CN220912205U - Symmetry measuring device - Google Patents

Abstract

The application discloses a symmetry measuring device, and belongs to the technical field of machining precision detection in the machining industry, in particular to a symmetry measuring device for detecting key grooves of shaft parts, so as to solve the technical problems that the current key groove symmetry measuring device has high requirements on measuring conditions and the measuring device and the measured shaft parts need to relatively move, so that the measuring operation is complicated and the error is large. The symmetry measuring device comprises a frame, a measuring cavity and a containing cavity, wherein the containing cavity is provided with an opening above and used for containing shaft parts, and the measuring cavity is communicated with the containing cavity through the opening; the switching shaft is slidably and rotatably connected to the frame along the axial direction of the switching shaft, and at least part of the switching shaft is positioned in the measuring cavity; the limiting piece is used for limiting the movement of the switching shaft towards the measuring cavity and is clamped on the switching shaft; the limiting piece is positioned outside the frame; the dial indicator is detachably connected to the adapter shaft and is provided with a measuring head which is arranged at an angle with the adapter shaft, and the measuring heads of the dial indicator are respectively contacted with two side faces of the key groove which are symmetrically distributed along the radial direction of the shaft part under the rotation action of the adapter shaft so as to measure the symmetry degree of the key groove of the shaft part.

Description

Symmetry measuring device

Technical Field

The application belongs to the technical field of machining precision detection in the machining industry, and particularly relates to a symmetry measuring device for detecting a key slot of a shaft part.

Background

In various mechanical devices, it is common to use a key-to-keyway fit as a coupling mechanism to transfer torque and power through the sides of the key-to-keyway. In order to ensure good contact between the key and the side surface of the key slot, uniform loading of the key, reliability of mechanism operation and interchangeability of maintenance, the accurate detection of the symmetry error of the key slot has important significance. The key symmetry degree that the keyway was the axle type part and other parts assembly directly influences the installation accuracy, if keyway machining accuracy is low, can influence key connection quality, can appear unable problem of assembly even.

The central plane of the key way must lie between two parallel planes at a distance of tolerance t, symmetrically arranged on either side of an auxiliary plane passing through the reference axis, as defined by the national machining process standards. According to the requirement of evaluating the symmetry error of the alignment line, the ideal center plane of the measured element passes through the reference axis, so that the maximum deviation of the measured actual center plane relative to the ideal center plane is minimum, and at the moment, the two times of the maximum deviation is the symmetry error value. When the error value is expressed by the method of locating the minimum inclusion region, that is, an ideal plane is taken as a symmetrical plane, and the width f between two parallel planes of a pair of tight-packed actual central planes is the symmetry error.

As a result of the processing of the key groove, there is generally a symmetry error in one cross section (i.e., a symmetry error between two sidewalls of the key groove in a cross section perpendicular to the axis of the shaft-like component, generally referred to as a cross-sectional symmetry of the key groove) and a symmetry error along the length direction of the axis (i.e., a symmetry error with respect to the axis of the shaft-like component, generally referred to as a longitudinal symmetry of the key groove), and therefore, it is necessary to evaluate the symmetry of the key groove by taking both errors into consideration. The measuring method of the section and the longitudinal symmetry degree specified in the national standard comprises the following steps: taking a flat plate, a V-shaped block, a positioning block and a measuring frame with an indicator as a gauge; the reference axis is simulated by a V-block and the measured center plane is simulated by a locating block.

