Scratch seal for ball screw actuator

Abstract

A scratch seal assembly for sealing a ball screw actuator includes a scratch element. The inner circumferential surface has a first helical extension extending toward the longitudinal axis configured to be disposed within the ball screw thread. A plurality of microgrooves are formed on the inner circumferential surface. The icebreaker element has on its inner circumferential surface a second helical extension extending toward the longitudinal axis configured to be disposed within the ball screw thread. The second helical extension extends to the front side of the icebreaker element, forming an icebreaker lip. The scraping element is disposed adjacent to the icebreaker element. The scraping element and the icebreaker element are mechanically locked relative to each other in rotation.

Description

[0001] Inventor: Tudor B. Hotnog

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to provisional application 63 / 481,562, filed January 25, 2023, the entire contents of which are hereby incorporated by reference in their entirety. Technical Field

[0004] The present invention relates generally to seals and, more particularly, to a ball screw seal for use in ball screw actuators in aerospace applications. Background Art

[0005] Ball screw actuators require seals to contain the grease within the actuator. Furthermore, these seals must be able to break up ice that forms externally while preventing external debris from entering the actuator and other flight systems. Current designs have not been entirely successful in applications with high temperature fluctuations and suffer from drag issues, particularly in low-temperature applications due to the contraction of the ball screw's scraping material. The present invention overcomes these drawbacks.

[0006] Prior art publications and patents include, but are not limited to, the following: EP 3 392 526 Bl; EP 3 428 481 Bl; US 4,905,533; US 10,612,633; KR 101 584 435 Bl; US 697 6399 B2; JP 492 3624 B2; JP 492 362 4B2; US 201 403 524 70A1; JP 364 7597 B2; US 802 512 8B2; US 490 5533 A; and EP 3 428 481 Bl. Summary of the Invention

[0007] One embodiment of the present invention is a scraper seal assembly 10 configured to seal a ball screw actuator 11. A scraper element 12 is arranged annularly around a longitudinal axis 13. The scraper element defines a front side 14 opposite to a back side 15, and the front side and the back side are substantially perpendicular to the longitudinal axis. The scraper element further defines an outer peripheral surface 16 opposite to an inner peripheral surface 17, and the outer peripheral surface and the inner peripheral surface are substantially parallel to the longitudinal axis. The inner peripheral surface includes a first helical extension 18 extending toward the longitudinal axis, wherein the first helical extension is configured to be capable of being disposed within a ball screw thread 19 of a shaft 20 of the ball screw actuator, and wherein the shaft is configured to be capable of being disposed along the longitudinal axis. At least a portion 21 of the first helical extension includes a plurality of microgrooves 22 formed on the inner peripheral surface, wherein the plurality of microgrooves are configured to be capable of contacting the ball screw thread of the roller, i.e., the shaft of the ball screw actuator.

[0008] The icebreaker element 23 is arranged in an annular shape around the longitudinal axis. The icebreaker element defines a front side 24 opposite a back side 25, with the front and back sides being approximately perpendicular to the longitudinal axis. The icebreaker element defines an outer circumferential surface 26 opposite an inner circumferential surface 27, with the outer and inner circumferential surfaces being approximately parallel to the longitudinal axis. The inner circumferential surface includes a second helical extension 28 extending toward the longitudinal axis, wherein the second helical extension is configured to be disposed within the ball screw thread of the shaft of the ball screw actuator. The second helical extension extends to the front side of the icebreaker element, forming an icebreaker lip 29. A scraping element is arranged adjacent to the icebreaker element, with the back side of the scraping element adjacent to the back side of the icebreaker element. The scraping element and the icebreaker element are mechanically locked relative to each other in terms of rotation.

[0009] In another exemplary embodiment, the plurality of microgrooves may be disposed adjacent to one another, with each microgroove of the plurality of microgrooves being disposed annularly about the longitudinal axis and not following the helical profile 30. In other words, each microgroove is annular in shape and disposed adjacent to another annularly shaped microgroove.

