EP3504145B1

EP3504145B1 - Rotator arrangement

Info

Publication number: EP3504145B1
Application number: EP17844039.2A
Authority: EP
Inventors: Joakim Harr
Original assignee: Indexator Rotator Systems AB
Current assignee: Indexator Rotator Systems AB
Priority date: 2016-08-26
Filing date: 2017-08-28
Publication date: 2023-11-01
Anticipated expiration: 2037-08-28
Also published as: BR112019003971A2; RU2735199C2; SE541516C2; RU2019105316A; EP3504145A1; CA3032241A1; RU2019105316A3; WO2018038675A1; EP3504145A4; SE1651153A1; EP3504145C0

Description

TECHNICAL FIELD

The invention relates to a rotator arrangement for providing a rotating movement to a tool implement attached to said rotator arrangement.

BACKGROUND

Rotator arrangements are widely used in foresting, harvesting or the like where a carrier, truck, tractor or the like carries an arrangement for handling excavators, timber tools, harvest tools or the like. Often such arrangements are hydraulically driven and include a crane arm, wherein the rotator arrangement is arranged to the free end of the arm. The rotator arrangement typically includes a motor, i.e. a hydraulic motor, to provide rotational movement.
A challenge related with such rotator arrangements is that they are exposed to heavy forces both radially and axially. Conventionally, this has been solved by dimensioning the rotator arrangement and specifically the motor with components adapted to withstand very high efforts. A problem is that that the motor, and specifically the fit between the stator and rotor needs to be very accurate and precise, which is difficult to achieve in combination with the high demands on mechanical strength.
In US 7 311 489 this is solved by placing the motor off-set with respect to the rotation axis of the rotator. With such an arrangement the motor may be separated from the load distribution. A disadvantage is however that the rotator will be voluminous and bulky, in addition to that the solution will be relatively complex. In another embodiment disclosed in US 7 311 489 the motor is arranged concentrically with the rotation of the rotor. However, in this embodiment the problem with heavy loads acting between the rotor and stator is not solved.
In WO 2012/134370 a rotator arrangement is described in which the forces are arranged to be taken up in an arrangement arranged to leave the interaction between the rotor and stator separated from the load distribution other than the torque provided by the motor. The arrangement is advantageous but it is also relatively space demanding, especially in the radial direction. This document discloses the preamble of claim 1.
Therefore, there is a need of a rotator arrangement that radially is more compact than an ordinary arrangement, but that is capable of withstanding high efforts without affecting the precision, durability and wear of the motor.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide rotator arrangement for providing a rotational movement, which is compact and which is arranged to provide the rotational movement without undue stress between the stator and rotor. A further object is to prolong the life time of the motor and rotator, specifically by minimising wear between the rotor and the stator.
The invention relates to a rotator arrangement for providing a rotating movement, the rotator arrangement comprising a motor with a stator and a rotor arranged inside the stator to rotate with respect to said stator around an axial axis, wherein the rotator arrangement comprises a rotor attachment piece connected to the rotor and a stator attachment piece connected to the stator, wherein one of the rotor attachment piece and stator attachment piece is arranged to be attached to a crane arm, and the other is arranged to be attached to a tool implement. A bearing is arranged to connect the rotor attachment piece to the stator attachment piece via the stator and to transmit loads acting between the rotor attachment piece and the stator attachment piece via the stator.
With the inventive arrangement torque may be transmitted via the stator without affecting the interaction between the stator and rotor. This is achieved in that the rotor has been separated from the load distribution in the axial direction and at least radially in the plane orthogonal to the axial axis. Hence, only the rotational forces are arranged over the rotor. The compactness of the rotator arrangement is accomplished in that the that loads acting on the rotator arrangement are distributed over the stator, still without affecting the rotor.
In a specific embodiment of the invention a torque transmission unit is arranged and comprises substantially no gap between the rotor and the rotor attachment piece in a direction of rotation around the axial axis, but wherein the torque transmission unit includes a freedom to move in an axial direction along the axial axis, and at least radially in a plane orthogonal to the axial axis, such that substantially no axial or radial forces are transmitted between the rotor and the stator. The torque transmission makes sure to separate the rotor from the load distribution in the axial direction and the plane orthogonal to the axial axis. Hence only forces related to the torque are transmitted over the torque transmission unit.
In another specific embodiment of the invention the torque transmission unit is arranged in an axial extension with respect to the rotor along the axial axis. This arrangement allows for a slimmed construction in respect of the radial direction.
In a specific embodiment of the invention the torque transmission unit comprises a connective element arranged to slide in a mating radial track extending in a radial direction orthogonal to the axial axis, so as to provide a connection between the rotor and the rotor attachment piece, which connection provides substantially no gap between the rotor and said rotor attachment piece in a direction of rotation around the axial axis, but includes a freedom to move in a radial direction orthogonal to the axial axis, and in an axial direction along the axial axis
In another specific embodiment the torque transmission unit comprises an intermediate element joining the rotor to the rotor attachment piece, the intermediate element comprising a first set of engagement portion connected to the rotor and allowing the intermediate element to slide with respect to said rotor in a first direction that is orthogonal to the axial axis, and a second set of engagement portions connected to the rotor attachment piece and allowing the intermediate element to slide with respect to said rotor attachment piece in a second direction that is orthogonal to said first direction and to the axial axis.
The first and second set of engagement portions may extend axially along the axial axis or radially, orthogonally with respect to the axial axis. They may also be arranged as recesses in the intermediate element, wherein the rotor and/or rotor attachment part comprise(s) protrusions to fit tightly inside said recesses.
In a specific embodiment of the invention an angle meter is arranged to monitor the rotation of the rotor with respect to the stator.
In another specific embodiment of the invention the rotor is hollow allowing hydraulic hoses to pass through the interior of the rotor, and wherein a swivel connection part is arranged provide hydraulic fluid from said hoses to the motor regardless of a rotational position of the motor.
Other embodiments and advantages of the invention will be apparent from the following detailed description.