According to GB/T1958-2017 geometric tolerance detection and verification of product geometry technical Specification (GPS), section symmetry measurement: the measuring frame is characterized in that a V-shaped block and a measuring frame with an indicator are placed on the flat plate, a notch is formed in the V-shaped block, a shaft part to be measured is placed in the notch, and a positioning block is installed in a key slot of the shaft part to be measured. The reference axis is simulated by a V-block and the measured center plane is simulated by a locating block. And adjusting the measured shaft to enable the positioning block to be parallel to the flat plate along the radial direction. And measuring the distance from the positioning block to the flat plate in the radial sections at the two ends of the length of the key groove. And rotating the shaft part to be measured by 180 degrees, repeating the measurement to obtain readings of two corresponding points respectively measured in the section, calculating the difference value of the readings, and substituting the difference value into a corresponding formula to calculate the section symmetry error value of the key slot. Measurement of longitudinal symmetry: and measuring along the length direction of the key slot, and taking the maximum reading difference value of the two points which are farthest from each other in the length direction as the length symmetry error value of the key slot. In the machining industry, the error in the symmetry of a keyway is generally assessed as the maximum of the measured error in the keyway cross-section or in the long direction.

In the key slot symmetry error measuring method commonly adopted in the current industry, a reference is needed for a measuring instrument and a measured part during measurement, so that the requirement on measuring conditions in practical application is high. The relative movement between the measuring instrument and the measured shaft part is required in the measuring process, so that the operation is complex, time and labor are wasted, the measuring error is large, and the requirements of process control and inspection judgment in the mass production process cannot be met.

Disclosure of utility model

The application aims to at least solve the technical problems of complicated measurement operation and larger error caused by higher requirements on measurement conditions and the need of relative movement between a measuring device and a measured shaft part to a certain extent. To this end, the application provides a symmetry measuring device.

The symmetry measuring device provided by the embodiment of the application is used for measuring the symmetry of a key groove of a shaft part, and comprises the following components: the frame is provided with a measuring cavity and a containing cavity which is used for containing the shaft parts and is provided with an opening above, and the measuring cavity is communicated with the containing cavity through the opening; the switching shaft is slidably and rotatably connected to the frame along the axial direction of the switching shaft, and the switching shaft is at least partially positioned in the measuring cavity; the limiting piece is used for limiting the transfer shaft to move towards the measuring cavity and is clamped with the transfer shaft; the limiting piece is positioned outside the frame; the dial indicator is detachably connected to the adapter shaft and is provided with a measuring head which is arranged at an angle with the adapter shaft, and the measuring heads of the dial indicator are respectively contacted with two side faces of the key groove which are symmetrically distributed along the radial direction of the shaft part under the rotation action of the adapter shaft so as to measure the symmetry degree of the key groove of the shaft part.

In some embodiments, the symmetry measuring device further comprises a positioning piece detachably connected to the adapter shaft, and provided with a positioning surface perpendicular to the adapter shaft and used for positioning the groove bottom of the key groove of the shaft part.

In some embodiments, the opening of the receiving cavity is arranged in an inverted V-shape to form a first taper that receives the shaft-like part.

In some embodiments, the symmetry measuring device further comprises a fastener in threaded connection with the frame, wherein a rod part of the fastener is positioned in the accommodating cavity so as to tightly prop against the peripheral surface of the shaft part; the fastener is disposed between two sidewalls of the first tapered portion.

In some embodiments, the adaptor shaft includes a stop section, a sliding section and a limiting section connected in sequence, where the stop section is located in the measurement cavity, the sliding section is slidably connected to the frame, and the limiting section is located outside the frame and connected to the locking member; the symmetry measuring device further comprises elastic pieces, wherein the two ends of the elastic pieces respectively act on the stop section and the frame, and the elastic pieces are positioned in the measuring cavity.

In some embodiments, the stop section of the adapter shaft is provided with a first adapter for detachable connection with a second adapter on the positioning element or a third adapter on the dial indicator.

In some embodiments, the outer diameter of the stop section is larger than the outer diameter of the slip-fit section, and the elastic member is a spring sleeved on the slip-fit section.

In some embodiments, the frame further comprises an auxiliary reference wall perpendicular to the top of the frame and arranged on the side wall of the frame, and the auxiliary reference wall is provided with a through hole.

In some embodiments, the measuring cavity is provided with an opening in a positive V-shape to form a second taper that accommodates the shaft-like part.