[0010] In another exemplary embodiment, the plurality of microgrooves may follow a helical profile 30 in a similar helical direction 31 compared to the first helical extension. Alternatively, the plurality of microgrooves may follow a helical profile 30 in an opposite helical direction 32 compared to the first helical extension.

[0011] In another exemplary embodiment, the first helical extension may be disposed helically compared to the second helical extension, wherein both the first and second helical extensions are configured to be disposed within a ball screw thread of a shaft of the ball screw actuator.

[0012] In another exemplary embodiment, the edge 33 of the ice breaker lip can be configured to be 0.012 inches (0.30 mm) or less from the ball screw threads of the shaft of the ball screw actuator.

[0013] In another exemplary embodiment, the front side of the scraper element may have an annular channel 34 formed therein, arranged about the longitudinal axis. An annular metal spring element 35 may be disposed within the annular channel. The spring element may include a flat ribbon-like coil spring 36. The spring element may have a U-shaped cross-section 37, with the open top 38 of the U pointing along the longitudinal axis and away from the back side of the scraper element. The front side of the scraper element may include an outer diameter grease seal lip 39 and an inner diameter grease seal lip 40 separated by the annular channel.

[0014] The scraping element and the ice breaker element may not be made of the same material. The scraping element may include PTFE, unfilled PTFE, mixed PTFE, glass-molybdenum-filled PTFE, PEEK and / or thermoplastic materials. The ice breaker element may include aluminum bronze and / or stainless steel.

[0015] The wiper seal assembly may be mounted between the outer housing 41 and the shaft of the ball screw actuator, wherein the front side of the wiper element is configured to be disposed toward the grease side 42 and the front side of the ice breaker element is configured to be disposed toward the ambient side 43 .

[0016] At least one (two) finger-like portion 44 may extend from the back side of the ice breaker element toward the scraper element parallel to the longitudinal axis. At least one recess 45 may be formed in the back side of the scraper element, wherein the at least one finger-like portion of the ice breaker element is arranged in the at least one recess of the scraper element and mechanically locks the scraper element with respect to rotation relative to the ice breaker element.

[0017] At least one (two) tongues 46 may extend from an outer circumferential surface of the ice breaker element radially to the longitudinal axis, wherein the at least one tongue is configured to be positionable in at least one recess 47 formed in the outer shell 41 and mechanically lock the ice breaker element with respect to a rotation relative to the outer shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings illustrate the present invention. In the drawings:

[0019] Figure 1 is an isometric view of one embodiment of a wiper seal assembly according to the present invention;

[0020] Figure 2 yes Figure 1 Another isometric view of the structure shown from a rear perspective;

[0021] Figure 3 yes Figure 1 Isometric view of only the scraping elements of the structure shown;

[0022] Figure 4 yes Figure 3 Another isometric view of the structure shown from a rear perspective;

[0023] Figure 5 yes Figure 1 Isometric view of only the icebreaker element of the structure shown;

[0024] Figure 6 yes Figure 5 Another isometric view of the structure shown from a rear perspective;

[0025] Figure 7 It is from Figure 1 a cross-sectional view of the structure shown taken along line 7-7;

[0026] Figure 8 yes Figure 7 a side view of the cross-section shown;

[0027] Figure 9 yes Figure 7 an enlarged isometric view of the illustrated structure, which now includes the shaft of the ball screw actuator;

[0028] Figure 10 yes Figure 9 a side view of the structure shown;

[0029] Figure 11 yes Figure 7 An enlarged isometric view of the structure shown, which is similar to Figure 9 , which now includes an outer housing of the ball screw actuator;

[0030] Figure 12 yes Figure 11 a side view of the structure shown;

[0031] Figure 13 yes Figure 12 an enlarged view of the structure shown, better illustrating the multiple microgrooves of the sealing element;

[0032] Figure 14A is a theoretical plan view of the inner circumferential surface of the scraping element without microgrooves;

[0033] Figure 14B yes Figure 14A The illustrated structure shows one embodiment of how microgrooves can be provided on both the flat and spiral portions of the inner circumferential surface of a scraping element;

