JP5363512B2 - Backlash measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlash measuring device capable of easily measuring a backlash between gears assembled in a gear case, without requiring any special experience and skill. <P>SOLUTION: A backlash measuring device measures a backlash between a first gear 16, and second gears 17 and 18 which are engaged with each other in a gear case 1 and supported by the gear case 1, and to which a first transmission shaft 3 and a second transmission shaft 10 are respectively coupled. The backlash measuring device comprises a work holding body 40 for holding the gear case 1 at a predetermined position; a normal/reverse rotation driving mechanism 45 capable of normally and reversely rotating the first transmission shaft 3, and having rotation state sensors 99 and 107 for detecting the rotation state of the first transmission shaft 3; and an electronic control unit 46 which computes a backlash value by receiving detection signals of the rotation state sensors 99 and 107 when reversely rotating the first transmission shaft 3 after normally rotating that by the actuation of the normal/reverse rotation driving mechanism 45, and determines the propriety of the value. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention includes a first gear coupled to a first transmission shaft supported on a gear case, a second gear coupled to or connectable to a second transmission shaft supported on the gear case, and meshing with the first gear. The present invention relates to a backlash measuring device for measuring backlash between the two.

  The backlash measuring device is already known as described in Patent Document 1.

Japanese Unexamined Patent Publication No. 1-165929

  As disclosed in Patent Document 1, the conventional backlash measuring device is configured to directly support only a pair of gears that are to be measured for backlash and mesh with each other. When the gear is installed in the gear case, there is no guarantee that the backlash as measured is guaranteed.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a backlash measuring device that can easily measure backlash between gears incorporated in a gear case without requiring special skill. Objective.

To achieve the above object, the present invention provides a first gear connected to a first transmission shaft supported on a gear case and a first gear connected to or connected to a second transmission shaft supported on the gear case. A backlash measuring device for measuring backlash between a second gear meshing with a gear, the workpiece holding body for holding the gear case in a predetermined position, and the second gear in a state where the second gear is rotatable. After the first transmission shaft is rotated forward by more than the angle corresponding to the assumed backlash, the first transmission shaft can be rotated more than the angle corresponding to the assumed backlash, and the rotation state of the first transmission shaft is detected. a reverse rotation drive mechanism having a rotation state sensor, said first transmission shaft by operation of said forward and reverse drive mechanism in a state of being rotatable with the second gear, versus the backlash envisaged To After angle or more forward, when reversed over an angle corresponding to the backlash envisaged from the start reverse rotation of the first transmission shaft of the rotation angle of the first transmission shaft to surge timing of torque A first feature is that it includes an electronic control unit that receives a signal from the rotation state sensor , calculates the backlash value, and determines whether the value is appropriate. The rotational state sensor corresponds to a rotational position sensor 99 and a torque sensor 107 in an embodiment of the present invention described later.

  In addition to the first feature, the present invention is a rotational position sensor for detecting the rotational position of the first transmission shaft, and a torque sensor for detecting the rotational torque of the first transmission shaft. A second feature is that the electronic control unit receives the detection signals of the rotational position sensor and the torque sensor and calculates the backlash value.

  Furthermore, in addition to the first or second feature, the present invention is supported by the gear case so that the first transmission shaft and the second transmission shaft are orthogonal to each other, and the first gear is a bevel-type drive gear. The second gear is a pair of bevel type driven gears meshing with both sides of the drive gear, and each driven gear is connected to the second transmission shaft between the driven gear and the second transmission shaft. Is provided with a switching device that can selectively connect to or disengage both driven gears from the connection with the second transmission shaft, and a switching drive mechanism capable of switching the switching device and the second transmission shaft. A third feature is that it further includes a thrust load applying mechanism capable of applying a thrust load to one of the driven gears.

In addition to the third feature of the present invention, the gear case constitutes a lower part of the casing of the outboard motor, the first transmission shaft is a drive shaft driven by an engine, 2 The transmission shaft is a propeller shaft with a propeller mounted on the rear end, the switching device is a forward / reverse switching device, the one driven gear is a forward driven gear, and is connected via an angular contact bearing. At the time of measuring the backlash between the drive gear and the forward driven gear, which is supported by the gear case and the other driven gear is a reverse driven gear and is supported by the gear case via a radial bearing. By operating the switching drive mechanism, the forward / reverse switching device is controlled to be in a neutral state in which both driven gears are released from the connection with the propeller shaft. The operation of the strike load applying mechanism, and a fourth, characterized in that loading the said forward driven gear to impart a thrust load to the angular contact bearing through the propeller shaft.

The present invention, in addition to the third feature, the gear case, the vertical position of one of the first transmission shaft and second transmission shaft, and may also retain position-decided Me their other in a horizontal posture workpiece A fifth feature is that a holding body is provided.

  Furthermore, the present invention is characterized in that, in addition to the first or fifth feature, the work holder is provided with a plurality of positioning means corresponding to a plurality of types of the gear cases.

  Furthermore, in addition to the first feature of the present invention, the forward / reverse drive mechanism includes a support base, a forward / reverse shaft having a chuck at the tip and supported by the support base via a centering bearing. A forward / reverse drive motor coupled to a rear end portion of the forward / reverse rotation shaft, and a support cylinder supported by the support base through a centering mechanism so as not to rotate and supporting the forward / reverse drive motor. 7 features.