In some embodiments, the symmetry-measuring device further comprises a grip portion detachably connected to the frame for gripping a circumferential surface of the shaft-like part against an opening of the measuring cavity to provide a gripping force to the shaft-like part from the measuring cavity towards the receiving cavity.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 illustrates a schematic diagram of a symmetry-measuring device according to some embodiments of the present disclosure; and

FIG. 2 illustrates a schematic diagram of positioning a shaft-type part by a positioning member in a symmetry-measuring device according to some embodiments of the present disclosure.

Reference numerals:

1. A limiting piece; 2. a spring;

300. a transfer shaft; 302. a stop section; 304. a slip fit section; 306. a limiting section;

4. a dial indicator; 402. a dial indicator body; 404. a measuring head;

5. a frame; 502. a measurement cavity; 504. a receiving chamber; 506. an auxiliary reference wall; 508. a first through hole; 510. a second through hole;

5022. A second taper; 5042. a first taper;

6. Shaft parts;

7. A fastener;

800. A positioning piece; 802. a positioning rod; 804. a positioning block;

9. An auxiliary measuring instrument.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that all the directional indicators in the embodiments of the present utility model are only used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture, and if the specific posture is changed, the directional indicators are correspondingly changed. In the present utility model, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances. Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

The application is described below with reference to specific embodiments in conjunction with the accompanying drawings:

in the key slot symmetry error measuring method commonly adopted in the current industry, a reference is needed for a measuring instrument and a measured part during measurement, so that the requirement on measuring conditions in practical application is high. The relative movement between the measuring instrument and the measured shaft part is required in the measuring process, so that the operation is complex, time and labor are wasted, the measuring error is large, and the requirements of process control and inspection judgment in the mass production process cannot be met.

The symmetry measuring device provided by the embodiment of the application at least solves the problems. The symmetry measuring device provided by the embodiment of the application provides the reference for measuring the key slot through the processing precision and the assembly relation among all the parts, so that the measurement can be performed without the help of an external reference, and the symmetry measuring device can be suitable for various actual processing environments. In addition, the movement of the shaft part to be measured and the movement of the measuring instrument relative to the shaft part to be measured can be realized by only depending on the machining precision and the assembly relation among the parts of the symmetry measuring device, and the relative movement between the reference of the measuring instrument and the reference of the shaft part to be measured can not be generated. Therefore, the symmetry error of the key slot of the shaft part can be conveniently measured, and the measuring process is greatly simplified. The repeated measurement does not need to correct the standard repeatedly, so that the measurement efficiency is obviously improved, and the requirements of process control, inspection and judgment in a mass production process can be met.

Fig. 1 illustrates a schematic diagram of a symmetry-measuring device according to some embodiments of the present disclosure. As shown in fig. 1, some embodiments of the present application provide a symmetry measuring device for an axle speed measuring device, which can be used to measure the symmetry of a key slot of an axle part 6. The symmetry measuring device includes: a frame 5 provided with a measuring cavity 502 and a containing cavity 504 with an opening above for containing the shaft-like part 6, wherein the measuring cavity 502 is communicated with the containing cavity 504 through the opening; the adapter shaft 300 is slidably and rotatably connected to the frame 5 along the axial direction of the adapter shaft 300, and the adapter shaft 300 is at least partially positioned in the measuring cavity 502; the limiting piece 1 is used for limiting the movement of the adapter shaft 300 towards the measurement cavity 502 and is clamped to the adapter shaft 300; the limiting piece 1 is positioned outside the frame 5; the dial indicator 4 is detachably connected to the adapter shaft 300, and is provided with a measuring head 404 which is arranged at an angle with the adapter shaft 300, and the measuring heads 404 of the dial indicator 4 are respectively contacted with two side surfaces of the key groove which are symmetrically distributed along the radial direction of the shaft part 6 under the rotation action of the adapter shaft 300 so as to measure the symmetry degree of the key groove of the shaft part 6.

