Guiding and centering device

Abstract

To provide a guiding and centering device which ensures desired guiding and centering accuracy without the need of additional accurate centering units.SOLUTION: A device 10 in which both mold halves 1 and 5 are guided and centered by guide means 7 is provided with: a protruded guide body 4 formed as a circular cylindrical bolt 12 provided at the first mold half 1; a guide recess 6 formed as a bush 14, and provided with a cylindrical inner surface 20 on the second mold half 5; and a rolling element cage 16 with rolling elements 17 inserted in a plurality of rows 18. The rolling element cage 16 is supported by the circular cylindrical inner surface 20 of the bush 14 and positioned via positioning means 30 in such a way that when closing the forming tool, the circular cylindrical bolt 12 runs practically simultaneously in a first row of the rolling elements and a second row of the rolling elements of the rolling element cage 16.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a guiding and centering device for guiding and aligning first and second half-molds. The guiding and centering device of the present invention can be used in molding tools such as injection molding tools and die-casting tools, which include a first half-mold and a second half-mold. The first half-mold and the second half-mold are guided by guiding means so that each split surface of the two half-molds can be moved from a closed position where the split surfaces are pressed against each other to an open position, and vice versa. The guiding and centering device is formed by a plurality of protruding guiding bodies attached to the first half-mold and a plurality of guiding grooves attached to the second half-mold. Through these guiding bodies, the two half-molds are accurately guided and centered in the closed position. In particular, the guiding and centering device according to the present invention is preferably configured to provide accurate guiding from the start to the end of centering and guiding with the maximum load capacity in combination with round precision centering used for individual guiding and centering of gaps, parting surfaces, and plate parts.

Background Art

[0002] Molding tools or general molding tools including a first half-mold and a second half-mold are well-known. In such molding tools, the half-molds are provided together with a plurality of plate parts according to the complexity of the mold. These plate parts are guided in a plurality of pillar guiding parts and can move from a closed position to an open position and vice versa from an open position to a closed position. The mold disposed between the parting surfaces of the two half-molds is filled with, for example, a casting material that is pushed into the mold when the mold is closed.

[0003] Generally, a guide device comprises at least a bushing or sleeve provided on one side of a mold having a first bearing surface, a guide post provided on the other side of a mold having a second bearing surface, and a bearing adapted to reduce sliding friction along the bearing surface when the members are fitted together by bearing engagement between the bushing and the guide pin or post. Thus, the bushing or sleeve is formed from a sliding bushing that provides a defined sliding surface. However, common problems with sliding friction pairs are known, including jittering or crawling caused by unbalanced friction on their set, and such problems can affect the quality of the workpiece and the lifespan of the guide device.

[0004] Furthermore, in order to obtain accurate molding of molded products that meet appropriate standards and specifications, it is necessary that the two mold halves forming the mold are precisely aligned. However, this cannot be ensured within the desired range by the guide device, especially the column guide section that guides the mold halves. For this reason, a positioning device, also called a centering device, is used. This device precisely aligns one mold half with the other mold half, in particular, at the end of the stroke until it reaches the end point of the closed position.

[0005] A typical centering device consists of a first component, which is attached to one half of the mold and is configured as a guide pin, or generally as the male part of the mold; and a second component, which is attached to the other half of the mold and is configured as a bushing, or generally as the female part of the mold. The first and second components fit together when the mold is closed. The fit between the male and female parts determines the magnitude of the positioning error between the mold halves.

[0006] Prior art has shown that a replaceable insertion portion, configured as a bearing equipped with rolling elements, is provided between the first bearing surface of the male portion and the second bearing surface of the female portion. In particular, such an insertion portion is configured as a cage that rotatably supports multiple needle bearings or rolling elements, thereby reducing friction along the bearing surfaces when fitting the members together.

[0007] Patent Document 1 (EP2363263A) describes a centering device in which a rolling element cage is arranged, with multiple protrusions each formed as cylindrical bolts and rolling elements inserted in rows on top of them. In the open state, the device is positioned via positioning means so that the first row of rolling elements directed towards the first half of the mold rests on the circular surface of the bolt, and the second row of rolling elements rests on the peripheral edge ending at the circular cylindrical surface of the bolt. Each guide groove is formed from a sleeve having a circular cylindrical inner surface that abuts against the rolling elements of the rolling element cage when the mold is closed.

