A high-precision displacement measurement device with a constant and stable measuring force

Abstract

The present invention discloses a high-precision displacement measuring device with a constant and stable measuring force, comprising a ruler frame, a threaded tube, and a fixed anvil disposed on the ruler frame. The ruler frame is provided with a measuring rod, an elastic element, and a measuring element. One end of the measuring rod is a probe, and the probe is adapted to the fixed anvil. The elastic element is used to provide a constant measuring force to parts of the same specification through the measuring rod. The measuring element is used to measure the displacement of the measuring rod. The threaded tube is slidably sleeved on one end of the ruler frame away from the fixed anvil, and the other end of the measuring rod is transmission-connected to the threaded tube via a connecting member. When the threaded tube moves, the measuring rod is driven by the connecting member to perform linear motion along the axial direction of the measuring rod. The present invention provides the same, constant, and stable measuring force to parts of the same or different specifications to be measured through the elastic element, thereby avoiding measurement errors caused by changes in the measuring force and improving measurement accuracy.

Description

Technical Field

[0001] The present invention relates to a displacement measuring device, and particularly to a high-precision displacement measuring device with a constant and stable measuring force. Background Art

[0002] Displacement measuring devices, such as micrometers, can accurately measure lengths to 0.01 mm. Existing micrometers have the following disadvantages:

[0003] 1. Ordinary micrometers use a ratchet device. The measuring force is relatively stable when the ratchet device rotates at a constant speed, but the rotation speed of the ratchet is easily affected by external factors and fluctuates. Eventually, the generated measuring force is not stable enough, and large errors will occur when measuring the dimensions of the same part. Therefore, the measurement repeatability accuracy is relatively low.

[0004] 2. In traditional measuring tools, the measuring shaft and the driving structure are rigidly connected. There must be a gap when the driving part can move. This gap will transmit the force outside the measuring tool to the measuring shaft through the rigid connection. Therefore, the measuring rod will be skewed after being subjected to a lateral force, resulting in the loss of the original parallel accuracy between the measuring rod and the anvil, generating a parallelism error, thereby affecting the measurement accuracy. The axial force causes the measuring force to be non-constant and also affects the measurement accuracy.

[0005] 3. An excessive measuring force acting on the measuring rod will affect the accuracy of the measuring tool and damage the measured part at the same time. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a high-precision displacement measuring device with a constant and stable measuring force. By using an elastic element, the same, constant, and stable measuring force is provided for workpieces to be measured with the same or different specifications, avoiding measurement errors caused by changes in the measuring force and improving the measurement accuracy.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A high-precision displacement measuring device with a constant and stable measuring force includes a frame, a threaded tube, and a fixed anvil provided on the frame. A measuring rod, an elastic element, and a measuring element are provided inside the frame. One end of the measuring rod is a measuring head, and the measuring head is adapted to the fixed anvil;

[0009] The connecting member is used to cooperate with the threaded tube to finely adjust the measuring rod and ensure that the measuring rod can stop at any position;

[0010] The elastic element is used to cooperate with the connecting member to provide a constant measuring force for the workpiece to be measured through the measuring rod;

[0011] The measuring element is used to measure the displacement of the measuring rod;

[0012] The threaded tube is slidably sleeved on one end of the ruler frame away from the fixed measuring anvil, and the other end of the measuring rod is transmission-connected to the threaded tube via a connecting member. When the threaded tube moves, the measuring rod is driven to move linearly along the axial direction of the measuring rod via the connecting member.

