NL1043521B1 - A drive belt provided with a plurality of transverse segments and a ring stack that is confined in a central opening of these transverse segments - Google Patents

Abstract

The present invention concerns a transverse segment (1) for a drive belt (50) comprising a row of such transverse segments (1) mounted on a ring stack (8). The 5 transverse segment (1) defines a centra! opening (5) between a base part (10) of the transverse segment (1) and two pillar parts (11) thereof extending from a respective side of the base part (10) for accommodating the ring stack (8). According to the present invention the drive belt (50) is designed to provide the ring stack (8) with a clearance in axial direction relative to the transverse segments (1) that is larger for the radially 10 innermost (81) of the ring stack (8) than for at least one other ring thereof. 1043521

Description

A DRIVE BELT PROVIDED WITH A PLURALITY OF TRANSVERSE SEGMENTS AND A RING STACK THAT IS CONFINED IN A CENTRAL OPENING OF THESE

TRANSVERSE SEGMENTS This invention relates to a drive belt for a continuously variable transmission with two pulleys and the drive belt. Such a transmission is commonly known and is, for example, applied in the drive train of passenger cars and other motor vehicles, In the transmission the drive belt runs around and between the pulleys that are each provided with two conical sheaves that define a V-groove wherein a respective circumference part ofthe drive belt is held. The width of the V-groove of the pulleys can be changed in mutually opposite directions, by moving the pulley sheaves towards, respectively away from one another, to control a radius at which the drive belt is {effectively} in friction contact with the respective pulleys, i.e. to control a speed ratio provided by the transmission within a continuous range between a smallest and a largest speed ratio, A known type of drive belt comprises an essentially contiguous row of fransverse segments made of steel that are mounted on and around the circumference of a ring stack composed of a number of flexible endless bands or rings that are mutually stacked, one around the other, and that are likewise made of steel, In the above and below description, the axial, the radial and the circumference directions are defined relative to the drive belt when placed in a circular posture, A thickness direction and a thickness dimension of the transverse segments are defined in the said circumference direction, a height direction and a height dimension of the fransverse segments are defined in the said radial direction and a width direction and a width dimension of the transverse segments are defined in the said axial direction. A thickness direction and a thickness dimension of the rings and of the ring stack are defined in the said radial direction, a width direction and a width dimension of the rings and of the ring stack are defined in the said axial direction and a length direction and a length dimension of the ring stack is defined in the said circumference direction. Up and down directions and above and below positions are respectively defined in radial outward and radial inward direction.

The known flexible ring is provided with an essentially rectangular cross-section, albeit with rounded sides, such that its thickness is much smaller than its width, typically by a factor of at least forty to one hundred or more. Also in absolute terms, the thickness of the ring is small and typically has a value of 185 to 200 micrometer, such that it can bend relatively easily in its circumference direction. In the ring stack, a number of such rings are arranged mutually concentric, i.e. are nested with minimal play, such that these share the load when the drive belt is operated in the transmission, it is common practice in the art to roughen the inner surface of the rings, as part of the manufacturing process thereof, in the sense that an regular or irregular pattern of indentations and/or ridges is impressed on it, with the aim of drawing-in and/or capturing lubricant between the adjacent rings in the ring stack.

The known transverse segments each define a central opening that is open towards the radial outside of the drive belt and that accommodates and confines a respective circumference section of such ring stack, while allowing the transverse segment to move along the circumference thereof.

This central opening is defined by and between a base part of the transverse segment that is located radially inward of the ring stack and two pillar parts thereof that respectively extend from a respective side of the base part in radial outward direction.

The two pillar parts thus define respective axial boundaries of the central opening, whereas in radial inward direction the central opening itis bounded by the base part.

In radially outward direction the central opening is atleast partly closed by some means, in order to confine the ring stack to the central opening.

This type of drive belt is, for example, known from the British patent GB1288777-A and, more recently, from the international patent publication WO2018/210458-A1. Ht is noted that according to these documents, the said means for confining the ring stack in radial outward direction are embodied by respective hook portions of the pillar parts that each extend axially towards the respectively other, i.e. axially opposite, pillar part at some distance away from the base part, These hook portions of the transverse segment can have equal axial extent or such axial extent can be different between the two hook portions, in which case these respective hook portions are preferably provided on opposite sides of the transverse segment for successive transverse segments in the drive belt, as a/o taught by WO2018/210456-A1, As seen in radial direction, an outer portion of the known transverse segment is provided with an essentially constant thickness, whereas a thickness of an inner portion thereof decreases in radially inward direction.

