Measurement probe
The non-circular hole design with a groove and clamped object mechanism addresses the unreliable connections in measuring probes by ensuring a stable, vibration-resistant assembly through a simple and reliable alignment process.
Patent Information
- Application Number
- JP2025061067
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-04-03
- Filing Date
- 2025-04-02
- Publication Date
- 2025-10-16
AI Technical Summary
Existing measuring probes face issues with unreliable connections due to misalignment and loosening of components under vibration and shock loads, leading to high reject rates and assembly challenges.
A non-circular hole design with a groove and clamped object mechanism allows for a reliable, axially parallel connection of parts by rotating the second part relative to the first part, using a clamped object to secure alignment and facilitate a materially bonded connection.
Ensures a stable, simple, and reliable assembly of measuring probe components, reducing misalignment and loosening issues, and enabling a secure, vibration-resistant connection without external retaining means.
Smart Images
Figure 2025158107000001_ABST
Abstract
Description
[Technical Field]
[0001] The invention relates to a measurement probe according to the preamble of claim 1 . [Background technology]
[0002] Measuring probes are typically contact distance sensors that provide an electrical signal proportional to the measured distance, which can be further processed by downstream electronic evaluation equipment. Such measuring probes are used, inter alia, in production metrology to perform a wide variety of tasks within the framework of quality assurance.
[0003] Measuring probes operating on the Abbe principle are known from the prior art. Such measuring probes generally have an elongated base body within which a measuring bolt is arranged, with a probe element at its free end. The measuring bolt is guided axially relative to the base body by a guide and is protected from dirt by a bellows between the guide and the probe element. In the case of such measuring probes, the measuring bolt guide is inserted into a through-hole in the base body during manufacture and, for example, glued to the base body. The diameter of this through-hole is preferably selected to be large enough to allow the adhesive to develop its adhesive and cohesive properties to the required extent. However, this exposes the guide in the hole to a certain degree of play until the adhesive has fully hardened. This results in a high reject rate, because, sporadically, the axis of the guide is no longer aligned parallel to the axis of the hole after the adhesive has hardened.
[0004] Alternatively, the guide can also be pressed into the bore of the base body by a press fit, so that the axis of the guide is aligned with the axis of the bore of the base body. In practice, however, this measure has proven to be disadvantageous, since measuring probes are often exposed to environments with high vibration and shock loads, which can loosen the press fit between the guide and the base body in the medium and long term. Summary of the Invention [Problem to be solved by the invention]
[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved measuring probe which has a simple construction and in which a more reliable connection of the individual parts is achieved. [Means for solving the problem]
[0006] This problem is solved according to the invention by the features of claim 1. Advantageous configurations and variants are respectively set out in the dependent claims. The measurement probe according to the present invention includes a first part and a second part. The first part includes a non-circular hole having a first axis. The second part is cylindrical and has a second axis. The second part extends axially into the non-circular hole of the first part. The non-circular hole is formed so that the second part can be fitted into the non-circular hole along at least two contact surfaces of the first part, axially parallel to the first axis of the non-circular hole. The first part has a groove extending circumferentially around the non-circular hole. The measurement probe has at least one clamped object that can be accommodated in the groove. By rotating the second part relative to the first part, the clamped object accommodated in the groove achieves removably fixing of the second part to at least the contact surface of the first part. At this time, the second axis of the second part is aligned parallel to the first axis of the non-circular hole.
[0007] According to one advantageous variant of the invention, the groove comprises at least a first section which narrows in the circumferential direction in the radial direction relative to the first axis, and the groove additionally comprises a further section which widens in the radial direction relative to the first axis, so that the clamped body barely or instead does not interlock with the first and second parts.
[0008] In a further embodiment, the clamped object and groove are configured such that the clamped object can be moved within the groove by rotating the second part relative to the first part. By rotating in a first direction, the clamped object causes clamping or locking between the first and second parts within the first section. The clamped object is carried from the further section to the first section by rotating in the first direction. This clamping can then be released again by carrying the clamped object from the first section to the further section. This occurs by rotating the second part relative to the first part in a second direction opposite to the first direction.