[0008] Patent Document 2 (US2004 / 043103A1) describes a bearing mechanism for a positioning device to reduce friction along a bearing surface, which, when fitted, moves relative to at least one of a first member having a male portion, or preferably a second member having male and female portions, between a first position and a second position. An elastic member elastically supports the bearing mechanism, and a retainer is coupled to the bearing mechanism to counteract the elastic member, which is configured as a spring, as the bearing mechanism moves between the first and second positions. The spring functions as a means of applying force to the bearing mechanism. The retainer prevents the bearing mechanism from moving beyond a position where only a portion of the rolling elements are free from the bearing surface supporting the rolling element cage.

[0009] Furthermore, different embodiments of retainers are known to prevent the bearing mechanism from slipping out of the bushing of the positioning device. For example, a locking member, such as a snap ring, can be provided at the entrance of the bushing to hold the bearing mechanism in place. Alternatively, the retainer with rolling elements may be provided with outwardly projecting elements that can engage with a contact surface on the inner surface of the bushing.

[0010] To obtain accurate molded products, it is necessary that the two mold halves forming the mold are precisely aligned, but this is often not achievable with guide and positioning devices known in the art. There is still a need for a guide and centering device that can obtain the maximum load capacity at the start of centering and ensure that one mold half is precisely aligned and guided accurately to the other mold half. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] European Patent Application Publication No. 2363263 [Patent Document 2] U.S. Patent Application Publication No. 2004 / 043103 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The object of the present invention is to create a guide and centering device that guarantees desired guide and centering accuracy without requiring additional precision centering units such as flat centering devices. Furthermore, the object of the present invention is to provide a guide and centering device that can minimize wear on the device and provides play-free guidance from the start to the end of centering. Thereafter, such a guide and centering device has a long service life and can reduce replacement cycles. Another object of the present invention is to create a guide and centering device that can be used as a play-free fine centering system, is applicable with no lubrication or minimal lubrication, and is configured to be adaptable to different forming tools. [Means for solving the problem]

[0013] The objectives of the present invention are to provide a guide and centering device for a molding tool, particularly an injection molding tool or a die-casting tool, comprising a first mold half and a second mold half, wherein the mold halves are guided by a guide means from a closed position in which the separating surfaces of the two mold halves are pressed against each other to an open position, and vice versa. Multiple guide and centering devices can be provided on the molding tool. Each guide and centering device comprises a protruding guide body formed from a guide column as a circular, cylindrical bolt provided on the first mold half, a guide groove formed as a bush with a circular, cylindrical inner surface provided on the second mold half, and a rolling element cage into which rolling elements are inserted in a row, thereby guiding both mold halves to the closed position and precisely centering them.

[0014] Advantageously, the guiding and centering device according to the present invention provides precise and accurate playless guidance with high repeatability along the entire stroke path. This is achieved in particular by preloaded rolling guides with rolling element cages and a combination of bushings, bolts, and rolling element cages. Furthermore, high precision in the positioning of the mold half is achieved long before reaching the closed position, thus reducing wear on the contact surfaces of the mold half even at high traverse speeds.

[0015] According to the present invention, the rolling element cage is supported by a circular, cylindrical inner surface of a bushing, and a positioning means is used to position a circular, cylindrical bolt so as to close the forming tool, it runs substantially simultaneously through the first row of rolling elements and the second row of rolling elements of the rolling element cage.

[0016] The advantages of rolling bearings provided by the rolling element retainer minimize the need for lubricants.

[0017] With this arrangement of the guide and centering device according to the present invention, when the forming tool is closed, the circular, cylindrical bolts run substantially simultaneously through the first row of rolling elements and the second row of rolling elements, resulting in a high initial load capacity already obtained at the start of centering. Furthermore, since the load on the rolling elements and the support surface or centering surface can be separated, wear of the guide and centering device is reduced and the service life is extended. This is particularly advantageous compared to prior art centering systems configured as a guide block system, where the very high surface pressure during initial engagement increases wear on the centering surface.

