TWIST PROMOTION

Description

[0001] The invention relates to a wobble drive for a high-pressure cleaning device, comprising a motor with a motor shaft rotatably mounted about an axis of rotation and a wobble unit with a wobble body rotatably driven about the axis of rotation and a swashplate, the end face of which facing away from the wobble body is inclined to the axis of rotation, wherein a swashplate bearing is arranged between the wobble body and the swashplate, wherein the wobble body has a first, spherically curved contact surface on a front side facing the swashplate and a second contact surface on a rear side facing the motor shaft, wherein a central opening extends from the first contact surface to the second contact surface, and wherein the wobble body can be connected to the motor shaft in a rotationally fixed manner by means of a screw connection device, wherein the screw connection device comprises a connecting screw extending through the central opening.whose longitudinal axis is aligned coaxially to the axis of rotation, wherein the screw connection device can be applied flatly to the first contact surface, and wherein the second contact surface can be applied to a flatly designed holding surface oriented perpendicular to the axis of rotation, which is arranged directly on the motor shaft or on a component non-rotatably connected to the motor shaft.

[0002] CN 113107799 A relates to a piston pump suitable for high-pressure cleaning equipment. The piston pump comprises a pump cover, a pump cavity, a piston ring, an oil cylinder, and an overflow valve assembly.

[0003] US 2020 / 347836 A1 discloses a swashplate piston water pump for use in a high-pressure cleaner, driven by a drive device, wherein the water pump comprises a pump body, a swashplate, four or more pistons and a water passage defined by a water inlet and a water outlet.

[0004] DE 10 2011 054 442 A1 relates to a piston pump for a high-pressure cleaning device, with several pistons that can be moved back and forth, each of which immerses in a pumping chamber and is slidably held on a piston guide part, wherein the piston guide part has a support wall on which several guide elements are arranged, each of which guides a piston.

[0005] From DE 42 05 859 A1, a wobble drive is known that comprises a motor with a motor shaft rotatably mounted about a rotational axis and a wobble unit. The wobble unit includes a swashplate and a wobble body formed from sheet metal. The swashplate is supported by a swashplate bearing against a support surface of the wobble body. Such wobble drives are used in axial piston pumps to convert the rotary motion of the motor shaft into a reciprocating motion of pistons bearing against an end face of the swashplate. By means of the pistons, liquid, preferably water, can then be periodically drawn in, pressurized, and discharged via a pressure line. If the delivery rate of the axial piston pump is to be changed, the stroke of the pistons can be altered by changing the inclination of the swashplate. The greater the inclination of the swashplate to the axis of rotation, the greater the piston stroke.

[0006] If the piston stroke needs to be changed, this can be achieved by tilting the wobble body, which has a spherically curved contact surface on its rear side facing the motor shaft. This allows the piston stroke to be adjusted, and it is possible to use a single wobble body design for various axial piston pumps with different delivery rates. The wobble body's tilt must be set during assembly and subsequently checked, which makes the assembly process complex.

[0007] Manufacturing the swashplate body as a sheet metal component requires a forming process and post-processing, such as heat treatment. This heat treatment hardens the support surface on which the swashplate bearing rests, which is necessary to achieve the required wear resistance of the swashplate body. Manufacturing the swashplate drive requires several production steps, making it a complex process.

[0008] The object of the present invention is to provide a wobble drive of the type mentioned above which has simple assembly and manufacturing.

[0009] This problem is solved in a wobble drive of the generic type according to the invention by the fact that the wobble body is designed as a one-piece solid component, wherein the second contact surface is designed to be flat and is aligned perpendicular to the axis of rotation, and that the wobble disk bearing is supported on a support disk connectable to the wobble body, which rests on a support surface of the wobble body aligned parallel to the end face of the wobble disk, wherein the wobble body has at least one centering element for centering the support disk relative to the wobble body, and wherein the at least one centering element forms a positive locking element, wherein the support disk can be connected to the wobble body in a rotationally fixed manner by means of the positive locking element.

[0010] In the wobble drive according to the invention, the wobble body is designed as a single, solid component. Due to the one-piece construction of the wobble body, manufacturing can be carried out in a single step. Likewise, the assembly of various components into a wobble body is not required. Thus, the number of manufacturing steps can be reduced.

