A flexible hardness machine spindle with the function of adjusting load distribution

Abstract

The present invention provides a flexible hardness machine spindle with the function of adjusting load distribution, which includes a guiding spindle, a lower-end spindle, a first centering device, a hanging device, a second centering device, an elastic buffer device and a indenter device. The guiding spindle is connected to the lower-end spindle, and the lower-end spindle is connected to the upper crossbeam of the hanging device through the first centering device. The upper crossbeam of the hanging device is then connected to the indenter device through the second centering device and the elastic buffer device. The hardness machine spindle as a whole has an automatic centering function through the two centering devices, effectively reducing the radial force of the guiding spindle and improving the guiding accuracy and test force accuracy. Moreover, the upper and lower crossbeams of the hanging device adopt a circumferential three-equal-part structure, which can effectively reduce the eccentricity caused by the processing technology and improve the test force accuracy. The elastic buffer device can effectively reduce the impact and improve the measurement accuracy of the hardness machine. Ultimately, the comprehensive metrological performance of the hardness machine is improved.

Description

Technical Field

[0001] The present invention relates to a hardness standard machine, and more specifically, to a main shaft of a hardness standard machine.

Background Art

[0002] The hardness standard machine is used to calibrate standard hardness blocks and mostly adopts a static weight test force loading method. At present, the main shaft structure of the hardness machine is mainly guided by a ball spline, and a hanging bracket for weights is connected to the lower end of the ball spline. The hanging bracket generally adopts a crossbeam with a symmetric structure, connecting two suspension rods, and the lower ends of the suspension rods are connected to a tray. Therefore, it has the following disadvantages:

[0003] Disadvantage 1: In actual manufacturing, the centers of gravity of components such as weights cannot be exactly on the center line of the main shaft. The hanging bracket exerts a radial force on the main shaft, resulting in the eccentricity of the main shaft. Moreover, it increases the friction during the movement process and affects the accuracy of the hardness machine.

[0004] Disadvantage 2: The reaction frame structure of two suspension rods plus a crossbeam is more likely to tilt, affecting the stability of the main shaft.

[0005] Disadvantage 3: During the loading process of the main shaft, it is easy to generate impacts, affecting the accuracy of the hardness machine.

Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a flexible hardness machine main shaft with a function of adjusting load distribution. By adjusting the load distribution, the main shaft of the hardness machine has an automatic centering function, improving the guiding accuracy and test force accuracy of the hardness machine.

[0007] To achieve the foregoing invention purpose, the technical solution adopted in the embodiment of the present invention is: a flexible hardness machine main shaft with a function of adjusting load distribution, including:

[0008] A guiding main shaft, axially arranged vertically and capable of moving along the axis;

[0009] A lower-end main shaft; including a main shaft sleeve, a main shaft connecting plate, a main shaft locking and positioning nut, three side wall openings, and a indenter installation groove; the main shaft sleeve has a cavity; the main shaft connecting plate covers above the cavity and is fixedly connected to the main shaft sleeve; the main shaft connecting plate has a main shaft insertion hole, the bottom end of the guiding main shaft is inserted into the main shaft insertion hole and locked by the main shaft locking and positioning nut; the three side wall openings are equally distributed on the side wall of the main shaft sleeve; the indenter installation groove is arranged at the bottom of the main shaft sleeve;

[0010] A first centering device, arranged in the cavity, including a first hard ball and a first ball seat, the first hard ball freely falls into the first ball seat and bears the pressure from the main shaft locking and positioning nut;

[0011] The hanging device includes an upper cross beam, a lower cross beam and three suspension rods; the upper cross beam is located below the spindle locking and positioning nut, and has a central body and three upper beam arms. A first ball seat groove is provided on the upper surface of the central body, and a second ball seat groove is provided on the lower surface, and the central body does not directly contact the lower end spindle; the first ball seat groove is used to fix the first ball seat. The inner ends of the three upper beam arms are fixedly connected to the central body, and the outer ends respectively pass through a side wall opening horizontally and are fixedly connected to the top end of a suspension rod. The lower cross beam has three lower beam arms and is respectively connected to the bottom end of a suspension rod through the three lower beam arms, so that the hanging device forms a circumferentially equally divided structure;