  Furthermore, in addition to the first or seventh feature, the present invention provides that the forward / reverse drive mechanism is supported by a support base and an alignment bearing on the support base, and has the first transmission shaft at the tip. A forward / reverse shaft having a chuck that can be connected to the forward / reverse shaft, a forward / reverse drive motor connected to the rear end portion of the forward / reverse shaft, and the support base and the forward / reverse shaft. An eighth feature is that a friction mechanism that provides resistance is provided.

According to a first aspect of the present invention, first, second transmission shaft and the first, after holding the second gear case incorporating formic Ya at a predetermined position of the workpiece holding member, forward and reverse drive to the first transmission shaft When the mechanism is connected and operated, the first transmission shaft is rotated forward by more than the angle corresponding to the assumed backlash and then reversed more than the angle corresponding to the assumed backlash. An electronic control unit that detects the rotation status of the shaft and receives the detection signal calculates a backlash value between the first gear and the second gear from the detection signal, and automatically determines whether the value is appropriate. Can be determined. Therefore, the backlash between the gears incorporated in the gear case can be easily and accurately measured without requiring special skills.

  According to the second feature of the present invention, after the first transmission shaft is rotated forward by an angle corresponding to the assumed backlash or more by the operation of the forward / reverse driving mechanism, the angle corresponding to the assumed backlash. When the rotation is reversed as described above, the tooth of the first gear connected to the first transmission shaft moves from one adjacent tooth of the second gear toward the other tooth, and the load state is in contact with the other tooth. Is detected by the torque sensor, the idling section is detected by the rotational position sensor, and the electronic control unit can accurately calculate the backlash value between the first and second gears from these detection signals. it can.

According to the third aspect of the present invention, the switching device is controlled by the operation of the switching drive mechanism to a neutral state in which both driven gears are released from the connection with the second transmission shaft, and the thrust load applying mechanism is operated. 2 Measure the backlash between the drive gear and one driven gear by operating the forward / reverse drive mechanism as described above while applying a thrust load to the transmission shaft and applying a load to one driven gear. In addition, the switching device is controlled by the operation of the switching drive mechanism so that the other driven gear is connected to the second transmission shaft, and the thrust load applying mechanism is returned to the non-operating state. By operating the mechanism as described above, the backlash between the drive gear and the other driven gear can be measured, and at each measurement, a minimum load is applied to each driven gear. Ri, hence the rotational torque of the normal and reverse driving mechanism suffices relatively small, prevents during the measurement, is elastically deformed in the gears occur, it is possible to accurately measure the backlash.

According to the fourth aspect of the present invention, when measuring the backlash between the drive gear and the forward driven gear, a thrust load is applied to the angular contact bearing via the propeller shaft to apply the load to the forward driven gear. The state is the same as the state in which the thrust generated by the propeller acts as a thrust load on the propeller shaft during the operation of the outboard motor, and the backlash is accurately measured with the angular bearing backlash removed. be able to.

According to a fifth aspect of the present invention, the gear case, the vertical position of one of the first transmission shaft and second transmission shaft, and by keeping position-decided Me their other in the horizontal posture, the workpiece holder The space occupied by the gear case can be minimized, which can contribute to the compactness of the backlash measuring device, and can be fixed and easily stabilized, and the backlash measurement accuracy can be increased.

  According to the sixth aspect of the present invention, the same workpiece holder can be used for positioning and holding the gear cases of a plurality of models, and versatility can be given to the backlash measuring device.

According to a seventh aspect of the present invention, when connecting the normal and reverse rotation shaft through the chuck to the first heat transfer rotary shaft, even axial misalignment between the forward and reverse shafts and the first transfer rotary shaft occurs, aligning The bearing and alignment mechanism cooperate to absorb the shaft misalignment, and the forward / reverse drive motor can smoothly forward / reverse the forward / reverse shaft and the first transmission shaft, contributing to accurate measurement of backlash. To do.

According to the eighth feature of the present invention, when the backlash is measured, the rotation of the forward / reverse rotation shaft is changed from the forward rotation to the reverse rotation. The rotation can be prevented by the action of the friction mechanism, so that the backlash can be accurately measured by the next reversal.

FIG. 3 is a longitudinal side view of a gear case of an outboard motor equipped with a gear measured by the backlash measuring device of the present invention. The top view of measuring equipment provided with the backlash measuring device of the present invention. FIG. 3 is an enlarged plan view around a backlash measuring device in FIG. 2. 4-4 arrow line view of FIG. FIG. 5 is a view taken in the direction of arrow 5 in FIG. 4. The principal part enlarged view of FIG. FIG. 7 is a view taken in the direction of arrow 7 in FIG. 6. FIG. 4 is an enlarged view of the work clamp mechanism in FIG. 3, showing the operating state of the mechanism. FIG. 9 is a diagram corresponding to FIG. 8, showing an inoperative state of the clamp mechanism. FIG. 10 is an enlarged view taken in the direction of arrow 10 in FIG. 4 and shows a shift switching drive mechanism. FIG. 11 is a sectional view taken along line 11-11 in FIG. 10; 12 is a cross-sectional view taken along line 12-12 in FIG. FIG. 13 is a sectional view taken along line 13-13 of FIG. The control tower is shown in the view of arrow 14 in FIG. The backlash measurement explanatory drawing between a drive gear and a driven gear. FIG. 6 is a relationship diagram of the reverse position and torque of the drive gear displayed on the monitor of the electronic control unit during backlash measurement.

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

  First, referring to FIG. 1, a description will be given of a forward / rearward transmission device for an outboard motor that measures backlash of a gear using the backlash measuring device of the present invention.