In some embodiments, the frame 5 may be substantially quadrilateral in configuration, and the interior of the frame 5 may be hollow. The upper half of the hollow interior of the frame 5 is a measuring chamber 502 for accommodating the adapter shaft 300 and the measuring instrument, and the lower half of the hollow interior of the frame 5 is an accommodating chamber 504 for accommodating the shaft-like part 6 to be measured. A first through hole 508 may be provided at the top of the frame 5 for the insertion of the adapter shaft 300, and the machining precision of the two ensures that the adapter shaft 300 can rotate in the first through hole 508 and the coaxiality with the first through hole 508 is ensured during the rotation. One end of the adapter shaft 300 is located in the measuring chamber 502 and the other end is located outside the frame 5. The other end of the adapter shaft 300 located outside the frame 5 may be provided with a limiting member 1, where the limiting member 1 is clamped to the other end of the adapter shaft 300 located outside the frame 5 to limit the movement of the adapter shaft 300 toward the measurement cavity 502. The measuring instrument may be a lever dial indicator 4, or other measuring instrument that may be used to measure distance, without limitation. Thus, in actual use, after the measuring device is connected to the adapter shaft 300, the measuring device can rotate in the measuring cavity 502 to contact with two sides of the key slot of the shaft part 6 in the accommodating cavity 504 by the rotatable connection of the adapter shaft 300 and the first through hole 508 at the top of the frame 5, so as to measure the corresponding cross-section symmetry error or longitudinal symmetry error. The first through hole 508 at the top of the frame 5 enables to ensure the perpendicularity of the transfer shaft 300 relative to the reference surface at the top of the frame 5 in the rotation process through machining precision, so as to ensure the measurement foundation of the measuring instrument to be stable, and further ensure the measurement precision. Thus, the measurement can be accurately and rapidly performed under various field conditions.

In some embodiments, the symmetry-measuring device may further include a positioning member 800. The positioning member 800 is detachably connected to the adapter shaft 300, and is provided with a positioning surface perpendicular to the adapter shaft 300 for positioning the bottom of the key groove of the shaft-like component 6.

Fig. 2 illustrates a schematic diagram of positioning a shaft-like part 6 by a positioning member 800 in a symmetry-measuring device according to some embodiments of the present disclosure. As shown in fig. 2, the positioning member 800 may include a positioning rod 802 and a positioning block 804, and the positioning rod 802 may be configured to be detachably connected to the adapter shaft 300. One end of the positioning rod 802 may be detachably connected to the adapter shaft 300, the other end of the positioning rod 802 may be detachably connected to the positioning block 804, or the positioning rod 802 and the positioning block 804 may be integrally formed to form the positioning member 800. The perpendicularity of the bottom surface of the positioning block 804 and the axis of the positioning rod 802 is guaranteed through machining precision, and the coaxiality of the positioning rod 802 and the adapter shaft 300 after detachable connection is guaranteed through machining precision, so that after the positioning rod 802 and the adapter shaft 300 are detachably connected, the positioning block 804 is used for contacting the bottom of a key groove, and the axis of the adapter shaft 300 and the axis of the positioning rod 802 are perpendicular to the bottom surface of the key groove. After this, the measuring instrument is connected to the adapter shaft 300 again, and the axis of the measuring instrument is also perpendicular to the bottom surface of the key groove. In addition, after the positioning block 804 is inserted into the key slot, only the positioning surface at the bottom of the positioning block 804 contacts with the bottom surface of the key slot, the positioning block 804 does not contact with the side surface of the key slot to avoid damaging the side surface of the key slot, and the positioning block 804 can play a role in centering and aligning orientation, so that the position of the shaft part 6 to be measured in the first taper portion 5042 or the second taper portion 5022 is the same as the position of the positioning block 804 in the key slot. So that the axis of the adapter shaft 300 is perpendicular to the bottom surface of the key groove and passes through the center of the cross-sectional circle of the shaft-like part 6 to be measured.

In some embodiments, the opening of the receiving cavity 504 is arranged in an inverted V-shape to form a first taper 5042 that receives the shaft-like part 6.