[0012] The second centering device is arranged in the cavity and includes an upper ball seat, a lower ball seat and a second hard ball. The upper ball seat is fixedly connected to the second ball seat groove in an inverted manner. The lower ball seat is correspondingly higher than the lower part of the upper ball seat. The second hard ball is freely located between the upper ball seat and the lower ball seat and bears the pressure from the upper ball seat;

[0013] The elastic buffer device is arranged below the lower ball seat and bears and buffers the pressure from the lower ball seat;

[0014] The indenter device is fixed in the indenter mounting groove.

[0015] Furthermore, the bottom of the spindle locking and positioning nut has a hemispherical groove, and the hemispherical groove is buckled on the first hard ball.

[0016] Furthermore, the elastic buffer device includes a positioning pin, a spring, a guide block and a sliding bearing. The positioning pin is fixed to the bottom of the cavity. The sliding bearing is arranged on the inner wall of the lower section of the cavity. The spring is sleeved on the positioning pin. The guide block is connected to the top of the spring and can slide up and down along the sliding bearing. The guide block is in free plane contact with the lower ball seat and bears and buffers the pressure from the lower ball seat.

[0017] Furthermore, the indenter device includes a hardness indenter and an indenter locking nut. The hardness indenter is embedded into the indenter mounting groove from bottom to top and is locked with the indenter locking nut.

[0018] Furthermore, the guide spindle is a ball spline shaft, a linear guide shaft or an air bearing shaft.

[0019] The advantages of the present invention are as follows: By providing two centering devices, the main shaft of the hardness tester has an automatic centering function as a whole, which can effectively reduce the radial force on the guiding main shaft, improve the guiding accuracy, and enhance the test force accuracy of the hardness tester. The upper and lower crossbeams of the hanging structure adopt a circumferential three-equal-part structure, which can effectively reduce the eccentricity caused by the processing technology and improve the test force accuracy. An elastic buffer device is installed at the lower end of the upper crossbeam for loading, which can effectively reduce the impact and improve the measurement accuracy of the hardness tester. Ultimately, the comprehensive metrological performance of the hardness tester is improved.

Description of the Drawings

[0020] The present invention will be further described below with reference to the accompanying drawings in conjunction with embodiments.

[0021] Figure 1 is a three-dimensional structural schematic diagram of the flexible main shaft of the hardness tester of the present invention.

[0022] Figure 2 is a top-view structural schematic diagram of the flexible main shaft of the hardness tester of the present invention.

[0023] Figure 3 is a bottom-view structural schematic diagram of the flexible main shaft of the hardness tester of the present invention.

[0024] Figure 4 is an axial sectional structural schematic diagram of the flexible main shaft of the hardness tester of the present invention.

[0025] Figure 5 is an axial sectional structural schematic diagram of the flexible main shaft of the hardness tester of the present invention, with the guiding main shaft not installed.

[0026] Figure 6 is a schematic diagram of the working principle of the flexible main shaft of the hardness tester of the present invention.

Specific Embodiments

[0027] In the embodiments of the present invention, a flexible main shaft of a hardness tester with a function of adjusting the load distribution is provided. By adjusting the load distribution, the main shaft of the hardness tester has an automatic centering function, improving the guiding accuracy and test force accuracy of the hardness tester.

[0028] The technical solutions in the embodiments of the present invention for solving the above problems generally have the following ideas: By providing upper and lower centering devices, the main shaft of the hardness tester has an automatic centering function as a whole, so that the connections between the hanging structure and the guiding main shaft and the lower-end main shaft have a certain flexibility and the function of adjusting the load distribution, which can effectively reduce the radial force on the guiding main shaft, improve the guiding accuracy, and enhance the test force accuracy of the hardness tester. Moreover, the upper and lower crossbeams of the hanging structure adopt a circumferential three-equal-part structure, which can effectively reduce the eccentricity caused by the processing technology and also improve the test force accuracy. An elastic buffer device is installed at the lower end of the upper crossbeam for loading, which can effectively reduce the impact and improve the measurement accuracy of the hardness tester. Ultimately, the comprehensive metrological performance of the hardness tester is improved.

