figure 2. In these views according to Figures 2 and 3, it can be seen that the thread 204 of the worm 202 engages in the helical teeth 207 of the cross-worm gear 205, causing the cross-worm gear 205 to rotate about the cross-worm gear axis 208. The face 206 of the cross-worm gear 205 with the helical teeth 207, which meshes with the thread 204 of the worm 202, is also visible. When the cross-worm gear 205 rotates, the crank 210, located on the face 211, is also rotated about the geometric cross-worm gear axis 208. A connecting rod 212 is mounted at one end on the crank 210. For this purpose, the connecting rod 212 has a first connecting rod head 213 at its first end.Figures 2 and 4 show that the first connecting rod end 213 has a circular through-hole through which the crank 210 passes. The first connecting rod end 213 thus engages the crank 210. It is rotatably mounted on the crank 210. The second end of the connecting rod 212, opposite the first end, has a second connecting rod end 214. The second connecting rod end is not visible in Figure 2 because the connecting rod 212 is cut off. This second connecting rod end 214 is also equipped with a circular through-hole 215. This is visible in Figures 3, 5, and 6. The second connecting rod end serves to couple the linear drive 200 to a driven component. This driven component is not shown in the drawing.
[0114] Rotation of the worm 202 about the geometric worm axis 203 leads to rotation of the cross-winding worm wheel 205 and thus of the crank 210 about the geometric cross-winding worm wheel axis 208. The connecting rod 212, which is mounted on the crank 210, is moved back and forth longitudinally, thus performing a translational movement. Figure 3 shows that the second connecting rod head 214 is moved along a geometric linear axis.
[0115] Figures 3a and 3b show the coupling of the second connecting rod head 214 via a journal 225 to a component 226, which is mounted in a linear guide 227. The illustrations show how the second connecting rod head 214, the journal 225, and the component 226 move within the linear guide 227 when the first connecting rod head 213 rotates together with the worm gear 205.
[0116] The linear drive 200 has a linear drive base 216, which is designed as a housing. The worm 202 is rotatably mounted at one end in this linear drive base 216. For this purpose, the linear drive base 216 is equipped with a bearing 217. A threadless section 218 of the worm 202 projects from the linear drive base 216. A motor or a manual drive can be coupled to this section. The cross worm gear 205 is equipped with two stub axles 219, 220, which are also rotatably mounted in the linear drive base 216. A first stub axle 219 is located on the face 206, which is equipped with the face teeth. A second stub axle 220 is arranged on the crank 210 via a connecting part 221 in such a way that it does not impede the movement of the connecting rod 212. The linear drive base is equipped with bearings 222, 223 in which the axle stubs 219, 220 of the cross worm gear are mounted.The linear drive base 216 encloses the section of the worm 202 equipped with the thread 204, the cross worm gear 205, and the section of the connecting rod 212 that has the first connecting rod end 213. The linear drive base 216 has an opening 224 through which the connecting rod 212 passes. This opening 224 can also serve as a linear guide for the connecting rod 212.
[0117] Figures 9 to 12 show in detail a gear stage 1 with a worm 2 and a cross-worm gear 5, which essentially corresponds to the worm 202 and the cross-worm gear 205 of the first embodiment of a linear drive in Figures 1 to 8. Figures 9 to 12 illustrate the engagement of the worm 2 with the cross-worm gear 5 and the distance d between the geometric worm axis 3 and the geometric cross-worm gear axis 8. The worm 2 engages with its thread 4 with the helical teeth 207, which are located on the face 6 of the cross-worm gear 5. The geometric worm axis 3 and the geometric cross-worm gear axis 8 are skew geometric lines, the distance d between which is smaller than the outer radius R of the cross-worm gear 5. The distance d and the radius R are shown in Figure 9.