[0018] Depending on the geometric configuration of the guide and centering device, a cage with rolling elements may have additional rows of rolling elements to improve centering.

[0019] In a preferred embodiment of the present invention, a positioning means adapted to precisely position a cage of rolling elements such that substantially two rows of rolling elements simultaneously pre-engage between a guide and a centering comprises a spring element and an axial retainer element, between which the cage with rolling elements is axially positioned on the circular, cylindrical inner surface of a bushing.

[0020] Advantageously, a compression spring as a spring element is inserted into the bushing, specifically positioned between a support means at one end of the bushing and a rolling element cage provided within the bushing at the opposite end, so that the spring element functions as a bias element (a means of applying tensile force in one direction) to the rolling element cage. This positions the rolling element retainer by the spring element, causing it to abut against the axial retainer, ensuring that the rolling element retainer is in the correct position when the forming tool opens. The axial retainer also positions the rolling element retainer together with the spring element and can be used with tools that disengage from engagement.

[0021] In a preferred embodiment of the present invention, shoulders projecting inward from the circular cylindrical inner surface of the bush, and / or grooves provided on the circular cylindrical inner surface of the bush, into which a circlip can be inserted, are formed at the ends of the circular cylindrical inner surface, so as to support the positioning means. For example, a shoulder supporting a spring element is formed at one end of the circular cylindrical inner surface, and a groove into which a circlip or snap ring (retaining ring) forming an axial retainer element is inserted is provided at the opposite end of the circular cylindrical inner surface. Thus, within the bush, accurate axial positioning is ensured by an axial arrangement in which a spring element biases (tensile force in one direction) the rolling element cage from one side, and an axial retainer element holds the rolling element cage in place from the other side. This achieves the desired precise arrangement of the rolling element cage within the bush and can be manufactured in a simple and inexpensive manner.

[0022] Alternative embodiments of the bushing may exist for positioning the arrangement inside the bushing. For example, shoulders or grooves can be formed at both ends of the circular, cylindrical inner surface.

[0023] The spring element configuration must ensure that when the rolling element cage is in the centering start position, the spring element generates sufficient bias force so that at least the first and second rows of rolling elements enter preload. When the mold is closed, the spring force should not be too strong; otherwise, the rolling element retainer will be pressed by the preload. The spring element is configured to ensure that the rolling element cage is precisely positioned in the open position of the forming tool, and furthermore, it is independent of the mounting position of the guide and centering devices in the forming tool.

[0024] In another preferred embodiment of the present invention, the bushes and / or guide columns formed from circular cylindrical bolts have a lead-in geometry at their inlet portions. In a preferred embodiment, the lead-in geometry of the bushes is configured to be directed towards the rolling element cage, to form an edge of the circular cylindrical inner surface, and to have an end that merges with a second circular cylindrical inner surface. Thus, the point where a complete preload is applied to the rolling elements is accurately defined.

[0025] The circular cylindrical bolt is provided with an edge that circumscribes its circumferential surface, and this end transitions to a conical draw-in region that forms the lead-in geometry of the bolt head.

[0026] The bush is provided on the second type of half body and is particularly connectable to the second type of half body. The connection between the bush and the second type of half body is effected via a locking member, which is insertable into any one of a series of circumferential grooves formed along the axial length of the bush surrounding the bush and projects into a groove formed in the second type of half body.

[0027] Furthermore, the guide column configured as a circular cylindrical bolt is connectable to the first type of half body via a locking member. The locking member is configured to surround the bolt and be insertable into one of a series of circumferential grooves formed along the axial length of the bolt, and the insertable locking member projects into a groove formed in the first type of half body.

[0028] The locking member can be configured as a circlip, snap ring, or ring part. Preferably, the locking member is configured as two ring parts, and both of these ring parts are insertable into one of the circumferential grooves forming a complete ring structure. Furthermore, the ring structure is formed by a circumferential groove suitable for incorporating a seal ring so that the two ring parts are firmly fixed in the circumferential groove of the bush.

[0029] Advantageously, the bushing and bolt can be individually positioned by fixing the second half of the bushing to a guide post formed from a circular, cylindrical bolt via these locking members, which can be individually positioned along at least a portion of the bushing's axial length and along the length of the bolt. For example, the guiding and centering device can be used in different situations, adapting particularly to the thickness of the plate portion, regardless of the size of the plate portion used in the forming tool.