[0034] Figure 14C yes Figure 14A The illustrated structure shows another embodiment of how microgrooves can be provided on both the flat portion and the spiral portion of the inner circumferential surface of the scraping element;

[0035] Figure 14D yes Figure 14A The illustrated structure shows another embodiment of how microgrooves can be provided on both the flat portion and the spiral portion of the inner circumferential surface of the scraping element;

[0036] Figure 14E yes Figure 14A The structure shown shows another embodiment of how microgrooves can be provided on both the flat portion and the spiral portion of the inner circumferential surface of the scraping element; and

[0037] Figure 14F yes Figure 14A The illustrated structure shows another embodiment of how microgrooves can be provided on both the flat portion and the spiral portion of the inner circumferential surface of the scraping element. DETAILED DESCRIPTION

[0038] Reference is now made to provisional application 63 / 481,562 Figure 1-13 . The present invention is an easy to install press fit seal that has a spring energized outer diameter grease sealing lip and a low temperature ice breaker lip located on the rear end. The present invention is designed as a two piece solution to avoid lock up issues. The seal is designed to be reliable in low torque and low temperature solutions. The present invention includes a ball screw scraper energized by a metal "U" shaped spring or a metal flat ribbon coil spring to assist the PTFE sealing element in providing a low temperature seal on the ball nut housing.

[0039] The metal ice breaker on the back side of the sealing scraper protects the PTFE sealing element by breaking up ice that forms on the screw as it rotates. The ball screw scraper and ice breaker are mechanically locked together by multiple ice breaker fingers, which insert into an identical number of slots machined into the back side of the ball screw scraper component. The ball screw scraper and ice breaker are perfectly timed to eliminate the possibility of the ice breaker acting as a locknut. This feature is achieved by positioning a timing feature formed by one of the locking fingers.

[0040] A feature of the present invention is that micro grooves extending through the entire inner profile of the wiper seal provide a plurality of wipers and reduce the wiper seal component friction torque at low temperatures due to reduced wiper seal surface contact area.

[0041] Figure 1This is a front isometric view of a seal according to the present invention. As shown, the first component is a light blue PTFE scraper seal, which is connected to the second component (the tan icebreaker). The PTFE seal is mechanically locked to the icebreaker component via an equal number of seal scraper root grooves and icebreaker fingers. The mechanical locking feature is a loose fit rather than a press fit. Depending on the application requirements, the scraper seal material can be unfilled PTFE, blended PTFE, and / or thermoplastic.

[0042] This sealing element provides a reliable seal against the ball screw housing due to its sealing outer profile. Due to the "sealing" contour of the screw, the inner sealing profile resembles a thread. In other words, this inner sealing profile is not a closed loop, so this sealing element is called a wiper seal because it pushes the grease into the interior of the ball screw housing.

[0043] Figure 1 The scraper assembly shown in Figure 1 consists of three components. First, there is the ball scraper seal. This material has a high ratio of glass-molybdenum-filled PTFE or a thermoplastic such as PEEK to reduce the shrinkage of the scraper material due to low temperatures, thereby preventing the ball screw torque from increasing.

[0044] Secondly, a metal spring located within the wiper seal cavity is configured to prevent the wiper's outer diameter from shrinking, leading to external leakage. The spring element, installed within the wiper seal, applies equal thrust to both the outside and inside of the wiper seal. At low temperatures, the metal spring prevents the wiper's outer diameter from shrinking. The metal spring is made of 300 SST, 17-7PH SST, 17-4PH SST, or Elgiloy Inconel.

[0045] Third, there are ice breakers made of aluminum bronze or stainless steel to break up ice behind the scraper, preventing ice particles and water from entering the ball screw housing and damaging the ball bearings. Furthermore, the ice breaker has the added function of preventing the scraper seal from rotating with the ball screw shaft (i.e., anti-rotation). The scraper seal is mechanically locked to the ice breaker fingers via a root groove. All scraper seal and ice breaker combinations are locked into the ball screw housing by external ears or fingers that enter a groove in the housing.

