JP2005214646A - Testing method for gear tooth break strength of gearwheel and arrangement of testing the gear tooth break strength - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure the gear tooth break strength of gear by loading the gear tooth of a gearwheel. <P>SOLUTION: By arranging a gearwheel with inclination of which the teeth are formed obliquely to the axial direction and positioning and fixing on a stage 1, and pressing a cone 3 supported with a guide 2 on one tooth of the gear from above, the gear tooth strength is tested from the load added to the cone when the tooth pressed with the cone 3 in the tooth width direction breaks. The gearwheel A is desirably provided with a positioning tool arranged in the front of the gearwheel A for fixing on the stage 1, and positioned on tooth standard by pressing to the positioning tool. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a test method and a test apparatus for examining the breaking strength of gears, in particular, the breaking strength of sintered gears (strength when teeth are broken).

  Sintered gears obtained by sintering metal compacts tend to have variations in tooth strength compared to gears manufactured by machining 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.

  In general, there is no prescribed method for the gear tooth breakage strength test, and the current situation is that each company conducts its own method.

  Many of the general strength testing machines apply a load from above, and using such a testing machine, the gear teeth are inclined with respect to the axial direction like bevel gears, helical gears, and helical gears. In order to measure the breaking strength of the formed gear, an ingenious device is required.

  For example, as a test method for examining the bending strength by applying a load to the teeth of the bevel gear from above, the bevel gear is placed facing upward, and the pressurizer is brought into contact with the tooth surface of the adjacent tooth in this state. A method of pushing into the tooth gap is conceivable.

  Although the bending strength can be obtained from the load when the tooth is broken by the pushing, the load is simultaneously applied to two teeth in this method, so it is difficult to accurately obtain the breaking strength of each tooth.

  Depending on the setting condition of the bevel gear, it can be considered that there is a difference in the load applied to the two teeth, and it is difficult to accurately determine how much load is applied to the broken tooth.

  In particular, sintered gears generally have a larger variation in dimensional accuracy than machined gears, and variations in test conditions due to variations in dimensional accuracy also cause a reduction in measurement accuracy.

  If the bending strength of the sintered gear can be accurately obtained, quality assurance can be easily performed and the reliability of the product can be further increased.

  Therefore, an object of the present invention is to make it possible to accurately measure the breaking strength by applying a load from above to the gear teeth formed with the gear teeth formed obliquely with respect to the axial direction.

In order to solve the above-described problems, the present invention provides the following gear breakage strength test method (1).
(1) A gear having gear teeth formed obliquely with respect to the axial direction is positioned and fixed with an inclination to the upper side, a cone is pressed against one tooth of the gear from above, and the tooth is A method for testing the breaking strength of gears, which examines the breaking strength based on the load applied to the cone when the teeth pressed in the thickness direction are broken.

In addition, the present invention also provides the following (2) and (3) breaking strength test apparatus.
(2) A base that supports a gear in which gear teeth are formed obliquely with respect to the axial direction and supports the gear in an inclined posture, and a cone that is supported by a guide attached to the base and is arranged above the gear on the base. And a spacer interposed between the reference surface of the base and the back surface of the gear, a shaft that is held by the base and is prevented from rotating by the base and passed through the hole in the center of the gear, and rotated by this shaft And a fastener that engages with the front surface of the gear so as not to rotate relative to the front surface of the gear, and a fastening tool that receives the reaction force from the shaft and presses the pressure tool. A gear tooth breakage strength test apparatus which is positioned and fixed with reference to the back surface in this state, and in this state the tooth breakage strength is examined by the method of (1) above.
(3) A holder that supports the back surface of the conical portion of the bevel gear in an inclined posture, a base that supports the holder so as to be axially slidable, and a gear that is supported by a guide attached to the base and that gear on the holder And at least two ridges to be engaged with the teeth of the gear on the inner surface, the ridges are inserted into the gear grooves of the gear, and the front surface of the gear is partially covered A positioning tool for fitting and fixing in the groove of the base in a state, and a position adjusting tool for displacing the holder, and a gear supported by the holder by displacing the holder by the position adjusting tool. A gear tooth breakage strength testing apparatus in which the gear is positioned on the basis of the tooth part and the tooth breakage strength is examined by the method of (1) above.