  The gear case 1 constituting the lower part of the casing of the outboard motor is composed of a vertical case portion 1a in the vertical direction and a horizontal case portion 1b projecting from the lower end to the rear (pointing to the rear of the hull not shown). The vertical case portion 1a supports the upper and lower portions of a vertical drive shaft 3 driven by the engine 2 via a double-row angular contact roller bearing 4 and a needle bearing 5, and is not shown in its front position. A vertical shift shaft 7 that is rotated by the forward / reverse switching operation device 6 is supported. A propeller shaft holder 8 is fitted to the horizontal case portion 1b from the rear end to the middle portion, and the rear end portion is fixed to the rear end of the horizontal case portion 1b by a bolt 9. The propeller shaft holder 8 supports a middle portion and a rear end portion of a propeller shaft 10 in a horizontal posture in which a propeller 14 is mounted at the rear end via a thrust needle bearing 11 and a radial needle bearing 12, respectively.

The propeller shaft 10 extends forward from the propeller shaft holder 8 so as to traverse directly under the drive shaft 3. Transmission between the propeller shaft 10 and the drive shaft 3 is performed and the transmission direction is switched. A forward / reverse switching device 15 is provided. The forward / reverse switching device 15 includes a bevel-type drive gear 16 that is spline-fitted and fixed to the lower end portion of the drive shaft 3, and meshes with the front and rear portions of the drive gear 16. The forward driven gear 17 and the reverse driven gear 18, and a dog clutch member 19 slidably fitted to the propeller shaft 10 between the driven gears 17 and 18, are provided. The hub 17a is supported by the gear case 1 via the angular contact roller bearing 20 and is arranged so as to support the front end portion of the propeller shaft 10 via the needle bearing 21. A hub 18a is supported on the front end portion of the propeller shaft holder 8 via a double row ball bearing 23, and a needle bearing. It is arranged to support the propeller shaft 10 via two. The hubs 17a and 18a of the forward and reverse driven gears 17 and 18 are provided with dogs 17b and 18b opposed to both ends of the dog clutch member 19 at their inner ends. Thus, the dog clutch member 19 can be switched to a neutral position, a forward position in front of it, and a reverse position behind the neutral position by rotating the shift shaft 7. Since the driven gears 17 and 18 are not engaged with any of the dogs 17b and 18b, the driven gears 17 and 18 are freed from the propeller shaft 10 to block transmission between the drive shaft 3 and the propeller shaft 10. In the forward position, the dog clutch member 19 engages with the dog 17b of the forward driven gear 17 to connect the forward driven gear 17 to the propeller shaft 10, so that the rotation of the drive shaft 3 is rotated to the propeller shaft 10 in the forward direction. In the reverse drive position, the dog clutch member 19 engages with the dog 18b of the reverse drive gear 18 to connect the reverse drive gear 18 to the propeller shaft 10, so that the drive shaft 3 rotates. It will be transmitted as rotation of the rear advancing direction to the propeller shaft 10.

  In order to properly adjust the backlash between the drive gear 16 and the forward and reverse driven gears 17 and 18, the backlash between the gears is adjusted in advance. The selected first shim 24, second shim 25, and third shim 26 are located between the lower end of the inner race of the double row angular contact roller bearing 4 and the flange 3 a formed on the drive shaft 3. 20 between the opposing thrust surfaces of the outer race and the gear case 1, and between the opposing thrust surfaces of the outer race of the double row ball bearing 23 and the propeller shaft holder 8.

  The backlash measuring device determines whether or not the backlash between the drive gear 16 adjusted by the first to third shims 24 to 26 and the forward and reverse driven gears 17 and 18 is appropriate. Next, an assembly facility including the backlash measuring device will be described with reference to FIG.

In FIG. 2, reference numeral 30 is an assembly conveyor for incorporating interior parts such as the drive gear 16, forward and reverse driven gears 17 and 18 into the gear case 1, and extends from a carry-in port 31a at one end. A first conveyor 31, a second conveyor 32 that is bent at a right angle from the downstream end of the first conveyor 31, and that is shorter than the first conveyor 31, and extends from the downstream end of the second conveyor 32 in parallel with the first conveyor 31. a third conveyor 33 leading to the outlet port 33a, and more a fourth conveyor 34 for connecting the inlet port 31a and outlet port 33a, and a rectangular in plan view. A backlash measuring device 35 is installed on the floor between the first and third conveyors 31 and 33.

In the first conveyor 31, the gear case 1 loaded with the first worker M1 from the carry-in port 31 a is placed on the pallet 36, and the drive case 3, the propeller shaft 10, the forward / reverse switching device 15, etc. are installed in the gear case 1. After incorporating the components, the gear case 1 with the interior is moved to the third conveyor 33 via the second conveyor 32. In the third conveyor 33, first, second operator M2 is changed the attitude of the interior already gear case 1 on the pallet 36, horizontally drives shaft 3 upwardly causes the rear end of the propeller shaft 10. Next, the third worker M3 projects the work holder 40 in the backlash measuring device 35 to the third conveyor 33, and transfers the mounted gear case 1 whose posture has been changed onto the work holder 40 to fix the positioning. Then, the workpiece holder 40 is sequentially moved to the model discrimination position and measurement position inside the third conveyor 33, and the model of the gear case 1 with the interior is determined at the model discrimination position, and the backlash measuring device 35 is operated at the measurement position. Automatically measures the backlash between the drive gear 16 and the forward and reverse driven gears 17 and 18 in the built-in gear case 1, and determines whether or not the measured value is appropriate, corresponding to the appropriateness. Marking is attached to the gear case 1 with the interior after measurement. Thereafter, the gear case 1 with the interior is returned again to the third conveyor 33 by the work holder 40, and the fourth worker M4 transfers the gear case 1 with the interior from the work holder 40 to the pallet 36, and then to the carry-out port 33a. And carry. Then, those determined to be appropriate are transported to the next further assembly process, and those determined to be inappropriate are transported to the backlash readjustment process.