[0046] Additionally, the ice breaker has a large gap between the shaft thread and the ice breaker. The ice breaker should maintain a large gap between the ball screw profile and the inner profile of the ice breaker to prevent the inner profile of the ice breaker from contacting the ball screw profile and thus scratching / damaging the ball screw profile during rotation.

[0047] Figure 2 yes Figure 1 Rear isometric view of the structure shown.

[0048] Figure 3 It is a front isometric view showing only the ball screw scraper.

[0049] Figure 4 yes Figure 3 Rear isometric view of the structure shown.

[0050] Figure 5 is a front isometric view showing only the ice breaker. The ice breaker shown here has four locking fingers and two radial tongues to lock into the ball screw housing and prevent the scraper seal and ice breaker from rotating with the ball screw. Here, it can be seen that there are two protrusions (i.e., tongues) that extend radially from the outer diameter surface of the component. These two protrusions are used to prevent the scraper seal and ice breaker from rotating with the ball screw. In addition, there are four protrusions (i.e., fingers) that extend parallel to the longitudinal axis. These four protrusions are matched to fit into the recesses in the first component. Therefore, the two components are configured to be able to lock together in a loose fit with perfect timing characteristics.

[0051] Figure 6 yes Figure 5 Rear isometric view of the structure shown.

[0052] Figure 7 It is from Figure 1 Cutaway cross-section. This image shows a cross-section with the wiper seal / ice breaker and spring assembly intact. The micro-groove construction can also be seen, which is a novel feature of the present invention.

[0053] Figure 8 yes Figure 7 Side view of the structure shown.

[0054] Figure 9 is similar to Figure 7 An enlarged cross-sectional view of the ball screw in which a cross-sectional view of the present invention is now shown, where the micro grooves formed as part of the ball screw scraper can be better seen. Figure 10 yes Figure 9 Side view of the structure shown.

[0055] Figure 11 is similar to Figure 9 , which now shows the components installed in the ball seal actuator housing. Figure 12 yes Figure 11 Side view of the structure shown. Figure 11 and Figure 12 Shown is the complete wiper seal / ice breaker and spring assembly on the ball screw.

[0056] It is known to use microgrooves on flat sealing surfaces. However, it is not known to use microgrooves on features that wipe the thread profile, in this case, the ball screw thread. When the ID thread rotates in one direction, a portion of the thread profile will fully contact the shaft thread profile, increasing the torque value. Adding microgrooves would reduce the wiper contact by half.

[0057] The micro grooves according to the present invention can follow a helical thread profile that is in the same helical direction as the ball screw thread (or in the opposite direction to the ball screw thread). Alternatively, the micro grooves can be arranged in an annular manner, while the ball screw thread will have a helical head profile. In addition, the micro grooves can be arranged to follow the helical thread profile of the ball screw thread. As will be appreciated by those skilled in the art, there can be a variety of micro groove thread profiles.

[0058] A secondary benefit of the micro grooves is also the scraping effect, as the micro grooves act like scraping lips, making it more difficult for pollutants from the environment to penetrate into the ball screw scraper assembly and similarly for grease to escape from the ball screw scraper assembly.

[0059] Reference is now made to the drawings of the present application, which are very similar to the drawings of the '562 provisional application. Figure 1-13 One embodiment of the present invention is shown, which is a wiper seal assembly 10 configured to seal a ball screw actuator 11. Figure 11-2 1 is best shown.

[0060] like Figure 3 and Figure 4 As best shown, the scraping element 12 is annularly arranged about a longitudinal axis 13. The scraping element defines a front side 14 opposite a back side 15. The front side and the back side are generally perpendicular to the longitudinal axis. The scraping element further defines an outer peripheral surface 16 opposite an inner peripheral surface 17. The outer peripheral surface and the inner peripheral surface are generally parallel to the longitudinal axis.