[0029] To better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0030] The main shaft of the hardness tester in this embodiment has a certain flexibility, thus having the function of adjusting the load distribution.

[0031] Please refer to Figures 1 to 6 As shown, the main shaft 100 of the hardness tester in this embodiment includes a guiding main shaft 1, a lower-end main shaft 2, a first centering device 3, a suspension 4, a second centering device 5, an elastic buffer device 6, and a indenter device 7.

[0032] The guiding main shaft 1 is axially arranged vertically and can move axially; the guiding main shaft 1 is used for guiding, restricting the radial direction to enable the main shaft 100 of the hardness tester to move axially (i.e., vertically). The guiding main shaft 1 generally adopts a ball spline shaft, but is not limited to this form, and can also adopt a linear guide shaft or an air-bearing shaft, and axially moves in cooperation with the main shaft sleeve 200 on the hardness tester.

[0033] The lower-end main shaft 2; includes a main shaft sleeve 21, a main shaft connecting plate 22, a main shaft locking and positioning nut 23, three side-wall openings 24, and an indenter mounting groove 25; the main shaft sleeve 21 has a cavity 212; the main shaft connecting plate 22 covers above the cavity 212 and is fixedly connected to the main shaft sleeve 21; the main shaft connecting plate 22 has a main shaft insertion hole 222, and the bottom end of the guiding main shaft 1 is inserted into the main shaft insertion hole 222 and locked by the main shaft locking and positioning nut 23; the three side-wall openings 24 are equally distributed on the side wall of the main shaft sleeve 21; the indenter mounting groove 25 is provided at the bottom of the main shaft sleeve 21; the lower-end main shaft 2 is a key component of the main shaft 100 of the hardness tester, having the function of automatically adjusting the unbalanced moment, reducing the radial force of the guiding main shaft 1, enabling the test force to be conducted to the guiding main shaft 1 through the cemented carbide ball, and improving the loading accuracy of the test force.

[0034] The first centering device 3 is arranged in the cavity 212 and includes a first hard ball 31 and a first ball seat 32. The first hard ball 31 freely falls into the first ball seat 32 and bears the pressure from the main shaft locking and positioning nut 23; since the first hard ball 31 can roll relative to the first ball seat 32, it can thus produce an automatic centering effect on the guiding main shaft 1, and then adjust the direction of the test force.

[0035] The suspension 4 includes an upper crossbeam 41, a lower crossbeam 42, and three suspension rods 43; the upper crossbeam 41 is located below the spindle locking and positioning nut 23, and has a central body 411 and three upper beam arms 412. On the upper surface of the central body 411, a first ball socket groove 413 is provided, and on the lower surface, a second ball socket groove 414 is provided, and the central body 411 does not directly contact the lower end spindle 2; the first ball socket groove 411 is used to fix the first ball socket 32. The inner ends of the three upper beam arms 413 are fixedly connected to the central body 411, and the outer ends respectively pass through a side wall opening 24 horizontally and are fixedly connected to the top end of a suspension rod 43. The lower crossbeam 42 has three lower beam arms 422, and the bottom ends of the three suspension rods 43 are respectively connected through the three lower beam arms 422. The upper beam arms 412 and the lower beam arms 422 are circumferentially and evenly distributed, so that the suspension 4 as a whole forms a circumferential three-equal-part structure, thereby effectively reducing the eccentricity caused by the processing technology, effectively reducing the unbalanced moment, and improving the test force accuracy.