[0011] The swashplate bearing is supported by a support disc, which rests against a support surface of the swashplate body oriented parallel to the end face of the swashplate. The surface on which the swashplate bearing is supported is subject to high mechanical loads and, according to the invention, is formed by the support disc. Mechanical wear of the surface on which the swashplate bearing is supported can be counteracted, for example, by selecting a hard material for the support disc or by means of a heat treatment that hardens the surface of the support disc. Because the swashplate bearing is supported by the support disc instead of directly on the support surface of the swashplate body, post-processing of the swashplate body, for example by heat treatment to harden the support surface, is unnecessary. This reduces the manufacturing effort for the swashplate body.

[0012] The second contact surface of the wobble body is flat and arranged perpendicular to the axis of rotation. The support surface of the wobble body, which is aligned parallel to the end face of the swashplate, creates an angle of inclination between this support surface and the second contact surface. This angle determines the piston stroke of pistons that are reciprocally movable, arranged parallel to the axis of rotation, and resting against the end face of the swashplate. The second contact surface can be placed against the flat mounting surface of the motor shaft, or of a component rigidly connected to the motor shaft, which is also perpendicular to the axis of rotation. The flat design of the second contact surface, which is also perpendicular to the axis of rotation, and the flat mounting surface, which is also perpendicular to the axis of rotation, enable very simple assembly of the wobble body, whose geometry determines the piston stroke.Therefore, the tilt angle does not need to be adjusted and checked during assembly.

[0013] The swashplate has a front and a back. The spherically curved first contact surface is located on the front of the swashplate, and the flat second contact surface, oriented perpendicular to the motor shaft, is located on the back. This second contact surface can be placed against the flat mounting surface, which is also oriented perpendicular to the motor shaft. The screw connection, which allows the swashplate to be connected to the motor shaft in a rotationally fixed manner, can be placed flat against the first contact surface. The spherically curved first contact surface allows the screw connection to make full contact with the first contact surface regardless of the angle of inclination, thus ensuring a uniform force distribution from the screw connection, via the first and second contact surfaces, to the mounting surface and ultimately to the motor shaft. The center point of the sphere forming the first contact surface is defined by the intersection of the axis of rotation with the end face of the swashplate.This ensures that the swashplate is centered relative to the axis of rotation regardless of the tilt angle. The flat design of the second contact surface allows for a simple geometric design of the back of the swashplate body.

[0014] Preferably, the spherically curved first contact surface is designed to be concave.

[0015] Depending on the desired piston stroke, the wobble drive according to the invention uses a wobble body with an inclination angle between the support surface and the second contact surface that corresponds to the piston stroke. Different wobble bodies are thus distinguished only by their different inclination angles, whereby the front surface of the wobble body can be designed identically for all inclination angles, and only the inclination angle of the flat second contact surface relative to the support surface needs to be changed. Manufacturing wobble bodies with different inclination angles is therefore very simple.

[0016] To make the manufacturing of the wobble body particularly easy, the wobble body is preferably manufactured using a tool that includes at least one molded part.

[0017] Advantageously, the tool comprises a first and a second mold part. The first mold part forms the front of the wobble body, while the second mold part forms the back. Due to the spherically curved design of the first molding surface, only the geometrically simple design of the back, and thus the second mold part, needs to be adjusted for wobble bodies with different angles of inclination. Therefore, the first mold part, which forms the front of the wobble body, can remain the same for all desired angles of inclination. This enables the simple production of wobble bodies with varying angles of inclination and easy assembly.

[0018] The wobble body has at least one centering element for centering the support disc relative to the wobble body. This facilitates the precise positioning of the support disc on the wobble body.

[0019] Furthermore, the at least one centering element forms a positive locking element, whereby the support disc can be connected to the wobble body in a rotationally fixed manner by means of the positive locking element. The support disc can, for example, be connected to the wobble body by pressing.

[0020] Preferably, the wobble body is a cast part. This allows for particularly simple and cost-effective manufacturing.

[0021] The wobble body is preferably made of die-cast aluminum. The die-casting process allows for the production of particularly dimensionally accurate components with good surface quality, eliminating the need for post-processing.

[0022] It is advantageous if the swashplate bearing is designed as a rolling bearing.