[0118] Figure 11 shows a section of Figure 10, labeled B, detailing the engagement of the worm 2 with the cross-worm gear 5. Each tooth of the helical gear 7 of the cross-worm gear has a convex tooth flank 10 and a concave tooth flank 11. The thread of the worm 2 has an asymmetrical profile with a first thread flank 4a and a second thread flank 4b. The first thread flank 4a of the worm thread engages with the convex tooth flank 10 of the teeth of the helical gear of the cross worm 5. The second thread flank 4a of the worm thread 4 engages with the concave tooth flank 11 of the teeth of the helical gear of the cross worm 5. The first pressure angle aa of the first thread flank 4a with the convex tooth flank 10 is smaller than the second pressure angle from the second thread flank 4b with the concave tooth flank 11.The first pressure angle aa and the second pressure angle ab define the contact geometry between the worm 2 and the cross worm wheel 5.
[0119] Figures 11 and 12 further show that the toothing 7 of the cross-worm gear 5 has an elliptically rounded tooth root shape. Furthermore, it can be seen in Figure 11 that the toothing 7 of the cross-worm gear 5 has a tip chamfer, which reduces the mechanical stress on the tooth tips.
[0120] Figure 13 shows the gear stage 1 with a motor 12 and a shaft 13, which is arranged on the cross worm gear 5. The worm shaft 9 shown in Figure 9 is non-rotatably connected to a motor shaft of the motor 12 (not shown). The second end of the worm 2, opposite the motor 12, is free. It is not additionally supported. The motor 12 drives the worm 2 to rotate. The torque of the motor is transmitted to the worm and from the worm to the cross worm gear 5. The cross worm gear 5 is equipped with an axle 13.
[0121] Figures 14 and 15 show a threaded stage 14 upstream of gear stage 1. This stage comprises an input gear 15, a shaft 16 (which may be coupled to a motor or another upstream gear stage, not shown), and an output gear 17. The input gear 15 meshes with the output gear 17, which in turn is rotationally connected to the worm 2. For this purpose, the output gear 17 is coupled to the worm shaft 9. The upstream gear stage 14 serves to adjust the gear ratio between a drive (not shown), for example, a motor, and the worm 2.
[0122] Figure 16 shows a second embodiment of a cross-worm gear 18. This embodiment differs from the first embodiment of a cross-worm gear 5 according to Figures 9 to 15 in that, in the second embodiment, the teeth 19 have a shape referred to as a comma head. The width of each tooth 19 is greater at its inner end 19a, which faces the geometric axis 8 of the cross-worm gear, than at its outer end 19b, which faces away from the inner end 19a and the geometric axis 8 of the cross-worm gear. The width of each tooth 19 thus decreases from the inside out.
[0123] Figures 17 to 21 show another embodiment of a gear stage 20 comprising a worm, a cross worm gear, and a motor. The cross worm gear 5 with geometric cross worm gear axis 8 corresponds to the gear stage 1 according to Figures 9 to 13. The motor 12 is identical to the motor shown in Figure 13. Therefore, the same reference numerals are given for these corresponding components in Figures 17 to 21. However, the worm 22 differs from the worm 2 of gear stage 1 according to Figures 9 to 13. Unlike the worm 2, the worm 22 is rotatably mounted at its end facing away from the motor 12 in a bearing 28. This bearing 28 is arranged in a bearing receptacle 27, which is part of a linear drive base 24. The bearing 28 is shown in Figure 21. The motor housing 12 and the cross worm gear 5 are mounted on the linear drive base 24.The worm 22 is driven by the motor 12 to rotate about the geometric worm axis 23. Figure 20 shows that the linear drive base 24 is closed by a cover 25. Figure 12 also shows an output shaft 26 protruding from the linear drive base 24. It is connected to the cross-worm gear 5.
[0124] Figures 14 to 22 show various embodiments of a worm gear.
[0125] The third embodiment of a cross-worm gear 35, shown in Figures 22 to 25, has a helical toothing 37 on its face 36 with continuous run-out on both sides and no tooth edges. The cross-worm gear 35 has the outer shape of a cylindrical disk with a central through-opening 41. The central through-opening 41 serves to receive an axle or shaft (not shown in Figures 22 to 25) or other connecting element. The helical toothing 37 is located on the face 36, which, with respect to the geometric shape of the cross-worm gear, forms a lid of the cylinder. The toothing 37 is formed by recesses on the face 36. These recesses extend radially in a helical pattern. However, they do not extend to the central through-opening or to an outer circumferential side of the cross-worm gear 35.Therefore, there are no tooth edges at either the through-opening or the circumferential side. Instead, each of the recesses is equipped with an inner outlet 38 near the central through-opening 41 and an outer outlet 39 near the circumferential side of the worm gear 35. The depth of the recesses decreases continuously at the inner outlet 38 and the outer outlet 39. This is particularly evident in the sectional view according to Figure 25.