In between the said inner and outer portions, a front surface of the transverse segment, facing in a circumference direction of the drive belt, includes a width-wise extending surface part that is curved in radial direction and that is often referred to in the art as a rocking edge or a tilting zone.

The rocking edge allows successive transverse segments in the drive belt to mutually rotate about the axial direction, while these remain in contact at the rocking edge, whereby the drive belt as a whole follows a curved trajectory.

Although the rocking edge can be located in the base part of the transverse segment, it is preferably located at least partly in the pillar parts thereof. it is common practice in the art to provide the transverse segment with a protrusion projecting from the said front surface or from an oppositely facing rear surface thereof and with a corresponding, however somewhat larger cavity in iis respectively opposite main surface. In the row of transverse segments in the drive belt, the profrusion of a first transverse segment is received in the cavity of a second, i.e. adjacent transverse segment, atleast in part. Hereby, a mutual displacement of the successive transverse segments perpendicular to the circumference direction of the drive belt is limited to a play of the protrusion inside the cavity. The protrusions and cavities thus serve to both mutually align the transverse segments in a row in the straight parts of the drive belt’s trajectory and to limit a rotation thereof in the said curved trajectory parts. In particular, at least a pitching {i.e. rotation about the axial direction) and a yawing (i.e. rotation about the radial direction) of the transverse segments and preferably also a rolling (i.e. rotation about the tangential direction) of the transverse segments relative to the ring stack is limited thereby. The known transverse segments each include a single protrusion (and corresponding cavity) provided centrally in its base part and/or two protrusions (and corresponding cavities), one provided in each of it pillar parts.

During operation in the fransmission, the ring stack is tensioned by the transverse _ segments being urged in radial outward direction at the two pulleys by being clamped between the conical discs thereof. At these pulleys, the drive belt thus follows a curved trajectory, in which curved trajectory parts the transverse segments bear against the radial inside of the ring stack through, at least, a part of the surface of their base part that is located between the pillar parts, which surface part is denoted a bearing surface hereinafter. Due to the said tensioning thereof at the pulleys, the ring stack extends essentially straight between the two pulleys, while guiding the transverse segments as these traverse from the one pulley to the other in such straight trajectory parts.

In the presently considered design of the drive belt, the ring stack is thus confined in opposite axial directions, i.e. width-wise, in the central openings of the transverse segments, by and between the pillar parts thereof. The width of the ring stack is somewhat smaller than the width of the central openings of the transverse segments to accommodate a mutual misalignment of, i.e. axial offset between the pulley V-grooves that occurs during operation of the transmission in dependency on the speed ratio, as afo discussed in US4820242. Nevertheless, such axial clearance of the ring stack relative to the transverse segments cannot prevent contact in axial direction between the ring stack and the pillar parts altogether during operation of the drive belt.

Underlying the present invention is the general development aim to improve upon the existing drive belt design and existing design considerations in terms of the wear resistance and/or the fatigue strength of the known drive belt. According to the present invention, an improvement can in this respect be obtained by applying the axial clearance between the ring stack and the transverse segments that is larger for the radially innermost ring of the ring stack as compared to at least one of the other rings of the ring stack.

The present invention relies on the observation that the wear and/or the ultimate fracture of the ring stack is not equally distributed between the individual rings of the ring stack. Rather, the radially innermost ring of the ring stack was observed by applicant to experience the most wear, at least on average. Therefore, according to the present invention, it is beneficial to the overall performance of the drive belt, to reduce the severity of the axial contact between the transverse segment and the innermost ring of the ring stack, e.g. in terms of a rate of incidence and/or an intensity thereof.

According to the present invention the drive belt is designed to provide the ring stack with a clearance in axial direction relative to the transverse segments that is larger for the radially innermost of the ring stack than for at least one other ring of the ring stack. Within this design concept of the drive belt two principle embodiments are available.

in a first principle embodiment of the drive belt, the radially innermost ring of the ring stack is provided with a width that is less than the width of the at least one other ring of the ring stack. in this way, the sald axial contact between the transverse segments and the innermost ring of the ring stack is reduced, favourably with a minimal impact on the cross-sectional surface area of the ring stack as a whole. After all, such cross-sectional surface area determines the strength of the ring stack as a whole and is thus preferably reduced as little as possible.