[0023] In an advantageous embodiment of the invention, the screw connection device is designed in one piece in the form of a connecting screw, which has a screw head that rests flat against the first contact surface. The screw head is shaped according to the first, spherically curved contact surface, so that a uniform force distribution from the connection device via the first contact surface and the second contact surface to the holding surface and thus to the motor shaft is enabled.

[0024] Alternatively, the screw connection can be designed in two parts, comprising a connecting screw and a washer, with the washer bearing flat against the first contact surface. This allows the use of a standard screw as the connecting screw. In combination with a washer surface that is spherically curved to match the first contact surface and faces it, a uniform force distribution from the connection, across the first and second contact surfaces, to the holding surface and thus to the motor shaft can be achieved.

[0025] Advantageously, in addition to the screw connection, the wobble body can be connected to the motor shaft by means of a positive-locking connection. This enables an anti-rotation device between the wobble body and the motor shaft.

[0026] The following description of preferred embodiments of the invention, in conjunction with the drawing, serves for further explanation. The drawing shows: Figure 1: a sectional view of a high-pressure cleaning device with a first embodiment of a wobble drive; Figure 2: an enlarged view of detail X from Figure 1 Figure 3: a perspective view of a wobble unit of the wobble drive made of Figure 1 oblique view from behind; Figure 4: a sectional view of the wobble unit along line 4-4 from Figure 3 Figure 5: a perspective view of a wobble body of the wobble drive made of Figure 1 oblique view from the front; Figure 6: a sectional view accordingly Figure 4 a second embodiment of a wobble drive; Figure 7: a sectional view accordingly Figure 4 a third embodiment of a wobble drive; Figure 8: an enlarged view accordingly Figure 2a fourth embodiment of a wobble drive; Figure 9: a perspective view of a wobble unit of the wobble drive made of Figure 8 oblique view from behind; Figure 10: a sectional view of the wobble unit along line 10-10 from Figure 9 ;

[0027] In the Figures 1 to 5 Figure 1 is a schematic representation of a first embodiment of a wobble drive according to the invention for a high-pressure cleaning device, which is generally designated with reference numeral 10.

[0028] The high-pressure cleaning device comprises an axial piston pump 12 with pistons 14, which are driven by the oscillating drive 10. The oscillating drive 10 comprises a motor 16 with a motor shaft 20 rotatably mounted about a pivot axis 18 and an oscillating unit 22. The rotatable mounting of the motor shaft 20 is effected by means of a ball bearing 24, which has an inner ring 26 non-rotatably connected to the motor shaft and an outer ring 29 non-rotatably connected to a housing 28.

[0029] The swash unit 22 comprises a swash body 32 connected to the motor shaft 20 by means of a screw connection device 30 and a flat, annularly designed swashplate 34, on the end face 36 of which, facing away from the swash body 32, the pistons 14 of the axial piston pump 12 bear resiliently by means of piston springs 38.

[0030] The screw connection device 30 is designed as a connecting screw 40. The longitudinal axis 42 of the connecting screw 40 is aligned coaxially with the axis of rotation 18. A swashplate bearing 44 is arranged between the swashplate 34 and the swashplate body 32. The swashplate bearing 44 comprises spherical rolling elements 46 and a bearing cage 48 that surrounds the rolling elements 46. The swashplate bearing 44 is supported by a support disk 50 connected to the swashplate body 32. The support disk 50 is annular in shape and bears flat against a support surface 51 of the swashplate body 32, which is aligned parallel to the end face 36 of the swashplate 34.

[0031] The wobble body 32 comprises a front section 52 extending from the support surface 51 towards the swashplate 34 and a rear section 53 extending from the support surface 51 towards the motor shaft 20. The support surface 51 divides the wobble body 32 into the front section 52 and the rear section 53.

[0032] The wobble body 32 has a first, spherically inwardly curved contact surface 56 on a front side 54 facing the wobble disk 34 and arranged on the front section 52, and a second contact surface 60 that is flat and aligned perpendicular to the axis of rotation 18 on a rear side 58 facing the motor shaft 20 and arranged on the rear section 53.