  Next, the backlash measuring device 35 will be described in detail.

3 to 5, the backlash measuring device 35 includes the workpiece holder 40 that can move between a workpiece transfer position A on the third conveyor 33 and a measurement position C via an intermediate model discrimination position B. And a workpiece clamping mechanism 41 for positioning and holding the gear case 1 with the drive shaft 3 horizontally and the rear end of the propeller shaft 10 facing upward on the workpiece holding body 40, and the workpiece holding mechanism by the workpiece clamping mechanism 41. A model discriminating mechanism 42 for detecting the height of the internally mounted gear case 1 positioned and held at 40 and the length of the propeller shaft 10 to discriminate the model, and a thrust on the propeller shaft 10 at the measurement position C of the work holder 40 A thrust load applying mechanism 43 that can apply a load to apply a load to the angular contact roller bearing 20 and the shift shaft 7 can be switched. A forward / reverse drive mechanism 45 capable of forward / reverse rotation of the drive shaft 3 to detect backlash between the drive mechanism 44 and the drive gear 16 in the gear case 1 with the interior and the forward and reverse driven gears 17 and 18. And a control tower 47 that includes an electronic control unit 46 that displays the backlash value detected by the forward / reverse drive mechanism 45 and determines the suitability of the value.

  First, as shown in FIGS. 3 to 6 and FIG. 8, the work holder 40 is supported by a fixed base 38 installed on the floor so as to be slidable between the measurement position C and the workpiece transfer position A. 38 is provided with drive means 37 for moving the work holder 40. The work holding body 40 is composed of a horizontal wall plate 40a and a vertical wall plate 40b standing from the downstream side end of the third conveyor 33 of the horizontal wall plate 40a. A slit 52 is provided to receive the drive shaft 3 of the gear case 1 that has been installed to the center. Further, a plurality of a pair of positioning holes 51a, 51a; 51b, 51b into which a pair of positioning pins (see FIG. 1) planted on the upper end surface 1E of the built-in gear case 1 are fitted on the outer surface of the vertical wall plate 40b. Provided for each model. Thus, the upper end surface 1E of the gear case 1 with the interior is made to contact the vertical wall plate 40b while the positioning pins 50, 50 are fitted in the positioning holes 51a, 51a or 51b, 51b. The positioning holes 51a, 51a; 51b, 51b corresponding to a plurality of models are arranged so that the position of the drive shaft 3 of the gear case 1 in each model positioned by the positioning holes is always constant.

As shown in FIGS. 8 and 9, stabilizer fins 1F projecting in the horizontal direction perpendicular to the drive shaft 3 are formed on the outer periphery of the gear case 1, and the work clamp mechanism 41 is formed on the inner wall of the vertical wall plate 40b. Between the closed position D (see FIG. 8) for clamping the stabilizer fin 1F to the vertical wall board 40b through the vertical wall plate 40b from the side, and the open position E (see FIG. 9) for releasing the clamp to the stabilizer fin 1F. A pair of clamp arms 53, 53 that can actuate is provided. These clamp arms 53, 53 are connected to rotating plates 54, 54 supported by the vertical wall plate 40b via links 55, 55 and to a single operating lever 57 via a link mechanism 56. By reciprocating the operation lever 57, the clamp arms 53 and 53 can be opened and closed as described above. Clamp arm 53, the presser portion against the stabilizer fin 1F is attached an elastic member 58, so as to prevent the damage of the stabilizer fins 1F.

  4 to 6 again, the thrust load applying mechanism 43 includes a tower 60 supported by a fixed base 59 installed on the floor so as to be movable in a horizontal direction perpendicular to the flow direction of the third conveyor 33, and the tower 60. A tower driving means 61 for moving 60, a lifting plate 62 supported by the tower 60 so as to be movable up and down, a lifting plate driving means 63 attached to the tower 60 for driving the lifting plate 62, and a third conveyor on the lifting plate 62. 33, a support base 64 supported so as to be movable in a horizontal direction parallel to the flow direction of 33, support base drive means 65 attached to the elevating plate 62 for driving the support base 64, and slidable up and down on the support base 64. And a thrust shaft driving means 67 attached to a support base 64 to drive the thrust shaft 66 up and down. The thrust shaft 66 is provided with a conical holding portion 66a at the lower end, and this holding portion 66a is engaged with a conical center hole 68 on the front end surface of the propeller shaft 10 protruding from the rear end of the gear case 1 with built-in. , By applying a thrust load to the propeller shaft 10 by pressing, the load can be applied to the forward driven gear 17 and the angular contact roller bearing 20.

  A plurality of hooks 69 (only one of which is shown in FIG. 6) are provided at the lower end portion of the support base 64 so as to be able to advance and retract radially around the lower extension axis of the thrust shaft 66. When the propeller shaft 10 is pressed, these hooks 69 engage with the inward shoulders 8a (see FIG. 1) of the propeller shaft holder 8 of the gear case 1 that has been installed, pull up the gear case 1 that has been installed, Unnecessary movement of the gear case 1 with built-in force due to the pressing force is prevented.