  In the above-described broken strength test apparatus (3), as a positioning tool, a tooth that forms a relationship between a bevel gear tooth and a male and female is formed on the inner surface, and the tooth is meshed with the gear tooth to be tested as the ridge. It is preferable to use it.

  The above-described broken strength test apparatus (2) and (3) may be provided with a fine adjustment mechanism for the cone contact angle with respect to the gear teeth in which the gear teeth are formed obliquely with respect to the axial direction. it can.

  Since the test method and the test apparatus according to the present invention support the gear in an inclined arrangement, it is possible to apply a load to only one tooth of the gear from above, and to accurately measure the breaking strength.

  When the test is performed with the gear positioned on the back surface, there is a concern about variation in measurement accuracy due to a dimensional error of the gear. The broken strength test apparatus (2) can adjust the measurement position of the gear teeth by interposing a spacer.

  In particular, if a sintered gear, which is likely to cause a large dimensional error in the manufacturing method, is positioned with respect to the back surface, variations in the positional relationship between the cone and the teeth contacting the cone can be suppressed due to the influence of the dimensional error in the axial direction. However, when the variation of each gear is large, it is necessary to adjust the spacer each time.

  On the other hand, since the bending strength test apparatus (3) performs the test by positioning with the bevel gear on the basis of the tooth part, the influence of the dimensional error of the gear is eliminated, and the test under the same conditions is reproduced. More accurate measurement can be performed.

  Further, the bending strength test apparatus of (3) has the advantage that the direction of the bevel gear can be freely changed by engaging the protrusion provided on the positioning tool with any tooth, and the strength test can be performed on any tooth. There is also an advantage that the structure is further simplified.

  In addition, as a positioning tool employed in the breaking strength test apparatus of (3), if a tooth forming a bevel gear and a male / female tooth is formed on the inner surface, the tooth portion on the inner surface of the positioning tool is formed. It can be simplified. That is, the bevel tooth portion of the workpiece molding die is processed using an electric discharge machine. If the tooth part processing electrode used at that time is diverted and the tooth part of the positioning tool is formed by electric discharge machining, the tooth part of the positioning tool can be easily and inexpensively formed. In addition, a wide meshing area with the bevel gear to be tested can be secured, and the bevel gear can be stably held during the test.

  In addition, the bending strength test apparatus to which a fine adjustment mechanism of the cone hitting angle with respect to the gear teeth is used, for example, a bevel tooth such as a bevel tooth, a helical bevel tooth, a spiral bevel tooth, and a zero-rubbe bevel gear. The test cone can be made to abut at an optimum angle even on teeth whose gear teeth are formed obliquely with respect to the axial direction, such as helical teeth, mountain teeth, and counter teeth, thereby improving the stability of the test. .

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 to FIG. 6 show an embodiment of the breaking strength test apparatus of the above-described form (2). This breaking strength test apparatus includes a base 1, a guide 2 fixed to the upper portion of the base 1, a cone 3 supported by the guide 2, a shaft 4 that is attached to the base 1 and a shaft 4, and a gear. A spacer 5 disposed on the back side of the bevel gear A exemplified as a gear whose teeth are formed obliquely with respect to the axial direction, a presser 6 for positioning and fixing the bevel gear A to the base 1, and the presser 6 and a stop ring 7 for applying a tightening pressure.