[0126] Figure 24 shows the engagement area 40 of a worm gear (not shown). The illustration shows that the engagement area is located within the fully formed tooth profile between the inner outlet 38 and the outer outlet 39. Figure 26 shows a fourth embodiment of a cross-cutting worm gear 45. This differs from the cross-cutting worm gear 35 shown in Figure 22 in that the cross-cutting worm gear 45 has a toothed section with an outer outlet 49, while the recesses extend to the central through-hole, so that tooth face edges are formed there.
[0127] Figure 27 shows a fifth embodiment of a cross-worm gear 55. This differs from the cross-worm gear 35 shown in Figure 22 in that the cross-worm gear 55 has a toothing with an inner outlet 58, while the recesses extend outwards to the circumferential side, so that tooth face edges are formed there.
[0128] Figures 28 to 30 show a sixth embodiment of a cross worm gear 65. Like the preceding embodiments, the cross worm gear 65 has a through-opening 71 centrally located with respect to the geometric axis 68 of the cross worm gear. The cross worm gear 65 comprises an insert 69, which is placed into an injection mold (not shown in the drawing) during manufacturing by plastic injection molding. The insert 69 consists of a first material, for example, metal or ceramic. In the region 70 of the helical teeth 67 on the face 66, the insert 69 is overmolded with a plastic. The cross worm gear 65 can also be manufactured by multi-component injection molding. In this case, the insert 69 consists of a first component and the region 70 of a second component.
[0129] Figures 31 and 32 show a second embodiment of a linear drive 120. This drive is equipped with a spindle drive. The drive 120 comprises a motor 129, which drives a worm 122 to rotate. The worm 122 is in operative engagement with a cross-worm gear 125, which is driven to rotate about the cross-worm gear axis 128 by the motor 129 and the worm 122. The spindle drive comprises a threaded spindle 130, which is non-rotatably connected to the cross-worm gear 125, so that the rotation of the cross-worm gear 125 is transmitted to the threaded spindle 130, which is also driven to rotate about the geometric cross-worm gear axis 128. A spindle nut 131 is in operative engagement with the threaded spindle 130. The spindle nut 131 is twisted and linearly movable on a linear drive base or other component.A rotation of the threaded spindle 130 therefore results in a linear movement of the spindle nut 131 in the direction of the geometric cross worm gear axis 128.
[0130] Figure 32 shows the linear drive base 134, which surrounds the worm 122 and the cross worm gear 125. The mounting of the threaded spindle 131 on the linear drive base is not shown in the drawing.
[0131] Figures 33 to 36 show a third embodiment of a linear drive 140. This drive is also equipped with a spindle drive, but unlike the previous embodiment, the worm gear 145 also serves as the spindle nut. The drive 140 comprises a motor with a motor housing 12, the motor driving a worm 22 to rotation. The worm 22 is rotatably mounted at its end opposite the motor on a linear drive base 144. The worm 22 engages with a worm gear 145, which is driven to rotation about the worm gear axis 148 by the motor and the worm 22. The worm gear 145 has a through-hole 151. In the region of the through-hole 151, the worm gear 145 is provided with an internal thread 152. A threaded spindle 150 engages with this internal thread 152.This is mounted on the linear drive base in a rotationally fixed and linearly movable manner. Rotation of the cross-worm gear 145 about its geometric axis 148 thus results in a linear movement of the threaded spindle 150 along the geometric axis 148. Figure 36 shows the cross-worm gear 145 in isolation. The illustration shows that the cross-worm gear 145 has teeth 147 on its face 146. With the exception of the through-hole 151 with internal thread 152, the cross-worm gear 145 is identical to the cross-worm gear 65 shown in Figures 28 to 30.
