Patent Description:
The present application relates to the technical field of testing devices, and in particular, to a spline screw testing device.

With the rapid development of Industry <NUM>, the demand for industrial robots in the field of industrial automation is increasing, and at the same time, higher and higher requirements are also put forward for their performance parameters. As a result, the performance requirements of the spline screw, one of the core components of industrial robots, have also increased. Therefore, how to test the spline screw to ensure the performance of the spline screw in actual use has become an urgent technical problem to be solved.

Spline screw testing devices are known from <CIT> and <CIT>.

The purpose of this application is to provide a spline screw testing device, which can test the spline screw and improve the testing efficiency of the spline screw.

In order to solve the above technical problems, the present application provides a spline screw testing device, the spline screw testing device base, a clamping assembly and a first testing mechanism which are arranged on the base, and the clamping assembly is configured to clamp a spline screw, the first testing mechanism includes:.

Further, the clamping assembly includes a fixed clamping member and a movable clamping member that cooperate with each other; the movable clamping member is movably connected with the base, and the fixed clamping member and the movable clamping member are provided with clamping through holes.

Further, the fixed clamping member and the movable clamping member include a fixed end and a movable end, the movable end is hinged on the fixed end; the fixed end is provided with a first half hole, and the movable end is provided with a second half hole, and the first half hole and the second half hole are matched to form the clamping through hole.

Further, the diameter of the clamping through hole decreases in a stepwise manner along the direction away from the clamped spline screw.

Further, the testing device further includes a position adjustment mechanism, and the position adjustment mechanism includes:.

Further, a linear guide rail is provided on the base, and the movable clamping member is slidably connected to the linear guide rail through a first jacking assembly, and the first jacking assembly includes:.

Further, the testing device further includes a locking assembly, and the locking assembly includes:.

Further, the testing device also includes a second test mechanism, and the second test mechanism includes:.

Further, a linear guide rail is provided on the base, and the mounting base is slidably connected to the linear guide rail through a second jacking assembly, and the second jacking assembly includes:.

Further, the testing device also includes a third test mechanism, and the third test mechanism includes:.

As can be seen from the above technical solutions, the application at least has the following advantages and positive effects:
The present application provides a testing device for a spline screw, the device includes a base, a clamping assembly and a first testing mechanism arranged on the base, the clamping assembly is configured for clamping the spline screw, and the first testing mechanism includes a mounting base, a first driving member and a distance meter, wherein the mounting base is movably connected with the base, the mounting base can move along the axial direction of the clamped spline screw, the first driving member is fixed on the mounting base, the output shaft of the first driving member is connected to the inner ring of the spline nut of the spline screw through the connecting assembly, the first driving member can apply the force of the rotation of the driver to the inner ring through the connecting assembly, and the range finder is arranged on the mounting base, the range finder can be configured to detect the amount of rotation of the inner ring when a force is applied. Therefore, through the first testing mechanism, By testing the rotation amount of the inner ring of the spline nut of the spline screw when the fixed force is applied, the rotation clearance and rotation stiffness of the spline nut can be tested. Compared with manual detection, the first test mechanism ensures the accuracy of the test of the spline screw, thus ensuring the accuracy of the test results of the spline screw, and also improving the test efficiency of the spline screw.

Reference numerals are explained as follows: X-spline screw; Y-spline nut; <NUM>-base; <NUM>-fixed clamping member; <NUM>-movable clamping member; <NUM>-mounting base; <NUM>-first driving member <NUM> -connecting components; <NUM>-range finder; <NUM>-Clamping through hole; <NUM>-Fixed end; <NUM>-movable end; <NUM>-Second driving member; <NUM>-First ball screw; <NUM>- linear guide rail; <NUM>-first movable base; <NUM>-first fixing member; <NUM>-bar-shaped hole; <NUM>-second fixing member; <NUM>-third driving member; <NUM>-second ball screw; <NUM>-force sensor; <NUM>-push rod; <NUM> - mirror group; <NUM> - Laser interferometer.