  As shown in FIGS. 6 and 7, the model discrimination mechanism 42 includes a support plate 70 that is supported by the third conveyor 33 side end of the support base 64 so as to be movable up and down, and the support plate 70 that drives the support plate 70. A support plate driving means 71 attached to the base 64, a pair of propeller shaft sandwiching arms 72, 72 supported on the support plate 70 so as to be openable and closable, and a sandwiching arm drive means 73 for opening and closing the propeller shaft sandwiching arms 72, 72 And a bracket 74 fixed to the support plate 70 above the propeller shaft sandwiching arms 72, 72, and a laser type propeller shaft sensor 75 and a gear case sensor 76 attached to the bracket 74.

Thus, the workpiece holding body 40 that positions and holds the gear case 1 with the interior is set at the intermediate position between the third conveyor 33 and the measurement position, and the model holding position B is set. When reaching, the holding arm driving means 73 is operated with the support plate 70 held at a specified height, and the propeller shaft 10 is fixed by gripping the pair of propeller shaft holding arms 72, 72. In this state, the propeller shaft The electronic control unit uses the sensor 75 and the gear case sensor 76 to irradiate the end surfaces of the propeller shaft 10 and the gear case 1 with laser beams, sense the respective reflected beams, and detect the distances to the end surfaces of the propeller shaft 10 and the gear case 1 as detection signals. 46 is input.

  10 and 11, the switching drive mechanism 44 includes a gear box 78 supported by a second vertical wall plate 40c erected on the horizontal wall plate 40a of the workpiece holder 40 so as to be movable up and down. Gear box driving means 77 attached to the horizontal wall plate 40a to raise and lower the gear box 78, a motor shaft 79 and a shift driving shaft 80 which are rotatably supported by the gear box 78 and arranged in parallel to each other, and these motor shafts 79, a transmission gear train 81 for connecting the shaft 79 and the shift drive shaft 80, and a shift drive motor 82 for driving the motor shaft 79 and capable of forward / reverse rotation. The second vertical wall plate 40c is provided with a pair of upper and lower stopper bolts 90, 90 'that receive the member 89 that moves up and down together with the gear box 78 and regulates the upper and lower limits of the gear box 78.

  A cylindrical shaft 85 having a connecting hole 84 at the tip that can be fitted to the angular shaft portion 7a at the tip of the shift shaft 7 is slidably fitted to a portion of the shift drive shaft 80 that protrudes outside the gear box 78. . A long hole 86 in the axial direction is provided in the peripheral wall of the cylindrical shaft 85, and a connecting pin 87 slidably engaged with the long hole 86 is fixed to the shift drive shaft 80, and the gear box 78 and the cylindrical shaft 85 are fixed. A coil spring 88 that urges the tube shaft 85 forward, that is, toward the shift shaft 7 is contracted between the two.

Further to the connecting pin 87, the sensor ring 87a is solid deposited which surrounds the outer periphery of the cylindrical shaft 85, first and second position sensors 91 and 92 of the pair corresponding to the sensor ring 87a is fixed to the gear box 78 Attached to the stay 93.

The rear end portion of the shift drive shaft 80 also protrudes outside the gear box 78, and a disc 94 is fixed to the rear end portion. The disc 94 is arranged symmetrically in the horizontal direction across the center. A pair of first connection pins 95, 95 are fixed, and are fixed to the first connection pins 95, 95 and a stay 96 fixed to the gear box 78, and are disposed above the first connection pins 95, 95. A pair of balance springs 98, 98 having the same spring strength are connected between the pair of second connection pins 97 , 97. When the shift drive motor 82 is in an inoperative state, the shift drive motor 82 is held in a forward / reverse neutral state via the disk 94 by the balancing action of the urging forces of the balance springs 98 and 98.

Thus, the phase of the angular shaft portion 7a of the shift shaft 7 at the neutral position is constant, and when the shift drive motor 82 is in the forward / reverse neutral state, the connecting hole 84 of the cylindrical shaft 85 is in phase with the angular shaft portion 7a. There has been made to match. Therefore, when fitting the connecting hole 84 to the angular shaft portion 7a of the shift shaft 7 at the neutral position, first, the gear box 78 is moved so that the cylinder shaft 85 is positioned coaxially with the shift shaft 7, and then the gear box 78 is moved. If the box 78 is moved forward by a predetermined distance toward the shift shaft 7, the connecting hole 84 is fitted into the square shaft portion 7a. At this time, if there is a slight phase shift between the square shaft portion 7a and the connecting hole 84, the cylinder shaft 85 abuts against the tip surface of the shift shaft 7, but the shift drive shaft 80 compresses the coil spring 88. While moving forward with the gear box 78 to a predetermined position. Therefore, if the shift drive motor 82 is slightly rotated forward or reverse, the cylindrical shaft 85 is moved forward by the urging force of the coil spring 88 when the phase of the angular shaft portion 7a and the connection hole 84 coincide with each other. It can be fitted to the square shaft portion 7a. If the operation of the shift drive motor 82 is stopped after the fitting, the shift drive motor 82 can be returned to the forward / reverse neutral state by the balance action of the urging forces of the balance springs 98, 98.