[0132] Figures 37 to 44 show a fourth embodiment of a linear drive 160. This drive is equipped with a combination of a spur gear 170 and a rack 171. The drive 160 comprises a motor 169 with a motor housing 172, the motor 169 driving a worm 162 to rotate about a geometric worm axis 163. The worm 162 is not additionally rotatably mounted at its end opposite the motor. It is in operative engagement with a cross-worm gear 165, which is equipped with a helical toothing 167 on its face 166. The cross-worm gear 165 is driven to rotate about the cross-worm gear axis 168 by the motor 169 and the worm 162. The gear 170 is non-rotatably connected to the worm gear 165, so that the rotation of the worm gear 165 about the geometric worm gear axis 168 is transferred to the gear 170.The gear 170 is in effective engagement with the rack 171, so that the rotation of the gear 170 is transmitted as a linear movement of the rack 171 along the geometric linear axis 176. Figure 40 shows that the geometric linear axis 176 of the rack 171 is parallel to the geometric worm axis 163 of the worm 162. The geometric worm gear axis 168 is perpendicular to both of these axes, without intersecting them. The geometric worm gear axis 168 is a straight line skew to both the geometric worm axis 163 and the geometric linear axis 176. The worm 162, the worm gear 165, the gear 170, and partially also the rack 171 are mounted in a linear drive base 174. This base is closed by a cover 175.
[0133] Figures 45 to 50 show a fifth embodiment of a linear drive 240. This drive is equipped with a cam 250 and a rod 252. Components corresponding to the first embodiment of a linear drive 200 according to Figures 1 to 8 are designated with the same reference numerals. A worm 202 is in operative engagement with a cross-worm gear 245. A rotation of the worm 202 about its geometric worm axis 203 is transmitted as a rotation of the cross-worm gear 245 about its geometric cross-worm gear axis 248. The cross-worm gear 245 has a helical toothing 207 on a first face 206, in which the worm 202 meshes with its thread. On a second face 211, a circular cylinder 250 is arranged eccentrically to the geometric cross-worm gear axis 248, so that it forms a cam.The cross-worm gear 245 is rotatably mounted in a linear drive base 256 via bearings 222 and 223 by means of the axle stubs 258 and 259. The worm 202 is rotatably mounted in the linear drive base 256 via a bearing 217. A rod 252 is slidably and spring-loaded mounted in a linear guide 255 of the linear drive base 256. For this purpose, the linear guide is equipped with a helical spring 257. The rod 252 has a spherical head 253 at one end. This is pressed against the cylinder 250 by the spring 257. The rotation of the cross-worm gear 245 causes the eccentrically arranged cylinder 250 to rotate, which deflects the rod 252 like a cam. The spring 257 ensures that the rod 252 with its spherical head 253 remains in constant contact with the cylinder 250. This causes the rod 252 to move along a geometric linear axis 260.
[0134] Figures 51 to 54 show a sixth embodiment of a linear drive 270. This sixth embodiment differs from the fifth embodiment shown in Figures 45 to 50 in that, instead of a cylinder designed as a cam, a cam disk 280 is provided on the worm gear 275. The components corresponding to the fifth embodiment are designated with the same reference numerals in Figures 51 to 54. For details, refer to the description above for Figures 45 to 50. Rotation of the worm 202 causes rotation of the worm gear 275 and thus of the cam disk 280. The rod 252 is pressed against the cam disk 280 by the spring 257. This ensures that the rod 252, with its spherical head 253, remains in constant contact with the cam disk 280.Since the cam disc is not rotationally symmetric with respect to the geometric worm gear axis 278, a rotation of the worm gear 275 leads to a deflection of the rod 252 along the geometric linear axis 260.
[0135] Figure 55 shows a seventh embodiment of a linear drive 290. For simplicity, only the worm gear 295, a pin 296 arranged eccentrically in the worm gear relative to the geometric axis 298, a slide 297 with an elongated hole 299, and a linear guide 300 are shown. The pin 296 is received in the elongated hole 299 of the slide 297. Rotation of the worm gear 295 about the geometric axis 298 causes the pin 296 to also rotate about the geometric axis 298. In doing so, the pin 296 carries the slide 297 with it. Since the slider 297 cannot move laterally due to the linear guide 300, its movement results in a motion of the slider 297 along a geometric linear axis 301. Figure 55 shows various settings of the pin 296 and the slider 297.