[0030] In another preferred embodiment of the present invention, at least one of the bushing and the circular, cylindrical bolt is configured with a lead-in shape. The bolt, which travels within the rolling element cage, may advantageously have a lead-in shape in its head portion, which is formed from a conical recessed region adjacent to the edge that brings together the circular circumferential surface.

[0031] In another embodiment, the bushing has a lead-in geometry in which the circular cylindrical inner surface of the bushing is joined at the edge, and a second circular cylindrical inner surface having a larger diameter than the first circular cylindrical inner surface is provided next to the edge. Preferably, the circular cylindrical inner surface of the bushing transitions at the edge region to a second circular cylindrical inner surface having a curvature or roundness that matches the curvature of the rolling element. As a result, the bolt entry into the rolling element cage does not place excessive stress on the rolling element cage, which is advantageous in terms of service life.

[0032] In one preferred embodiment, the rolling elements are rollers or balls, resulting in a simpler structure for the rolling element cage and enabling low-cost manufacturing. Furthermore, since the rolling elements are configured to center by rolling rather than sliding and to make line contact, wear is significantly reduced.

[0033] The guiding and centering device according to the present invention offers simple and flexible placement, and can be easily installed and positioned to provide backlash-free guiding and centering. Furthermore, the guiding and centering device of the present invention is suitable for cleanroom applications and can achieve extremely low wear and abrasion, enabling a wide range of applications, including long-stalk and short-stalk applications. The guiding and centering device of the present invention has a compact configuration and can be attached to forming tools as a plug-and-play solution.

[0034] Another advantage of the guiding and centering device according to the present invention is that the bushings are interchangeable with various guide posts conforming to the same tolerances, eliminating the need to use specific guide posts together with the bushings that constitute the rolling element cage. Thus, the guiding and centering device provides interchangeability and replaceability, and furthermore, offers a so-called two-in-one solution that does not require a separate fine centering device in addition to the guiding device. Therefore, since the guiding and centering device combines both guiding and fine centering, an additional fine centering device is unnecessary.

[0035] To better understand the present invention and its advantages, exemplary embodiments of the invention will be described in more detail below with reference to the accompanying drawings. In the drawings, similar parts are denoted by the same reference numerals. [Brief explanation of the drawing]

[0036] [Figure 1] Figure 1 schematically shows a guide and centering device according to prior art. [Figure 2] Figure 2 shows a schematic guide and centering device according to one embodiment of the present invention. [Figure 3] Figure 3 is a schematic diagram partially showing a guide and centering device according to one embodiment of the present invention. [Figure 4a] Figure 4a is a schematic cross-sectional view of a guide and centering device according to one embodiment of the present invention, showing the movement of the guide body into the guide groove when the forming tool is closed. [Figure 4b]Figure 4b shows a schematic guide and centering device in a partially cross-section, according to an embodiment of the present invention shown in Figure 4a, in another position when the forming tool is closed. [Figure 5] Figure 5 schematically shows a locking element of one embodiment of the present invention for positioning a guide and centering device relative to a molding tool. [Modes for carrying out the invention]

[0037] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated herein and constitute part thereof. The drawings illustrate certain embodiments of the present invention and, together with the description in the specification, are useful in explaining the principles of the present invention.

[0038] Referring to Figure 1, a known mold configuration with a centering device and guide means is shown. In the first mold half 1 of the molding tool 2, a cubic-shaped, protruding guide body 4 is fixed in the region of the separation surface 3. Other forms of the protruding guide body are known to be conical or cylindrical. Furthermore, a guide means 7 formed from known guide columns is arranged to guide the molding tool 2 during movement. Although not shown in Figure 1, the second mold half mode 5 (second mold half 5) of the molding tool 2 has a slot shape and is provided with a guide groove 6 corresponding to the guide body 4 of the first mold half 1. When the molding tool 2 is closed, the guide body 4 is located within the guide groove 6, enabling optimal alignment of the first mold half 1 and the second mold half 5. Due to the design of the guide body 4 and the guide groove 6, they must be used at least twice in pairs to enable centering in all directions. Therefore, the guide body 4 and the guide groove 6 must basically be positioned facing each other, which can result in space problems. Furthermore, in this known centering device, the surface pressure acting on the guide body and the guide groove can become very high. In addition, the corresponding guide surfaces must slide against each other, resulting in severe wear, which in turn necessitates replacing these centering devices after a certain period of time.

