Integrated recirculation component, recirculation threaded member and ball screw mechanism

Abstract

The invention discloses an integrated recirculation component, a recirculation threaded member and a ball screw mechanism. An integral recirculation component intended to be received in a cavity of a threaded member of a ball screw mechanism comprises a bottom facing a reference direction of a reference axis, a recirculation path facing an opposite direction and designed to pass through a thread of the threaded member, and at least one deflector, the at least one deflector extends from the recirculation path in a direction opposite the reference direction. The deflector forms a guide surface located at a distance from the recirculation path and facing the reference direction, opposite an internal cavity in the unitary component extending parallel to the reference axis and leading to the bottom and the recirculation path. When projected orthogonally onto a reference plane perpendicular to the reference axis, the first lumen surrounds or coincides with a guide surface of the first deflector.

Description

Technical Field

[0001] The present invention relates to a ball screw mechanism, and more particularly to a ball screw mechanism provided with a recirculator intended to connect two adjacent portions of a groove on both sides of the thread of the threaded portion of the ball screw mechanism. The present invention particularly relates to a recirculator for such a mechanism, and to a recirculating threaded member incorporating such a recirculator, which may be a screw or a nut. Background Art

[0002] EP 1537345 B1 describes a ball screw mechanism, the nut of which has a thread for guiding balls, and the ball screw mechanism is equipped with an integral recirculation component housed in a cavity housing the nut, the recirculation component passing through the thread of the threaded portion to define an S-shaped recirculation path, the S-shaped recirculation path connecting two parts of the groove of the threaded portion on both sides of the thread. The integral recirculation component has a guide surface, which is intended to deflect the balls along the S-shaped path. Direct molding of the component is impossible because there are too many undercuts. For this reason, the integral component is composed of two halves connected by a joint, so that the component can be molded in an open position in an axial mold and then closed in its final operating position. However, this manufacturing method remains complex.

[0003] Document US2018 / 0216711 A1 describes a ball screw mechanism, the nut of which has a threaded portion for guiding balls, and the ball screw mechanism is equipped with an integral recirculation component housed in a closed cavity housing the nut, the recirculation component passing through the threads of the threaded portion to define an S-shaped recirculation path that connects two parts of the groove of the threaded portion on both sides of the thread. In addition, the recirculation component has deflectors at both ends of the recirculation path, the deflectors facing the recirculation path to guide the balls toward the recirculation path. The resulting component has a complex geometry with undercuts that complicate molding. Summary of the invention

[0004] The object of the present invention is to overcome the disadvantages of the prior art and to provide an integral recycling component which is simple to manufacture.

[0005] According to a first aspect of the present invention, there is provided an integral recirculation component housed in a cavity of a threaded member of a ball screw mechanism, the integral recirculation component having:

[0006] - a bottom portion turned in a reference direction parallel to the reference axis of the recycling part and intended to abut against the bottom of the cavity of the threaded member;

[0007] a recirculation path which turns in a direction opposite to the reference direction and is designed to pass through the threads of the threaded member along the recirculation path;

[0008] at least one first deflector extending from the recirculation path in a direction opposite to a reference direction, the first deflector forming a guide surface located at a distance from the recirculation path and facing the reference direction; and

[0009] - at least one first inner cavity which opens on the one hand to the bottom and on the other hand to the recirculation path opposite the guide surface, the first inner cavity having an orthogonal projection on a reference plane perpendicular to the reference axis, which surrounds or coincides with an orthogonal projection of the guide surface of the first deflector on the reference plane.

[0010] The first inner cavity prevents the first deflector from overlapping the body of the integral component defined by the bottom, the side walls and the recirculation path, as seen in a projection on the reference plane. This allows the guide surface to be molded axially along an axis parallel to the reference axis without undercutting. The present invention makes use of the fact that in areas where the deflector is required to bend the recirculation path, the balls of the ball screw mechanism (which form a ball circuit with very small relative clearance) are lifted closer to the recirculation path to contact the guide surface of the deflector. Therefore, an inner cavity can be provided that at least partially interrupts the recirculation path without affecting the guidance of the balls along the recirculation path. In addition, the inner cavity reduces the amount of material required to form the integral recirculation component.

[0011] In one embodiment, the integral recycling component has a second deflector extending from the recycling path in a direction opposite to a reference direction, the second deflector forming a guide surface, the guide surface being located at a distance from the recycling path and facing the reference direction, the integral component including at least one second inner cavity leading to the bottom of the integral recycling component and the recycling path, the recycling path being opposite to the guide surface of the second deflector, the second inner cavity having an orthogonal projection on the reference plane, the orthogonal projection surrounding or coinciding with the orthogonal projection of the guide surface of the second deflector on the reference plane.