[0136] All features of the invention can be essential to the invention, both individually and in any combination. Reference numerals
[0137] 1 gear stage
[0138] 2 snails
[0139] 3 Geometric worm axis
[0140] 4 threads
[0141] 4a first thread flank
[0142] 4b second thread flank
[0143] 5 paddling worm gear
[0144] 6 Plan page
[0145] 7 Spiral toothing
[0146] 8 Geometric worm gear axle
[0147] 9 worm shaft
[0148] 10 Convex flank of the face gear teeth
[0149] 11 Concave flank of the face gear teeth
[0150] 12 engine
[0151] 13th wave
[0152] 14 Upstream gear stage
[0153] 15 Drive-side gear of the upstream gear stage 16 Shaft
[0154] 17 Output-side gear of the upstream gear stage 18 Crossworm gear
[0155] 19 teeth
[0156] 19a inner tooth end
[0157] 19b outer end of tooth
[0158] 20 Adjustable and linear drives
[0159] 22 snail
[0160] 23 Geometric worm axis
[0161] 24 Linear drive base
[0162] 25 lids
[0163] 26 Output shaft
[0164] 27 Bearing mount 28 Bearing for screw
[0165] 35 Splash worm gear
[0166] 36 Plan page
[0167] 37 Spiral toothing
[0168] 38 outlet inside
[0169] 39 outlet outside
[0170] 40 Intervention area of the snail
[0171] 41 Passage opening
[0172] 45 Splash worm wheel
[0173] 49 outlet outside
[0174] 55 Splash worm gear
[0175] 58 outlet inside
[0176] 65 Splash worm wheel
[0177] 66 Plan page
[0178] 67 spiral teeth
[0179] 68 geometric worm gear axle
[0180] 69 inserts made from a first material
[0181] 70 Overmolded area made of a second material 71 Through opening
[0182] 120 linear actuator
[0183] 122 snail
[0184] 125 Splash worm gear
[0185] 128 geometric worm gear axle
[0186] 129 Engine
[0187] 130 spindle
[0188] 131 Spindle nut
[0189] 134 Linear drive base
[0190] 140 linear actuator
[0191] 144 Linear drive base
[0192] 145 Splash worm gear
[0193] 146 Plan page
[0194] 147 spiral gearing 148 geometric worm gear shaft 150 spindle
[0195] 151 Passage opening
[0196] 152 internal threads
[0197] 160 linear drive
[0198] 162 snail
[0199] 163 geometric worm axis
[0200] 165 Splash worm gear
[0201] 166 Plan page
[0202] 167 spiral teeth
[0203] 168 geometric worm gear axle 169 motor
[0204] 170 Gear with face teeth
[0205] 171 Rack and pinion
[0206] 172 Engine housings
[0207] 173 wave
[0208] 174 Linear drive base
[0209] 175 lids
[0210] 176 geometric linear axis of the rack 200 linear drive
[0211] 202 snail
[0212] 203 geometric worm axis
[0213] 204 threads
[0214] 205 Splash worm wheel
[0215] 206 Plan page
[0216] 207 spiral toothing
[0217] 208 geometric worm gear axle 210 crank
[0218] 211 Plan page
[0219] 212 Connecting rod
[0220] 213 first connecting rod head
[0221] 214 second connecting rod head 215 through-hole
[0222] 216 Linear drive base
[0223] 217 warehouses
[0224] 218 threadless section of the worm 219 shaft stub
[0225] 220 axle stubs
[0226] 221 Connecting part
[0227] 222 warehouses
[0228] 223 warehouses
[0229] 224 Opening
[0230] 225 cones
[0231] 226 Component
[0232] 227 Linear guide
[0233] 240 linear actuator
[0234] 245 Splash worm gear
[0235] 248 geometric worm gear axle 250 cylinders
[0236] 252 bars
[0237] 253 spherical head
[0238] 255 Linear guide
[0239] 256 Linear drive base
[0240] 257 spring
[0241] 258 axle stubs
[0242] 259 axle stubs
[0243] 260 Linear geometric axis
[0244] 270 Linear drive
[0245] 275 Splash worm gear
[0246] 278 geometric worm gear axle 280 cam disc
[0247] 290 linear actuator
[0248] 295 Splash worm gear
[0249] 296 Pin sliders
[0250] geometric face worm wheel axle, long hole
[0251] Linear guide
[0252] geometric linear axis
Claims