[0061] like Figure 11-13 As best shown, the inner circumferential surface includes a first helical extension 18 extending toward the longitudinal axis. The first helical extension is configured to be disposed within a ball screw thread 19 of a shaft 20 of a ball screw actuator, wherein the shaft is configured to be disposed along the longitudinal axis. At least a portion 21 of the first helical extension includes a plurality of microgrooves 22 formed on the inner circumferential surface. The plurality of microgrooves are configured to contact the ball screw thread of the shaft of the ball screw actuator.

[0062] like Figure 5 and Figure 6As best shown, the icebreaker element 23 is annularly arranged about the longitudinal axis. The icebreaker element defines a front side 24 opposite a back side 25. The front and back sides are generally perpendicular to the longitudinal axis. The icebreaker element further defines an outer peripheral surface 26 opposite an inner peripheral surface 27. The outer and inner peripheral surfaces are generally parallel to the longitudinal axis.

[0063] like Figure 11-12 As best shown, the inner circumferential surface comprises a second helical extension 28 extending towards the longitudinal axis. The second helical extension is configured to be disposed within a ball screw thread of a shaft of a ball screw actuator.

[0064] like Figure 6 As shown, the second helical extension extends to the front side of the ice breaker element, forming an ice breaker lip 29. The scraper element is arranged adjacent to the ice breaker element, with the back side of the scraper element adjacent to the back side of the ice breaker element. The scraper element and the ice breaker element are mechanically locked relative to each other in terms of rotation, as will be explained further below.

[0065] The plurality of microgrooves may be arranged adjacent to one another, wherein each of the plurality of microgrooves is annularly arranged about the longitudinal axis and does not follow a helical profile 30. In another exemplary embodiment, the plurality of microgrooves may follow a helical profile 30 that is in a similar helical direction 31 as compared to the first helical extension. Alternatively, the plurality of microgrooves may follow a helical profile 30 that is in an opposite helical direction 32 as compared to the first helical extension.

[0066] The first and second helical extensions are both arranged within the same ball screw thread. Thus, the first helical extension is arranged helically relative to the second helical extension, wherein the first and second helical extensions are both configured to be arranged within the ball screw thread of the shaft of the ball screw actuator.

[0067] Reference Figure 10 The edge 33 of the ice breaker lip can be configured to be 0.012 inches (0.30 mm) or less from the ball screw threads of the shaft of the ball screw actuator. The edge 33 should not contact the ball screw threads, but should be very close to be able to scrape off any debris and / or ice.

[0068] Reference Figure 10 The scraping element may have an annular channel 34 formed in the front side thereof, arranged around the longitudinal axis. An annular metal spring element 35 may be disposed within the annular channel. The spring element may include a flat ribbon-like coil spring 36. The spring element may have a U-shaped 37 cross-section, wherein the open top 38 of the U-shape points along the longitudinal axis and away from the back side of the scraping element.

[0069] The front side of the scraper element is divided into two halves due to the annular channel 34, wherein the scraper element has an outer diameter grease sealing lip 39 and an inner diameter grease sealing lip 40 separated by the annular channel. The spring element 35 can then push the lip 39 upward into the outer housing, push the lip 40 downward into the shaft, or do both at the same time.

[0070] The scraping element and the ice breaker element may not be made of the same material. The scraping element may include PTFE, unfilled PTFE, mixed PTFE, glass-molybdenum-filled PTFE, PEEK and / or thermoplastic materials. The ice breaker element may include aluminum bronze and / or stainless steel.

[0071] The wiper seal assembly is mounted between the outer housing 41 and the shaft of the ball screw actuator. The front side of the wiper element is configured to be positionable towards the grease side 42 , while the front side of the ice breaker element is configured to be positionable towards the ambient side 43 .

[0072] Reference Figure 5-6 At least one finger 44 can extend from the back side of the ice breaker element toward the scraping element parallel to the longitudinal axis. Here, four fingers 44 are shown. Those skilled in the art will understand that one, two, three, four or any number of fingers can be used.

[0073] Reference Figure 3-4 At least one recess 45 can be formed in the back side of the scraper element. The at least one (two) finger-shaped portion of the icebreaker element is disposed within the at least one recess of the scraper element and mechanically locks the scraper element from rotating relative to the icebreaker element. Similar to the finger-shaped portion, the recess 45 can be one, two, three, four, or any other number of recesses, as will be understood by those skilled in the art.