[0013] Furthermore, the inner wall of the threaded tube is provided with a thread groove, the inner wall of the threaded tube is provided with a thread groove, the inside of the ruler frame is provided with a sliding seat, the sliding seat is provided with a horizontal sliding groove, the outside of the measuring rod is fixed with a connecting support, and the bottom of the connecting support is provided with a guide rod that slides with the sliding groove;

[0014] The connecting member includes a connecting seat, a first supporting sleeve and a second supporting sleeve;

[0015] The cross-section of the connecting seat is Y-shaped, and the end of the measuring rod away from the measuring head is connected to the connecting seat. The first support sleeve and the second support sleeve are annular, and the first support sleeve and the second support sleeve are coaxially arranged on the outside of the connecting seat. A plurality of first connecting holes are evenly distributed on the outer circumference of the first support sleeve, and a plurality of second connecting holes are evenly distributed on the outer circumference of the second support sleeve. A first pin and a second pin are respectively provided in the first connecting hole and the second connecting hole, and the first pin and the second pin both extend into the thread groove.

[0016] Furthermore, the first support sleeve and the second support sleeve are slidably arranged outside the support seat, and the inner circumferential surfaces of the first support sleeve and the second support sleeve are respectively provided with a mounting groove, and a first spring is provided in the mounting groove.

[0017] Furthermore, the first support sleeve and the second support sleeve are both provided with anti-rotation holes, the axes of the anti-rotation holes are parallel to the axis of the measuring rod, and the first support sleeve and the second support sleeve are connected through the anti-rotation holes and a third pin provided in the anti-rotation holes.

[0018] Furthermore, the end of the ruler frame away from the fixed anvil is provided with a tail end sleeve, the cross section of the tail end sleeve is H-shaped, the measuring rod is slidably arranged in the tail end sleeve, and the threaded tube sliding sleeve is arranged outside the tail end sleeve.

[0019] Furthermore, the elastic element includes a first anti-rotation sleeve, a second anti-rotation sleeve and a second spring, the first anti-rotation sleeve is slidingly sleeved on the outside of the tail end shaft sleeve, the end of the first anti-rotation sleeve abuts against the threaded tube, the second anti-rotation sleeve is fixedly arranged on the outside of the tail end shaft sleeve, and the second spring is sleeved on the outside of the first anti-rotation sleeve and the second anti-rotation sleeve.

[0020] Furthermore, the first anti-rotation sleeve is evenly distributed with a plurality of first easing grooves, and the second anti-rotation sleeve is evenly distributed with a plurality of second easing grooves that are offset from the first easing grooves.

[0021] Further, the measuring element is a coded grating, which includes a fixed grating that is stationary relative to the scale frame and a moving grating that moves synchronously with the measuring shaft.

[0022] Further, a wrench seat is also provided on the scale frame. A wrench is hinged on the wrench seat. The wrench is in contact with the edge of the threaded tube, and the wrench is used to push the threaded tube to move away from the scale frame.

[0023] Further, a detachable end face cover is provided at one end of the threaded tube away from the scale frame.

[0024] The beneficial effects of the present invention are as follows:

[0025] 1) The present invention provides the same, constant, and stable measuring force for the workpieces to be measured with the same or different specifications through the elastic element, avoiding the measurement error caused by the change of the measuring force and improving the measurement accuracy.

[0026] 2) The measuring rod is non-rigidly connected to the external driving part (threaded tube) through the circumferentially arranged first pin and second pin. If the threaded tube continues to rotate after the measuring head contacts the workpiece to be measured, since the measuring rod presses against the workpiece to be measured, the workpiece to be measured will not move at this time, and the threaded tube moves away from the fixed anvil. Therefore, during the measurement process, the external force can be avoided from being transmitted to the measuring rod. Compared with ordinary measuring tools, the influence of the speed of the measuring personnel rotating the driving structure on the measurement accuracy is eliminated; at the same time, the measuring rod can be self-locked at any position of the stroke.

[0027] 3) The first support sleeve and the second support sleeve are provided to support the first pin and the second pin. The elastic force of the first spring arranged between the first support sleeve and the second support sleeve acts on the first support sleeve and the second support sleeve, so as to ensure that the first pin and the second pin are respectively pressed against the left side wall and the right side wall of the thread groove, eliminating the gap between the threaded tube and the first pin and the second pin.