[0039] Referring to Figures 2 and 3, a guide and centering device 10 according to the present invention is shown in one possible arrangement within the forming tool 2. According to this embodiment, each protruding guide body 4 consists of a circular, cylindrical bolt 12, in particular a guide column of the guide means 7. Each guide groove 6 consists of a bush 14 having a circular, cylindrical inner surface 20 that supports a rolling element cage 16 having rolling elements 17 inserted in rows 18. The circular, cylindrical bolt 12 runs through the rolling elements 17 of the rolling element cage 16 when the forming tool 2 is closed. Figure 2 shows a first mold half 1 of the forming tool 2. This forming tool 2 is designed in particular as a guide column known in the prior art and comprises a guide means 7 consisting of circular, cylindrical bolts 12 according to the present invention. Thus, in the illustrated embodiment, the forming tool 2 generally comprises four guide sets, with four such bolts 12 inserted into the first mold half 1. In principle, two bolts 12 are required to achieve optimal centering, but any number of bolts 12 can be used in the forming tool 2, depending on the size and configuration of the forming tool 2.

[0040] Figure 3 shows one viewpoint of the forming tool 2. The forming tool 2 comprises a first half-body 1 having a circular, cylindrical bolt 12 as a guide body 4, the bolt 12 in particular serving as a guide column for the guide means 7, and also as a guide column for the second half-body 5 having a bush 14 into which the rolling element cage 16 is inserted when in the open state.

[0041] The guide groove 6 is configured as a bush 14 having a circular, cylindrical inner surface 20, and is fixed to the second mold half 5 of the molding tool 2, as will be described later. A rolling element cage 16 is inserted into the bush 14, which is supported by the circular, cylindrical inner surface 20. The rolling element cage 16 is equipped with rolling elements 17 arranged in rows 18, and the rolling elements 17 can be configured as rollers or balls.

[0042] A positioning means 30 is provided for positioning the rolling element cage 16. According to one embodiment shown in Figure 3, the positioning means 30 comprises a retainer element 32, which is made of a circlip 34 or a snap ring and is positioned near the opening of the bush 14 toward the circular, cylindrical bolt 12. Here, the circlip 34 is inserted into a groove provided in the circular, cylindrical inner surface 20. Furthermore, the positioning means 30 comprises a spring element 31 configured to bias the rolling element cage 16 toward the retainer element 32 from its opposite end. The end of the spring element 31 that is away from the rolling element cage 16 is supported by a stop element, which may be formed by another circlip 34 inserted into a groove provided in the circular, cylindrical inner surface 20 at the end opposite to the opening into which the bolt 12 is inserted, or by a shoulder protruding inward from the circular, cylindrical inner surface 20. A spring element 31 made from a compression spring presses the rolling element cage 16 against a retainer element 32, which means that the rolling element cage 16 is in the correct position when the forming tool 2 is open. The correct position of the rolling element cage 16 ensures that when the forming tool 2 is closed, the circular, cylindrical bolt 12 travels over the first row and the second row of rolling elements 17 simultaneously and substantially simultaneously, thereby dividing the load on the rolling elements 17 and their support surfaces, resulting in a longer service life, as shown in detail in Figures 4a and 4b.

[0043] Advantageously, the bush 14 has a lead-in shaped entrance portion, which includes an edge 21 that brings together the circular cylindrical inner surface 20 and provides a transition to the second circular cylindrical inner surface 22. As a result, the point where the rolling element 17 is subjected to full preload is precisely defined, and the rolling element 17 is driven slowly through the conical retraction region 22. The circular cylindrical bolt 12 has a lead-in shape formed on its head so that the bolt 12 can be easily inserted into the rolling element cage 16, as will be described later.