As shown in fig. 1, the receiving chamber 504 at the lower portion of the frame 5 may be provided with an opening in an inverted V shape to form the first tapered portion 5042. The side wall of the first tapered portion 5042 tapers from the bottom of the frame 5 to the top of the frame 5, so that the shaft part 6 to be tested can rest against the side wall of the first tapered portion 5042, and the axis of the first through hole 508 at the top of the frame 5 and the axis of the adapter shaft 300 penetrate through the circle center of the cross-section circle of the shaft part 6 to be tested through the machining precision. Therefore, the shaft part 6 to be measured abuts against the first taper part 5042 to be used as a reference, so that the shaft part 6 can be moved conveniently, the reference of the shaft part 6 to be measured and the reference of the measuring instrument cannot move relatively, and the measuring precision and the convenience of operation are ensured.

In some embodiments, the symmetry measuring device may further include a fastener 7 screwed with the frame 5, wherein a stem portion of the fastener 7 is located in the accommodating cavity 504 to press against the circumferential surface of the shaft part 6; the fastener 7 is disposed between the two side walls of the first tapered portion 5042.

As shown in fig. 1, in some embodiments, the fastener 7 may be disposed at the bottom of the frame 5, connected to the frame 5 through a threaded through hole on a side surface of the bottom of the frame 5, and further, by screwing the fastener 7, one end of the fastener 7 may enter the accommodating cavity 504 to contact with the axial surface of the shaft part 6 to be tested resting against the first tapered portion 5042, so as to provide a fastening force to the shaft part 6 consistent with the tapered direction of the first tapered portion 5042, that is, may provide a fastening force to the shaft part 6 from the bottom of the frame 5 toward the top of the frame 5. The fastener 7 is arranged to enable the shaft part 6 to be tested to be stable after the key groove is perpendicular to the axis of the adapter shaft 300 by the locating piece 800, so that displacement can not occur in the installation and debugging processes of other parts, and the measurement accuracy is ensured.

In some embodiments, the adaptor shaft 300 may include a stop section 302, a sliding fit section 304 and a limit section 306 connected in sequence, where the stop section 302 is located in the measurement cavity 502, the sliding fit section 304 is slidably connected to the frame 5, and the limit section 306 is located outside the frame 5 and connected to the locking member; the symmetry measuring device further comprises elastic elements with two ends respectively acting on the stop section 302 and the frame 5, the elastic elements being located in the measuring cavity 502.

As illustrated in fig. 1, the adapter shaft 300 may include a stop segment 302, a slip segment 304, and a stop segment 306, which are connected in sequence. The stop segment 302 is positioned within the measurement cavity 502, and the diameter of the stop segment 302 may be greater than the diameters of the slip fit segment 304 and the stop segment 306. The sliding fit section 304 can be inserted into the first through hole 508 at the top of the frame 5, so that the sliding fit section 304 can rotate in the first through hole 508 at the top of the frame 5 through machining precision and coaxiality between the axis of the adapter shaft 300 and the axis of the first through hole 508 at the top of the frame 5 is ensured in the rotating process. The limiting section 306 may be located on the outer side of the top of the frame 5, and the limiting section 306 may be provided with a notch for accommodating the locking member. The limiting piece 1 may be clamped with a notch on the limiting section 306 to limit the movement of the adaptor shaft 300 towards the measurement cavity 502, for example, the limiting piece 1 may be a part that limits axial movement, such as a clamp. And the limiting piece 1 can also select parts such as a gasket, and is clamped with a notch on the limiting end so as to adjust the depth of the adapter shaft 300 which can be inserted into the measuring cavity 502. When the adapter shaft 300 is connected with the positioning piece 800 or the measuring instrument, the positioning block 804 at the lower part of the positioning piece 800 or the distance between the measuring head 404 of the measuring instrument and the shaft part 6 to be measured can be adjusted through the notch of the limiting piece 1, such as the clamping clips or the gaskets with different numbers, which are clamped on the limiting section 306, so that the adapter shaft can be adapted to the shaft part 6 with different diameters, and the range of the shaft part 6 to be measured, which can be adapted by the symmetry measuring device, is improved.

