Axis pin force sensor

Abstract

The present invention relates to a pin force sensor. The pin force sensor comprises an elastic shaft, a cup structure and a sensitive detection circuit. The elastic shaft has a mounting hole that passes through the elastic shaft. The axial direction of the mounting hole intersects with the longitudinal direction of the elastic shaft. The cup structure is installed inside the mounting hole. The cup structure has a first end face and a second end face that are opposite to each other in the axial direction of the mounting hole. The first end face is recessed inward to form an inner cavity. The sensitive detection circuit is formed at a position where the second end face is opposite to the inner cavity by means of coating photolithography. The above-mentioned pin force sensor takes into account both a longer service life and better long-term stability.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to an axle pin force sensor. Background Art

[0002] Axle pin force sensors are widely used in mechanical products, test and detection, and are mainly used for overload control or load research. At present, there are two main types of common axle pin force sensors at home and abroad, mainly involving shear stress and bending normal stress. In traditional axle pin force sensors, a groove is directly opened on the elastic shaft, and the resistance strain gauge is glued into the groove with glue. Usually, the resistance strain gauge is directly glued to the elastic shaft to form a Wheatstone bridge, which is convenient for subsequent force value detection.

[0003] However, due to the defects of this patch technology such as poor stability, large drift, easy aging of adhesive, and difficulty in patching, the axle pin force sensor has problems such as poor long-term stability and short service life. Summary of the invention

[0004] Based on this, it is necessary to provide a pin force sensor that has higher detection accuracy, better long-term stability and longer service life to address the problems of poor long-term stability and short service life of traditional pin force sensors.

[0005] A shaft pin force sensor, comprising:

[0006] The elastic shaft has a mounting hole penetrating the elastic shaft; the axial direction of the mounting hole intersects with the longitudinal direction of the elastic shaft;

[0007] A cup structure is installed inside the mounting hole; the cup structure has a first end face and a second end face opposite to each other in the axial direction of the mounting hole; the first end face is recessed inward to form an inner cavity;

[0008] A sensitive detection circuit is formed at a position where the second end surface is opposite to the inner cavity by means of coating photolithography.

[0009] In one embodiment, the axial direction of the mounting hole is perpendicular to the longitudinal direction of the elastic shaft.

[0010] In one embodiment, the first end surface and the second end surface are parallel to the central axis of the elastic shaft and are symmetrically arranged relative to the central axis of the elastic shaft.

[0011] In one of the embodiments, the elastic shaft is provided with an annular groove along its circumference; and the openings at both ends of the mounting hole are both located in the annular groove.

[0012] In one embodiment, the cup body structure is inserted into the mounting hole and is interference fit with the mounting hole.

[0013] In one embodiment, a first avoidance groove is provided at a position of the elastic shaft opposite to the first end surface; a second avoidance groove is provided at a position of the elastic shaft opposite to the second end surface; and the openings at both ends of the mounting hole are respectively located in the first avoidance groove and the second avoidance groove.

[0014] In one embodiment, the first avoidance groove and the second avoidance groove are both coaxially arranged with the mounting hole.

[0015] In one embodiment, a limiting groove communicating with the mounting hole is formed on the bottom wall of the first avoiding groove along the circumference of the mounting hole;

[0016] The outer wall of the cup body structure away from the second end surface is circumferentially provided with a limiting ridge; the limiting ridge is clamped in the limiting groove.

[0017] In one of the embodiments, a transition chamfer is provided at the outer edge of the first end surface; the transition chamfer is fixedly connected to the inner wall of the limiting groove by welding.

[0018] In one embodiment, the elastic shaft is provided with a plurality of mounting holes along its axial direction; the cup body structures are multiple and are respectively installed in the plurality of mounting holes in a one-to-one correspondence; and the sensitive detection circuit is formed at a portion of each second end surface corresponding to the inner cavity.