  When the gear box 78 moves forward a predetermined distance and the connecting hole 84 of the cylinder shaft 85 is properly fitted to the angular shaft portion 7a of the shift shaft 7, the first position sensor 91 or the second position sensor 92 is moved to the position of the sensor ring 87a. , And the appropriate fitting state is input to the electronic control unit 46 as a detection signal. The electronic control unit 46 performs shift driving from the detection signal to the shift shaft 7 of the model corresponding to the measurement. The connection of the shaft 80 can be confirmed. The shift shaft 7 can be rotated from the neutral position to the forward switching position or the reverse switching position by rotating the shift drive motor 82 forward or backward by a predetermined angle.

  12 and 13, the forward / reverse drive mechanism 45 includes a support base 101 supported on a fixed base 100 installed on the floor so as to be movable in the horizontal direction along the flow direction of the third conveyor 33, and Support base drive means 102 attached to the fixed base 100 to drive the support base 101, and forward / reverse rotation supported by the support wall 101a standing upright on the support base 101 via the aligning bearing 104 and the ball bearing 105 surrounded by it. And a shaft 106. A forward / reverse drive motor 110 is connected to the rear end portion of the forward / reverse shaft 106 through a rotational position sensor 99, a torque sensor 107, a torque limiter 108, and a joint 109 arranged in series. The forward / reverse drive motor 110 is attached to a support cylinder 111 described later. For the rotational position sensor 99, for example, a rotary encoder is used.

  A large flange 106a is integrally formed at the front end of the forward / reverse rotation shaft 106, and a chuck 112 is provided on the large flange 106a. The chuck 112 includes a chuck driving unit 112a attached to the large flange 106a and a pair of chuck claws 112b and 112b that are supported by the chuck driving unit 112a and can be opened and closed to grip the tip of the drive shaft 3.

  The inner race of the aligning bearing 104 and the outer race of the ball bearing 105 are connected via an intermediate race 113 interposed therebetween. A front end flange 111a of a support cylinder 111 surrounding the torque sensor 107, the torque limiter 108 and the joint 109 is fixed to the rear end surface of the intermediate race 113 by a bolt 115 with a first flange plate 114 interposed therebetween. The forward / reverse drive motor 110 is supported at the rear end.

  The support cylinder 111 is supported by the support wall 101a through an alignment mechanism 116. This aligning mechanism 116 is connected to a guide shaft 117 protruding from the outer peripheral surface of the support wall 101a and extending along the radial line of the aligning bearing 104, and is bolted to the first flange plate 114. The guide shaft 117 is And a connecting arm 119 having a long hole 118 slidably passing therethrough. Therefore, the support cylinder 111 can swing with the forward / reverse rotation shaft 106 while being prevented from rotating about its axis.

  An elastic holding mechanism 120 that normally holds the support cylinder 111 in a horizontal state is provided between the support wall 101 a and the first flange plate 114. The elastic holding mechanism 120 is provided with a plurality of cylindrical spring seats 121, 121... Which are annularly fixed to the first flange plate 114, and the spring seats 121, 121. Are formed by a plurality of support bolts 122 passing through 121... And a coil spring 123 that is contracted between the head of each support bolt 122 and the spring seat 121. Thus, the support cylinder 111 is normally held in a horizontal state by the elastic force of the many coil springs 123, 123. At that time, the tightening degree of the support bolts 122, 122... Is adjusted so that the set load of the coil springs 123, 123. Held horizontally against.

  A second flange plate 125 facing the large flange 106a is fixed to the front end surface of the intermediate race 113, and an appropriate rotational resistance for rotation of the forward / reverse rotation shaft 106 is provided between the large flange 106a and the second flange plate 125. A friction mechanism 126 is provided for imparting. The friction mechanism 126 has one or more cylinders 127 (in the illustrated example, symmetrical on the diameter line of the large flange 106a) that are screwed and fixed to the outer peripheral portion of the large flange 106a so as to penetrate the large flange 106a in the axial direction. Two cylinders 127 are disposed in the cylinder 127), and a plunger 128 that is slidably fitted to the cylinder 127 and abuts the spherical surface of the tip against the second flange plate 125, and is accommodated in the cylinder 127. And a spring 129 that urges the plunger 128 in a contact direction with the second flange plate 125. Thus, when the forward / reverse rotation shaft 106 rotates, friction that gives an appropriate resistance to the rotation of the forward / reverse rotation shaft 106 is generated at the contact portion between the plunger 128 that receives the biasing force of the spring 129 and the second flange plate 125. This prevents the forward / reverse shaft 106 from reluctance.

  When the forward / reverse shaft 106 is rotated by the operation of the forward / reverse drive motor 110, the rotational position sensor 99 detects the rotational angle of the forward / reverse shaft 106, and the torque sensor 107 detects the torque of the forward / reverse shaft 106, respectively. A detection signal is input to the electronic control unit 46. The torque limiter 108 works to protect the torque sensor 107 by slipping when the driving torque from the forward / reverse driving motor 110 to the forward / reverse shaft 106 exceeds the allowable value of the torque sensor 107, and the slip state is signaled. To the electronic control unit 46.

  As shown in FIG. 14, the electronic control unit 46 is input with appropriate value data of backlash between the drive gear 16 of a plurality of models and the forward and reverse driven gears 17 and 18. , An electronic control circuit (not shown) that automatically and sequentially operates the power switch 130, the model display 131 for displaying the model of the backlash measurement target, the model discrimination mechanism 42, the thrust load applying mechanism 43, and the forward / reverse drive mechanism 45. ), A monitor 132 for displaying the torque waveform during the backlash measurement, a numerical display 133 for displaying the measured backlash value, a pass / fail lamp 135, 136 for displaying the appropriateness of the measured backlash value, etc. I have.