[0028] 4) When the threaded tube rotates until both the measuring rod and the fixed anvil are in contact with the workpiece to be measured, if the threaded tube continues to rotate, at this time, since the measuring rod is limited by the workpiece to be measured and cannot continue to move. Due to the action of the unloading gap, when the threaded tube continues to rotate, the threaded tube continues to separate from the scale frame (that is, the threaded tube moves away from the fixed anvil). In this way, when the measuring head and the fixed anvil are in contact with the workpiece at the same time, if the threaded tube is continuously rotated by applying force, the threaded tube continues to separate from the scale frame. Therefore, the external force will not be transmitted to the measuring tool and the workpiece, which can prevent the excessive measuring force from acting on the measuring rod and affecting the accuracy of the measuring tool, and at the same time, it can avoid damaging the workpiece to be measured.

[0029] 5) When measuring a soft workpiece to be measured, by first adjusting the distance between the fixed anvil and the measuring head to be close to the workpiece to be measured and then cooperating with a wrench for measurement, it can be ensured that regardless of the size of the workpiece to be measured, the deformation of the second spring is the allowance of the workpiece to be measured (i.e., the deformation is the same). Therefore, it is ensured that the measuring force applied by the second spring remains constant regardless of the position of the measuring rod and will not change due to the change in the size of the workpiece to be measured, ensuring that the measuring force applied when measuring different workpieces to be measured is the same, effectively avoiding the influence of the change in the measuring force on the measuring accuracy. Brief Description of the Drawings

[0030] Figure 1 is a perspective view of the high-precision displacement measuring device with a constant and stable measuring force in the embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the connection relationship between the sliding seat and the guide rod;

[0032] Figure 3 is a top view of the high-precision displacement measuring device with a constant and stable measuring force in the embodiment of the present invention;

[0033] Figure 4 is Figure 3 the sectional view taken along the A-A direction in

[0034] Figure 5 is a schematic diagram of the initial positions of the first anti-rotation sleeve and the second anti-rotation sleeve;

[0035] Figure 6 is a schematic diagram of the positional relationship between the first anti-rotation sleeve and the second anti-rotation sleeve after the threaded tube drives the first anti-rotation sleeve to move axially;

[0036] In the figure, 1. scale frame; 2. threaded tube; 3. fixed anvil; 4. measuring rod; 5. threaded groove; 6. sliding seat; 7. sliding groove; 8. guide rod; 9. connecting seat; 10. first support sleeve; 11. second support sleeve; 12. first pin; 13. second pin; 14. first spring; 15. third pin; 16. end shaft sleeve; 17. first anti-rotation sleeve; 18. second anti-rotation sleeve; 19. second spring; 20. first relief groove; 21. second relief groove; 22. fixed grating; 23. moving grating; 24. wrench; 25. end face cover; 26. unloading gap. Detailed Embodiment

[0037] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0038] Refer to Figures 1-6, the present invention provides a technical solution:

[0039] Example:

[0040] like Figures 1-6 As shown, a high-precision displacement measuring device with constant and stable measuring force includes a ruler frame 1, a threaded tube 2, and a fixed anvil 3 disposed on the ruler frame 1. The ruler frame is provided with a measuring rod 4, an elastic element, and a measuring element. One end of the measuring rod 4 is a measuring head, and the measuring head is adapted to the fixed anvil 3.

[0041] The connecting member is used to cooperate with the threaded tube to fine-tune the measuring rod and ensure that the measuring rod can stop at any position;

[0042] The elastic element is used to cooperate with the connecting member to provide a constant measuring force to the test piece via the measuring rod 4; the measuring force is directed toward the measured point. Here, the constant measuring force provided to the test piece means that the measurement provided by the elastic element maintains the same constant value when measuring test pieces of the same or different specifications.

[0043] The measuring element is used to measure the displacement of the measuring rod 4;

[0044] The threaded tube 2 is slidably mounted on one end of the ruler frame 1 away from the fixed measuring anvil 3, and the other end of the measuring rod 4 is transmission-connected to the threaded tube 2 via a connecting member. When the threaded tube 2 moves, the measuring rod 4 is driven by the connecting member to perform linear motion along the axial direction of the measuring rod 4.