In some embodiments, an elastic member may be further disposed between the stop section 302 and the inner side surface of the top of the frame 5, and when the adaptor shaft 300 is detachably connected to the positioning member 800 for positioning the bottom surface of the key slot of the shaft part 6 to be tested, the elastic member is compressed to apply a pre-tightening force to the bottom surface of the key slot, so that the shaft part 6 that is already positioned does not undesirably move when the fastener 7 is screwed to fasten the shaft part 6 after the positioning is completed. On the other hand, by providing the elastic member between the stop section 302 and the inner side surface of the top of the frame 5, when the adapter shaft 300 is detachably connected with the measuring instrument, the measuring instrument can be prevented from being collided with the frame 5 when being lifted upwards, so that the measuring instrument can be quickly lifted upwards to rotate the measuring instrument to prevent the measuring head 404 of the measuring instrument from being damaged due to collision with the key slot, and the measuring instrument can be quickly lifted upwards to prevent the measuring head 404 of the measuring instrument from being damaged by the movement of the shaft part 6 when the shaft part 6 needs to be moved. Therefore, the convenience of operation is greatly improved, and the measurement speed and efficiency are improved.

In some embodiments, the stop section 302 of the adapter shaft 300 is provided with a first adapter for removable connection with a second adapter on the fixture 800 or a third adapter on the dial indicator 4. The first switching portion may be a blind hole formed at the bottom side of the stop section 302, and the second switching portion and the third switching portion are coaxial after being matched with each other through machining precision, and a threaded hole may be machined in the side wall of the blind hole formed at the bottom side of the stop section 302, and fastening is achieved through a set screw after the second switching portion and the third switching portion are inserted into the first switching portion.

In some embodiments, the first transition may be a profiled mechanical interface disposed on the bottom side of the stop segment 302. For example, the profiled mechanical interface may comprise a blind hole which is open on the bottom side of the stop section 302, and a through slot (not shown in the drawing) which is "T" shaped in side view is machined in the side wall of the blind hole on the bottom side of the stop section 302. A "T" shaped adapter block (not shown in the drawings) may also be provided, the vertical section of which may be machined with a blind hole for detachable connection with the second adapter on the fixture 800 or the third adapter on the dial indicator 4, and the transverse section of which may be rotated by an angle after being inserted into the "T" slot through the vertical section of the "T" shaped through slot on the side wall of the blind hole on the bottom side of the stop section 302, such that the transverse section of the "T" shaped adapter block is screwed into the transverse section of the "T" shaped through slot. The assembly precision of the transverse section of the T-shaped through notch and the transverse section of the T-shaped transfer interface is ensured through the machining precision, so that the coaxiality of the vertical section of the T-shaped transfer block and the transfer shaft 300 is ensured after the T-shaped transfer block is screwed into the transverse section of the T-shaped through notch. The vertical section of the "T" shaped adapter may be detachably connected to the second adapter on the positioning member 800 or the third adapter on the dial indicator 4 by a jackscrew, or by a threaded connection, or the like.

In some embodiments, the first, second and third transfer portions may be cylindrical, and a transfer block (not shown in the drawings) is provided, and one end of the transfer block is connected to the first transfer portion and then connected to the second and third transfer portions, respectively. The connection of the first adapter part with the second adapter part and the third adapter part can be realized by jackscrews, threaded connection and the like. By arranging the adapter blocks, rapid assembly among the components can be realized.

In some embodiments, the outer diameter of the stop section 302 is larger than the outer diameter of the sliding section 304, the elastic member is a spring 2, and the spring 2 is sleeved on the sliding section 304.