In a first elaboration of this first principle embodiment, a ring of the ring stack between the radially innermost and the radially outermost rings thereof is provided with the largest width among all rings of the ring stack. In this way, the axial contact between the transverse segments and the ring stack is favourably concentrated at such in-between ring that is not otherwise in contact with the transverse segments.

in second principle embodiment of the drive belt, a side face of at least one of the pillar parts of the transverse segments facing the central opening is at least partly oriented towards the opposite pillar part in radial outward direction. As a result, an axial width of the central opening is smallest at some radial position other than the radial position of the radially innermost ring of the ring stack. In this way, the said axial contact between the transverse segments and the innermost ring of the ring stack is reduced.

In a first elaboration of this second principle embodiment, the said side face of the pillar part is oriented towards the opposite pillar part in radial outward direction starting from the base part of the transverse segment up to the hook portion of that pillar part. As a result, an axial width of the central opening continually decreases in radially outward direction from the radial position of the innermost ring of the ring stack to the radial position of the radially outer ring thereof. In this way, the axial contact between the transverse segments and the ring stack is favourably concentrated at the radially outer rings of the ring stack.

5 In a second elaboration of this second principle embodiment, the said side face of the pillar part is provided with a middle section in radial direction that protrudes towards the opposite pillar part relative to radial bottom and top sections thereof. In this way, the axial contact between the transverse segments and the ting stack is favourably concentrated at a ring of the ring stack between the radially innermost and the radially outermost rings thereof, which ring is not otherwise in contact with the transverse segments. Alternatively, an upper section of the said side face of the pillar part protrudes towards the opposite pillar part relative to a lower section thereof. In this way, the axial contact between the transverse segments and the ring stack is favourably concentrated at the radially outer rings of the ring stack.

The above-described invention and the technical working principles underlying the invention will now be explained further with reference to the drawing figures, whereof: - figure 1 is a simplified and schematic side elevation of a known transmission with two pulleys and a drive belt consisting of a ring stack and a row of transverse segments mounted on the ring stack along the circumference thereof; - figure 2 schematically illustrates the known drive belt in a cross-section thereof facing in its circumference direction and also includes a separate, transverse cross-section of only the transverse segment thereof; ~ figure 3 schematically illustrates a first novel embodiment of the drive belt in accordance with the present invention; - figure 4 schematically illustrates a second novel embodiment of the drive belt in accordance with the present invention; - figure 5 schematically illustrates a third novel embodiment of the drive belt in accordance with the present invention; and - figure 8 schematically illustrates a fourth novel embodiment of the drive belt in accordance with the present invention.

Figure 1 schematically shows, in a cross-section thereof, the central parts of a continuously variable transmission 51 for use in a driveline of, for example, passenger motor vehicles. This transmission 51 is well-known and comprises at least a first variable pulley 52, a second variable pulley 53 and a drive belt 50 fitted around these pulleys 52,

53. In the driveline, the first pulley 52 is coupled to and driven by a prime mover of the vehicle, such as an electric motor or a combustion engine, and the second pulley 53 is coupled to and drives a driven wheel of the vehicle, typically via a number of gears. The pulleys 52, 53 each typically comprise a first conical sheave that is fixed fo a respective pulley shaft 54, 55 and a second conical sheave that is axially displaceable relative to such respective pulley shaft 54, 55 and that is fixed thereto in rotational direction. As appears from figure 1, the trajectory of the drive belt 50 in the transmission 51 includes two straight parts ST, where the drive belt 50 crosses over between the pulleys 52, 53 and two curved parts CT where the drive belt 50 is wrapped around the two pulleys 52, 53 while being accommodated between the conical sheaves thereof.

The drive belt 50 is composed of a ring stack 8 and a plurality of transverse segments 1 that are mounted on the ring stack 8 along the circumference thereof in an, at least essentially, contiguous row. For the sake of simplicity, only a few of the transverse segments 1 of the drive belt 50 are shown in figure 1, which transverse segments 1 are, moreover, not drawn to scale in relation to, for example, the diameter of the pulleys 52,

53. in the drive belt 50, the transverse segments 1 are movable along the circumference ofthe ring stack 8, which ring stack 8 is composed of a number of relatively thin and flexible endless steel bands or rings that are mutually nested, as can be seen more clearly in figure 2 that shows the ring stack 8 with eight individual rings.