In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. and other indicated orientations or positional relationships are based on those shown in the attached drawing, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on this application. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined as "first", "second" may expressly or implicitly include one or more of said features. In the description of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected with" and "connected to" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection connected, or integrally connected. It can be a mechanical connection or an electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication between two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

Referring to Fig. and <FIG>, <FIG> is a schematic structural diagram of a spline screw testing device from a first perspective according to an embodiment of the present application, and <FIG> is a schematic structural diagram of a spline screw testing device from a second perspective according to an embodiment of the present application.

As shown in <FIG> and <FIG>, an embodiment of the present application provides a spline screw testing device. The spline screw testing device includes a base (<NUM>), and a clamping assembly and a first testing mechanism which are arranged on the base (<NUM>).

Among them, the base <NUM> is configured to carry various types of devices, which can be plate-like structures of various shapes. For example, the base <NUM> can be a plate-like structure such as a rectangle, a square, a circle, or other polygons, which is not limited in this application.

The clamping assembly is disposed on the base <NUM> and is configured for clamping the spline screw X to be tested, so as to realize the stable placement of the spline screw X during testing, and prevent the shaking of the spline lead screw x during the test from affecting the test results.

The first testing mechanism is disposed on the base <NUM>, and the first testing mechanism includes a mounting base <NUM> , a first driving member <NUM> and a range finder <NUM>. Among them, the mounting base <NUM> is movably connected with the base <NUM>, so that the mounting base <NUM> can slide on the base <NUM>. Specifically, the mounting base <NUM> can reciprocate along the axial direction of the clamped spline screw X, Therefore, the performance of each position of the spline screw X can be tested, which not only improves the accuracy of the test on the spline screw X, but also improves the application range of the testing device.

The first driving member <NUM> is fixed on the mounting base <NUM>, and the output shaft of the first driving member <NUM> is connected with the inner ring of the spline nut Y of the spline screw X through the connecting assembly <NUM>, so that the first driving member <NUM> can apply a force to drive the inner ring to rotate through the connecting assembly <NUM>. Optionally, the first driving member <NUM> may be a servo motor, a driving motor, a pneumatic pump or a hydraulic pump, or the like. and the range finder (<NUM>) is arranged on the mounting base (<NUM>), and the range finder (<NUM>) is configured to measure the amount of rotation of the inner ring when the action force is applied. Specifically, the range finder <NUM> may be an infrared range finder <NUM> or a distance measuring device such as a laser range finder <NUM>. The distance meter <NUM> can detect the rotation amount of the inner ring of the spline nut Y when the inner ring of the spline nut Y is exerted by the first driving member <NUM>, so that the rotational clearance and rotational stiffness of the spline screw x can be calculated based on the rotational amount, the magnitude of the force applied by the first driving member <NUM>, and the torque. It should be noted that the calculation methods of the rotation clearance and the optional stiffness may adopt the existing calculation methods, which are not specially limited in this application.

In this way, when the first testing mechanism tests the spline screw X, the clamping assembly can be used to clamp the spline screw X to be tested, and the first driving member <NUM> applies a force to the inner ring of the spline nut y of the spline screw x, and the range finder <NUM> can detect the rotation amount of the inner ring of the spline nut y of the spline screw X, so as to realize the test of the rotation clearance and rotation stiffness of the spline screw X, ensuring the accuracy of the test results for the spline screw X. At the same time, since the first driving member <NUM> and the range finder <NUM> are disposed on the mounting base <NUM>, and the mounting base <NUM> can reciprocate along the axial direction of the clamped spline screw X, the first testing mechanism can detect each position of the spline screw X, which further ensures the accuracy and comprehensiveness of the test results.

Referring to <FIG>, in an embodiment of the present application, the connecting assembly <NUM> includes a first connecting rod, a second connecting rod and a third connecting rod, wherein one end of the first connecting rod is fixedly connected to the output shaft of the first driving member <NUM>, and the axial direction of the first connecting rod is perpendicular to the axial direction of the output shaft of the first driving member <NUM>, the other end of the first connecting rod is hinged with one end of the second connecting rod, and one end of the third connecting rod is hinged with the other end of the second connecting rod, and the other end of the third connecting rod is fixed with the inner ring of the spline nut Y.