[0044] A further advantageous embodiment of the present invention is that a locking member 40 provides individual positioning and variability of the thickness of the forming tool 2, particularly the dimensions of the plate portion of the forming tool 2, thereby enabling the bushing 14 to be positioned relative to the second mold half 5 and the bolt 12 to be positioned relative to the first mold half 1. The locking member 40 is formed as a ring or ring component 44 that can be inserted into a circumferential groove 41. This forms a series of circumferential grooves 41 that surround at least one of the bushing 14 and the bolt 12 and are formed along the axial length of at least one of the bushing 14 and the bolt 12. The ring or ring component 44 inserted into one of the circumferential grooves 41 protrudes into a groove 42 of the plate portion of the forming tool 2. The groove 42 can be formed from the shoulder between the plate portions.

[0045] As can be seen in Figure 3, the guide body 4 can similarly be fixed to the first half-body 1 via the locking member 40. The locking member 40 is inserted into a circumferential groove 41 formed on the outer surface of the guide body 4 and protrudes between the groove portion 42 formed in the first half-body 1 or the plate portion forming the first half-body 1.

[0046] Figures 4a and 4b show a cross-section and enlarged detail of the guiding and centering device 10 when the forming tool 2 is closed. This allows the circular, cylindrical bolt 12 to enter a rolling element cage 16 located within a bush 14 via positioning means 30 formed as a spring element 31 (not shown) and a retainer element 32. The bush 14 has a circular, cylindrical inner surface 20 joined at an edge 21. Adjacent to the edge 21, a transition region is configured to transition from the edge 21 to a second circular, cylindrical inner surface 22 having a larger diameter than the circular, cylindrical inner surface 20. The transition region between the inner surfaces 20 and 22 may preferably be formed with a curvature or roundness that matches the roundness of the rolling element 17. Furthermore, the circular, cylindrical bolt 12 has a circular circumferential surface 52 fastened by an edge 51. Adjacent to the edge 51, the head of the bolt 12 is formed from a conical retraction region 50, which provides a lead-in shape.

[0047] When the mold 2 is closed, the circular, cylindrical bolt 12 enters the rolling element cage 16 in a lead-in shape formed from the conical retraction region 50. As can be seen in Figure 4a, the bolt 12 passes over the first row 18.1 of rolling elements 17 arranged in the rolling element cage 16. This is because the rolling elements 17 in the first row 18.1 are located in the region of the second circular, cylindrical inner surface 22, particularly the region of the edges 21, and are therefore related to the bushings 14 which are in a recessed position. As the circular, cylindrical bolt 12 advances further, the edge 51 of the bolt 12 comes into contact with the second row 18.2 of rolling elements 17 arranged within the rolling element cage 16. As soon as the edge 51 of the bolt 12 passes over the rolling elements 17 of the first row 18.1, these rolling elements 17 begin to rotate, pushing the rolling element cage 16 into the bush 14 and moving the rolling elements 17 of the second row 18.2, as can be seen in Figure 4b. In this arrangement, the rolling elements 17 of the first row 18.1 and the rolling elements 17 of the second row 18.2 are subjected to pre-tensioning substantially simultaneously, thereby allowing the load to be divided.

[0048] In the further closing step of the forming tool 2, the circular, cylindrical bolt 12 passes over the rolling elements 17 of an additional row 18 arranged within the rolling element cage 16. In the fully closed position of the forming die 2, the circular, cylindrical bolt 12 is pushed into the rolling element cage 16, and as a result, the centering force is transmitted from the rolling elements 17 of the rolling element cage 16. By opening the forming die 2, the bolt 12 is pulled out from the bush 14, and the rolling element cage 16 is thus positioned to allow the next centering step to be performed in an optimal manner.

[0049] In Figure 5, the locking member 40 is shown in perspective. The locking member 40 is formed from two halves of a ring 44. The ring 44 provides a circumferential slot 45 into which a seal ring 46 is inserted to hold the two halves of the ring together. This arrangement allows for easy placement of the bushing 14 in a predetermined position on the second mold half 5 and the bolt 12 in a predetermined position on the first mold half 1. Thus, the guiding and centering device 10 can be adapted to different dimensions of the plate portion of the mold 2, providing a universally applicable guiding and centering device with optimal centering and guiding characteristics.