[0019] When processing the above-mentioned axle pin force sensor, a sensitive detection circuit is first formed on the second end face of the cup body structure by using the coating photolithography technology, and then the cup body structure is installed in the installation hole of the elastic shaft, which solves the problem that the current coating photolithography technology cannot be directly used for coating photolithography on the elastic shaft. By using the coating photolithography technology to grow the sensitive detection circuit on the cup body structure, the bonding force between the sensitive detection circuit and the cup body structure is greatly enhanced, and the probability of the sensitive detection circuit detaching from the cup body structure is reduced, thereby extending the service life of the axle pin force sensor. Moreover, by using the coating photolithography technology to grow the sensitive detection circuit on the cup body structure, the stability of the axle pin force sensor can be improved. Even under high pressure, the drift of the axle pin force sensor is extremely small; even at high operating temperatures, the axle pin force sensor has high stability and extremely small zero temperature drift. Therefore, the above-mentioned axle pin force sensor has high long-term stability and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the axle pin force sensor in a preferred embodiment of the present invention;

[0021] Figure 2 for Figure 1AA section view of the shaft pin force sensor shown;

[0022] Figure 3 It is a schematic diagram of the structure of an elastic shaft in one embodiment of the present invention;

[0023] Figure 4 for Figure 3 BB section view of the elastic shaft shown;

[0024] Figure 5 It is a schematic structural diagram of an elastic shaft in another embodiment of the present invention;

[0025] Figure 6 for Figure 1 Schematic diagram of the structure of the cup structure in the axle pin force sensor shown.

[0026] Explanation of reference numerals: 100, axle pin force sensor; 110, elastic shaft; 111, mounting hole; 112, annular groove; 113, first avoidance groove; 114, second avoidance groove; 115, limiting groove; 120, cup body structure; 121, first end face; 122, second end face; 123, inner cavity; 124, limiting ridge; 125, transition chamfer. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] When describing positional relationships, unless otherwise specified, when an element is referred to as being "on" another element, it can be directly on the other element or there can be an intermediate element. It is also understood that when an element is referred to as being "between" two elements, it can be the only one between the two elements, or there can be one or more intermediate elements.

[0030] In the case of using “including”, “having”, and “comprising” described herein, another component may be added unless a clear limiting term such as “only”, “consisting of”, etc. is used. Unless mentioned otherwise, a term in the singular form may include a plural form and should not be understood as being one in number.

[0031] In addition, the drawings are not drawn to a 1:1 scale, and the relative sizes of the elements in the drawings are drawn only as examples and not necessarily according to the true scale.

[0032] Figure 1 and Figure 2 The figure shows a schematic diagram of the structure of the axle pin force sensor in one embodiment of the present invention. For the convenience of description, the figure only shows the structure related to the embodiment of the present invention.

[0033] See also Figure 1 and Figure 2 The pin force sensor 100 in the preferred embodiment of the present invention includes an elastic shaft 110, a cup structure 120 and a sensitive detection circuit (not shown).

[0034] Please also read Figures 3 to 5 , the elastic shaft 110 has a mounting hole 111 that passes through the elastic shaft 110. The axial direction of the mounting hole 111 intersects with the longitudinal direction of the elastic shaft 110. It should be noted that the axial direction of the mounting hole 111 intersects with the longitudinal direction of the elastic shaft 110 means that the axial direction of the mounting hole 111 is perpendicular to or crosses the longitudinal direction of the elastic shaft. Among them, the mounting hole 111 is a through hole that passes through the elastic shaft.

[0035] Please also read Figure 6 , the cup body structure 120 is installed inside the mounting hole 111. The cup body structure 120 has a first end face 121 and a second end face 122 opposite to each other in the axial direction of the mounting hole 111. The first end face 121 is recessed inward to form an inner cavity 123. Among them, the cup body structure 120 is a hollow structure with one end open, such as a cup or a cylinder. The cup body structure 120 can be installed inside the mounting hole 111 by means of clamping, welding, etc. Specifically, the cup body structure 120 is a cylindrical structure or a cubic structure. The mounting hole 111 is a through hole that matches the cup body structure 120.