In some embodiments, the frame 5 further includes an auxiliary reference wall 506 disposed on a side wall of the frame 5 and perpendicular to the top of the frame 5, and the auxiliary reference wall is provided with a second through hole 510. The perpendicularity of the auxiliary reference wall 506 and the outer side surface of the top of the frame 5 is ensured through machining precision, and then the perpendicularity of the second through hole 510 and the first through hole 508 and the adapter shaft 300 is ensured. The auxiliary reference wall 506 or the second through hole 510 on the auxiliary reference wall 506 may be used as a reference of the auxiliary measuring instrument 9, for example, a reference of the dial indicator 4 or a caliper, so as to measure whether the perpendicularity of the adapter shaft 300, the perpendicularity of the dial indicator body 402, and the like meet the measurement accuracy requirement, and may also be used to measure the perpendicularity error of the dial indicator body 402 before and after rotation or before and after fixing each component to each other, and correct the measurement or calculation result of the keyway symmetry error.

In some embodiments, the measurement cavity 502 may be provided with an opening in a positive V-shape to form a second taper 5022 that accommodates the shaft-like part 6. The measuring cavity 502 at the upper part of the frame 5 may be provided with an opening in a positive V-shape to form a second taper 5022. The side wall of the second tapered portion 5022 tapers from the top of the frame 5 to the bottom of the frame 5, so that the shaft part 6 to be measured can be placed against the side wall of the second tapered portion 5022, and the axis of the first through hole 508 at the top of the frame 5 and the axis of the adapter shaft 300 penetrate through the circle center of the cross-section circle of the shaft part 6 to be measured through machining precision. Therefore, the shaft part 6 to be measured abuts against the second tapered part 5022 to be used as a reference, so that the shaft part 6 can be moved conveniently, the reference of the shaft part 6 to be measured and the reference of the measuring instrument cannot move relatively, and the measuring precision and the convenience of operation are ensured. When the shaft part 6 is placed on the second tapered portion 5022, the placement of the shaft part 6 is more stable because the gravity is consistent with the tapered direction of the second tapered portion 5022.

In some embodiments, the fastener may be used to provide a fastening force to the shaft part 6 consistent with the tapering direction of the first taper 5042 or the second taper 5022 after the shaft part 6 abuts the first taper 5042 or the second taper 5022.

In some embodiments, the fastening member may be a gripping portion detachably connected with the frame 5 for gripping the circumferential surface of the shaft-like part 6 placed against the positive V-shaped opening of the measuring cavity 502, i.e. the second tapered portion 5022. In this case, the grip force is provided to the shaft-like part 6 in conformity with the tapering direction of the second tapered portion 5022, that is, from the measuring chamber 502 toward the receiving chamber 504, by screwing the fastener 7 to the outside of the frame 5. The gripping portion may be configured to grip, for example, a lasso, etc., to bind and fasten the shaft-like member 6. When the shaft-like part 6 comprises a ferromagnetic material, the grip may be a permanent magnet.

In some embodiments, the steps of making the actual measurements are as follows:

The shaft part 6 to be measured is placed into the first taper portion 5042 or the second taper portion 5022 in the frame 5, and the shaft part 6 to be measured is rotated so that the positioning block 804 of the positioning piece 800 enters the key groove. Under the action of the elastic piece on the adapter shaft 300, the positioning surface of the positioning block 804 is tightly contacted with the ground of the key slot of the shaft part 6 to be tested, and the positioning block 804 is not contacted with the side surface of the key slot. The fastener 7 is screwed to provide a tightening force in accordance with the tapering direction of the first tapering portion 5042 or the second tapering portion 5022 to the shaft-like part 6 to be measured. So that the shaft-like part 6 to be measured is fixed in the first tapered portion 5042 or the second tapered portion 5022;

The positioning block 804 plays roles of centering, aligning and orienting, so that the position of the shaft part 6 to be measured in the first tapered portion 5042 or the second tapered portion 5022 is the same as the position of the positioning block 804 in the key slot. So that the axis of the adapter shaft 300 is perpendicular to the bottom surface of the key slot and passes through the center of the cross-sectional circle of the shaft-like part to be measured. At this time, the positioning piece 800 can be removed, a measuring instrument such as a lever dial indicator 4 can be replaced, and the measuring instrument and the adapter shaft 300 can be locked and fixed;