[0074] Refer again Figure 5 and Figure 6 , at least one tongue 46 may extend radially from the outer circumferential surface of the ice breaker element to the longitudinal axis. Those skilled in the art will appreciate that one, two, three, four, or any number of tongues may be used. The at least one tongue is configured to be disposed within at least one recess 47 formed in the outer shell 41, such as Figure 11 As shown, the ice breaker element is mechanically locked with respect to rotation relative to the outer housing.

[0075] Reference Figure 13 , microgrooves are formed along the first helical extension 18, and also along the flat cylindrical portion 48. The microgrooves may be formed in similar shapes along portions 18 and 48, or in different shapes along portions 18 and 48. Figures 14A-14FIt is helpful to illustrate some of the different embodiments that the microgrooves can take.

[0076] Figure 14A is a simplified representation showing what the inner circumferential surface 17 of the scraping element 12 would look like if it had no microgrooves formed on its surface and was cut in half and laid flat so that its plan view could be seen. As can be seen from this theoretical plan view, the forward tilt lines represent areas of flat cylindrical portions 48 that are alternately arranged between the first helical extensions 18, or as it is now described, between the portions 18. This in turn forms a further Figures 14B to 14F The basis of the structure comprising multiple microgrooves shown in the embodiment.

[0077] Figure 14B Shown in Figure 8 One embodiment can be best seen in FIG, wherein the microgrooves 22a along portion 48 have no pitch and are simply positioned adjacent to each other. The microgrooves 22b along portion 18 have a pitch that matches the pitch of the first helical extension.

[0078] Figure 14C Another embodiment is shown in which the microgrooves 22b are arranged in the same manner whether along portion 18 or portion 48. Here, the microgrooves are parallel to the pitch of the first helical extension.

[0079] Figure 14D Another embodiment is shown in which the pitch of the microgrooves 22 c along portions 18 and 48 is steeper than the pitch of the first helical extension 18 .

[0080] Figure 14E Another embodiment is shown in which the pitch direction of the microgrooves 22d along portions 18 and 48 is opposite to the pitch direction of the first helical extension.

[0081] Figure 14F Another embodiment is shown in which the direction of the microgrooves 22d along portion 48 is opposite to the direction of the first spiral extension. Then, the microgrooves 22c are arranged in a steeper manner along portion 18 than the first spiral extension. As will be understood by those skilled in the art, the microgrooves 22d may be arranged according to the direction of the first spiral extension. Figures 14B to 14F Various embodiments are contemplated as the present teachings are not intended to be limited to only the embodiments shown and taught herein.

[0082] Although several embodiments have been described in detail for purposes of illustration, various modifications can be made to each embodiment without departing from the scope and spirit of the invention. Therefore, the invention is not to be restricted except as defined in the appended claims.