[0033] Starting from the first contact surface 56, a central opening 62 extends to the second contact surface 60. The connecting screw 40 comprises a screw head 64 and a screw shank 66. The screw shank 66 passes through the central opening 62 and is screwed into a central threaded bore 68 located on an end face 70 of the motor shaft 20, which is aligned coaxially with the axis of rotation 18. The screw head 64 is designed to be complementary to the first contact surface 56 and rests flat against the first contact surface 56. The second contact surface 60 rests against a flat retaining surface 71, which is oriented perpendicular to the axis of rotation 18 and is formed by an end face 72 of the inner ring 26 of the radial groove ball bearing 24 facing the wobble body 32. The support surface 51 of the wobble body 32, arranged parallel to the front face 36 of the swashplate 34, forms an angle of inclination α relative to the second contact surface 60.

[0034] As from Figure 5 As can be clearly seen, the wobble body 32 has 54 centering elements 73 on its front side, which in turn form positive locking elements 74 and extend parallel to the axis of rotation 18 in the direction of the wobble disk 34. An inner edge 76 of the annular support disk 50 rests against the outer surfaces 75 of the positive locking elements 74.

[0035] At the front section 52, the swashplate body 32 has a first mounting element 78 and a second mounting element 80 arranged circumferentially offset from the first mounting element 78. The mounting elements 78, 80 each comprise a wing 82, 84 and a flank 86, 88. The wings 82, 84 extend perpendicular to the support surface 51 in the direction of the swashplate 34. The flanks 86, 88 extend radially outwards from the support surface 51.

[0036] The wobble drive 10 can be assembled as follows: First, the support disc 50 is pressed onto the wobble body 32 so that the outer surfaces 75 of the positive locking elements 74 bear against the inner edge 76 of the support disc 50, and the support disc 50 bears against the support surface 52 of the wobble body 32. Next, the swashplate bearing 44 is placed onto the support disc 50. Following this, the swashplate 34 is positioned on the swashplate bearing 44. To prevent the wobble unit 22 from falling apart during the assembly process, the swashplate bearing 44 and the swashplate 34 can be pressed against the wings 82, 84 of the mounting elements 78, 80. In a further assembly step, the parallel outer surfaces 90, 92 of the flanks 86, 88 can be gripped using an assembly tool. The wobble unit 22 can now be positioned and screwed to the motor shaft 16 using the connecting screw 40.By the flat contact of the screw head 64 with the first contact surface 56, the wobble body 32 is clamped with its second contact surface 60 against the holding surface 71 and thus connected to the motor shaft 20 in a rotationally fixed manner.

[0037] In Figure 6Figure 1 schematically shows a wobble unit of a second embodiment of a wobble drive according to the invention. The wobble unit of the second embodiment is identical to the wobble unit 22 of the first embodiment. In the second embodiment, the screw connection device 30 is designed in two parts and comprises a connecting screw 94 and a washer 96. The connecting screw 94 comprises a screw head 98 and a screw shank 100. The washer 96 is arranged between the screw head 98 and the wobble body 32 and, like the central opening 62 of the wobble body 32, is penetrated by the screw shank 100. A longitudinal axis 102 of the connecting screw 94 is arranged coaxially with the axis of rotation 18. The washer 96 is flat on a front surface 104 facing the screw head and spherically curved on its rear surface 106 facing away from the screw head 98.

[0038] In Figure 7 A tumbling unit of a third embodiment of a tumbling drive according to the invention is shown schematically. The third embodiment differs from the first and second embodiments in the geometry of the tumbling body.

[0039] In the third embodiment of the wobble drive, a wobble body 108 corresponding to the wobble body 32 of the first embodiment is used. The wobble body 108 has a first contact surface 110, which is spherically curved, a second contact surface 112, which is flat and arranged perpendicular to the axis of rotation 18, and a support surface 113, which is aligned parallel to the end face of the swashplate 34. The first contact surface 110 is arranged on a front section 114 of the wobble body 108 extending from the support surface 113 towards the swashplate 34. The second contact surface 112 is arranged on a rear section 115 of the wobble body 108 extending from the support surface 113 towards the motor shaft 20. The front section 114 and the rear section 115 are separated from the support surface 113.