SHORT DESCRIPTION OF THE DRAWINGS

Below the invention will be describe in detail with reference to accompanying drawings, of which:

Fig. 1: is a perspective view of a rotator arrangement in accordance with a first embodiment of the invention;
Fig. 2: is a sectional view of the rotator arrangement of fig. 1;
Fig. 3: is a perspective view of the rotator arrangement of fig. 1 with the rotor attachment piece removed;
Fig. 4: is a perspective view of the rotator arrangement of fig. 1 with the rotor attachment piece and bearing removed;
Fig. 5: is an exploded view of rotor attachment piece, torque transmission unit and rotor of a rotator arrangement of fig. 1;
Fig. 6: is a perspective view of a rotator arrangement in accordance with a second embodiment of the invention;
Fig. 7: is an exploded view of rotor attachment piece, torque transmission unit and rotor of a rotator arrangement of fig 6;
Fig. 8: is a sectional view of the rotator arrangement of fig. 6; and
Fig. 9: is an exploded view of a specific embodiment of a torque transmission unit between a rotor and an attachment piece; and
Fig. 10: is an exploded view of the torque transmission unit in fig. 9 seen from the opposite side.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENT

In fig. 1 a rotator arrangement 10 in accordance with a specific first embodiment of the invention is shown in a perspective view. The rotator arrangement 10 comprises a rotor attachment piece 15 and a stator attachment piece 16 arranged to rotate with respect to each other via a bearing 18. The bearing may be a ball bearing, a plain bearing, or the like. A motor 11 is arranged to provide for the rotation. The motor comprises a stator 13, of which the outer part is shown in fig. 1, and a rotor arranged to rotate inside the stator. One of the rotor attachment piece 15 and stator attachment piece 16 is arranged to be attached to a crane arm or the like, and the other is arranged to be attached to a tool implement. In the shown embodiment the rotor attachment piece 15 is adapted to be arranged to a crane arm, typically a hydraulic pivot arm or the like. The stator attachment piece 16 of the shown embodiment is hence arranged to be attached to a tool implement, typically a hydraulically manoeuvrable tool implement such as a grip arm, bucket, harvesting tool or the like.
In figure 1, two pairs of hydraulic couplings 30,31 to the hydraulic motor 11 are visible on the stator attachment piece 16; a first pair 30 on the circumferential side of the stator attachment piece and a second pair 31 on the axial side of the stator attachment piece. Only one pair is intended to be used at a time depending on the corresponding connections on the tool implement connected there to. Different tool implements may be adapted to fit either the first pair 30 on the circumferential side or the second pair 31 on the axial side of the stator attachment piece.
The stator attachment piece 16 comprises tool attachment means 33, here in the form of threaded bores, for attachment of the tool implement. Further, an angle meter 32 is arranged to monitor the angular position of the rotor 12 with respect to the stator 13, and hence the rotor attachment piece 15 with respect to the stator attachment piece 16. Thereby the exact position of the tool implement attached to the rotator arrangement 10 with respect to the crane arm to which the rotator arrangement is attached may be continuously monitored.
Fig. 2 is a sectional view of the rotator arrangement 10 of fig. 1. for providing a rotating movement, the rotator arrangement comprises a motor 11 with a stator 13 and a rotor 12 arranged inside to rotate around an axial axis A with respect to said stator 13. The rotor 12 is arranged with a close fit inside the stator. In the shown embodiment the motor 11 is a hydraulic motor, in which the rotor is driven to rotate by means of a hydraulic fluid acting on wings 27 that are spring mounted on the cylindrical periphery of the rotor 12. The wings are mounted to the rotor in recesses 27a shown in fig. 5. Hydraulic motors are well known to a person skilled in the art and are not described in detail in this specification.
As is apparent from fig. 2 the rotor attachment piece 15 is connected to the rotor 12 via a torque transmission unit 14 and to the stator via a bearing 18, such that the rotor attachment piece 15 is arranged to rotate with respect to the stator 13. The stator attachment piece 16 of the shown embodiment is firmly connected to the stator 13. It may even be an integral part of the stator. The bearing 18 comprises two parts, one stator part 18a that is rigidly connected to the stator attachment piece 16 via the stator 13, e.g. via attachment screws 19, and one rotor part 18b that is rigidly connected to the rotor attachment piece 15, e.g. via attachments screws 20.
