JP2006010600A - Method and tool for testing breakage strength of gear tooth - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a tool for testing breakage strength for a gear tooth capable of carrying out a test efficiently using a general strength testing machine, and capable of conducting the stable test even when a testing gear is a helical gear. <P>SOLUTION: An outer circumferential one-portion of the testing gear A is fallen into a setting groove 6 provided in an upper face of a receiving table 5 in the testing jig, the center-symmetric-positional teeth of the testing gear A are reception-supported by left and right edges 6a, 6b of the setting groove 6, a vertical load is applied from the testing machine onto a pressurizing piece 11 abutting to an upper part of the setting groove 6, under this condition, and the tooth breakage strength of the testing gear A is investigated, based on the applied load at the time when the teeth supported by the edges 6a, 6b of the setting groove 6 are broken. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  According to the present invention, a method for testing the breaking strength of a gear (strength when a tooth is broken), a method for testing the breaking strength of the gear, and the method can be easily implemented, and a stable test can be performed on a helical gear. The present invention relates to a fracture strength test jig.

  Sintered gears obtained by sintering metal compacts are more likely to have variations in tooth strength compared to gears formed from molten metal. Therefore, for quality assurance, it is necessary to inspect whether or not the broken gear strength is ensured as required for the manufactured gear.

  With respect to this breaking strength test method (no specific method is specified), Patent Document 1 below introduces a commonly used method and proposes a gear load test apparatus that solves the problems of the method. The gear load testing device disclosed in Patent Document 1 fixes a gear to be tested to a rotating shaft supported by a support, and meshes the gear to be tested with a fixed gear having a higher strength than the gear to be tested. When a rotational moment is applied to the rotating shaft with a semicircular flywheel, the support base is vibrated with a shaker in this state, an impact load is applied to the teeth of the gear to be tested, and the teeth are destroyed. The applied load is determined to check whether the tooth strength meets the requirement.

  Patent Document 2 below discloses a gear bending fatigue test method and apparatus in which a pair of racks are engaged with both sides of a test gear, the test gear is pushed and pulled in the longitudinal direction of the rack, and a load is repeatedly applied to the teeth of the test gear. Therefore, the breaking strength can be measured using this method and apparatus.

However, the methods disclosed in Patent Document 1 and Patent Document 2 require a dedicated test apparatus. Also, it is difficult to set up the test gear and change the setup when the type and size of the test gear changes, making it difficult to increase the inspection efficiency.
JP 2000-65688 A JP-A-11-230881

  Many general strength testing machines apply a load in the vertical direction. If the breaking strength can be easily checked using a general strength tester that applies a load in the vertical direction, an existing strength tester can be used, and the economic burden can be reduced. Further, if the setting of the test gear and the setup change when the type and size of the test gear are changed, the efficiency of the test can be improved. However, the test methods disclosed in Patent Document 1 and Patent Document 2 described above can be used. And devices cannot meet that demand.

  Therefore, the present invention is capable of performing an efficient test using a general strength testing machine, and a gear tooth breakage strength test method and a tooth breakage strength capable of performing a stable test even if the test gear is a helical gear. It is an object to provide a test jig.

  In order to solve the above problem, in the present invention, a part of the outer periphery of the test gear that is horizontally oriented is dropped into a set groove provided on the upper surface of the receiving table, and the right and left edges of the set groove have the test gear. The gear of the gear for examining the breaking strength of the test gear from the applied load when the tooth supported at the edge of the set groove is broken by applying a vertical load to the test gear in this state. To provide a method for testing the fracture strength.

  In addition, the set groove includes a cradle having a set groove on the upper surface and a pressurizer arranged immediately above the set groove, and a part of the outer periphery of the test gear that is horizontally oriented is dropped into the set groove. The left and right edges of the test gear support and support the teeth at the center symmetrical position of the test gear. In this state, the pressurizer is placed on top of the test gear, and a vertical load is applied to the test gear from the test machine via the pressurizer. Also provided is a gear breaking strength test jig in which the breaking strength of the test gear is examined from the applied load when the teeth supported by the edges of the gear are broken.

  This bending strength test jig has opposite directions on the left and right edges of the set groove at an angle corresponding to the helical twist angle of a helical gear (here, a helical gear including a screw gear). When it is inclined to, the helical gear tooth breakage strength test can be performed stably.