During operation of the transmission 81, the transverse segments 1 of the drive belt 50 can be driven by the first pulley 52 in the direction of rotation thereof by friction.

These driven transverse segments 1 push preceding transverse segments 1 in the circumference direction of the ring stack 8 and, ultimately, rotationally drive the second pulley 53, again by friction. in order to generate such friction (force) between the transverse segments 1 and the pulleys 52, 53, the said pulley sheaves of each pulley 52, 53 are urged towards each other, whereby these clamp the transverse segments 1 between them in the respective curved trajectory part CT of the drive belt 50. To this end, electronically controfiable and hydraulically acting movement means {not shown) that act on the moveable pulley sheave of each pulley 52, 53 are provided in the transmission 51. These movement means also control respective radial positions R1 and R2 of the drive belt 50 at the pulleys 52, 53 and, hence, the speed ratio that is provided by the transmission 51 in.

the driveline between the pulley shafts 54, 55 thereof.

Also during operation of the transmission 51 drive belt 50, the transverse segments are urged radial outward by being clamped between the conical pulley sheaves and are being forced into contact with the radial inside of the ring stack 8 that is tensioned thereby. Since, as mentioned hereinabove, in the drive belt 50 the transverse segments 1 can move relative to the ring stack 8 along the circumference thereof, the ring stack 8 is tensioned ic a relatively low level in relation to a torque transmitted by the drive belt 50 between the pulleys 52, 53, at least compared to other types of drive belt.

In figure 2 the known drive belt 50 is schematically illustrated in more detail. On the left side of figure 2 the drive belt 50 is shown In a cross-section thereof facing in circumference direction and on the right side of figure 2 a cross-section A-A of only the transverse segment 1 is included. From figure 2 it appears that the transverse segments 1 of the drive belt 50 are generally shaped similar to the letter "V", i.e. are generally V- shaped. In other words, side faces 12 of the transverse segments 1 through which it arrives in {friction} contact with the pulleys 52, 53, are mutually diverging in radial outward direction by being oriented at an angle that closely matches an angle that is present between the conical sheaves of these pulleys 52, 53. The pulley contact faces 12 of the transverse segment 1 are typically either corrugated hy a macroscopic profile or are provided with a rough surface structure, such that only the higher lying peaks of the corrugation or of the surface roughness arrive in contact with the pulleys 52, 53. This particular feature of the transverse segment design provides that the friction between the drive belt 50 and the pulleys 52, 53 is optimised by allowing cooling oil that is applied in the known transmission 51 to be accommodated in the lower lying parts of the corrugation or of the surface roughness.

Each fransverse segment 1 includes a hase part 10 and two pillar parts 11, whereof the base part 10 extends mainly in the axial direction of the drive belt 50 and whereof the pillar parts 11 extend mainly in the radial direction of the drive belt 50, each from a respective axial side of the base part 10. In its thickness direction, the transverse segment 1 extends between a front main body surface, i.e. front surface 2 and a rear main body surface, ie. rear surface 3 thereof that are both oriented, at least generally, in the circumference direction of the drive belt 50. An opening 5 is defined centrally between the pillar parts 11 and the base part 10 of each transverse segment 1, wherein a circumference section of the ring stack 8 is accommodated. In radial outward direction the central opening 5 is partly closed-off by respective hook portions 9 of the pillar parts 11. Each such hook portion 9 extends from a respective pillar part 11 generally in the direction of the respectively opposite pillar part 11. Thus, the hook portions 9 confine the ring stack 8 to the central opening 5 of the transverse segment 1 in radial outward direction. In between the pillar pants 11, the base part 10 defines a bearing surface 13 for confining and supporting the ring stack 8 in radially inward direction.