Attorney file: 525002-PCT Applicant: Framo Morat GmbH & Co KG Franz-Morat-Straße 6 79871 Eisenbach Title: Linear actuator REQUIREMENTS 1. Linear drive, which converts a rotational movement into a linear movement, with a cylindrical worm (2, 22, 122, 162, 202) which is driven to rotation about a geometric worm axis (3, 23, 163, 203) and which has at least one thread (4, 204) on its circumferential surface, with a cross-worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) which has a helical toothing (7, 37, 167, 207) on one face (6, 36, 146, 166, 206), wherein the worm (2, 22, 122, 162, 202) is in effective engagement with the cross-cutting worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) such that the worm (2, 22, 122, 162, 202) with its at least one thread (4, 204) meshes in the teeth (7, 37, 167, 207) of the cross-cutting worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) and the worm (2, 22, 122, 162, 202) thereby driving the worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) around a geometric worm gear axis (8, 68, 108, 128, 148, 168, 298) to rotation, where the geometric worm axis (3, 23, 163) and the geometric worm gear axis (8, 68, 108, 128, 148, 168, 298) are skew geometric straight lines whose distance d is less than an outer radius R of the worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295), wherein a first gear part (130, 152, 170, 210, 250, 280, 296) is rotatably connected to or integrally formed with the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) and wherein a second gear part (131, 150, 171, 214, 252, 297) is directly or indirectly coupled to the first gear part (130, 152, 170, 210, 250, 280, 296) such that a rotation of the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) and the first gear part (130, 152, 170, 210, 250, 280, 296) rotating together with the cross-worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) sets the second gear part (131, 150, 171, 214, 252, 297) into a linear motion.
2. Linear drive according to claim 1, characterized in that it is equipped with a linear drive base (24, 114, 134, 144, 174, 216, 256) on which the worm (2, 22, 122, 162, 202) and the cross worm wheel (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) are at least indirectly rotatably mounted.
3. Linear drive according to claim 1 or 2, characterized in that the worm (2, 22, 122, 162, 202) is rotatably mounted at a first end relative to the linear drive base (24, 114, 134, 144, 174, 216, 256).
4. Linear drive according to claim 3, characterized in that a second end of the worm (2, 122, 162) opposite the first end is a free end.
5. Linear drive according to claim 3, characterized in that a second end of the worm (22) opposite the first end is rotatably mounted.
6. Linear drive according to one of the preceding claims, characterized in that the toothing (7, 37, 67, 167, 207) of the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) has an elliptically rounded tooth root.
7. Linear drive according to one of the preceding claims, characterized in that the toothing (7, 37, 67, 167, 207) of the cross worm gear (5, 35, 105, 125, 145, 165, 205, 245, 275, 295) has a head edge fracture.
8. Linear drive according to one of the preceding claims, characterized in that the toothing (37) of the cross worm gear (35, 45, 55) has a continuous run-out on one or both sides without tooth end edges.
9. Linear drive according to one of the preceding claims, characterized in that each tooth of the helical toothing (7) of the worm gear (5) has a convex tooth flank (10) and a concave tooth flank (11).
10. Linear drive according to one of the preceding claims, characterized in that, in each tooth (19) of the worm gear (18), its width at the tooth head decreases from an inner tooth end (19a), which is facing the geometric worm gear axis (8), to an outer tooth end (19b) facing away from the inner tooth end (19a).
11. Linear drive according to one of the preceding claims, characterized in that the at least one thread (4, 204) of the worm (2, 22, 122, 162, 202) is in effective engagement with the toothing (7, 37, 167, 207) of the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) at at least three contact points.
12. Linear drive according to one of the preceding claims, characterized in that the first gear part is designed as a threaded spindle (130) and that the second gear part is designed as a spindle nut (131) which engages with the threaded spindle (130).