[0012] In one embodiment, the recirculation path describes an S-shaped path having two ends, each end being intended to be continuous with a thread root on one side of the thread traversed by the recirculation path. Preferably, the first deflector is located at a curved portion of the S-shaped path and the second deflector is located at a second curved portion of the S-shaped path.

[0013] In one embodiment, the bottom of the integral recirculation component is flat. Preferably, the bottom of the integral recirculation component is perpendicular to the reference axis. Alternatively, the bottom of the integral component may be a left side surface, such as concave or convex, such as a cylindrical envelope surface.

[0014] The first port (and, where applicable, the second port) preferably has an envelope consisting of a controlled surface preferably having a generatrix forming a draft angle with the reference axis, preferably greater than 2°, leading to the bottom of the monolithic part.

[0015] In a preferred embodiment, the first and, if applicable, the second lumen are open in the reference direction without undercuts, which means that when any two sections of the lumen are orthogonally projected onto the reference plane through a section parallel to the reference plane, the projection of the section through the section closest to the bottom of the monolithic component surrounds and, if applicable, contacts the projection of the section through the section farthest from the bottom of the monolithic component. The monolithic component can then be manufactured by axial molding.

[0016] Another aspect of the present invention relates to a recirculating threaded member for a ball screw mechanism, the recirculating threaded member having a threaded portion, the recirculating threaded member being equipped with one or more recirculators, each recirculator being accommodated in a shell cavity of the recirculating threaded member, the shell cavity passing through the thread of the threaded portion, characterized in that each recirculator is an integral recirculating component according to any of the preceding embodiments, the bottom of the integral recirculating component abutting against the bottom of the shell cavity, the recirculation path of the integral recirculating component interconnecting two parts of a groove in the thread on both sides of the thread traversed by the shell cavity. Preferably, the recirculating threaded member is equipped with a number N of recirculators, N being greater than or equal to two and preferably equal to three, the N recirculators being angularly offset from each other around the helical axis of the threaded portion by an angle

[0017] In one embodiment, the recirculating threaded member may be a ball screw mechanism screw or a ball screw mechanism nut.

[0018] Another aspect of the present invention relates to a ball screw mechanism, which includes two threaded members (i.e., a screw and a nut) and balls, one of the two threaded members being a recycling threaded member as described above, and the ball screw mechanism also includes balls forming one or more ball circuits, each ball circuit being associated with one of the integral recycling components, and each ball circuit being arranged along a circuit path that passes through the recycling path of the associated integral recycling component and through two portions of a thread groove located on both sides of the thread passed through the housing cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features and advantages of the present invention will become apparent from reading the following disclosure with reference to the accompanying drawings.

[0020] Figure 1 A ball screw mechanism according to an embodiment of the present invention is shown.

[0021] Figure 2 Shows Figure 1 0026] The recirculation threaded member (in this case a screw) of a ball screw mechanism shown in FIG. 1 is equipped with an integral recirculation component according to an embodiment of the present invention.

[0022] Figure 3 A cross section along section III-III is shown, showing one of the integral recycling components inserted into Figure 2 Detail of the threaded member shown.

[0023] Figure 4 Shows Figure 2 integral component.

[0024] Figure 5 Shows Figure 2 Orthogonal projection of a detail of the integral component shown in onto a reference plane.

[0025] For greater clarity, the same or similar elements are denoted by the same reference numerals throughout the drawings. DETAILED DESCRIPTION

[0026] Figure 1 A ball screw mechanism 10 is shown, which includes two threaded members, namely a screw 12 and a nut 14, and balls 16 arranged between a threaded portion 18 of the screw 12 and a threaded portion 20 of the nut 14 to guide relative helical motion between the screw 12 and the nut 14. Each threaded portion 18, 20 is defined by a helical groove, the sides of which form a helical thread.

[0027] One of the two threaded members (in this case the screw 12) will be referred to hereinafter as the recirculation threaded member, since it is equipped with a recirculator 22, such as Figure 2 and Figure 3 Each recirculator 22 is housed in an associated housing cavity 24, each recirculator 22 is formed in the recirculation threaded member 12, and each recirculator 22 passes through the threads 26 of the threaded portion 18 of the recirculation threaded member 12. Two portions 28, 30 of the groove leading to the threaded portion are formed on both sides of the threads 26.