[0045] The measuring element is a coded grating, which includes a fixed grating 22 relatively stationary with the scale frame 1 and a moving grating 23 moving synchronously with the measuring axis. The measuring element is a conventional technical means in this field and will not be described in detail here.

[0046] The ruler frame 1 is also provided with a wrench 24 seat, on which a wrench 24 is hinged. The wrench 24 fits against the edge of the threaded tube 2 , and the wrench 24 is used to push the threaded tube 2 to move away from the ruler frame 1 .

[0047] Working principle: During measurement, (1) adjust the measuring gap x1: adjust the measuring gap x1 to the actual size y minus z of the workpiece to be measured (z is the size, which is a specific value and can be set according to the measurement requirements, such as 1mm, 2mm...). The measuring gap refers to the distance between the probe and the fixed anvil 3. Figure 4 The threaded tube is rotated in the direction of the fixed anvil 3, and the threaded tube rotates, driving the measuring rod 4 to move in the direction away from the fixed measuring anvil 3.

[0048] (2)Measurement of the workpiece to be measured: Move the wrench 24 or axially pull the threaded tube 2. During this process, the measuring rod 4 continues to move away from the fixed anvil 3, so that the measurement gap x1 increases to be greater than the actual size y of the workpiece to be measured. At this time, the measurement gap is x2. Then place the workpiece to be measured between the measurement gaps x2, loosen the wrench or the threaded tube, and the threaded tube moves towards the direction close to the fixed anvil 3 under the action of the elastic element until the measuring head, the fixed anvil and the workpiece to be measured are in contact. At this time, the displacement of the threaded tube under the action of the elastic element is z.

[0049] (3)Reading: After step (2) is completed, read the value through the measuring element, and the measurement ends after the reading is completed.

[0050] (4)Measurement of another workpiece to be measured: Repeat the above steps (1)-(3).

[0051] As can be seen from the above, when measuring different workpieces to be measured, the displacement of the threaded tube is z, and the displacement of the elastic member is also z. Then the elastic member ensures the supply of a constant and same measuring force through the same displacement amount during each measurement.

[0052] During measurement, a constant and same measuring force is provided by the elastic element, and when adjusting the measurement gap through the threaded tube and the connecting member, it can ensure that the measuring rod 4 stops at any position.

[0053] The present invention provides the same constant and stable measuring force for workpieces to be measured of the same specification or different specifications through the elastic element, avoiding measurement errors caused by changes in the measuring force and improving the measurement accuracy.

[0054] Further, as Figures 2-6 shown, the inner wall of the threaded tube 2 is provided with a thread groove 5. The inner wall of the threaded tube 2 is provided with a thread groove 5. A sliding seat 6 is arranged inside the measuring frame 1. The sliding seat 6 is provided with a horizontal sliding groove 7. A connecting support is fixedly arranged outside the measuring rod 4. The bottom of the connecting support is provided with a guide rod 8 that is slidably matched with the sliding groove 7.

[0055] The connecting member includes a connecting seat 9, a first support sleeve 10 and a second support sleeve 11;

[0056] One end of the connecting seat 9 is provided with a groove, and the other end is a cylinder with a Y-shaped cross-section. The end of the measuring rod 4 away from the measuring head is connected to the groove of the connecting seat 9. The first support sleeve 10 and the second support sleeve 11 are annular. The first support sleeve 10 and the second support sleeve 11 are coaxially arranged outside the connecting seat 9. Three first connecting holes are evenly distributed on the outer circumferential surface of the first support sleeve 10. Three second connecting holes are evenly distributed on the outer circumferential surface of the second support sleeve 11. First pins 12 and second pins 13 are respectively arranged in the first connecting holes and the second connecting holes. The first pins 12 and the second pins 13 both extend into the thread groove 5.