13. Linear drive according to claim 12 insofar as it refers back to claim 2, characterized in that the threaded spindle (130) is rotatably mounted on the linear drive base (134) and is connected to the worm gear (125) in a twistable manner, and that the spindle nut (131) is mounted on the linear drive base (134) in a twistable and linearly displaceable manner.
14. Linear drive according to claim 2 or according to one of claims 3 to 11, insofar as it relates back to claim 2, characterized in that the first gear part is designed as a spindle nut which is arranged in a twisted manner on the worm gear or is an integral part (152) of the worm gear (145), and that the second gear part is designed as a threaded spindle (150) which is received in a twisted and linearly displaceable manner on the linear drive base (144).
15. Linear drive according to one of claims 1 to 11, characterized in that the first gear part is designed as a linear drive gear (170), that the second gear part is designed as a rack (171), and that the linear drive gear (170) engages with the rack (171).
16. Linear drive according to claim 15, characterized in that the linear drive gear (170) and the worm gear (165) are arranged on a common shaft (173).
17. Linear drive according to any one of claims 1 to 11, characterized in that the first transmission part is designed as a crank (210) which is arranged eccentrically on the worm gear (205) with respect to the geometric axis (208) of the worm gear, that a connecting rod (212) with a first connecting rod head (213) is rotatably connected to the crank (210), and that a second connecting rod head (214) of the connecting rod is designed as a second transmission part.
18. Linear drive according to claim 17, characterized in that the second connecting rod head (214) is received in a linear guide.
19. Linear drive according to claim 2 or according to one of claims 3 to 11 insofar as these are related back to claim 2, characterized in that the first gear part is designed as a cam (250, 280), that the second gear part is designed as a rod (252) which is spring-loaded and linearly displaceable on the linear drive base (256) such that a spring (257) presses the rod (252) against the cam (250, 280) and the rod (252) transmits the movement resulting from the rotation of the cam (250, 280) at the edge of the cam (250, 280).
20. Linear drive according to claim 19, characterized in that the cam (250) is designed as a cylinder which is arranged eccentrically on the worm gear (245) with respect to the worm gear axis (248).
21. Linear drive according to claim 19, characterized in that the cam (280) is formed by a cam disk.
22. Linear drive according to one of claims 1 to 11, characterized in that the first gear part is designed as a pin (296) which is arranged eccentrically on the worm gear (295) with respect to the geometric axis (298) and projects in the axial direction beyond the flat side of the worm gear (295) facing away from the toothing, and that the second gear part is designed as a linearly movable slide (297) which rests loosely on the pin (296) and which is deflected by the pin (296) which rotates together with the worm gear (295).
23. Linear drive according to one of the preceding claims, characterized in that it is equipped with at least one further gear stage (14) which is positioned upstream of the worm (2).
24. Linear drive according to one of the preceding claims, characterized in that the worm (2, 22, 122, 162, 202) and / or the cross worm wheel (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) are made of plastic.
25. Linear drive according to claim 24, characterized in that the worm (2, 22, 122, 162, 202) and / or the cross worm wheel (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) are manufactured by plastic injection molding.
26. Linear drive according to one of the preceding claims, characterized in that the worm gear (65) is manufactured by injection molding and comprises a metallic or ceramic insert (69) or a plastic insert.
27. Linear drive according to one of claims 1 to 23, characterized in that the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) is made of a metallic or ceramic material and is sintered at least in the area of the toothing.
28. Linear drive according to claim 27, characterized in that the worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) is impregnated with a lubricant or a plastic or a metallic impregnating agent.
29. Linear drive according to any one of claims 1 to 23, characterized in that the worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) is made of a metallic material and is manufactured by investment casting.
30. Linear drive according to one of claims 1 to 23, characterized in that the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) is made of a metallic material and is manufactured by means of cold extrusion.
31. Linear drive according to one of claims 1 to 23, characterized in that the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) is made of a metallic material and is produced by forging.
32. Linear drive according to one of the preceding claims, characterized in that the cross worm gear (5, 35, 45, 55, 65, 105, 125, 145, 165, 205, 245, 275, 295) is at least partially manufactured by machining.
33. Linear drive according to one of the preceding claims, characterized in that it is equipped with grease or oil lubrication.