[0009] Advantageously, the contact surfaces are configured to define at least first and second gaps between the first and second parts, the gaps being configured to be sufficient to accommodate means for forming a materially bonded connection between the first and second parts.
[0010] Preferably, the contact surface extends axially along the entire depth of the non-circular bore. In a further embodiment, the cross section of the non-circular bore is formed mirror-symmetrically, the contact surfaces are each formed in the form of a secant section, and the cross section of the non-circular bore otherwise extends as a contour with a constant radius relative to the first axis.
[0011] The cross section of a non-circular hole therefore consists of a circular contour extending partly circularly at a constant radius, which is made partly non-circular by two secants. Within the non-circular hole, the overlap area of the first and second components is preferably less than 2.5 times the diameter of the second component in the axial direction, or alternatively less than 1 time.
[0012] Advantageously, the clamped body is a rounded wedge or a body of revolution, in particular in the form of a sphere or cylinder. The groove and contact surface are preferably arranged in the non-circular bore so that they are radially opposed relative to the first axis.
[0013] By radially opposed, it is meant that the groove is located in one half of the non-circular hole and the contact surface is located in the other half of the non-circular hole. Furthermore, it is advantageous if the contact surfaces each have an angular distance to the first section with a value between 110° and 140°.
[0014] In this respect, for the contact surface, the impact point or impact line at which the cylindrical side surface of the second part strikes the surface of the contact surface is of importance. Advantageously, the first section and the contact surface each have an angular distance relative to one another of a value of 120°.
[0015] The invention will be explained in more detail below with respect to further features and advantages on the basis of the description of exemplary embodiments and with reference to the accompanying schematic drawings. [Brief explanation of the drawings]
[0016] [Figure 1] FIG. 2 is a perspective view of a measurement probe. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of mated first and second components. [Figure 3] FIG. 3 is a detailed view of the vertical cross section of FIG. 2. [Figure 4] 1 is a cross-sectional view of the region of the groove of one exemplary embodiment in which the first and second parts are mated, where the clamped body is in a further section. [Figure 5] 1 is a cross-sectional view of the groove area of one exemplary embodiment where the first and second parts are mated, and where the clamped body is in the first section. [Figure 6] FIG. 5 is a schematic diagram of optimal wedge point and contact surface angular positions according to the exemplary embodiment of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION
[0017] In the following, an embodiment of the present invention will be explained more precisely with reference to the figures. 1 shows in perspective a measuring probe 1 with a first housing element 2 and a second housing element 3. A measuring bolt passes through the second housing element 3, which is formed as a hollow shaft, and a probe element is attached to the end of the measuring bolt. Between the second housing element 3 and the probe element, the measuring bolt is protected from external dirt by a bellows.
[0018] As can be inferred from Figure 2, the first part 2 includes a non-circular hole 4 that extends partially into the first part 2. The non-circular hole 4 has a first axis A that passes through the center of the non-circular hole 4. The second part 3 is cylindrically shaped on its outside and has a second axis B. The second part 3 extends partially into the non-circular bore 4 of the first part 2, such that the first axis A of the non-circular bore 4 and the second axis B of the second part 3 are parallel, in particular coaxial.
[0019] Within the non-circular hole 4 there is a groove 7 which serves as a receiving section for a clamped object 8. This groove 7 extends radially relative to the axis A and in the circumferential direction U within the side surface of the non-circular hole 4. In the exemplary embodiment shown, a sphere is used as the clamped body 8, but other geometric shapes, for example in the form of a cylinder or a round wedge, are also suitable for forming a friction stop between the first and second parts 2, 3.
[0020] As can be seen from Fig. 3, the non-circular hole 4 is configured such that a loose fit exists between the first and second parts 2, 3 in the unclamped state. In this regard, it is advantageous if the clamped body 8 forms a frictional stop between the first and second parts 2, 3, thereby forming at least a first gap 5.1 and a second gap 5.2 between the first and second parts 2, 3. Both gaps 5.1, 5.2 should have a width in the radial direction relative to the axis A such that the material-bonding means 6, e.g., adhesive, can optimally develop its adhesive and cohesive properties. In the illustrated exemplary embodiment, the first gap 5.1 and the second gap 5.2 each have a width of approximately 50 µm, and in this regard Fig. 3 is not drawn to scale.