[0036] The second centering device 5 is arranged in the cavity 212 and includes an upper ball socket 51, a lower ball socket 52, and a second hard ball 53. The upper ball socket 51 is fixedly connected to the second ball socket groove 414 in an inverted manner. The lower ball socket 52 is correspondingly higher than the lower part of the upper ball socket 51. The second hard ball 53 is freely located between the upper ball socket 51 and the lower ball socket 52 and bears the pressure from the upper ball socket 51; since the second hard ball 53 can roll relative to the upper ball socket 51, an automatic centering effect can be generated on the upper crossbeam 41, and then the direction of the test force can be adjusted.

[0037] The elastic buffer device 6 is arranged below the lower ball socket 52 to bear and buffer the pressure from the lower ball socket 52; the elastic buffer device 6 can effectively reduce the impact force of the lower ball socket 52 and improve the measurement accuracy of the hardness tester.

[0038] The indenter device 7 is fixed in the indenter installation groove 25 and is used to contact the standard hardness block to obtain the axial test force.

[0039] Furthermore, as a more optimal or more specific implementation manner of the above embodiment, the following technical features may also be included:

[0040] The bottom of the spindle locking and positioning nut 23 has a hemispherical groove 232, and the hemispherical groove 232 is buckled on the first hard ball 31.

[0041] The elastic buffer device 6 includes a positioning pin 61, a spring 62, a guide block 63 and a sliding bearing 64. The positioning pin 61 is fixed to the bottom of the cavity 212. The sliding bearing 64 is arranged on the inner wall of the lower section of the cavity 212. The spring 62 is sleeved on the positioning pin 61. The guide block 63 is connected to the top of the spring 62 and can slide up and down along the sliding bearing 64. The guide block 63 is in free-plane contact with the lower ball seat 52 to receive and buffer the pressure from the lower ball seat 52.

[0042] The indenter device 7 includes a hardness indenter 71 and an indenter locking nut 72. The hardness indenter 71 is embedded into the indenter mounting groove 25 from bottom to top and locked with the indenter locking nut 72.

[0043] Both the first hard ball 31 and the second hard ball 53 are cemented carbide balls.

[0044] The working principle of the present invention is:

[0045] The lower spindle 2 at the lower end of the hardness tester spindle 100 is a key component, which has the function of automatically adjusting the unbalanced torque and reducing the radial force on the guiding spindle 1. During operation, the guiding spindle 1 is restricted in the radial direction by the spindle sleeve. The lifting mechanism 300 rises or falls from the lower end of the lower cross beam 42, thereby driving the upper cross beam 41 to rise or fall together.

[0046] When the lifting mechanism 300 descends, the guiding spindle 1 lands on the first hard ball 31 through the spindle locking and positioning nut 23, and the guiding spindle 1 moves downward by its own weight. At this time, the guiding spindle 1 is hardly affected by the radial force, so the axial guiding accuracy is improved.

[0047] When the hardness indenter 71 touches the standard hardness block 400, the hardness tester spindle 100 stops moving except for moving downward by a very shallow indentation depth, and needs to stay on the standard hardness block 300 for a certain period of time. At this time, the upper cross beam 41 continues to move downward following the lifting mechanism 300 to apply a test force to the hardness tester spindle 100. The upper cross beam 41 is not in direct contact with the lower spindle 2, and the weight is applied to the first ball seat 32 through the first hard ball 31. The first hard ball 31 has an automatic centering function, thereby adjusting the direction of the test force and improving the loading accuracy of the test force. The spring 62 at the lower end of the guide block 63 has a buffering effect to avoid excessive impact when the upper cross beam 41 contacts the second hard ball 53 instantaneously. When the test force is loaded, the spring 62 compresses. The guide block 63 slides on the axis of the sliding bearing 64 to avoid deviation.

[0048] After the test force loading time has elapsed, the lifting mechanism 300 moves upward. The spring 62 gradually rebounds as the upper crossbeam 41 moves upward, providing a buffering effect. When the first hard ball 31 at the upper end of the upper crossbeam 41 contacts the main shaft locking and positioning nut 23, the guiding main shaft 1 starts to move upward, and the hardness indenter 71 disengages from the standard hardness block 400.