With this arrangement the loads acting on the rotator arrangement 10 between the rotor attachment piece 15 and the stator attachment piece 16 are arranged to be transmitted over the stator 13 and over the bearing 18. This is advantageous as it implies that said loads will not be transmitted in the interaction between the stator 13 and rotor 12, whereby a gap free tight fit may be achieved between the stator 13 and rotor 12 without the need of arranging the rotor 12 such that it should withstand the loads acting on the rotator.
The torque of the motor is transmitted via a torque transmission unit 14 that comprises substantially no gap in a direction of rotation around the axial axis A, but includes a freedom to move at least radially in a plane X-Y orthogonal to the axial axis A, and in an axial direction along the axial axis A, such that substantially no axial or radial forces are transmitted between the rotor 12 and the stator 13.
As is illustrated in fig. 2 the torque transmission unit 14 of the first specific embodiment is arranged in an axial extension with respect to the rotor 12 along the axial axis A. Specifically, the torque transmission unit 14 is located above the rotor 12, axially between the rotor 12 and the rotor attachment piece 15. The torque transmission unit 14 comprises an intermediate element 17 joining the rotor 12 to the rotor attachment piece 15 by means of a first set of engagement portions 21, in the form of protrusions, connected to the rotor attachment piece 15 and a second set of engagement portions 22, also in the form of protrusions, connected to the rotor 12. The first set of engagement portions 21 are arranged to allow a freedom of movement with respect to said rotor in a first direction X that is orthogonal to the axial axis A and the second set of engagement portions 22 are arranged to allow a freedom of movement with respect to said rotor attachment piece 15 in a second direction Y that is orthogonal to the axial axis A and to said first direction X.
The freedom of movement of the intermediate element 17 is shown in fig. 2 where a first axial gap 34 is apparent between the intermediate element 17 and the rotor attachment piece 15, and a second axial gap 35 is apparent between the intermediate element 17 and the rotor. Further, a gap 36 allows the intermediate element 17 to slide in the Y-direction, i.e. the second direction Y that is orthogonal to the axial axis A and the first direction X, which runs orthogonally to the plane of the section shown in fig. 2. A similar gap exists for first set of engagement portions 21 allowing the intermediate element 17 to slide in the X-direction, i.e. the first direction X that is orthogonal to the axial axis A.
In figure 3 the rotator arrangement is shown with the rotor attachment piece removed, revealing the free ends of the rotor attachment screws 20 that are arranged to be threaded into threaded bores of the rotor attachment piece to keep it fixed to the rotor part 18b of the bearing 18.
As apparent from figure 3 the first set of engagement portions 21 of the intermediate element 17 of the torque transmission unit 14 extend radially with respect to the axial axis A. The first set of engagement portions 21 are arranged to be in engaging contact with the rotor attachment piece. Further, as is apparent from figure 4 the second set of engagement portions 22 of the intermediate element 17 extend axially along the axial axis A. The second set of engagement portions 22 are arranged to be in engaging contact with the rotor 12.
Figure 5 reveals that the first set of engagement portions 21 allows for the intermediate element 17 of the torque transmission unit 14 to slide along a first direction X with respect to the rotor attachment piece 15. Specifically, the rotor attachment piece 15 comprises a rotor connector part 29 with torque engagement parts 26 in the form of radial recesses arranged to tightly receive the first set of engagement portions 21. Figure 4 and 5 reveal that the second set of engagement portions 22 allow for the intermediate element 17 of the torque transmission unit 14 to slide along a second direction Y with respect to the rotor 12. The rotor 12 comprises torque engagement parts 25 in the form of axial recesses arranged to tightly receive the second set of engagement portions 22. One or both of the interaction of the first set engagement portions 21 and the interaction of the second set of engagement portions 22 may allow for a freedom of movement along the axial axis A.
In the shown embodiment the protrusions of the first set of engagement portions 21 of the intermediate element 17 have parallel outer sides extending in the first direction X, wherein the recesses of the engagement parts 26 has mating parallel inner side walls also extending in the first direction X to tightly receive said protrusions. With this construction the parallel outer sides of the first set of engagement portions 21 are allowed to slide in the first direction X between the mating parallel inner side walls of the engagement parts 26, thus allowing the intermediate element 17 to slide in the first direction X with respect to the rotor attachment piece 15. Similarly, the protrusions of the second set of engagement portions 22 have parallel sides extending in the second direction Y, wherein the recesses of the engagement parts 25 in the rotor 12 has mating side walls also extending in the second direction Y to tightly receive said protrusions. This interaction thus allows the intermediate element 17 to slide in the second direction Y with respect to the rotor 12.