[0040] The screw head 64 of the connecting screw 40 can be placed flush against the first contact surface 110. The second contact surface 112 rests against the retaining surface 71. The support disc 50 rests flush against the support surface 113 of the swashplate body 108. The swashplate 34 is supported on the support disc 50 via the swashplate bearing 44. The support surface 113 and the second contact surface 112 assume an angle of inclination β relative to each other. The angle of inclination β of the third embodiment is smaller than the angle of inclination α of the first and second embodiments.

[0041] The front section 114 of the third embodiment of the wobble drive is identical to the front section 52 of the first and second embodiments, the rear section 115 differs from the rear section 53 of the first and second embodiments only by the different inclination angle β.

[0042] In the Figures 8 to 10A fourth embodiment of a wobble drive according to the invention is shown schematically. The fourth embodiment corresponds essentially to the first and second embodiments with respect to the wobble body shape. In the fourth embodiment, a wobble body 118 is used, which has a recess 120 on its rear side 58 facing the motor shaft 20. The recess 120 has a flat first side surface 122 and a flat second side surface 124 opposite the first side surface 122, which are connected to each other via a circular third side surface 126 and a circular fourth side surface 128. A motor shaft end section 130 shaped according to the recess 120 can be inserted into the recess 120. This serves to prevent rotation between the wobble body 118 and the motor shaft 20.

Claims

1. Wobble drive for a high pressure cleaning appliance, comprising a motor (16) having a motor shaft (20) that is mounted so as to be rotatable about a rotational axis (18) and comprising a wobble unit (22) having a wobble body (32; 108; 118) that is rotationally drivable about the rotational axis (18) and having a wobble plate (34), the face side (36) of which is inclined to the rotational axis (18), said face side facing away from the wobble body (32; 108; 118), wherein a wobble plate bearing (44) is arranged between the wobble body (32; 108; 118) and the wobble plate (34), wherein the wobble body (32; 108; 118) comprises a first, spherically curved abutment surface (56; 110) on a front side (54) facing toward the wobble plate (34) and a second abutment surface (60; 112) on a rear side (58) facing toward the motor shaft, wherein a central perforation (62) extends commencing from the first abutment surface (56; 110) to the second abutment surface (60; 112), and wherein the wobble body (32; 108; 118) is connectable to the motor shaft (20) in a rotationally-fixed manner by means of a screw connection device (30), wherein the screw connection device (30) comprises a connecting screw (40; 94) that passes through the central perforation (62), the longitudinal axis (42; 102) of which is oriented coaxially with the rotational axis (18), wherein the screw connection device (30) is able to abut in surface-to-surface contact against the first abutment surface (56; 110), and wherein the second abutment surface (60; 112) is able to abut against a holding surface (71) that is of planar configuration and is oriented perpendicularly to the rotational axis (18), said holding surface being arranged directly on the motor shaft (20) or on a component that is connected to the motor shaft in a rotationally-fixed manner, characterized in that the wobble body (32; 108; 118) is configured as a one-piece solid component, wherein the second abutment surface (60; 112) is of planar configuration and is oriented perpendicularly to the rotational axis (18), and in that the wobble plate bearing (44) is supported on a support plate (50) that is connectable to the wobble body (32; 108; 118), said support plate abutting against a support surface (51; 113) of the wobble body (32; 108, 118) oriented in parallel with the face side (36) of the wobble plate (34), wherein the wobble body (32; 108; 118) comprises at least one centering element (73) for centering the support plate (50) relative to the wobble body (32; 108; 118), and wherein the at least one centering element (73) forms a positive-locking element (74), wherein the support plate (50) is connectable to the wobble body (32; 108; 118) in a rotationally-fixed manner by means of the positive-locking element (74).

2. Wobble drive in accordance with Claim 1, characterized in that the wobble body (32; 108; 118) is a cast part.

3. Wobble drive in accordance with any one of the preceding Claims, characterized in that the wobble plate bearing (44) is configured as a roller bearing.

4. Wobble drive in accordance with any one of the preceding Claims, characterized in that the screw connection device (30) is of one-part configuration in the form of a connecting screw (40), which comprises a screw head (64) that abuts in surface-to-surface contact against the first abutment surface (56; 110).

5. Wobble drive in accordance with any one of Claims 1 to 3, characterized in that the screw connection device (30) is of two-part configuration and comprises a connecting screw (94) and a washer (96), wherein the washer (96) abuts in surface-to-surface contact against the first abutment surface (56; 110).