[0049] The advantages of the present invention are as follows: By providing upper and lower centering devices, the overall main shaft of the hardness tester has an automatic centering function, which can effectively reduce the radial force of the main shaft of the hardness tester, improve the guiding accuracy, and improve the test force accuracy of the hardness tester. The hanging upper and lower crossbeams adopt a circumferential three-equal-part structure, which can effectively reduce the eccentricity caused by the processing technology and improve the test force accuracy. An elastic buffer device is installed at the lower end of the upper crossbeam for loading, which can effectively reduce the impact and improve the measurement accuracy of the hardness tester. Ultimately, the comprehensive metrological performance of the hardness tester is improved.

[0050] Although the specific embodiments of the present invention have been described above, those skilled in the art of this technology should understand that the specific embodiments we described are illustrative rather than used to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered by the scope protected by the claims of the present invention.

Claims

1. A flexible hardness machine spindle with the function of adjusting load distribution, characterized in that: Comprising: A guiding main shaft, vertically arranged axially and capable of moving axially; A lower end main shaft; Comprising a main shaft sleeve, a main shaft connecting plate, a main shaft locking and positioning nut, three side wall openings, and a press head mounting groove; the main shaft sleeve has a cavity; the main shaft connecting plate covers above the cavity and is fixedly connected to the main shaft sleeve; the main shaft connecting plate has a main shaft jack, the bottom end of the guiding main shaft is inserted into the main shaft jack and locked by the main shaft locking and positioning nut; the three side wall openings are equally distributed at three equal intervals on the side wall of the main shaft sleeve; the press head mounting groove is arranged at the bottom of the main shaft sleeve; A first centering device, arranged in the cavity, comprising a first hard ball and a first ball seat, the first hard ball freely falls into the first ball seat and bears the pressure from the main shaft locking and positioning nut; A suspension, comprising an upper cross beam, a lower cross beam and three suspension rods; the upper cross beam is located below the main shaft locking and positioning nut and has a central body and three upper beam arms, a first ball seat groove is arranged on the upper surface of the central body, a second ball seat groove is arranged on the lower surface, and the central body does not directly contact the lower end main shaft; the first ball seat groove is used to fix the first ball seat, the inner ends of the three upper beam arms are fixedly connected to the central body, and the outer ends respectively horizontally pass through one of the side wall openings and are fixedly connected to the top end of one of the suspension rods, the lower cross beam has three lower beam arms and is respectively connected to the bottom end of one of the suspension rods through the three lower beam arms, so that the suspension forms a circumferential three-equal-part structure; A second centering device, arranged in the cavity, comprising an upper ball seat, a lower ball seat and a second hard ball, the upper ball seat is fixedly connected in the second ball seat groove in an inverted manner, the lower ball seat is correspondingly higher than the lower part of the upper ball seat, the second hard ball is freely located between the upper ball seat and the lower ball seat and bears the pressure from the upper ball seat; An elastic buffer device, arranged below the lower ball seat, bearing and buffering the pressure from the lower ball seat; A press head device, fixed in the press head mounting groove; The bottom of the main shaft locking and positioning nut has a hemispherical groove, and the hemispherical groove is inverted on the first hard ball; The elastic buffer device comprises a positioning pin, a spring, a guiding block and a sliding bearing, the positioning pin is fixed to the bottom of the cavity, the sliding bearing is arranged on the inner wall of the lower section of the cavity, the spring is sleeved on the positioning pin, the guiding block is connected to the top of the spring and can slide up and down along the sliding bearing, and the guiding block is in free plane contact with the lower ball seat, bearing and buffering the pressure from the lower ball seat; The press head device comprises a hardness press head and a press head locking nut, the hardness press head is embedded into the press head mounting groove from bottom to top and locked by the press head locking nut.

2. The flexible hardness machine spindle with the function of adjusting load distribution according to claim 1, characterized in that: The guiding main shaft is a ball spline shaft, a linear guide shaft or an air floating bearing shaft.

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