Before the test, the third connecting rod and the first connecting rod are horizontally arranged, and the axial direction of the third connecting rod points to the center position of the inner ring, and the second connecting rod is vertically connected between the first connecting rod and the third connecting rod. Therefore, when the output shaft of the first driving member <NUM> drives the first connecting rod to rotate upward, through the transmission of the connecting assembly <NUM>, a vertical upward force of the same magnitude can be applied to the inner ring through the third connecting rod, thereby testing the rotational rigidity and rotational clearance of the spline nut Y.

During the test, the first driving member <NUM> can exert a vertical upward force on both sides of the inner ring through the connecting assembly, and there will be obvious angular deformation when the torque is zero. Therefore, the angular deformation of the inner ring can be calculated under the condition of force on both sides, so as to obtain the rotation clearance of the inner ring. Similarly, when calculating the rotational stiffness of the spline screw, a vertical upward force can also be applied on both sides of the inner ring to obtain the forward rotational stiffness and reverse rotational stiffness of the spline screw.

Since it is also a vertical upward force, it can be ensured that the force output by the first driving member <NUM> is the same as the force received by the inner ring, so as to avoid the occurrence of wrong test results due to different force directions of the inner ring, and ensure the accuracy of the test results.

Referring to <FIG> and <FIG>, in an embodiment of the present application, the clamping assembly includes a fixed clamping member <NUM> and a movable clamping member <NUM> that are matched. Among them, the fixed clamping member <NUM> is fixed on the base <NUM>, and the movable clamping member <NUM> is movably connected with the base <NUM>, so that the movable clamping member <NUM> can move relative to the fixed clamping member <NUM> to move away from or close to the fixed clamping member <NUM>. Specifically, the movable clamping member <NUM> can reciprocate along the axial direction of the clamped spline screw X, so that the spline screw X of different lengths can be clamped, thereby improving the application range of the testing device.

The fixed clamping member <NUM> and the movable clamping member <NUM> are provided with clamping through holes <NUM>. In actual use, both ends of the spline shaft of the spline screw X can be placed on the fixed clamping member <NUM> and the clamping through hole <NUM> on the movable clamping member <NUM>, so as to realize the stable placement of the spline screw X.

Please refer to <FIG> is a schematic structural diagram of a movable clamping member in an embodiment of the present application. In an embodiment of the present application, both the fixed clamping member <NUM> and the movable clamping member <NUM> include a fixed end <NUM> and a movable end <NUM>, the movable end <NUM> is hinged on the fixed end <NUM>, and specifically, the movable end <NUM> is hinged on one side of the fixed end <NUM>, so that the movable end <NUM> can be turned over relative to the fixed end <NUM>. Meanwhile, the fixed end <NUM> is provided with a first half hole, and the movable end <NUM> is provided with a second half hole, and the first half hole and the second half hole cooperate to form the clamping through hole <NUM>.

Therefore, in the actual use process, the user can first turn over the movable end <NUM>, open the clamping through hole <NUM>, and then place the two ends of the spline shaft of the spline screw X to be detected on the movable clamping member <NUM> and the first half hole on the fixed clamping member <NUM>, and finally turn the movable end <NUM> back, so that the second half hole and the first half hole cooperate to clamp the spline shaft of the spline screw X.

Optionally, when the movable end <NUM> and the fixed end <NUM> are closed, a fixing member can be used to fix them to prevent the movable end <NUM> from rotating relative to the fixed end <NUM> during testing, so as to ensure the clamping effect of the spline screw X. Specifically, the fixing member may be a structure such as a bolt, a screw, or a buckle.

In an embodiment of the present application, the diameter of the clamping through hole <NUM> decreases in a stepwise manner along the direction away from the clamped spline screw X. It should be understood that not only the lengths of the spline screws X of different models are different, but also the diameters of the spline shafts. Therefore, the diameter of the clamping through hole <NUM> is reduced in steps, so that the clamping through hole <NUM> can be adapted to spline shafts of different diameters, so that spline shafts of different diameters can be clamped, improving the application scope of clamping assembly.

It should be noted that the aperture size of the clamping through hole <NUM> can be set in advance according to the different diameters of the spline shaft, and then the different apertures are arranged in a certain order to form a stepped distribution, and the apertures of the clamping through holes <NUM> on the fixed clamping member <NUM> and the movable clamping member <NUM> are symmetrical and decrease stepwise in the direction away from each other.