[0036] The sensitive detection circuit is formed by coating photolithography at the position where the second end surface 122 and the inner cavity 123 are opposite. In practical applications, the cup structure 120 undergoes elastic deformation under the axial force transmitted by the elastic shaft 110. At this time, the sensitive detection circuit collects strain information of the cup structure 120 to facilitate the subsequent acquisition of the axial force value.

[0037] During the processing of the pin force sensor 100, a sensitive detection circuit is first formed on the second end face 122 of the cup body structure 120 using coating photolithography technology, and then the cup body structure 120 is installed in the mounting hole 111 of the elastic shaft 110 to solve the problem that the current coating photolithography technology cannot directly perform coating photolithography on the elastic shaft 110. The sensitive detection circuit is successfully formed on the elastic structure composed of the elastic shaft 110 and the cup body structure 120 by coating photolithography.

[0038] Since the cup structure 120 is located inside the mounting hole 111, the height of the cup structure 120 is less than the diameter of the elastic shaft 110 in the axial direction of the mounting hole 111, and the strain of the cup structure 120 is greater than that of the elastic shaft 110. Furthermore, the thickness of the second end surface 122 at the position opposite to the inner cavity 123 is relatively small, which further increases the strain. When the elastic shaft 110 is subjected to a relatively small axial force, the portion of the cup structure 120 where the sensitive detection circuit is set will undergo elastic deformation, so that the sensitive detection circuit can quickly and accurately obtain the strain information of the cup structure 120, so that the detection accuracy and sensitivity of the shaft pin force sensor 100 are higher.

[0039] Furthermore, through the coating photolithography technology, the sensitive detection circuit can be grown on the cup body structure 120, which greatly improves the bonding force between the sensitive detection circuit and the cup body structure 120, reduces the probability of the circuits, resistors and other components in the sensitive detection circuit detaching from the cup body structure 120, and effectively extends the service life of the axle pin force sensor 100.

[0040] In addition, the sensitive detection circuit is grown on the cup structure 120 by using the coating photolithography technology, which can improve the stability of the pin force sensor 100. Even under high pressure, the drift of the pin force sensor 100 is very small; even under high operating temperature, the pin force sensor 100 has high stability and very small zero temperature drift. Therefore, the pin force sensor 100 has high long-term stability and a long service life.

[0041] In some embodiments, the axial direction of the mounting hole 111 is perpendicular to the longitudinal direction of the elastic shaft 110. Therefore, the axial direction of the mounting hole 111 is consistent with the diameter direction of the elastic shaft 110, and the side of the cup structure 120 is perpendicular to the axial direction of the elastic shaft 110, so that the axial force on the elastic shaft 110 can be vertically transmitted to the side of the cup structure 120, so as to further increase the strain of the cup structure 120, thereby making the measurement accuracy of the pin force sensor 100 higher.

[0042] Furthermore, in some embodiments, the first end face 121 and the second end face 122 are parallel to the central axis of the elastic shaft 110 and are symmetrically arranged relative to the central axis of the elastic shaft 110. In this way, under the action of the pin force on the elastic shaft 110, the portion of the cup structure 120 where the sensitive detection circuit is arranged is more likely to deform, further increasing the strain amount of the portion of the cup structure 120 where the sensitive detection circuit is arranged, and further improving the measurement accuracy of the pin force sensor 100.

[0043] Please refer again Figure 1 , Figures 3 to 5 In some embodiments, the elastic shaft 110 is provided with an annular groove 112 along its circumference. The openings at both ends of the mounting hole 111 are both located in the annular groove 112. In this way, the provision of the annular groove 112 can reduce the diameter of the elastic shaft 110 at the mounting hole 111, making it easier for the elastic shaft 110 to deform. When the elastic shaft 110 is deformed at the mounting hole 111, the cup structure 120 will inevitably deform to a certain extent. Therefore, the provision of the annular groove 112 can further increase the strain of the elastic structure composed of the elastic shaft 110 and the cup structure 120, and further improve the measurement accuracy of the pin force sensor 100.