  Next, the measurement procedure of the backlash of the gear in the built-in gear case 1 will be described.

  First, the workpiece holder 40 holding the gear case 1 by the workpiece clamp mechanism 41 is moved from the third conveyor 33 to the model determination position B. At the model discrimination position B, the model discrimination mechanism 42 operates as described above. That is, the propeller shaft 10 is fixed by gripping the pair of propeller shaft sandwiching arms 72 and 72, and in this state, the end surfaces of the propeller shaft 10 and the gear case 1 are irradiated with laser beams from the propeller shaft sensor 75 and the gear case sensor 76, respectively. The distance between the propeller shaft 10 and each end face of the gear case 1 is input to the electronic control unit 46 as a detection signal, and the electronic control unit 46 determines the length of the propeller shaft 10 and the gear case 1 based on the detected distance. The size is calculated, the model is determined, and the corresponding model display lamp 131 is turned on.

After the model is determined, the propeller shaft clamping arms 72 and 72 are opened and the model discrimination mechanism 42 is once raised, and then the workpiece holder 40 is moved to the measurement position C. In this case, first, prior to the measurement of the backlash between the drive gear 16 and the forward driven gear 17, the cylinder shaft 85 of the switching drive mechanism 44 is connected to the shift shaft 7 as described above, and the balance spring 98, The shift shaft 7 is held in the neutral position by the balance of the urging force of 98, and thereby the dog clutch member 19 is held in the neutral position. Next, the thrust load applying mechanism 43 is operated, the propeller shaft 10 is pressed by the thrust shaft 66, and a load is applied to the angular contact roller bearing 20 via the forward driven gear 17. At this time, as described above, the hook 69 is engaged with the inward shoulder 8a of the propeller shaft holder 8 of the gear case 1 to pull up the gear case 1 and prevent unnecessary movement of the gear case 1 due to the pressing force of the thrust shaft 66. Leave in.

  In this state, the forward / reverse drive mechanism 45 is operated, the drive shaft 3 is gripped by the chuck 112, and the forward / reverse shaft 106 is directly connected to the drive shaft 3. At this time, if there is a misalignment between the drive shaft 3 and the forward / reverse shaft 106, the tilting of the forward / reverse shaft 106 is allowed by the action of the aligning bearing 104 and the aligning mechanism 116, and the forward / reverse shaft Smooth drive of the drive shaft 3 by 106 is enabled.

Next, with the forward and reverse driven gears 17 and 18 being rotatable, the forward / reverse drive motor 110 rotates the forward / reverse shaft 106 several times, forward / reversely or reversely, thereby driving the drive gear 16 via the drive shaft 3. Turn several times, forward or reverse. Along with this, the drive gear 16 drives the forward and reverse driven gears 17, 18, and in particular, the angular contact roller bearing 20 receiving the thrust load via the forward driven gear 17 is adapted to rotate. During this time, if an excessive torque greater than or equal to the allowable torque of the torque sensor 107 is transmitted from the forward / reverse drive motor 110 to the forward / reverse shaft 106, the torque limiter 108 acts to transmit a torque greater than a predetermined value to the torque sensor 107. The torque sensor 107 can be protected by being cut.

After the familiar rotation, the forward / reverse shaft 106 causes the drive shaft 3 to rotate forward at a predetermined angle greater than the angle corresponding to the assumed backlash between the two gears 16, 17, for example, a predetermined angle greater than the pitch angle of the drive gear 16. Then, as shown in FIG. 15, one tooth G1 of the drive gear 16 is brought into contact with one tooth G2 of the forward driven gear 17 opposed thereto, and the operation of the forward / reverse drive motor 110 is stopped. At this time, the rotation of the forward / reverse shaft 106 is immediately stopped by the action of the friction mechanism 126, and inertial rotation is prevented.

Next, when the forward / reverse drive motor 110 is operated, the drive gear 16 is moved through the forward / reverse shaft 106 and the drive shaft 3 to a predetermined angle θ ( see FIG. 16) that is equal to or greater than the angle corresponding to the assumed backlash between the gears 16 and 17 . ), Gently reverse. When the drive gear 16 rotates, the forward and reverse driven gears 17 and 18 meshing with the drive gear 16 are simultaneously driven, but the angular contact roller bearing 20 that supports the forward driven gear 17 is in a load state as described above. In contrast, since the ball bearing 23 that supports the reverse driven gear 18 is in an unloaded state, the rotational torque of the forward driven gear 17 is much larger than the rotational torque of the reverse driven gear 18. ing. Therefore, the torque detected by the torque sensor 107 on the forward / reverse rotation shaft 106 when the drive gear 16 rotates in reverse depends on the rotational torque of the forward driven gear 17.

Thus, when the drive gear 16 starts reverse rotation from the contact position of the tooth G 1 with the one tooth G 2 of the forward driven gear 17, the tooth G 1 of the drive gear 16 moves to the other side of the forward driven gear 17. While moving toward the tooth G3 and moving through the backlash section, the drive gear 16 is not loaded, but as soon as the tooth G1 comes into contact with the other tooth G3, it drives it. Therefore, the torque of the forward / reverse shaft 106 increases rapidly, and the forward driven gear 17 follows the driving gear 16 against the thrust load.