  The base 1 is provided with a reference surface 8 that is inclined at an angle of about 40 ° to 50 ° with respect to the bottom surface, and a shaft hole 9 that opens at the center of the reference surface 8. The shaft hole 9 is a hole whose axis is orthogonal to the reference plane 8, and penetrates the inclined rear surface 10 of the base 1. Further, a portion of the shaft hole 9 close to the reference surface 8 is a non-circular hole 9a having two parallel planes at opposite positions (see FIG. 6).

  The guide 2 is fixed to the base 1 using a plurality of bolts 11 (two in the figure) and a guide presser 12. A square hole 13 is formed in a portion of the guide 2 that protrudes on the reference surface 8, and the cone 3 is passed through the square hole 13 so as to be movable up and down.

  Further, in the illustrated test apparatus, the hole diameter of the bolt hole 14 provided in the guide 2 is set to a size that allows moderate accommodation (gap) between the bolt 11 passing through the hole, and within the range of such accommodation. By swinging the protruding portion of the guide 2 to the left and right, the contact angle of the cone 3 with respect to the teeth of the bevel gear can be finely adjusted. The fine adjustment mechanism for the contact angle of the cone 3 is simple in structure and easy to make, but is not limited to this.

  As shown in FIG. 5, the shaft 4 is formed with a male threaded portion 4a at the tip and a flange 4b at the rear, and between the male threaded portion 4a and the flange 4b, two planes parallel to the outer periphery are formed so as to have a non-cross section. A circular shape is used. The shaft 4 is inserted into the shaft hole 9 of the base 1, and the flange 4 b is locked to the stepped portion of the shaft hole 9 to be stopped by the base 1. At this time, the non-circular section 4c of the shaft 4 fits into the non-circular section 9a of the shaft hole 9, thereby preventing the shaft 4 from rotating.

  The spacer 5 has a thickness equal to or greater than the protruding length of the boss B of the bevel gear, and the spacer 5 is between the reference surface 8 of the guide 2 and the back of the conical portion of the bevel gear A. Intervened.

  As shown in FIG. 5, the presser 6 is a disc (part of the outer periphery is cut away to avoid interference with the cone 3) along the front surface (vertical side end surface) of the bevel gear A. A non-circular shaft hole 15 in which the non-circular portion 4c of the shaft 4 fits and fits is provided, and a positioning projection 16 is provided on the back surface.

  Further, the retaining ring 7 is one that is screwed into the male threaded portion 4 a of the shaft 4.

  As shown in FIG. 1 and FIG. 2, the breaking strength test apparatus constituted by the above elements has a spacer 5 in which a bevel gear A to be tested is set on a reference surface 8 of a base through a shaft 4 in a central hole. Put it on. Accordingly, the bevel gear A is positioned in the axial direction with respect to the back surface of the conical portion in contact with the spacer 5.

  Next, the presser 6 is fitted on the outer periphery of the shaft 4, and the protrusion 16 of the presser 6 that is prevented from rotating by the shaft 4 is engaged with the positioning recess provided on the front surface of the bevel gear A so that the bevel gear A is engaged. Is positioned in the circumferential direction. Then, the retaining ring 7 is screwed into the male screw portion 4a, and the presser 6 is pressed by the retaining ring 7 to fix the bevel gear A.

  Thereafter, the cone 3 is lowered and applied to the teeth of the bevel gear A. In this state, the cone 3 is pressurized by a press or the like, and the load when the tooth applied with the cone 3 is broken is measured to obtain the broken strength. .

  In addition, you may perform rotation prevention of the shaft 4, the pressing tool 6, and the bevel gear A with a key and a keyway.

  Reference numeral 17 in FIG. 1 denotes a lid that prevents the shaft 4 from coming off from the shaft hole 9 and is provided as necessary.

  FIGS. 7-11 is an Example of the fracture strength test apparatus of the form of the above-mentioned (3). This broken strength test apparatus includes a base 21, a guide 22 provided on one side of the base 21, a cone 23 supported by the guide 222, and a holder 24 that supports the bevel gear A in an inclined state. The positioning tool 25 is detachably attached to the base 21 and the position adjusting tool 26 is configured to displace the holder 24.