[0044] In some embodiments, the cup structure 120 is inserted into the mounting hole 111 and has an interference fit with the mounting hole 111. The interference fit between the cup structure 120 and the mounting hole 111 enables the elastic shaft 110 to apply an inward extrusion force to the side of the cup structure 120, so that the cup structure 120 and the elastic shaft 110 are more tightly connected, and the connection stability between the cup structure 120 and the elastic shaft 110 is improved, which not only reduces the probability of the cup structure 120 and the elastic shaft 110 being separated, but also further improves the stability of the shaft pin force during use, so that the long-term stability of the shaft pin force sensor 100 is higher and the service life is longer.

[0045] In some embodiments, a first avoidance groove 113 is provided at a position where the elastic shaft 110 is opposite to the first end face 121. A second avoidance groove 114 is provided at a position where the elastic shaft 110 is opposite to the second end face 122. The openings at both ends of the mounting hole 111 are respectively located in the first avoidance groove 113 and the second avoidance groove 114. Specifically, the first avoidance groove 113 and the second avoidance groove 114 are located opposite to each other, and the opening directions are opposite to each other. Among them, the first avoidance groove 113 and the second avoidance groove 114 can be circular grooves, rectangular grooves, oval grooves, etc.

[0046] Since the openings at both ends of the mounting hole 111 are respectively located in the first avoidance groove 113 and the second avoidance groove 114, the presence of the first avoidance groove 113 and the second avoidance groove 114 further reduces the depth of the mounting hole 111, thereby reducing the height of the cup body structure 120, further improving the strain of the cup body structure 120, and thus making the measurement accuracy of the axle pin force sensor 100 smaller. In addition, the provision of the first avoidance groove 113 and the second avoidance groove 114 increases the operating space for the installation of the cup body structure 120 in the mounting hole 111, so as to facilitate the installation of the cup body structure 120.

[0047] Please refer again Figure 3 and Figure 5 It should be noted that, in the embodiment of the present invention, the elastic shaft 110 may be provided with only the annular groove 112, or only the first avoidance groove 113 and the second avoidance groove 114, or may be provided with the annular groove 112, the first avoidance groove 113 and the second avoidance groove 114 at the same time. When the annular groove 112, the first avoidance groove 113 and the second avoidance groove 114 are provided on the elastic shaft 110 at the same time, the first avoidance groove 113 and the second avoidance groove 114 at least partially overlap with the annular groove 112.

[0048] Furthermore, in some embodiments, the first avoidance groove 113 and the second avoidance groove 114 are both coaxially arranged with the mounting hole 111. In this way, the axial force received by the elastic shaft 110 can be more evenly transmitted to the cup structure 120, so that the sensitive detection circuit can collect more accurate strain information, further improving the measurement accuracy of the shaft pin force sensor 100.

[0049] In some embodiments, a limiting groove 115 connected to the mounting hole 111 is provided on the bottom wall of the first avoiding groove 113 along the circumference of the mounting hole 111. A limiting rib 124 is provided along the circumference of the outer wall of the cup body structure 120 away from the second end face 122. The limiting rib 124 is engaged in the limiting groove 115. When the cup body structure 120 is installed in the mounting hole 111, the limiting rib 124 is engaged in the limiting groove 115 to limit the axial position of the cup body structure 120 in the mounting hole 111, thereby improving the installation accuracy of the cup body structure 120, which is conducive to further improving the measurement accuracy of the shaft pin force sensor 100.