[0057] When the measuring rod moves, the rotation of the measuring rod is restricted by the chute 7 and the guide rod 8, ensuring that the measuring rod only moves axially.

[0058] When the threaded tube 2 is rotated, the measuring rod moves linearly axially under the action of the thread groove 5, three first pins 12, and three second pins 13. Rotating the threaded tube 2 clockwise / counterclockwise drives the measuring rod towards / away from the fixed anvil 3. Among them, when the threaded tube 2 is rotated, the lead is 10 mm / revolution, and the moving speed is much higher than that of the traditional micrometer at 0.5 mm / revolution.

[0059] The wrench 24 drives the axial movement of the threaded tube 2, driving the rapid reciprocating movement of the measuring rod within a small stroke of 3 mm, which is superior to the traditional lever micrometer that can only reciprocate within a very small stroke (0.05 mm) and requires zero calibration.

[0060] When the threaded tube 2 is rotated clockwise (i.e., when driving the measuring rod 4 towards the fixed anvil 3), the threaded tube 2 will not move linearly due to the limit of the wrench 24 and only rotates, thus ensuring the measurement accuracy.

[0061] Furthermore, as Figures 4-6 shown, the first support sleeve 10 and the second support sleeve 11 are slidably arranged outside the support seat. The inner circumferential surfaces of the first support sleeve 10 and the second support sleeve 11 are respectively provided with installation grooves, and a first spring 14 is arranged in the installation grooves. The first spring 14 is sleeved outside the connecting seat 9, and both ends of the first spring 14 are fixedly connected to the groove walls of the two installation grooves.

[0062] The first support sleeve 10 and the second support sleeve 11 are both provided with anti-rotation holes. The axis of the anti-rotation holes is parallel to the axis of the measuring rod 4. The first support sleeve 10 and the second support sleeve 11 are connected through the anti-rotation holes and the third pins 15 arranged in the anti-rotation holes.

[0063] Among them, the function of the third pin 15 is to prevent the first support sleeve 10 and the second support sleeve 11 from rotating.

[0064] The first support sleeve 10 and the second support sleeve 11 are provided to support the first pin 12 and the second pin 13. The elastic force of the first spring 14 arranged between the first support sleeve 10 and the second support sleeve 11 acts on the first support sleeve 10 and the second support sleeve 11, thereby ensuring that the first pin 12 and the second pin 13 are respectively in close contact with the left and right side walls of the thread groove 5, eliminating the gaps between the threaded tube 2 and the first pin 12 and the second pin 13, ensuring that there is no gap when the threaded tube 2 drives the measuring rod 4 to both sides, eliminating the influence of the gap on the measurement result, and effectively ensuring the measurement accuracy.

[0065] Among them, during measurement, the ground force exerted by the threaded tube 2 on the pins (the first pin 12 and the second pin 13) is always to the left (refer to Figure 4 ). The advantage of this structure is that when the measuring head of the measuring rod 4 contacts the fixed anvil 3 during measurement, the measured value can be obtained immediately when the measuring head of the measuring rod 4 contacts the workpiece. The measurement response is fast and stable, and there is no need to eliminate the thread clearance to obtain a stable measured value. Further, a tail-end bushing 16 is provided at one end of the frame 1 away from the fixed anvil 3. The cross-section of the tail-end bushing 16 is H-shaped. The measuring rod 4 is slidably arranged in the tail-end bushing 16, and the threaded tube 2 is slidably sleeved outside the tail-end bushing 16.

[0066] The elastic element includes a first anti-rotation sleeve 17, a second anti-rotation sleeve 18, and a second spring 19. The first anti-rotation sleeve 17 is slidably sleeved outside the tail-end bushing 16. The end of the first anti-rotation sleeve 17 abuts against the threaded tube 2. The second anti-rotation sleeve 18 is fixedly arranged outside the tail-end bushing 16. The second spring 19 is sleeved outside the first anti-rotation sleeve 17 and the second anti-rotation sleeve 18.