Referring to <FIG> and <FIG>, in an embodiment of the present application, the testing device further includes a position adjustment mechanism, and the position adjustment mechanism is configured to automatically adjust the relative position between the movable clamping member <NUM> and the fixed clamping member <NUM>. Specifically, the position adjustment mechanism includes a second driving member <NUM> and a first ball screw <NUM>. Both the second driving member <NUM> and the first ball screw <NUM> are disposed on the base <NUM>, and the screw rod of the first ball screw <NUM> is connected to the first ball screw <NUM>. The output shafts of the two driving members <NUM> are fixedly connected, so that the second driving member <NUM> can drive the screw of the first ball screw <NUM> to rotate through the output shaft, so that the nut of the first ball screw <NUM> reciprocates along the axial direction of the screw. At the same time, the nut of the first ball screw <NUM> is fixedly connected to the movable clamping member <NUM>, so that when the nut reciprocates, the movable clamping member <NUM> can be driven to move accordingly, so as to adjust relative position between the movable clamping member <NUM> and the fixed clamping member <NUM>.

Therefore, through the setting of the position adjusting mechanism, the position of the movable clamping member <NUM> can be automatically adjusted by the second driving member <NUM>, thus eliminating the trouble of manual adjustment, and the arrangement of the first ball screw <NUM> can make the movable clamping member <NUM> move smoothly and prevent the displacement during the movement from affecting the clamping of the spline screw X.

Please refer to <FIG>, <FIG>, <FIG> , in an embodiment of the present application, a linear guide rail <NUM> is provided on the base <NUM>. Specifically, the linear guide rail <NUM> can be along the clamped spline screw X axial setting. The movable clamp <NUM> is slidably connected to the linear guide <NUM> through the first lifting assembly, so that the movable clamp <NUM> can slide on the linear guide rail <NUM>, and the linear guide rail <NUM> may be disposed along the axial direction of the clamped spline screw X.

Specifically, the first jacking assembly includes a first movable base <NUM>, a first fixing member <NUM> and a first elastic member. Among them, the first movable base <NUM> is slidably connected to the linear guide rail <NUM>, and the first movable base <NUM> can reciprocate along the length direction of the linear guide rail <NUM>. The first fixing member <NUM> passes through the movable clamping member <NUM> and is fixedly connected to the first movable base <NUM> to fix the relative position between the movable clamping member <NUM> and the first movable base <NUM>, and the movable clamping member <NUM> can move along the first movable base <NUM>. The top of the first fixing member <NUM> is provided with a limiting portion that limits the movable range of the movable clamping member <NUM>, so as to prevent the movable clamping member <NUM> from coming out of the first fixing member <NUM>.

a first elastic member is sleeved on the first fixing member620, and the first elastic member is located between the movable clamping member <NUM> and the first movable base <NUM>, and both ends of the first elastic member are respectively abutted with the movable clamping member <NUM> and the first movable base <NUM>. Therefore, the first elastic member can apply a vertical upward force to the movable clamping member <NUM>, so that the movable clamping member <NUM> can be suspended in the air when the movable clamping member <NUM> reciprocates along the linear guide rail <NUM> to avoid contact with the base <NUM> to cause wear of the base <NUM> and the movable clamping member <NUM>. The maintenance cost is reduced, and the service life of the movable clamping member <NUM> is also prolonged. In one example, the first movable base <NUM> may be a guide rail slider matched with the linear guide rail <NUM>, and in other examples, the first movable base <NUM> may also be provided on the guide rail slider, so as to facilitate disassembly and and maintenance by technicians.

Please refer to <FIG>, <FIG> and <FIG>, in one embodiment of the present application, the testing device further includes a locking assembly, the locking assembly is configured for fixing the relative position between the bases <NUM> and the movable clamping member <NUM> without moving the movable clamping member <NUM>. Specifically, the locking assembly includes a bar-shaped hole <NUM> and a second fixing member <NUM>, wherein the bar-shaped hole <NUM> is opened on the base <NUM>, and the bar-shaped hole <NUM> is arranged along the axial direction of the first ball screw <NUM>, that is, the longitudinal direction of the bar-shaped hole <NUM> is parallel to the axial direction of the first ball screw <NUM>.