[0083] Reference Signs List

[0084] 10 Scrape seal assembly

[0085] 11 Ball Screw Actuator

[0086] 12 Scraping elements

[0087] 13 Longitudinal axis

[0088] 14 front

[0089] 15 dorsal

[0090] 16 Outer peripheral surface

[0091] 17 Inner circumferential surface

[0092] 18 first spiral extension

[0093] 19 ball screw threads

[0094] 20 axis

[0095] 21 At least part

[0096] 22 multiple microgrooves

[0097] 23 Ice breaker element

[0098] 24 front

[0099] 25 dorsal

[0100] 26 Outer peripheral surface

[0101] 27 Inner circumferential surface

[0102] 28 Second spiral extension

[0103] 29 Ice Breaker Lip

[0104] 30 spiral profile

[0105] 31 Similar spiral directions

[0106] 32 opposite spiral directions

[0107] 33 Edge, Icebreaker Lip

[0108] 34 Ring Channel

[0109] 35 Spring element

[0110] 36 Flat Strip Coil Spring

[0111] 37 U shape

[0112] 38 Open Top

[0113] 39 OD grease seal lip

[0114] 40 ID grease seal lip

[0115] 41 outer shell

[0116] 42 Grease side

[0117] 43 Environmental side

[0118] 44 at least one finger

[0119] 45 at least one recess

[0120] 46 At least one tab

[0121] 47 at least one recess

[0122] 48 flat cylindrical portion

Claims

1. A wiper seal assembly configured to seal a ball screw actuator, comprising: a scraping element annularly disposed about the longitudinal axis; The scraping element defines a front side opposite the back side, the front side and the back side being generally perpendicular to the longitudinal axis; The scraping element defines an outer peripheral surface opposite the inner peripheral surface, the outer peripheral surface and the inner peripheral surface being generally parallel to the longitudinal axis; wherein the inner circumferential surface includes a first helical extension extending toward the longitudinal axis, wherein the first helical extension is configured to be disposed within a ball screw thread of a shaft of the ball screw actuator, wherein the shaft is configured to be disposed along the longitudinal axis; wherein at least a portion of the first helically extending portion includes a plurality of microgrooves formed on an inner circumferential surface, wherein the plurality of microgrooves are configured to be contactable with ball screw threads of a shaft of a ball screw actuator; and an ice breaker element annularly disposed about the longitudinal axis; The ice breaker element defines a front side opposite the back side, the front side and the back side being generally perpendicular to the longitudinal axis; The ice breaker element defines an outer peripheral surface opposite the inner peripheral surface, the outer peripheral surface and the inner peripheral surface being generally parallel to the longitudinal axis; wherein the inner circumferential surface includes a second helical extension extending toward the longitudinal axis, wherein the second helical extension is configured to be disposed within a ball screw thread of a shaft of the ball screw actuator; wherein the second helical extension extends to the front side of the ice breaker element to form an ice breaker lip; wherein the scraping element is disposed adjacent to the ice breaker element, with a back side of the scraping element adjacent to a back side of the ice breaker element; and In this case, the scraper element and the ice breaker element are mechanically locked in rotation relative to one another.

2. The wiper seal assembly according to claim 1, wherein: The plurality of microgrooves are disposed adjacent to one another, each microgroove of the plurality of microgrooves being disposed annularly about a longitudinal axis and not following a helical profile.

3. The wiper seal assembly according to claim 1, wherein: The plurality of microgrooves follows a helical profile in a similar helical direction as compared to the first helical extension.

4. The wiper seal assembly according to claim 1, wherein: The plurality of microgrooves follows a helical profile that is in an opposite helical direction compared to the first helical extension.

5. The wiper seal assembly according to claim 1, wherein: The first helical extension is helically disposed relative to the second helical extension, wherein both the first and second helical extensions are configured to be disposed within a ball screw thread of a shaft of the ball screw actuator.

6. The wiper seal assembly according to claim 1, wherein: The edge of the ice breaker lip is configured to be 0.012 inches or less from the ball screw threads of the shaft of the ball screw actuator.

7. The wiper seal assembly according to claim 1, wherein: An annular channel is formed in the front side of the scraping element and is arranged around the longitudinal axis.

8. The wiper seal assembly of claim 7 including an annular metal spring element disposed within the annular channel.

9. The wiper seal assembly according to claim 8, wherein: The spring element includes a flat strip-shaped coil spring.

10. The wiper seal assembly according to claim 8, wherein: The spring element has a U-shaped cross section, wherein the open top of the U is directed along the longitudinal axis and away from the back side of the scraping element.

11. The wiper seal assembly according to claim 8, wherein: The front side of the scraping element includes an outer diameter grease seal lip and an inner diameter grease seal lip separated by the annular channel.

12. The wiper seal assembly according to claim 1, wherein: The scraping element and the ice breaker element are not of the same material.

13. The wiper seal assembly according to claim 11, wherein: The scraping element includes PTFE, unfilled PTFE, mixed PTFE, glass-molybdenum-filled PTFE, PEEK and / or thermoplastic material.

14. The wiper seal assembly according to claim 11, wherein: The ice breaker elements include aluminum bronze and / or stainless steel.