A more preferable form of this bending strength test jig will be described below.
(1) The cradle is provided with a stopper for receiving the one end surface and the other end surface of the test gear supported by the cradle and preventing the test gear from moving in the axial direction.
(2) A base that supports the cradle and the pressurizer is included, and the cradle can be freely attached to and detached from the base so that the cradle can be replaced with one that matches the type and size of test gear. .
(3) The cradle is provided with a first region provided with the set groove and a second region without the set groove, and the groove longitudinal protrusion of the test gear from the set groove is higher than the first region. It is arranged above the second region where the height is lowered.

  According to the present invention, the bending strength test method and the test jig apply a load to the test gear from above by supporting it with the left and right edges of the set groove provided in the cradle of the test gear at the center symmetrical position. The test can be performed using a simple strength tester.

  The setting of the test gear is completed simply by fitting the gear into the set groove provided on the cradle, and the setting work is simple. Changing the type and size of the test gear can be handled by exchanging the cradle, so it is easy to change the setup when the type and size of the test gear changes, and increase the efficiency of the test. Is also possible.

  In addition, since the helical gear is set to the cradle provided with the set groove for the spur gear, the inclination directions of the two teeth at the center symmetrical position supported by the left and right edges of the set groove are opposite to each other. The tooth is supported at one point and the support becomes unstable, and the gear movement due to the load occurs, and a stable test cannot be performed. Therefore, a cradle tilted in the opposite direction of the left and right edges of the set groove is used. When the cradle is used, the helical gear can be stably supported, and the load is uniformly applied to the two teeth at the centrally symmetric position, thereby improving the stability and reliability of the test.

  The stopper (1) described above is particularly effective for the test jig that supports the tooth at the center symmetrical position at the edge of the set groove inclined in the opposite direction and applies a vertical load to the helical gear in this state. The reason will be described in the next section.

  In addition, the detachable attachment of the cradle to the base can cope with variations in the type and size of the test gear with the same test jig.

  Further, the cradle is provided with a first region and a second region having a height lower than that of the first region, and the groove longitudinal protrusion of the test gear from the set groove is disposed above the second region. In this case, it is possible to prevent the teeth other than the tooth to be tested from interfering with the test jig and to perform the tooth break strength test of the stepped gear (a gear in which different diameter gears are integrally formed in series).

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. An exemplary tooth break strength test jig is for performing a tooth break strength test of a helical gear, and includes a base 1 having a stand 2 and a cradle 5 provided on the base 1; A screw 10 with a knob for fixing the cradle 5 and a pressurizer 11 for applying a vertical load to the test gear (helical gear) A from above are provided.

  The stand 2 has an overhanging portion 3 with a cantilever structure in the upper portion thereof, a guide hole 4 (see FIG. 3) is provided in the overhanging portion 3, and a pressurizer 11 is inserted into the guide hole 4 so as to be movable up and down. is doing.

  The cradle 5 is provided with a set groove 6 provided on the upper surface of the first region 5a and further provided with a second region 5b having a height lower than that of the first region 5a in front of the first region 5a. . The illustrated test gear A is a stepped gear in which two helical gears having different diameters are integrally formed, and teeth other than the tooth to be tested may interfere with the jig. Although the height of the second region 5b is set lower than that of the first region (to escape the second region), the second region is not particularly necessary when the test gear A is a normal spur gear.

The set groove 6 is a groove extending in the front-rear direction and opening to the front end face of the first region 5a, and the groove width is constant. Further, the left and right edges 6a and 6b of the set groove 6 are inclined such that one edge 6a rises forward and the other edge 6b leans forward. The inclination angles θ ₁ and θ ₂ of the left and right edges 6a and 6b are made to correspond to the torsion angles of the helical gear teeth to be tested, and both the angles θ ₁ and θ ₂ are equal.

  The groove width W of the set groove 6 is such that the left and right edges 6a and 6b are in the groove between the teeth at a position that is swung approximately 45 ° to the left and right with respect to the center line C (the position α in FIG. 1 is approximately 45 °). When set to enter, the support of the test gear A is particularly stable, and an ideal test can be performed.