[0028] In this embodiment, there are four recirculators 22, each recirculator 22 together with the portions 28, 30 of the grooves of the threaded portion on both sides of the thread 26 define a one-turn circuit path for the circuit of the balls 16. The four recirculators 22 are arranged along the axis 100 of the recirculating threaded member 12 at a distance from each other, the axial distance is greater than the pitch P of the threaded portion of the recirculating threaded member, and are angularly offset from each other by 90°. However, in other embodiments, the number N of recirculators can be any number. For a balanced, compact arrangement, the angular offset between two adjacent recirculators 22 is And the axial distance is

[0029] It is worth noting that each recirculator 22 is in the form of a monolithic component manufactured by molding in an axial mold. Figure 4 The integral component 22 shown in the figure includes a bottom 32, a top surface and a side wall 36, the bottom 32 facing the reference direction 200 parallel to the reference axis 300 of the integral component 22, the top surface is opposite to the bottom 32 and forms a recirculation path 34 on the top surface, and the side wall 36 connects the bottom to the top surface. The recirculation path 34 is a groove, the profile of which can be, for example, an arc or an arch, and the recirculation path is defined between the two ends 38 of the groove. When the integral recirculation component 22 is accommodated in the associated housing cavity 24 of the recirculation threaded member 12, the bottom 32 of the integral recirculation component 22 abuts against the bottom 40 of the housing cavity 24, the side wall 36 of the integral recirculation component 22 abuts against the side wall 42 of the housing cavity 24, and the end 38 of the recirculation path 34 is aligned with the thread groove portions 28, 30 on both sides of the thread 26 of the recirculation threaded member 12.

[0030] The recirculation path 34 is preferably S-shaped, with a middle portion 44 connected to the end portions 38 by two curved portions 46 ensuring two changes of direction.

[0031] The integral recycling component 22 also includes two deflectors 48, each of which is positioned at one of the two curved portions 46, extending from the recycling path 34 in a direction opposite to the reference direction 200, and each of which forms a guide surface 50 facing the reference direction 200 at a distance from the recycling path 34 in a direction opposite to the reference direction 200.

[0032] It is worth noting that the monolithic part 22 has two internal cavities 52, each of which is associated with one of the two deflectors 48. The two internal cavities 52 extend parallel to the same reference axis 300 of the monolithic part and open at one end to the bottom 32 and at the opposite end to the recirculation path 34 opposite the associated deflector 48. The two internal cavities 52 have an opening draft angle towards the bottom 32 sufficient to allow axial demolding, for example greater than 2°.

[0033] In an orthogonal projection onto a reference plane 400 perpendicular to the reference axis 300, and as Figure 5 As shown in , each inner cavity 52 has an inner circumference 54 which surrounds or coincides with an orthogonal projection 56 of the guide face 50 of the associated deflector 48. In practice, this means that the guide face 50, and in this case the entire integral recycling component 22, can be produced by injection molding in a double shell mold that does not require a slide to produce the deflector 48. In practice, a relief can be formed in one of the shells forming the mold cavity, which constitutes the bottom 32, the inner cavity 52 and the guide face 50 in the finished molded component, and a complementary relief is provided in the other shell to define the opposite face of the deflector 48, the demoulding axis of the mold being parallel to the reference axis 300 of the component.

[0034] Along the circuit path defined by two adjacent portions 28, 30 of the thread groove (on both sides of the thread 26 of the recirculating threaded member 12), and by the associated recirculator 22 and by the thread 20 of the other threaded member 14 of the ball screw mechanism 10, the ball 16 forms a continuous thread, and the gap between two adjacent balls is less than the radius of the ball 16, and preferably less than 1 / 10 of the radius of the ball. When the ball 16 reaches a curved portion in which one of the cavities 52 in the curved portion 46 is open, the ball 16 is no longer in contact with the recirculation path 34, but is lifted by the adjacent ball to contact the guide surface 50 of the deflector 48. Therefore, the presence of the cavity 52 does not affect the guidance of the ball 16. In addition, the cavity 52 is preferably sized so that the ball 16 cannot penetrate the cavity, so as to manage the extreme operating conditions where the ball 16 contacts the cavity 52. ​​Since the ball 16 has a very small load in the recirculation circuit, the operation will not be affected.

[0035] Naturally, the examples shown in the drawings and discussed above are given by way of illustration only. The principle of inserting one or more cavities in an integral recirculation component also applies to a recirculator positioned on a ball screw mechanism nut. It also applies to a recirculator 22 having a single deflector 48.

Claims

1. An integral recirculation component (22) intended to be received in a cavity (24) of a threaded member (12, 14) of a ball screw mechanism (10), the integral recirculation component (22) having: a bottom portion (32) turned in a reference direction (200) parallel to a reference axis (300) of the recycling member (22) and intended to bear against a bottom portion (40) of the cavity (24) of the threaded member (12, 14); a recirculation path (34) that turns in a direction opposite to the reference direction (200), the recirculation path (34) being designed to pass through the threads (26) of the threaded member (12, 14) along the recirculation path; at least one first deflector (48) extending from the recirculation path (34) in a direction opposite to the reference direction (200), the first deflector (48) forming a guide surface (50) located at a distance from the recirculation path (34) and facing the reference direction (200); It is characterized in that The integral component (22) comprises at least one first inner cavity (52), which on the one hand opens to the bottom (32) and on the other hand opens to the recirculation path (34) opposite to the guide surface (50), and the first inner cavity (52) has an orthogonal projection (54) on a reference plane (400) perpendicular to the reference axis (300), and the orthogonal projection (54) surrounds or coincides with the orthogonal projection (56) of the guide surface (50) of the first deflector (48) on the reference plane (400).