[0021] 3, the non-circular hole 4 does not extend entirely through the first part 2, thereby forming an abutment surface 4.1. When manufacturing the measurement probe 1, the second part 3 is inserted into the non-circular hole 4 of the first part 2 until the bottom surface of the second part 3 comes into contact with the abutment surface 4.1, thereby forming an overlap area 9 of the first and second parts 2, 3.
[0022] The overlapping region 9 extending in the axial direction (z-direction) can in this measuring probe 1 in particular be shorter than 2.5 times the diameter of the second part 3. As shown in Figure 3, the overlapping region 9 can even be shorter than 1 time the diameter of the second part 3. A clamping mechanism, which will be explained in more detail below, allows a reliable axially parallel connection of the first and second parts 2, 3 even with such a short mating length.
[0023] Since the groove 7 is arranged in the non-circular hole 4, the groove 7 is within the overlap region 9. In addition, it is advantageous if the groove 7 is centered in the z-direction within the overlap region 9. This allows the pressing force generated by the self-locking connection between the clamped body 8 and the first and second parts 2, 3 to optimally act on the second part 3, thereby pressing the second part 3 against the contact surfaces 2.1, 2.2. The contact surfaces 2.1, 2.2 extend in the z-direction at least across the overlap region 9, and preferably even along the entire hole depth of the non-circular hole 4.
[0024] As can be gathered from Figures 4 and 5, the groove 7 extends over a defined sector of the non-circular hole 4. According to the exemplary embodiment in Figures 4 and 5, the groove 7 has a curvature that varies in the circumferential direction U, whereby the groove 7 is formed asymmetrically with respect to a plane of symmetry running radially relative to the first axis A. The groove 7 can be divided in the circumferential direction U into a first section 7.1 that narrows radially relative to the axis A and a further section 7.3 that widens radially.
[0025] In the first section 7.1, the groove 7 tapers continuously over the entire length of this first section 7.1 until it finally merges into the non-circular hole 4, i.e. the groove 7 ends as soon as its radius coincides with the radius of the non-circular hole 4. The taper angle is preferably selected to be less than or equal to the arctangent of the sliding friction coefficient.
[0026] The further section 7.3 is formed to be wider in the radial direction so that the clamped body 8 barely fits into the first and second parts 2, 3, i.e., in the further section 7.3, the radius of the groove 7 is the same as the radius of the non-circular hole 4 plus the diameter of the clamped body 8. However, the further section 7.3 can alternatively be formed to be larger in the radial direction so that the clamped body 8 is completely accommodated, i.e., the radius of the groove 7 in the further section 7.3 is larger than the radius of the non-circular hole 4 plus the diameter of the clamped body 8. In this case, the parts 2, 3 to be fitted together can be aligned during the turning process as the clamped body 8 reaches the first section 7.1 of the groove 7 due to its own weight and is "carried" by frictional forces.
[0027] According to the illustrated exemplary embodiment, the further section 7.3 is adjacent to the second section 7.2 on the opposite side to the first section 7.1 in the circumferential direction U. The second section 7.2 also tapers radially relative to the first axis A, but is shorter than the first section 7.1 in the circumferential direction U. When the clamped object 8 is in the further section 7.3 and the second part 3 continues to rotate relative to the first part 2 in the second direction R2, the second section 7.2 prevents the clamped object 8 from being clamped by the first and second parts 2, 3.
[0028] However, as an alternative, an additional first section 7.1 can be formed instead of the second section 7.2. The non-circular hole 4 has a substantially circular symmetrical cross section with a first secant section forming the first contact surface 2.1 and a second secant section forming the second contact surface 2.2. The center line of symmetry therefore passes midway between the first and second secant sections and through the axis A.
[0029] The cross section of the non-circular hole 4 includes a contour with a constant radius between the first and second secant sections. The first axis A is the center point of the non-circular hole 4, and the constant radius corresponds to this first axis A.