  The base 21 has a holder insertion hole 27 whose axis is inclined at an angle of about 40 ° to 50 ° with respect to the bottom surface, and a groove 28 into which the protrusion (first member 25a) on the back surface of the positioning tool 25 is fitted. An attachment reference surface 29 for the positioning tool 25 is provided at the entrance portion with the holder insertion hole 27 interposed therebetween. The holder insertion hole 27 is a stepped hole whose axis is perpendicular to the attachment reference plane 29. The attachment reference surface 29 is constituted by the uppermost groove surface of the groove 28 whose width is gradually increased toward the inlet side.

  In the illustrated test apparatus, the holder insertion hole 27 is provided through the rear surface 30 of the base 21 in consideration of workability, and the inlet of the hole on the rear surface 30 side is closed with a lid 31 fixed to the base 21. An end wall corresponding to the lid 31 may be formed integrally with the base 21 with the insertion hole 27 as a non-through hole.

  The guide 22 has a structure in which an H-shaped cone 23 is inserted into a vertically long T slot 22a so as to be movable up and down. The guide 22 and the cone 23 are as shown in FIG. Also good.

  The holder 24 includes a large-diameter portion 24a that supports the back surface of the conical portion of the bevel gear A, a hole 24b that receives a boss portion at the center of the bevel gear A, and a small-diameter shaft portion 24c that is integral with the large-diameter portion 24a. Although the thing is used, it is not limited to the thing of illustration.

  Here, the positioning tool 25 is a combination of a first member 25a (see FIG. 11) provided with teeth 32 meshing with the teeth of the bevel gear A on the inner surface and a second member 25b fixed to the base 21 with a bolt 33, The first member 25a brought into contact with the mounting reference surface 29 is pressed and fixed by the second member 25b.

  The ridges provided on the inner surface of the first member 25a and engaged with the teeth of the bevel gear A are not limited to the gear teeth. It is sufficient that the number of the ridges is at least two. However, the ridges provided with the teeth 32 forming the relationship between the teeth of the bevel gear and the male and female as the ridges are the electric discharge machining used for forming the teeth of the bevel gear used for the test. By using the machine electrode, the teeth 32 and the tooth grooves corresponding to the tooth portions of the bevel gear can be easily and inexpensively formed on the first member 25a by electric discharge machining. Fixing stability can also be increased.

  In addition, the first member 25a and the second member 25b may be integrally formed. However, when the first member 25a is independent as shown in the figure, when the shape or size of the bevel gear to be tested changes. Only the first member 25a can be exchanged to cope with it, and there is an advantage that the second member 25b can be shared.

  The position adjustment tool 26 is screwed into the lid 31, and the position adjustment tool 26 pushes and moves the holder 24.

  7 to 11 configured in this manner is particularly suitable for a bevel gear. For example, the bevel gear A to be tested is set in the holder 24.

  Next, the tooth 32 is meshed with the tooth of the bevel gear A, the first member 25a is fitted into the groove 28, and the second member 25b placed on the first member 25a is fixed to the base 21 with the bolt 33. . When the bolt 33 is tightened, the first member 25a is fixed on the attachment reference surface 29, and the first member 25a is also prevented from rotating by the side wall of the groove 28 at the same time.

  Thereafter, the position adjusting tool 26 is operated to push and move the holder 24, and the tooth portion of the bevel gear A held by the holder 24 is pressed against the inner surface of the first member 25a. Then, the cone 23 is lowered and applied to the teeth of the bevel gear A. In this state, the cone 23 is pressurized by a press or the like, and the load when the tooth applied with the cone 23 is broken is measured to obtain the broken strength. .

  According to this method, since the bevel gear A is positioned on the basis of the tooth portion, the positional relationship between the cone 23 and the teeth of the bevel gear is stable, and the same test conditions are reproduced even if a dimensional error occurs in the bevel gear A. The For this reason, the reliability of the measurement is further increased, and it becomes possible to determine the tooth break strength more accurately.