Both the first and second set of engagement portions 21,22 may extend axially along the axial axis A, or both may extend radially, orthogonally to the axial axis A.
In figures 6-8 a second embodiment of a rotator arrangement 110 is shown. In this embodiment the connection of hydraulics and electrics to drive the motor 111 and the tool are arranged to be connected from the rotor attachment piece 115 through the motor. Therefore, as is best shown in figure 8, the rotor 112 is hollow, allowing conduits 140, including hydraulic hoses, electric cables and Urea lines to pass through it. A swivel connection part 141 is arranged to connect to the hydraulic hoses and to distribute hydraulic fluid to the motor 111 and to the connected tool. The swivel connection part 141 comprises an inner part 142 that is rotatably connected to the rotor 12, and an outer part 143 that is rotatably connected to the stator 113 and stator attachment piece 116.
As is visible in figure 8 the rotor attachment part 115 is connected via a bearing 118 to the stator 113, which in turn is connected to the swivel connection part 141. The swivel connection part 141 is either integrated with or connected to a stator connection part 116 for connection to a tool implement.
An advantage of this second embodiment with respect to the first embodiment shown in figures 1-5 is that the hydraulic hoses will not limit the rotation of the motor 111. This is due to the swivel connection part 141, which allows the motor 111 to rotate at will.
In figure 7 the second embodiment of the rotator arrangement 110 is shown in an exploded view revealing the torque transmission unit 114, which comprises an intermediate element 117 joining the rotor 112 to the rotor attachment piece 115. The intermediate element 117 comprises a first set of engagement portions 121, in the form of protrusions extending in the axial direction A with parallel sides, which are to be received in engagement parts 126 in the form of recesses in the rotor attachment piece 115. A second set of engagement portions 122, also in the form of protrusions extending in the axial direction A with parallel sides, are received in engagement parts 126 in the form of recesses in the rotor 112. The first set of engagement portions 121 are arranged to allow a freedom of movement with respect to said rotor in a first direction X that is orthogonal to the axial axis A and the second set of engagement portions 122 are arranged to allow a freedom of movement with respect to said rotor attachment piece 115 in a second direction Y that is orthogonal to the axial axis A and to said first direction X. The parallel sides of the respective protrusions of the engagement portions are arranged to slide within the parallel sides of the respective engaging recess of the engagement parts. Both sets of engagement portions 121,122 allow a certain freedom of movement in the axial direction A. Typically, the width of the intermediate element 117 is less than the space available provided between rotor 112 and rotor attachment part 115, such that an axial gap 134 is available to provide the certain freedom of movement in the axial direction A.
Further, in a simpler embodiment shown in figs. 9 and 10 the torque transmission unit comprises a connective element 37, typically in the form of a dowel pin, that is arranged to slide in a mating track 38 that extends radially. In the embodiment shown in figs. 9 and 10 the connective element 37 is arranged in a bore 39 in the rotor attachment part 15, wherein the opposed rotor 12 comprises a mating track 38 that extends radially, said track 38 having a width that corresponds to the width of the connective element 37 so as to not allow any gap in the rotational direction but allowing a slight movement in the radial direction. In an alternative embodiment two connective elements may be arranged to slide in a track extending from side to side or two corresponding mating tracks extending parallel along the same line on opposite sides of the rotor 12. As a further alternative the connective element(s) 37 may be arranged on the rotor and the track(s) 39 may be arranged in the rotor attachment part. Also, the interaction may instead be arranged between the stator and the stator second attachment part, in which case the rotor may be fixedly connected to the rotor attachment part.
Above the invention has been described with reference to two specific embodiments. The invention is however no limited to these embodiments. The invention is only limited by the appended claims.