[0030] Advantageously, both secant sections smoothly transition into a circular contour at their ends, so that no corners are formed. However, the contact surfaces 2.1, 2.2 may not be formed flat, but may instead be curved and may have a surface structure in addition to or instead of this.
[0031] As can be seen from FIG. 6, the contact surfaces 2.1 and 2.2 are located opposite the groove 7. The first contact surface 2.1 is advantageously arranged at an angular distance α of -110° to -140° relative to the first section 7.1, in particular relative to the wedge point 7.4. The second contact surface 2.2 is advantageously arranged at an angular distance β of +110° to +140° relative to the first section 7.1, in particular relative to the wedge point 7.4. The angular distance between the first and second contact surfaces 2.1 and 2.2 is therefore γ of 80° to 140°. The impact point where the cylindrical side of the second part 3 comes into contact with the surfaces of the contact surfaces 2.1 and 2.2 is of interest in this regard. This is generally the point on the contact surfaces 2.1 and 2.2 where the distance between the center of the non-circular hole 4 and the surfaces of the contact surfaces 2.1 and 2.2 is minimal.
[0032] It is particularly advantageous if the contact surfaces 2.1, 2.2 have an angular distance of 120° between them and at the same time an angular distance of 120° relative to the first section 7.1, in particular relative to the wedge point 7.4, i.e. if both contact surfaces 2.1, 2.2 and the first section 7.1 or the wedge point 7.4 are evenly distributed over the entire angular range of 360° (α=β=γ=120°). This ensures optimal support of the cylindrical second part 3 and ensures its centered positioning.
[0033] In the following, with reference to Figures 4 and 5, reference will be made to a procedure or method for mating the first and second parts 2, 3 and for forming a locked, axially parallel connection of the first and second parts 2, 3 by means of a clamped body 8.
[0034] For this purpose, first, a first part 2, a second part 3, and a clamped body 8 are prepared. The first part 2 includes a non-circular hole 4 having a groove 7. The second part 3 is formed as a hollow shaft having a side surface and an annular bottom surface at the end face of the second part 3. The clamped body 8 is formed as a sphere.
[0035] First, the clamped object 8 is placed in the groove 7. This placement of the clamped object 8 preferably takes place in the region of the further section 7.3 of the groove 7. The second part 3 is then inserted into the first part 2. For this, the second part 3 is inserted axially into the non-circular hole 4 of the first part 2 until the bottom surface of the second part 3 touches the abutment surface 4.1 of the first part 2, forming an overlap area 9. During this insertion process, the second part 3 can be rotated in a second direction R2 about the second axis B relative to the first part 2 (see FIG. 4). This has the beneficial effect that the clamped part 8 does not accidentally reach the first section 7.1 of the groove 7 during the insertion process, or that if the clamped part 8 does reach the first section 7.1, it is removed from there.
[0036] After the two parts 2, 3 are mated, the second part 3 is rotated relative to the first part 2 in a first direction R1 (see FIG. 5). Friction occurs at least between the second part 3 and the clamped part 8, causing the clamped part 8 to move in the direction of the tapered section 7.1 and become caught between the first and second parts 2, 3. As soon as the clamped part 8 reaches the wedge point 7.4, locking occurs, and a sufficiently large radial pressure acts, pressing the second part 3 against the contact surfaces 2.1, 2.2 of the first part 2. The result is an axially parallel alignment of the second axis B of the second part 3 with the first axis A of the non-circular bore 4. Thus, the second part 3 is aligned axially with respect to the axis A of the non-circular bore 4 in a single operation and simultaneously locked without the need for external retaining means.
[0037] This clamping is released by rotating the second part 3 relative to the first part 2 in a second direction R2, i.e., opposite to the first direction R1 (see FIG. 4), which causes the clamped body 8 to move from the wedge point 7.4 in the direction of the further section 7.3, thereby releasing the clamping.