The second fixing member <NUM> passes through the movable clamping member <NUM> and is matched with the bar-shaped hole <NUM>, so as to fix the relative position between the movable clamping member <NUM> and the base <NUM>. Specifically, the second fixing member <NUM> passes through the movable clamping member <NUM> and the bar-shaped hole <NUM> in sequence, and protrudes from the bottom of the bar-shaped hole <NUM>. The second fixing member <NUM> can be a bolt. When the second fixing member <NUM> protrudes the bottom of the bar-shaped hole <NUM>, it can be matched with a nut, so as to achieve the purpose of fixing the movable clamping member <NUM>.

In actual use, if the movable clamping member <NUM> needs to be moved, the movable clamping member <NUM> can be released by rotating the nut matched with the second fixing member <NUM>, so that the movable clamping member <NUM> can reciprocate along the linear guide <NUM>. When the movable clamping member <NUM> needs to be fixed, after the movable clamping member <NUM> reaches the target position, the second fixing member <NUM> can drive the movable clamping member <NUM> to move downward by rotating the nut until it abuts with the base <NUM>, thereby achieving the purpose of fixing the movable clamp <NUM>.

In this way, the movable clamping member <NUM> can be fixed when necessary, and at the same time, the arrangement of the bar-shaped hole <NUM> may not affect the reciprocating movement of the movable clamping member <NUM> along the linear guide rail <NUM>, so as to adjust the position of the movable clamping member <NUM>.

Please refer to <FIG> and <FIG>, in one embodiment of the present application, the testing device further includes a second testing mechanism, the second testing mechanism is configured to test the magnitude of the resistance that the spline nut y bears when moving linearly relative to the spline shaft. Specifically, the second testing mechanism includes a third driving member <NUM>, a second ball screw <NUM> and a force sensor <NUM>. The third driving member <NUM> and the second ball screw <NUM> are both disposed on the base <NUM>, the screw of the second ball screw <NUM> is drivingly connected to the output shaft of the third drive, and the nut of the second ball screw <NUM> is fixedly connected to the mounting base <NUM>.

Therefore, when the third driving member <NUM> drives the screw of the second ball screw <NUM> to rotate, the nut of the second ball screw <NUM> can drive the mounting base <NUM> to move linearly along the axial direction of the screw of the second ball screw <NUM>. Meanwhile, the force sensor <NUM> is arranged on the mounting base <NUM>, and the detection end of the force sensor <NUM> is connected to the inner ring of the spline nut y. Therefore, when the mounting base <NUM> moves in a straight line, the detection end of the force sensor <NUM> can push the spline nut Y to move in a straight line on the spline shaft, and the force sensor <NUM> can measure the magnitude of the resistance that the spline nut y bears when moving. In addition, the third driving member <NUM> can push the spline nut Y to move at different speeds, so as to measure the force under different speeds, thereby ensuring the accuracy of the test.

In an embodiment of the present application, the mounting base <NUM> may be slidably connected to the linear guide rail <NUM> provided on the base <NUM> through the second jacking assembly. The second jacking assembly includes a second movable base, a second fixing member <NUM> and a second elastic member. Specifically, the second movable base is slidably connected to the linear guide rail <NUM> , and the second fixing member <NUM> is fixedly connected to the second movable base through the mounting base <NUM>, thereby fixing the relative position between the mounting base <NUM> and the second movable base. Meanwhile, the mounting base <NUM> can move up and down along the axial direction of the second fixing member <NUM>. The top of the second fixing member <NUM> is provided with a limiting portion that limits the movement range of the mounting base <NUM>, so as to prevent the mounting base <NUM> from coming out of the second fixing member <NUM>.

a second elastic member is sleeved on the first fixing member <NUM>, and the second elastic member is located between the movable clamping member <NUM> and the second movable base, and both ends of the second elastic member are respectively abutted with the mounting base <NUM> and the second movable base. Therefore, the second elastic member can exert an upward force on the mounting base <NUM> to lift off the mounting base <NUM>, so as to prevent the mounting base <NUM> from contacting the base <NUM> when moving along the linear guide rail <NUM>, thereby causing wear of both. In this way, the service life of the mounting base <NUM> can be prolonged, and the maintenance cost can be reduced.