Claims

1. A guiding and centering device (10) for a molding tool (2), in particular an injection molding or die casting tool, comprising a first mould half (1) and a second mould half (5) which are guided by a guiding means (7) from a closed position, in which the respective parting faces of both mould halves (1, 5) are pressed against one another, to an open position and from said open position to said closed position, said guiding and centering device (10) comprising: a protruding guide body (4) formed as a circular cylindrical bolt (12) provided on the first mould half (1); a guide groove (6) formed as a bush (14) and provided with a circular cylindrical inner surface (20) in the second mould half (5); a rolling element cage (16) in which rolling elements (17) are inserted in a number of rows (18), by means of which the two mould halves (1, 5) are guided and precisely centred in said closed position; Equipped with 1. The guiding and centering device (10), characterized in that the rolling element cage (16) is supported by the circular, cylindrical inner surface (20) of the bush (14) and is positioned via positioning means (30) in such a way that, when closing the forming tool, the circular, cylindrical bolt (12) enters the first row of rolling elements (18.1) and the second row of rolling elements (18.2) of the rolling element cage (16) substantially simultaneously.

2. A guiding and centering device (10) for a forming tool (2) as described in claim 1, characterized in that the positioning means (30) is formed from a spring element (31) and an axial retainer element (32) between which the rolling element cage (16) is arranged axially within the bushing (14).

3. A guiding and centering device (10) for a forming tool (2) as described in claim 1 or 2, characterized in that at least one end of the circular cylindrical inner surface (20) of the bushing (14) is provided with at least one groove (33), into which a circlip (34) can be inserted to axially position the positioning means (30).

4. A guiding and centering device (10) for a forming tool (2) according to any one of claims 1 to 3, characterized in that at least one shoulder is formed in at least one end portion of the circular, cylindrical inner surface (20) of the bush (14) forming a support for the positioning means (30).

5. The bushing (14) is connected to the second mold half (5) via a locking member (40), the locking member (40) being: a bushing (14) that is insertable into one of a series of circumferential grooves (41) that surround the bushing (14) and are formed along the axial length of the bushing (14); It protrudes into a groove (42) formed in the second mold half (5). A guiding and centering device (10) for a forming tool (2) according to any one of claims 1 to 4, characterized in that it comprises:

6. The circular cylindrical bolt (12) is connected to the first mold half (1) via a locking member (40), the locking member (40) being a series of circumferential grooves (41) surrounding the bolt (12) and formed along the axial length of the bolt (12); It protrudes into a groove (42) formed in the first mold half (1). A guiding and centering device (10) for a forming tool (2) according to one of the claims 1 to 5, characterized in that it is

7. A guiding and centering device (10) for a forming tool (2) as described in claims 5 and 6, characterized in that the locking member (40) is formed from a circlip (34).

8. A guiding and centering device (10) for a forming tool (2) as described in claims 5 and 6, characterized in that the locking member (40) is formed from two ring parts (44) with a circumferential slot (45), the two ring parts (44) being connected to each other via a sealing ring (46) insertable into the slot (45).

9. A guiding and centering device (10) for a forming tool (2) as described in any one of claims 1 to 8, characterized in that at least one of the bushing (14) and the circular cylindrical bolt (12) is configured with a lead-in geometric shape.

10. A guiding and centering device (10) for a forming tool (2) as described in any one of claims 1 to 9, characterized in that the circular, cylindrical bolt (12) has a conical retraction area (50) adjacent an edge (51), the retraction area (50) bringing together a circular circumferential surface (52) of the bolt (12).

11. A guiding and centering device (10) for a forming tool (2) as described in any one of claims 1 to 10, characterized in that the circular, cylindrical inner surface (20) of the bushing (14) is brought together by an edge (21) and, adjacent to the edge (21), a second circular, cylindrical inner surface (22) having a larger diameter than the circular, cylindrical inner surface (20) is formed.

12. A guiding and centering device (10) for a forming tool (2) as described in Claim 11, characterized in that the edge portion (21) transitions from the circular, cylindrical inner surface (20) to the second circular, cylindrical inner surface (22) having a curvature adapted to the curvature of the rolling element (17).

13. A guiding and centering device (10) for a forming tool (2) as described in any one of claims 1 to 12, characterized in that the rolling elements (17) are rollers or balls.

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