[0038] If a permanent, axially parallel connection between the first and second parts 2, 3 is to be formed, a material-binding means 6, for example an adhesive, is applied before the first and second parts 2, 3 are mated together. Suitable surfaces include the wall surfaces of the non-circular hole 4 and, additionally or instead, the outer surface of the second part 3. In this case, the locked, axially parallel mating of both parts 2, 3 allows the material-binding means to harden completely without the need for external retaining means. [Explanation of symbols]
[0039] 1 measuring probe 2. First part 2.1 First contact surface 2.2 Secondary contact surface 3 Second part 4 Non-circular holes 4.1 Contact surface 5.1 First gap 5.2 Second gap 6 Material combination type means 7 grooves 7.1 First Section 7.2 Second Section 7.3 Further Sections 7.4 Wedge Points 8 Object to be held 9 Overlapping Areas A First axis B Second axis R1 First Direction R2 Second direction U circumferential direction
Claims
1. A measurement probe (1) comprising a first part (2) and a second part (3), the first part (2) includes a non-circular hole (4) having a first axis (A); the second part (3) is cylindrically shaped and has a second axis (B), the second axis (B) extending into the non-circular hole (4) of the first part (2); The non-circular hole (4) is formed in such a way that the second part (3) can be fitted in the non-circular hole (4) along at least two contact surfaces (2.1, 2.2) of the first part (2) axially parallel to the first axis (A) of the non-circular hole (4), the first part (2) has a groove (7) in the non-circular hole (4) extending in the circumferential direction (U) of the non-circular hole (4); The measuring probe (1) has at least one clamped body (8) that can be accommodated in the groove (7); and a second axis (B) of the second part (3) being aligned parallel to the first axis (A) of the non-circular hole (4), the ...
2. 2. The measuring probe (1) of claim 1, wherein the groove (7) has at least a first section (7.1) in the circumferential direction (U) that gradually narrows in the radial direction relative to the first axis (A) and a further section (7.3) that widens in the radial direction relative to the first axis (A), so that the clamped body (8) barely engages or does not engage with the first and second parts (2, 3).
3. The clamped body (8) and the groove (7) are formed so that the clamped body (8) can be moved in the groove (7) by rotating the second part (3) relative to the first part (2), and thus the clamped body (8) can be moved in a first direction (R １ ), the clamped body (8) causes clamping between the first and second parts (2, 3) in the first section (7.1), and the first direction (R １ ) in a second direction (R ２ 3. The measuring probe (1) according to claim 2, wherein the clamped object (8) is conveyed from the first section (7.1) to the further section (7.3) by rotating the clamped object (8) from the first section (7.1) to the further section (7.3), thereby releasing the clamped object (8).
4. 4. The measuring probe (1) according to claim 1, wherein the contact surfaces (2.1, 2.2) are formed such that at least first and second gaps (5.1, 5.2) are formed between the first and second parts (2, 3), the gaps (5.1, 5.2) being formed to accommodate means for forming a material-bonded connection between the first and second parts (2, 3).
5. 5. Measuring probe (1) according to any one of claims 1 to 4, wherein the contact surfaces (2.1, 2.2) extend axially along the entire depth of the non-circular hole (4).
6. 6. The measuring probe (1) according to claim 1, wherein the cross section of the non-circular hole (4) is formed mirror-symmetrically, the contact surfaces (2.1, 2.2) are each formed in the form of a secant section, and the cross section of the non-circular hole (4) otherwise extends as a contour with a constant radius relative to the first axis (A).
7. 7. A measuring probe (1) according to any one of claims 1 to 6, wherein within the non-circular hole (4) the overlapping area (9) of the first and second parts (2, 3) is smaller in the axial direction than 2.5 times or 1 time the diameter of the second part (3).
8. 8. Measuring probe (1) according to any one of claims 1 to 7, wherein the clamped body (8) is a rounded wedge or a body of revolution, in particular in the form of a sphere or a cylinder.
9. 9. The measuring probe (1) according to claim 1, wherein the groove (7) and the contact surfaces (2.1, 2.2) are arranged in the non-circular hole (4) so as to face each other in a radial direction relative to the first axis (A).
10. 10. Measuring probe (1) according to any one of claims 1 to 9, wherein the contact surfaces (2.1, 2.2) each have an angular distance to the first section (7.1) of a value between 110° and 140°.
11. 11. The measuring probe (1) according to claim 10, wherein the first section (7.1) and the contact surfaces (2.1, 2.2) respectively have an angular distance relative to one another of a value of 120°.