  Since the illustrated broken strength test jig is for a helical gear, the cradle 5 includes stoppers 7 and 8 for supporting both end surfaces of the test gear A. The stoppers 7 and 8 have independent parts attached to the cradle 5 with fastening bolts 9 for ease of processing, but may be formed integrally with the cradle 5.

  The cradle 5 combined with the stoppers 7 and 8 is screwed with a knob screw 10 penetrating the stand 2 and fixed to the base 1 with the knob screw 10. It can be removed and removed from the base 1. For this cradle 5, a plurality of cradles suitable for the type and size of the test gear are prepared, and an optimum one is selected and used. Since the cradle 5 can be attached and detached simply by operating one screw 10 with a knob, it is easy to change the setup when the type and size of the test gear changes.

  A test gear (helical gear) A is set in the set groove 6 of the bending strength test jig configured as described above, and a pressurizer 11 is applied to the upper portion of the test gear A. Then, a vertical load is applied to the pressurizer 11 from a strength tester (this may be a general purpose universal tester). In the test gear A, the teeth at the center symmetrical position are supported by the left and right edges 6a and 6b of the set groove 6, and the load applied to the test gear A is transmitted to the teeth.

  When the applied vertical load exceeds the limit of the proof stress, the tooth receiving the load breaks, and by confirming the applied load at that time, it can be determined whether the broken strength meets the required value.

  In the illustrated test apparatus, since the edges 6a and 6b of the set groove are inclined in opposite directions, the test gear A tries to rotate when a vertical load is applied from the test machine, but the rotation is prevented. Since the stoppers 7 and 8 are provided, the test can be performed stably.

  FIG. 5 is a cradle for the spur gear breaking strength test jig. The set groove 6 provided in the pedestal 5 is a groove in which the left and right edges 6a and 6b are arranged horizontally and in parallel.

Front view showing an example of the fracture strength test jig of this invention Sectional view along the line II-II in FIG. Plan view of the test jig in FIG. (A) Perspective view showing the main part of the cradle provided in the test jig of FIG. 1, (b) Side view showing the inclined state of the edge of the set groove The perspective view which shows the principal part of the cradle of the spur gear tooth bending strength test jig

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Stand 3 Overhang | projection part 4 Guide hole 5 Receptacle 5a 1st area | region 5b 2nd area | region 6 Set groove 6a, 6b Edge 7 and 8 of set groove Stopper 9 Fastening bolt 10 Screw 11 with clamp 11 Pressurizer A test gear

Claims (6)

  A part of the outer periphery of the test gear in the horizontal orientation is dropped into a set groove provided on the upper surface of the receiving table, and the left and right edges of the set groove receive and support the teeth at the center symmetrical position of the test gear. A gear tooth breakage strength test method in which a vertical load is applied to a test gear and the tooth breakage strength of the test gear is examined from the applied load when the tooth supported by the edge of the set groove is broken.   A cradle having a set groove on the upper surface, and a pressurizer disposed immediately above the set groove, and a part of the outer periphery of the test gear that is horizontally oriented is dropped into the set groove so that the right and left sides of the set groove In this state, the pressurizer is placed on the upper part of the test gear, and a vertical load is applied to the test gear from the test machine via the pressurizer. Gear breakage strength test jig in which the breakage strength of the test gear is examined from the applied load when the tooth supported by the rod is broken.   The gear bending strength test jig according to claim 2, wherein the left and right edges of the set groove are inclined in directions opposite to each other at an angle corresponding to a helical angle of a helical gear tooth.   The gear breakage strength according to claim 2 or 3, wherein the cradle is provided with a stopper for receiving the one end surface and the other end surface of the test gear supported by the cradle and preventing the axial movement of the test gear. Test jig.   A base that supports the cradle and the pressurizer is included, and the cradle can be freely attached to and detached from the base so that the cradle can be replaced with one that matches the type and size of the test gear. Item 5. A gear breakage strength test jig according to any one of Items 2 to 4.   The cradle is provided with a first region provided with the set groove and a second region without the set groove, and the height of the second region is made lower than the height of the first region, and above the second region. The gear tooth breakage strength test jig according to any one of claims 2 to 5, wherein a groove longitudinal projecting portion from the set groove of the test gear is arranged.

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