[0050] Please refer again Figure 2 and Figure 6Furthermore, in some embodiments, a transition chamfer 125 is provided at the outer edge of the first end face 121. The transition chamfer 125 is fixedly connected to the inner wall of the limiting groove 115 by welding. Specifically, the transition chamfer 125 is fixed to the inner wall of the limiting groove 115 by laser welding. Wherein, the setting of the transition chamfer 125 allows the melted solder to flow between the transition chamfer 125 and the inner wall of the limiting groove 115 during the welding process to improve the welding effect. Moreover, by welding, the connection stability between the cup structure 120 and the elastomer can be further improved.

[0051] It should be noted that the cup body structure 120 can be fixed only by welding or by interference fit. In order to improve the stability of the cup body structure 120, it can also be fixed by welding while using interference fit.

[0052] Please refer again Figure 1 In some embodiments, the elastic shaft 110 is provided with a plurality of mounting holes 111 along its axial direction. There are a plurality of cup structures 120, which are respectively installed in the plurality of mounting holes 111 in a one-to-one correspondence. A sensitive detection circuit is formed at the portion corresponding to the second end surface 122 and the inner cavity 123 of each cup structure 120. The provision of a plurality of cup structures 120 can form a plurality of sensitive detection circuits on the elastic shaft 110, which helps to further improve the measurement accuracy of the shaft pin force sensor 100, and can also increase the measurement width of the shaft pin force sensor 100.

[0053] When the elastic shaft 110 is provided with an annular groove 112, the annular grooves 112 are multiple and correspond to the multiple mounting holes 111. When the elastic shaft 110 is provided with a first avoidance groove 113 and a second avoidance groove 114, each mounting hole 111 has a first avoidance groove 113 and a second avoidance groove 114 at both ends.

[0054] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A pin force sensor, characterized in that: include: The elastic shaft has a mounting hole penetrating the elastic shaft; the axial direction of the mounting hole intersects with the longitudinal direction of the elastic shaft; A cup structure is installed inside the mounting hole; the cup structure has a first end face and a second end face opposite to each other in the axial direction of the mounting hole; the first end face is recessed inward to form an inner cavity; A sensitive detection circuit is formed at a position of the second end surface opposite to the inner cavity by means of coating photolithography; Among them, a first avoidance groove is provided at a position where the elastic shaft is opposite to the first end face; a second avoidance groove is provided at a position where the elastic shaft is opposite to the second end face; openings at both ends of the mounting hole are respectively located in the first avoidance groove and the second avoidance groove; a limiting groove connected to the mounting hole is provided on the bottom wall of the first avoidance groove along the circumference of the mounting hole; a limiting ridge is protruded along the circumference of the outer wall of the cup body structure away from the second end face; the limiting ridge is clamped in the limiting groove.

2. The pin force sensor according to claim 1, characterized in that: The axial direction of the mounting hole is perpendicular to the longitudinal direction of the elastic shaft.

3. The pin force sensor according to claim 2, characterized in that: The first end surface and the second end surface are both parallel to the central axis of the elastic shaft and are symmetrically arranged relative to the central axis of the elastic shaft.

4. The pin force sensor according to claim 1, characterized in that: The elastic shaft is provided with an annular groove along its circumference; the openings at both ends of the mounting hole are both located in the annular groove.

5. The axle pin force sensor according to claim 1, characterized in that: The cup body structure is inserted into the mounting hole and is interference fit with the mounting hole.

6. The axle pin force sensor according to claim 1, characterized in that: The first avoidance groove and the second avoidance groove are both coaxially arranged with the mounting hole.

7. The pin force sensor according to claim 1, characterized in that: The outer edge of the first end surface is provided with a transition chamfer; the transition chamfer is fixedly connected to the inner wall of the limiting groove by welding.

8. The pin force sensor according to claim 1, characterized in that: The elastic shaft is provided with a plurality of mounting holes along its axial direction; there are a plurality of cup structures, which are respectively installed in the plurality of mounting holes in a one-to-one correspondence; and the sensitive detection circuit is formed at a portion of each second end surface corresponding to the inner cavity.

Images