2. The integrated recycling component (22) according to claim 1, characterized in that The integral recirculation component comprises a second deflector (48) extending from the recirculation path (34) in a direction opposite to the reference direction (200), the second deflector (48) forming a guide surface (50) located at a distance from the recirculation path (34) and facing the reference direction (200), the integral component comprising at least one second inner cavity (52) opening into a bottom portion (300) of the integral recirculation component (22) 2) and the recirculation path (34), the recirculation path (34) is opposite to the guide surface (50) of the second deflector (48), the second inner cavity (52) has an orthogonal projection (54) on the reference plane (400), and the orthogonal projection (54) surrounds the orthogonal projection (56) of the guide surface (50) of the second deflector (48) on the reference plane (400) or coincides with the orthogonal projection (56) of the guide surface (50) of the second deflector (48) on the reference plane (400).

3. The integrated recycling component (22) according to claim 1 or 2, characterized in that: The recirculation path (34) describes an S-shaped path having two ends (38), each end (38) being intended to be continuous with a thread root (28, 30) on one side of the thread (26) through which the recirculation path (34) passes.

4. The integrated recycling component (22) according to claim 2, characterized in that The recirculation path (34) describes an S-shaped path having two ends (38), each end (38) being intended to be continuous with a thread root (28, 30) on one side of the thread (26) through which the recirculation path (34) passes, the first deflector (48) being located at a bend (46) of the S-shaped path, and the second deflector (48) being located at a second bend (46) of the S-shaped path.

5. The integrated recycling component (22) according to claim 1 or 2, characterized in that: The bottom (32) of the integral recirculation component (22) is flat.

6. The integrated recycling component (22) according to claim 5, characterized in that The bottom (32) of the integral recirculation component (22) is perpendicular to the reference axis (300).

7. The integrated recycling component (22) according to claim 1 or 2, characterized in that: The first inner cavity (52) is open in the reference direction (200) without undercutting.

8. The integrated recycling component (22) according to claim 2, characterized in that: Each of the first inner cavity (52) and the second inner cavity (52) is open in the reference direction (200) without an undercut.

9. A recirculating threaded member (12) for a ball screw mechanism (10), the recirculating threaded member (12) having a threaded portion (18), the recirculating threaded member (12) being equipped with one or more recirculators (22), each of the recirculators (22) being accommodated in a housing cavity (24) of the recirculating threaded member (12), the housing cavity (24) passing through a thread (26) of the threaded portion (18), characterized in that Each of the recirculators (22) is an integral recirculation component according to claim 1 or 2, the bottom (32) of the integral recirculation component (22) bearing against the bottom (40) of the shell cavity (24), the recirculation path (34) of the integral recirculation component (22) interconnecting two parts (28, 30) of a groove in the thread on both sides of the thread (26) traversed by the shell cavity (24).

10. The recirculating threaded component (12) according to claim 9, characterized in that The recirculation threaded member (12) is provided with a number N of recirculators (22), N being greater than or equal to two, the recirculators (22) being angularly offset from one another around a helical axis (100) of the threaded portion (18) by an angle 11. The recirculating threaded component (12) according to claim 9, characterized in that The recirculating threaded member (12) is provided with three recirculators (22) which are angularly offset from each other around the helical axis (100) of the threaded portion (18) by an angle 12. The recirculating threaded component (12) according to claim 9, characterized in that The recirculation threaded member (12) is a ball screw mechanism screw.

13. The recirculating threaded component according to claim 9, characterized in that The recirculation threaded member is a nut (14) of a ball screw mechanism (10).

14. A ball screw mechanism (10) comprising two threaded members and balls (16), the two threaded members being a screw (12) and a nut (14), one of the two threaded members being a recirculating threaded member (12) according to claim 9, the ball screw mechanism (10) further comprising balls (16) forming one or more ball circuits, the one or more ball circuits being each associated with one of the integral recirculating components (22), and the one or more ball circuits being each arranged along a circuit path, the circuit path passing through the recirculation path (34) of the associated integral recirculating component (22) and through two portions (28, 30) of a thread groove on either side of the thread (26) passing through the housing cavity (24).

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