[0067] Among them, 1. The two ends of the second spring 19 are respectively fixedly connected to the first anti-rotation sleeve 17 and the second anti-rotation sleeve 18. 2. One end of the threaded tube 2 close to the frame 1 is a stepped stage, including a first matching part and a second matching part. The first matching part is slidably matched with the frame 1, and the second matching part is slidably matched with the tail-end bushing 16. Such a setting can ensure that the end part of the threaded tube 2 is slidably matched with the frame 1 and the tail-end bushing 16 respectively.

[0068] When the wrench 24 drives the threaded tube 2 to move axially in a straight line, the first matching part moves in a direction away from the fixed anvil 3, that is, the threaded tube 2 has a tendency to separate from the frame 1. At this time, the end face of the second matching part of the threaded tube 2 drives the first anti-rotation sleeve 17 to move in the direction of the second anti-rotation sleeve 18. The second spring 19 arranged between the first anti-rotation sleeve 17 and the second anti-rotation sleeve 18 is compressed during this process. The elastic force provided by the second spring 19 is transmitted to the measuring rod through the threaded tube 2 and the connecting member to provide a measuring force for the workpiece to be measured. According to Hooke's law, the elastic force provided by the spring is constant under the same displacement, and the displacements of the threaded tube 2 and the measuring rod corresponding to workpieces to be measured of the same specification are the same. Therefore, when measuring workpieces to be measured of the same specification, the second spring 19 can provide the same and constant measuring force.

[0069] Among them, the measuring force is provided by the second spring 19. When measuring a soft workpiece to be measured, the measuring process is as follows: Rotate the threaded tube 2 to pre-adjust the distance between the fixed anvil 3 and the measuring head to be close to the size of the workpiece to be measured (here, taking the workpiece to be measured as 5 mm (5 mm is the aforementioned y) as an example for illustration), and adjust the distance between the fixed anvil 3 and the measuring head to 4 mm (4 mm is the aforementioned measuring gap x1). Among them, the deformation of the spring is 1 mm of the remaining amount of the workpiece to be measured (1 mm is the aforementioned z). Here, the remaining amount of the workpiece to be measured is the actual size of the workpiece to be measured minus the distance between the fixed anvil 3 and the measuring head during pre-adjustment.

[0070] At this time, move the wrench 24. The wrench 24 drives the threaded tube 2 and the measuring rod 4 to move away from the fixed anvil 3, further increasing the distance between the fixed anvil 3 and the measuring head. When the distance is greater than 5 mm, place the workpiece to be measured. After the workpiece to be measured enters between the measuring head and the fixed anvil 3, release the wrench. The threaded tube 2 and the measuring rod 4 move towards the fixed anvil 3 under the action of the second spring 19, and the measuring rod stops moving until the workpiece to be measured contacts the fixed anvil 3 and the measuring head respectively. At this time, the actual deformation of the second spring 19 is 1 mm. When measuring a larger part, such as 8 mm, adjust the distance between the fixed anvil 3 and the measuring head to 7 mm, and repeat the above operation until the workpiece to be measured contacts the fixed anvil 3 and the measuring head respectively. At this time, the deformation of the second spring 19 is also 1 mm, that is, to ensure that when measuring workpieces of different sizes, the deformation of the second spring 19 is the remaining amount of the workpiece to be measured.

[0071] It should be noted that the first spring 14 is used to eliminate the gap between the first pin 12 and the second pin 13, and to avoid the influence of the gap between the first pin 12 and the second pin 13 on the deformation of the spring (reducing the deformation of the spring) when the wrench drives the threaded tube 2 to move.

[0072] Therefore, such a measuring method can ensure that during measurement, the measuring force provided by the measuring device at any position is always constant and will not change due to the change of the size of the measured part, ensuring that the measuring force applied when measuring different workpieces to be measured is the same. In this way, the influence of the change of the measuring force on the measuring accuracy can be avoided. When the measuring force changes, for example, when measuring a soft workpiece to be measured, the larger the size of the workpiece to be measured, the greater the measuring force. At this time, the deformation of the surface of the soft workpiece to be measured due to this measuring force is also greater, so it will directly affect the measuring accuracy. Of course, when measuring a rigid part, it can be measured in the conventional way.