15. The wiper seal assembly of claim 1, wherein: When the scraper seal assembly is mounted between the outer housing and the shaft of the ball screw actuator, the front side of the scraper element is configured to be disposed toward the grease side, while the front side of the ice breaker element is configured to be disposed toward the ambient side.

16. The wiper seal assembly of claim 1, comprising at least one finger extending parallel to the longitudinal axis from a back side of the ice breaker element toward the wiper element.

17. The wiper seal assembly of claim 16, comprising at least one recess formed in the back side of the wiper element, wherein The at least one finger of the ice breaker element is arranged in the at least one recess of the scraper element and is mechanically locked with respect to a rotation of the scraper element relative to the ice breaker element.

18. The wiper seal assembly of claim 1, comprising at least one tab extending radially from the outer peripheral surface of the ice breaker element relative to the longitudinal axis, wherein: The at least one tongue is configured to be positionable within at least one recess formed in the outer shell and mechanically lock the ice breaker element with respect to rotation relative to the outer shell.

19. A wiper seal assembly configured to seal a ball screw actuator, comprising: a scraping element, which is annularly arranged around the longitudinal axis, the scraping element comprising: an anterior side opposite to the dorsal side, the anterior and dorsal sides being approximately perpendicular to the longitudinal axis; an outer peripheral surface opposite the inner peripheral surface, the outer peripheral surface and the inner peripheral surface being generally parallel to the longitudinal axis; wherein the inner circumferential surface includes a first helical extension extending toward the longitudinal axis, wherein the first helical extension is configured to be disposed within a ball screw thread of a shaft of the ball screw actuator, wherein the shaft is configured to be disposed along the longitudinal axis; wherein at least a portion of the first helical extension comprises a plurality of microgrooves formed on an inner circumferential surface, wherein the plurality of microgrooves are configured to be contactable with ball screw threads of a shaft of a ball screw actuator; wherein an annular channel arranged around the longitudinal axis is formed in the front side of the scraping element; at least one recess formed in a back side of the scraping element; An ice breaker element is annularly arranged around a longitudinal axis, said scraping element comprising: an anterior side opposite to the dorsal side, the anterior and dorsal sides being approximately perpendicular to the longitudinal axis; an outer peripheral surface opposite the inner peripheral surface, the outer peripheral surface and the inner peripheral surface being generally parallel to the longitudinal axis; wherein the inner circumferential surface includes a second helical extension extending toward the longitudinal axis, wherein the second helical extension is configured to be disposed within a ball screw thread of a shaft of the ball screw actuator; wherein the second helical extension extends to the front side of the ice breaker element to form an ice breaker lip; at least one finger extending parallel to the longitudinal axis from the back side of the ice breaker element toward the scraping element; at least one tab extending from an outer circumferential surface of the ice breaker element radially to the longitudinal axis, wherein the at least one tab is configured to be disposed within at least one recess formed in the outer shell and mechanically lock the ice breaker element with respect to rotation relative to the outer shell; and an annular metal spring element disposed within the annular channel of the scraping element; wherein the scraping element is disposed adjacent to the ice breaker element, and a back side of the scraping element is adjacent to a back side of the ice breaker element; wherein the at least one finger of the icebreaker element is arranged in the at least one recess of the scraper element and is mechanically locked with respect to rotation of the scraper element relative to the icebreaker element, wherein the scraper element and the icebreaker element are mechanically locked with respect to rotation with respect to each other but are not press-fitted with each other; wherein the first helical extension is disposed helically relative to the second helical extension, wherein the first and second helical extensions are each configured to be disposed within a ball screw thread of a shaft of the ball screw actuator; Wherein, when the scraper seal assembly is installed between the outer shell and the shaft of the ball screw actuator, the front side of the scraper element is configured to be set towards the grease side, and the front side of the ice breaker element is configured to be set towards the environment side.

20. The wiper seal assembly of claim 19, wherein: The plurality of microgrooves follows a helical profile in a similar helical direction as compared to the first helical extension.

Images