  Further, the teeth on the inner surface of the first member 25a can be engaged with an arbitrary tooth of the bevel gear A, and the advantage that the tooth for checking the breaking strength can be selected at random or the first member to be engaged with the bevel gear can be selected. There is also an advantage that the stability of fixing the bevel gear can be increased by increasing the number of teeth.

Sectional drawing which shows one form of the fracture strength test apparatus of this invention Front view of the test apparatus of FIG. FIG. 1 is a plan view showing the test apparatus of FIG. 1 with a guide removed. A view of a part of the test apparatus of FIG. Perspective view of the presser viewed from the shaft and back side 1 is a perspective view showing the base of the test apparatus of FIG. 1 with a guide and a cone attached. Sectional drawing which shows the other form of the fracture strength test apparatus of this invention Front view of the test apparatus of FIG. FIG. 7 is a plan view of the guide and cone of the test apparatus. The perspective view which shows the use condition of the testing apparatus of FIG. The figure which shows the inner surface of the 1st member of the positioning tool used for the test apparatus of FIG.

Explanation of symbols

1, 21 Base 2, 22 Guide 3, 23 Cone 4 Shaft 5 Spacer 6 Presser 7 Stop ring 8 Reference surface 9, 15 Shaft hole 11 Bolt 12 Guide presser 13 Square hole 14 Bolt hole 16 Protrusion 24 Holder 25 Positioning tool 25a First member 25b Second member 26 Position adjustment tool 27 Holder insertion hole 28 Groove 29 Mounting reference surface 31 Lid 32 Teeth 33 Bolt

Claims (5)

  A gear tooth formed obliquely with respect to the axial direction is positioned and fixed so as to be inclined with respect to the upper side, and a cone is pressed against one tooth of the gear from above, and the cone is used in the tooth thickness direction. A method for testing the breaking strength of gears, which examines the breaking strength based on the load applied to the cone when the pressurized tooth is broken.   A base that supports the gear formed by tilting the gear teeth obliquely with respect to the axial direction in an inclined posture, a cone that is supported by a guide attached to the base and is arranged on the top of the gear on the base, A spacer interposed between a reference surface of the base and the back surface of the gear; a shaft that is held by the base and is prevented from rotating by the base and passed through a hole in the center of the gear; and A pressing tool that stops rotation and engages with the front surface of the gear so as not to rotate relative thereto; and a clamping tool that receives the reaction force from the shaft and presses the pressing tool. A gear tooth breakage strength test apparatus which is sandwiched between a pressing member and positioned and fixed with reference to the back surface, and in this state, the tooth breakage strength is examined by the method according to claim 1.   A holder that supports the back of the conical portion of the bevel gear in an inclined posture, a base that supports the holder in an axially slidable manner, and a guide that is attached to the base, and is supported on the top of the gear on the holder. The cone to be arranged and at least two ridges to be engaged with the teeth of the gear on the inner surface, the ridges are inserted into the gear grooves of the gear, and the front surface of the gear is partially covered A positioning tool that is fitted and fixed in a groove of a base; and a position adjusting tool that displaces the holder. The position adjusting tool is used to displace the holder and support the gear supported by the holder against the positioning tool. A gear breakage strength test apparatus that contacts the teeth and positions the gears on the basis of a tooth portion and examines the breakage strength by the method according to claim 1.   4. The gear tooth break according to claim 3, wherein the positioning tool is formed with teeth forming a male-female relationship with the teeth of the bevel gear on the inner surface, and the teeth are meshed with the gear teeth as the ridges. Strength test equipment.   The gear bending strength test device according to any one of claims 2 to 4, further comprising a fine adjustment mechanism for a contact angle of the cone with respect to the gear teeth formed so that the gear teeth are inclined with respect to the axial direction.

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