[0073] The measuring rod is non-rigidly connected to the external driving part (threaded tube 2) through the circumferentially arranged first pin 12 and second pin 13. If the threaded tube is continuously rotated after the measuring head contacts the workpiece to be measured, since the measuring rod presses against the workpiece to be measured, at this time the workpiece to be measured does not move, and the threaded tube moves away from the fixed anvil. Therefore, the external force can be avoided from being transmitted to the measuring rod during the measuring process. Compared with ordinary measuring tools, the influence of the speed of the measuring personnel rotating the driving structure on the measuring accuracy is eliminated; at the same time, the measuring rod can be self-locked at any position of the stroke.

[0074] During the reset process of the threaded tube, the measuring rod exerts a reaction force on the threaded tube to the right, causing it to continue compressing the second spring 19 to achieve the effect of shock resistance.

[0075] Among them, this structure also has the function of shock resistance. When a shock occurs, the second spring 19 continues to be compressed, thereby reducing the shock.

[0076] Furthermore, as Figures 4-6 shown, a plurality of first relief grooves 20 are evenly distributed on the first anti-rotation sleeve 17, and a plurality of second relief grooves 21 that are misaligned with the first relief grooves 20 are evenly distributed on the second anti-rotation sleeve 18. The first anti-rotation sleeve 17 and the second anti-rotation sleeve 18 are engaged through the first relief grooves 20 and the second relief grooves 21. Among them, a first clamping block adapted to the second relief groove 21 is formed between two adjacent first relief grooves 20. With this setting, when the first anti-rotation sleeve 17 moves towards the direction close to the second anti-rotation sleeve 18, the first clamping block extends into the second relief groove 21. This setting can reduce the length of the tail-end bushing 16. After shortening the length of the tail-end bushing 16, the displacement requirement of the first anti-rotation sleeve 17 can still be met.

[0077] Among them, when the first clamping block is engaged with the second relief groove 21, a force-relieving gap 26 is provided between the end of the first clamping block and the bottom of the second relief groove 21.

[0078] When the threaded tube 2 rotates, due to the fixation of the second anti-rotation sleeve 18 and the action of the first clamping block and the second relief groove 21, the first anti-rotation sleeve 17 will not be affected by the movement of the threaded tube 2.

[0079] When the threaded tube 2 rotates until the measuring rod and the fixed anvil 3 are both in contact with the workpiece to be measured, continue to rotate the threaded tube 2. At this time, since the measuring rod is limited by the workpiece to be measured and cannot move further. However, due to the action of the force-relieving gap 26, when the threaded tube 2 continues to rotate, the threaded tube 2 continues to disengage from the ruler frame 1 (that is, the threaded tube 2 moves towards the direction away from the fixed anvil 3). Thus, when the measuring head and the fixed anvil 3 are in contact with the workpiece at the same time and continue to apply force to rotate the threaded tube 2, the threaded tube 2 continues to disengage from the ruler frame 1. Therefore, the external force will not be transmitted to the measuring tool and the workpiece, which can prevent excessive measuring force from acting on the measuring rod 4 and affecting the accuracy of the measuring tool, and at the same time avoid damage to the workpiece to be measured.

[0080] Furthermore, as Figure 1 and Figure 4 shown, a detachable end face cover 25 is provided at one end of the threaded tube 2 away from the ruler frame 1. The provided end cover can improve the overall sealing performance of the device.