As illustrated in figure 2, the bearing surface 13 is a central part of a boundary surface of the central opening 5 that is defined by the base part 10 in radially inward direction and that thus predominantly extends in the axial and circumference directions of the drive belt 50. The bearing surface is convexly curved in, at least, the axial direction in a well-known manner, for realising, or at least promoting, a desired contact and interaction between the transverse segment 1 and the ring stack 8. On either side of bearing surface 13 the sald boundary surface of the base part 10 further includes a transition surface 15 forming a transition between the bearing surface 13 and a side face of a respective pillar part 11 facing the central opening 5. Typically, such transition surfaces 15 include a convexly curved part adjoining the bearing surface 13 and a concavely curved part adjoining the said side face of the respective pillar part 11. itis noted that convexly curved part of the transition surfaces 15 is curved according to a much smaller (e.g. by factor of

0.1 or less) radius of curvature than the bearing surface 13 is curved.

Both pillar parts 11 of the transverse segment 1 are provided with a protrusion 6 that protrudes in thickness direction from the front surface 2 of the transverse segment 1 and with a corresponding, however somewhat larger cavity 7 in the opposite side of the respective pillar part 11, Le. in the rear surface 3 of the transverse segment 1. In the row of transverse segments 1 in the drive belt 50, the protrusions 6 of a first transverse segment 1 are received in the cavities 7 of a second, i.e. adjacent transverse segment 1. By this engagement of the protrusions 6 and the cavities 7 of successive transverse segments 1, the transverse segments 1 mutually link to and align one another in radial direction and in axial direction in the said row thereof in the drive belt 50. In figure 2, the diameter of the cavity 7 is exaggerated relative to the diameter of the protrusion 8 to illustrate a play that exists there between.

Also in the said row of transverse segments 1 in the drive belt 50, at least a part of the front surface 2 of a first transverse segment 1 abuis against at least a part of the rear surface 3 of a second, i.e. adjacent transverse segment 1. Abulting transverse segments 1 are able to tilt relative to one another, while remaining in mutual contact at and through an axially extending, convexly curved surface part 4 of the front surface 2 thereof that is denoted rocking edge 4 hereinafter. Above, i.e. radially outward of such rocking edge 4, the transverse segment 1 has an essentially constant thickness, whereas below, Le. radially inward of such rocking edge 4, the transverse segment 1 is tapered, i.e. has a thickness that decreases in radially inward direction (whether gradually, stepwise or by a combination thereof}, to allow for the afore-mentioned relative tilting without interference between the respective base parts 10 of the abutting transverse segments 1.

It is noted that, although in figure 2 the rocking edge 4 is located partly in the pillar parts 11 and partly in the base part 10 of the transverse segment 1 such that ft overlaps with the bearing surface 13 in radial direction, it is also known to locate the rocking edge 4 fully in the base part 10, Le. radially inward of the bearing surface 13. In either case, the rocking edge 4 is preferably provided in two parts 4a, 4b separated by the central opening and/or by a recessed area 14 in the front surface 2 of the transverse segment 1 that is recessed in thickness direction relative to the rocking edge 4. The recessed area 14 provides a channel between the abutting transverse segments 1, allowing lubricant to flow from radially inside the drive belt 50 to the radial inside of the ring stack 8. Such lubricant 5 is supplied to the transmission during operation, not only for cosling it, but also for lubricating the dynamic contact between the transverse segments 1 and the ring stack 8, as well as between the individual rings of the ring stack 8. It is further noted that in the embodiment of the transverse segment 1 illustrated in figure 2, wherein the rocking edge 4 is located partly in the pillar parts 11 and the base part 10 of the transverse segment 1, the recessed area 14 is, in part, formed as a curved transition surface between the front surface 2 of the transverse segment 1 and the bearing surface 13 as an inevitable side- effect of the preferred manufacturing method of fine-blanking the transverse segment. In fine-blanking, the transverse segment 1 is cut from steel basic material by pressing a punch, having a contour corresponding to that of the transverse segment 1, through the basic material into a transverse segment-shaped hole of a die plate, while being supported by a counter punch on the opposite side thereof. An end face of the counter punch that contacts the basic material is a/o shaped to form the rocking edge 4 and is provided with a recess that serves as a mould for forming the protrusion 6, while the end face of the punch that contacts the basic material is protruding part to form the cavity 7.

As further illustrated in figure 2, the pulley contact faces 12 of the transverse segment 1 extend in radial direction from the underside of the base part 10 to somewhat above the rocking edge 4, i.e. partly in the pillar parts 11. However, such radial extend can also be less, e.g. the pulley contact faces 12 can be confined to the base part 10, or more, e.g. of the pulley contact faces 12 can extend in the pillar parts 11 to radially outward of the ring stack 8.