Claims

A rotator arrangement (10,110) for providing a rotating movement, the rotator arrangement comprising a motor (11,111) with a stator (13,113) and a rotor (12,112) arranged inside the stator (13,113) to rotate with respect to said stator (13,113) around an axial axis (A), wherein the rotator arrangement (10,110) comprises a rotor attachment piece (15,115) connected to the rotor and a stator attachment piece (16,116) connected to the stator, wherein one of the rotor attachment piece (15, 115) and stator attachment piece (16,116) is arranged to be attached to a crane arm or the like, and the other is arranged to be attached to a tool implement, characterised in that a bearing (18) is arranged to connect the rotor attachment piece (15,115) to the stator attachment piece (16,116) via the stator (13,113) and to transmit loads acting between the rotor attachment piece (15,115) and the stator attachment piece (16,116) via the stator (13,113).
The arrangement according to claim 1, wherein a torque transmission unit (14,114) is arranged and comprises substantially no gap between the rotor (12,112) and the rotor attachment piece (15,115) in a direction of rotation around the axial axis (A) and wherein the torque transmission unit (14,114) includes a freedom to move in an axial direction along the axial axis (A), and at least radially in a plane (X,Y) orthogonal to the axial axis (A), and such that substantially no axial or radial forces are transmitted between the rotor (12,112) and the stator (13,113).
The arrangement according to claim 2, wherein the torque transmission unit (14,114) is arranged in an axial extension with respect to the rotor (12,112) along the axial axis (A).
The arrangement according to claim 3, wherein the torque transmission unit comprises a connective element (37) arranged to slide in a mating radial track (38) extending in a radial direction orthogonal to the axial axis (A), so as to provide a connection between the rotor (12) and the rotor attachment piece (15), which connection provides substantially no gap between the rotor (12) and said rotor attachment piece (15) in a direction of rotation around the axial axis (A), but includes a freedom to move in radial direction orthogonal to the axial axis (A), and in an axial direction along the axial axis (A).
The arrangement according to claim 3, wherein the torque transmission unit (14,114) comprises an intermediate element (17,117) joining the rotor (12,112) to the rotor attachment piece (15,115), the intermediate element (17,117) comprising a first set of engagement portions (21,121) connected to the rotor attachment piece (15,115) and allowing the intermediate element (17,117) to slide with respect to said rotor attachment piece (15,115) in a first direction (X) that is orthogonal to the axial axis (A), and a second set of engagement portions (22,122) connected to the rotor (12,112) and allowing the intermediate element (17,117) to slide with respect to said rotor (12,112) in a second direction (Y) that is orthogonal to said first direction (X) and to the axial axis (A).
The arrangement according to claim 5, wherein at least one of the first and second set of engagement portions (21,22; 121,122) extends axially along the axial axis (A).
The arrangement according to claim 6, wherein both the first and second set of engagement portions (121,122) extend axially along the axial axis (A).
The arrangement according to claim 6, wherein one of the first and second set of engagement portions (21,22) extends axially along the axial axis (A), and the other extend radially with respect to the axial axis (A).
The arrangement according to anyone of the preceding claims, wherein an angle meter (32) is arranged to monitor the rotation of the rotor (12,112) with respect to the stator (13,113).
The arrangement according to anyone of the preceding claims, wherein the rotor (112) is hollow allowing hydraulic hoses (140) to pass through the interior of the rotor (112), and wherein a swivel connection (141) part is arranged provide hydraulic fluid from said hoses to the motor (111) regardless of a rotational position of the motor.