The rotating rod and the measuring head 404 of the measuring instrument such as the lever dial indicator 4 are adjusted, one side surface of the measuring instrument, which contacts with the key slot, reads the reading of the lever dial indicator 4, the rotating rod is gently rotated to enable the rotating rod to rotate 180 degrees, the measuring head 404 of the measuring instrument is driven to rotate and then contacts with the other side surface of the key slot, the reading of the lever dial indicator 4 is read again, and the difference value of the numerical values of the two measuring readings is substituted into the corresponding formula to calculate the symmetry error of the key slot. Or the maximum reading difference value of two points which are farthest from each other in the length direction of the key slot can be measured along the length direction of the key slot and used as the longitudinal symmetry error value of the key slot.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.

Claims (10)

1. Symmetry measuring device for measure the keyway symmetry of axle type part, its characterized in that, symmetry measuring device includes:

The frame is provided with a measuring cavity and a containing cavity which is used for containing the shaft parts and is provided with an opening above, and the measuring cavity is communicated with the containing cavity through the opening;

The switching shaft is slidably and rotatably connected to the frame along the axial direction of the switching shaft, and the switching shaft is at least partially positioned in the measuring cavity;

the limiting piece is used for limiting the transfer shaft to move towards the measuring cavity and is clamped with the transfer shaft; the limiting piece is positioned outside the frame;

The dial indicator is detachably connected to the adapter shaft and is provided with a measuring head which is arranged at an angle with the adapter shaft, and the measuring heads of the dial indicator are respectively contacted with two side faces of the key groove which are symmetrically distributed along the radial direction of the shaft part under the rotation action of the adapter shaft so as to measure the symmetry degree of the key groove of the shaft part.

2. The symmetry-measuring device according to claim 1, further comprising a positioning member detachably connected to the adapter shaft and provided with a positioning surface perpendicular to the adapter shaft for positioning a bottom of the key groove of the shaft-like component.

3. The symmetry-measuring device according to claim 1, wherein the opening of the receiving chamber is arranged in an inverted V-shape to form a first taper for receiving the shaft-like component.

4. A symmetry-measuring device according to claim 3, further comprising a fastener screw-connected to the frame, a stem portion of the fastener being positioned in the receiving chamber to bear against the peripheral surface of the shaft-like member; the fastener is disposed between two sidewalls of the first tapered portion.

5. The symmetry measuring device according to any of claims 1-4, wherein the adapter shaft comprises a stop section, a slip fit section and a limit section connected in sequence, wherein the stop section is positioned in the measuring cavity, the slip fit section is slidingly connected to the frame, and the limit section is positioned outside the frame and connected with the locking member; the symmetry measuring device further comprises elastic pieces, wherein the two ends of the elastic pieces respectively act on the stop section and the frame, and the elastic pieces are positioned in the measuring cavity.

6. A symmetry-measuring device according to any of claims 2-4, wherein the stop section of the adapter shaft is provided with a first adapter part for detachable connection with a second adapter part on the positioning element or a third adapter part on the dial indicator.

7. The symmetry-measuring device according to claim 5, wherein the outer diameter of the stop section is larger than the outer diameter of the slip-fit section, the elastic member is a spring, and the spring is sleeved on the slip-fit section.

8. The symmetry-measuring device according to any of claims 1-4, wherein the frame further comprises an auxiliary reference wall provided on a side wall of the frame perpendicular to the top of the frame, the auxiliary reference wall being provided with a through hole.

9. A symmetry-measuring device according to claim 1 or 2, wherein the measuring chamber is provided with a positive V-shaped opening to form a second taper for receiving the shaft-like element.

10. The symmetry-measuring device according to claim 9, further comprising a gripping portion detachably connected to the frame for gripping a peripheral surface of the shaft-like part against the opening of the measuring chamber to provide the shaft-like part with a gripping force from the measuring chamber toward the receiving chamber.