According to the present invention it is beneficial to the overall performance of the drive belt 50, to reduce the severity of the axial contact between the transverse segment 1 and an innermost ring of the ring stack B, e.g. in terms of a rate of incidence and/or an intensity thereof, In the conventional drive helt 50 this innermost ring typically shows the largest wear, le. as compared to the other rings of the ring stack 8, of, in particular its axial sides that arrive in contact with the pillar parts 11 of the transverse segments 1 during operation. Therefore, according to the invention and as illustrated in figure 3 and highlighted by the dotted circles C, the radially innermost ring 81 of the ring stack 8 is provided with a width that is less than the width of the other rings of the ring stack 8. In this way, the said axial contact between the transverse segments 1 and the innermost ring 81 of the ring stack 8 is reduced.

Alternatively or additionally, a side face 18 of the pillar parts 11 that faces the central opening 5 is oriented towards the opposite pillar part in radial outward direction. This particular embodiment of the transverse segment 1 according to the present invention is illustrated in figure 4. As a result, an axial width of the central opening 5 is largest at the radial position of the radially innermost ring 81 of the ring stack 8. Also in this way, the said axial contact between the transverse segments 1 and the innermost ring 81 of the ring stack 8 is reduced.

Further, figures 5 and 6 provide alternative embodiments of the transverse segment 1, in particular of the said pillar part side face 16 thereof, having the same effect of reducing the contact thereof with the sides of the innermost ring 81 of the ring stack 8.

In the embodiment of figure 5, the side face 16 of the pillar part 11 facing the central opening 5 is provided with a middle section 182 in radial direction that protrudes towards the opposite pillar part 11 relative to a bottom section 161 and a top section 163 thereof in radial direction. In the embodiment of figure 8, the lower section 164 of the said pillar part side face 18, corresponding in radial extend and position to, at least, the radially innermost ring 81 of the ring stack 8, is recessed relative to un upper section 185 thereof, The present invention, in addition to the entirety of the preceding description and all details of the accompanying figures, also concerns and includes all the features of the appended set of claims. Bracketed references in the claims do not limit the scope thereof, but are merely provided as non-binding examples of the respective features, The claimed features can be applied separately in a given product or a given process, as the case may be, but it is also possible to apply any combination of two or more of such features therein.

The invention is not limited fo the embodiments and/or the examples that are explicitly mentioned herein, but also encompasses amendments, modifications and practical applications thereof, in particular those that lie within reach of the person skilled in the relevant art,

Claims (5)

CONCLUSIONS | A drive belt (50) with a belt package {8} consisting of a number of mutually nested belts and with a number of successive and movable transverse segments (1) placed on the belt package (8), each of which is individually provided with a central opening (5) for receiving the belt package (8) of the drive belt (50), which central opening (5) is bounded on an underside thereof by a base portion {10} of the transverse segment {1} and on either side thereof by a pillar part (11) of the transverse segment {1}, respectively, which pillar parts (11) extend transversely on either side of the opening {5} in height direction from the base part (10) and of which at least one pillar part {11} is provided with a side surface {16} which can come into contact with the belt package (8), in which drive belt a transverse clearance is provided between the pillar parts (11) of the transverse segments (1), in particular the side face {18} thereof, and the belt package (8), with the characteristic k, that said transverse clearance at the level of a radially inner tire (81} of the tire pack {8} is greater than at the height of at least one other tire thereof, The drive belt (50) according to claim 1, characterized in that a transverse dimension of the radially inner tire (81) of the belt pack (8) is smaller than a transverse dimension of said at least one other tire of the said belt. band pack (8). The three-belt {50} according to claim 2, characterized in that said at least one other tire of the tire pack (8) is located between the radially inner tire (81) and a radially outer tire thereof. The drive belt (50) according to claim 1, 2 or 3, characterized in that the side face {16} of the pillar part (11) of a respective transverse segment {1} in height direction at least partially and preferably in its entirety in the direction of the other pillar part (11). The drift belt {50} according to claim 1, 2 or 3, characterized in that the side face {18} of the pillar part (11) of a respective transverse segment {1} is one with respect to one near the base part (10) located part thereof (161; 164) bulging portion {162; 165) includes,