In an embodiment of the present application, the mounting base <NUM> may also be provided with the locking assembly described in the above embodiment, so that when the mounting base <NUM> needs to be fixed, the relative position between the mounting base <NUM> and the base <NUM> is fixed by the locking assembly In addition, the two locking assemblies may share the same bar-shaped hole <NUM>, which eliminates the need for extra processing and saves the processing steps. For the specific installation method, refer to the above-mentioned embodiments, and details are not described herein again in this application.

In an example, the inner ring of the spline nut Y may be provided with a push-pull portion extending outward, and when the second testing mechanism is in operation, the detection end of the force sensor <NUM> may be fixed to the push-pull portion, so that the detection end of the force sensor <NUM> can be fixed to the push-pull part to facilitate the installation of the force sensor <NUM>. At the same time, it can ensure that the force receiving direction of the detection end of the force sensor <NUM> is parallel to the movement direction of the spline nut Y, so as to ensure the detection accuracy of the force sensor <NUM>. Preferably, the push-pull portion may be formed by extending outward from one end of the connecting assembly <NUM> connected to the inner ring.

In an example, the push-pull part is provided with a strip-shaped through hole, the detection end of the force sensor <NUM> can pass through the bar-shaped through hole, and the detection end of the force sensor <NUM> is provided with two limit parts, the two limit parts are arranged on both sides of the bar-shaped through-hole to prevent the detection end from coming out of the bar-shaped through-hole. Therefore, when the force sensor <NUM> is detecting, the push-pull portion can be pushed and pulled through the setting of the limiting portion, so as to detect the magnitude of the resistance received by the spline nut during moving.

When the first testing mechanism is in operation, the range finder <NUM> can measure the rotation of the spline screw X under the driving of the first driving member <NUM> by detecting the rotation of the push-pull portion, so as to obtain the rotation clearance and rotation stiffness of the spline nut Y to ensure the accuracy of the test results.

Please refer to <FIG> and <FIG> , in an embodiment of the present application, the testing device further includes a third testing mechanism, and the third testing mechanism is configured to detect the travel straightness of the spline nut Y when the spline nut Y moves linearly on the spline shaft, that is, to detect the offset amount of the spline nut Y in the horizontal direction and the vertical direction when the spline nut Y moves linearly.

Specifically, the third testing mechanism includes a push rod <NUM>, a mirror group <NUM> and a laser interferometer <NUM>. The push rod <NUM> is disposed on the mounting base <NUM> to push the spline nut Y of the spline screw X to move together when the mounting base <NUM> moves along the linear guide rail <NUM>, so that the spline nut Y moves linearly relative to the spline shaft.

The mirror group <NUM> is fixedly connected to the inner ring of the spline nut Y to move with the spline nut Y. The laser interferometer <NUM> is arranged opposite to the mirror group <NUM>. In this way, the running straightness of the spline nut Y can be measured by the movement of the laser light emitted by the laser interferometer <NUM> on the mirror group <NUM>.

Claim 1:
A spline screw testing device comprising a base (<NUM>), a clamping assembly (<NUM>, <NUM>) and a first testing mechanism (<NUM>, <NUM>, <NUM>) which are arranged on the base (<NUM>), and the clamping assembly (<NUM>, <NUM>) is configured to clamp a spline screw to be tested (X), the first testing mechanism (<NUM>, <NUM>, <NUM>) includes:
a mounting base (<NUM>), movably connected with the base (<NUM>), and the mounting base (<NUM>) is configured to move along the axial direction of the clamped spline screw;
a first driving member (<NUM>) is fixed on the mounting base (<NUM>), and an output shaft of the first driving membe (<NUM>) is connected to an inner ring of a spline nut (Y) of the spline screw to be tested (X) by means of a connecting assembly (<NUM>); by means of the connecting assembly (<NUM>), the first driving member (<NUM>) is configured to apply, to the inner ring, an action force for driving the inner ring to rotate;
characterized in that it further comprises: a range finder (<NUM>) arranged on the mounting base (<NUM>), and the range finder (<NUM>) is configured to measure the amount of rotation of the inner ring when the action force is applied.