[0081] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments. Instead, it can be used in various other combinations, modifications, and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in the relevant field. Any changes and variations made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A high-precision displacement measurement device with constant and stable measured force, characterized in that: It includes a ruler frame, a threaded tube, and a fixed anvil arranged on the ruler frame. A measuring rod, an elastic element, and a measuring element are arranged in the ruler frame. One end of the measuring rod is a measuring head, and the measuring head is adapted to the fixed anvil. The connecting member is used to cooperate with the threaded tube to fine-tune the measuring rod and ensure that the measuring rod can stop at any position; The elastic element is used to cooperate with the connecting member to provide a constant measuring force to the workpiece to be measured through the measuring rod; the measuring element is used to measure the displacement of the measuring rod; The threaded tube is slidably sleeved on one end of the ruler frame away from the fixed measuring anvil, and the other end of the measuring rod is connected to the threaded tube through a connecting member. When the threaded tube moves, the measuring rod is driven by the connecting member to make a linear motion along the axial direction of the measuring rod. The inner wall of the threaded tube is provided with a thread groove, the inside of the ruler frame is provided with a sliding seat, the sliding seat is provided with a horizontal sliding groove, the outside of the measuring rod is fixed with a connecting support, and the bottom of the connecting support is provided with a guide rod that slides with the sliding groove; The connecting member includes a connecting seat, a first supporting sleeve and a second supporting sleeve; The cross-section of the connecting seat is Y-shaped, and the end of the measuring rod away from the measuring head is connected to the connecting seat. The first support sleeve and the second support sleeve are annular, and the first support sleeve and the second support sleeve are coaxially arranged on the outside of the connecting seat. A plurality of first connecting holes are evenly distributed on the outer circumference of the first support sleeve, and a plurality of second connecting holes are evenly distributed on the outer circumference of the second support sleeve. A first pin and a second pin are respectively provided in the first connecting hole and the second connecting hole, and the first pin and the second pin both extend into the thread groove; The elastic element includes a first anti-rotation sleeve, a second anti-rotation sleeve and a second spring, the first anti-rotation sleeve is slidably sleeved on the outside of the tail end sleeve, the end of the first anti-rotation sleeve abuts against the threaded tube, the second anti-rotation sleeve is fixedly arranged on the outside of the tail end sleeve, and the second spring is sleeved on the outside of the first and second anti-rotation sleeves; A detachable end cover is provided at one end of the threaded tube away from the ruler frame.

2. The high-precision displacement measuring device according to claim 1, characterized in that: The first support sleeve and the second support sleeve are slidably arranged outside the support seat. The inner circumferential surfaces of the first support sleeve and the second support sleeve are respectively provided with a mounting groove, and a first spring is arranged in the mounting groove.

3. The high-precision displacement measuring device with a constant and stable measured force according to claim 2, wherein: The first support sleeve and the second support sleeve are both provided with an anti-rotation hole, the axis of the anti-rotation hole is parallel to the axis of the measuring rod, and the first support sleeve and the second support sleeve are connected through the anti-rotation hole and a third pin provided in the anti-rotation hole.

4. The high-precision displacement measurement device with constant and stable measured force according to any one of claims 1-3, characterized in that: The end of the ruler frame away from the fixed measuring anvil is provided with a tail end sleeve, the cross section of the tail end sleeve is H-shaped, the measuring rod is slidably arranged in the tail end sleeve, and the threaded tube sliding sleeve is arranged outside the tail end sleeve.

5. The high-precision displacement measuring device for measuring a constant and stable force according to claim 1, wherein: The first anti-rotation sleeve is evenly distributed with a plurality of first easing grooves, and the second anti-rotation sleeve is evenly distributed with a plurality of second easing grooves that are staggered with the first easing grooves.

6. The high-precision displacement measuring device for measuring a constant and stable force according to claim 5, characterized in that: The measuring element is a coding grating, which includes a fixed grating that is relatively stationary with the scale frame and a moving grating that moves synchronously with the measuring axis.

7. The high-precision displacement measurement device with constant and stable measured force according to claim 6, characterized in that: The ruler frame is also provided with a wrench seat, on which a wrench is hinged. The wrench fits against the edge of the threaded pipe and is used to push the threaded pipe to move in a direction away from the ruler frame.

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