  During forward rotation, stop and reverse rotation of the forward / reverse shaft 106, the rotational position of the forward / reverse shaft 106 is detected by the rotational position sensor 99 and the torque is detected by the torque sensor 107, and the respective detection signals are sent to the electronic control unit 46. When input, the electronic control unit 46 calculates the torque of the forward / reverse shaft 106 from the detection signal from the torque sensor 107, and from the detection signal from the rotational position sensor 99, the torque from the start of the reverse rotation of the forward / reverse shaft 106. The rotation angle of the forward / reverse shaft 106 until the sudden increase time is calculated, and the backlash value between the drive gear 16 and the forward driven gear 17 is calculated from the rotation angle. A relationship diagram (see FIG. 16) of the rotation angle and torque of the forward / reverse rotation shaft 106 is displayed on the monitor 132, the backlash value is displayed on the numerical display 133, and the backlash value is within the allowable range. When it is out of the allowable range, the pass lamp 135 is turned on.

  If measurement of such backlash due to forward rotation, stoppage and reverse rotation of the forward / reverse rotation shaft 106 is performed at a position where the drive gear 16 is changed, for example, by 90 °, the backlash between the drive gear 16 and the forward driven gear 17 is performed. Can be judged more accurately.

  Further, during the reverse rotation of the forward / reverse rotation shaft 106, when an overload greater than the thrust load is applied to the drive shaft 3 for some reason, the overload transmission to the torque sensor 107 is interrupted by the slip action of the torque limiter 108. The overload state is input to the electronic control unit 46 as a signal. Then, the electronic control unit 46 invalidates the signals input from the torque sensor 107 and the rotational position sensor 99 so far, and stops the calculation of the backlash value. By so doing, it is possible to eliminate backlash measurement errors caused by elastic deformation of the teeth G1, G3 due to overload.

  Next, the measurement shifts to the backlash between the drive gear 16 and the reverse driven gear 18. In this case, first, the thrust load applying mechanism 43 is returned to an inoperative state, and the propeller shaft 10 is freed. Next, the switching drive mechanism 44 is operated to hold the dog clutch member 19 in the reverse drive position via the shift shaft 7 by the shift drive shaft 80. In this state, the forward / reverse shaft 106 is forwardly rotated, stopped and rotated in the same manner as described above. In this case, the reverse driven gear 18 is connected to the propeller shaft 10 by the dog clutch member 19. Since the forward driven gear 17 is in a free state, even when the propeller shaft 10 is released from the thrust load applying mechanism 43 when the forward / reverse shaft 106 rotates, the reverse driven gear 18 and the forward / reverse shaft 106 , The static inertia force of the propeller shaft 10 acts as a load. Therefore, the torque detected by the torque sensor 107 on the forward / reverse rotation shaft 106 when the drive gear 16 rotates in reverse depends on the rotational torque of the reverse driven gear 18.

  In this case, if the load acting on the reverse driven gear 18 and the forward / reverse rotating shaft 106 is insufficient only by the static inertia force of the propeller shaft 10, the propeller shaft clamping arms 72, 72 of the model discrimination mechanism 42 are used. It is effective to moderately increase the load on the reverse driven gear 18 and the forward / reverse rotation shaft 106 so that the propeller shaft 10 is lightly sandwiched by using so as not to be overloaded.

  Thus, similarly to the measurement of the backlash between the drive gear 16 and the forward driven gear 17 described above, the forward / reverse shaft 106 is rotated forward, stopped, and reversely, and the detection signals of the rotational position sensor 99 and the torque sensor 107 are detected. Is input to the electronic control unit 46, the backlash value between the drive gear 16 and the reverse driven gear 18 can be obtained and its suitability can be determined.

  Similarly to the above, if measurement of backlash by forward rotation, stop and reverse rotation of the forward / reverse rotation shaft 106 is performed at a plurality of locations where the phase of the drive gear 16 is changed by 90 °, for example, the drive gear 16 and the reverse driven gear 18 are moved. It is possible to more accurately determine the suitability of backlash during the period.

  Thus, the backlash between the drive gear 16 incorporated in the gear case 1 and the forward and reverse driven gears 17 and 18 can be measured easily and accurately without requiring special skills.

  In addition, a minimum load is applied to each of the driven gears 17 and 18 during any backlash measurement between the drive gear 16 and the forward driven gear 17 and between the drive gear 16 and the reverse driven gear 18. Therefore, since the rotational torque of the forward / reverse drive mechanism 45 is relatively small, it is possible to prevent the gears 16, 17, and 18 from being elastically deformed during the measurement and to accurately measure the backlash.

  When measuring the backlash between the drive gear 16 and the forward driven gear 17, the thrust load is applied to the propeller shaft 10 and the forward driven gear 17 and the angular contact roller bearing 20 are loaded. During actual operation, the thrust generated by the propeller is the same as that applied to the propeller shaft 10, and the backlash is accurately measured in a state where the backlash in the thrust direction of the angular contact roller bearing 20 is eliminated. .

Furthermore gear case 1, a propeller shaft 10 to the vertical posture, so while the drive shaft 3 in a horizontal posture is positioned and held in the work holder 40, to be a space occupied by the gear case 1 in the work holder 40 to a minimum In addition to contributing to the compactness of the backlash measuring device 35, the gear case 1 can be easily fixed and stabilized, and the measurement accuracy of the backlash can be increased.

  Furthermore, the work holder 40 is provided with a plurality of positioning holes 51a, 51a; 51b, 51b corresponding to the positioning pins 50, 50 of the gear case 1 of a plurality of models, so that the same work holder 40 It can be used for positioning and holding the model gear case 1, and versatility can be given to the backlash measuring device 35.

  Further, when the forward / reverse shaft 106 is connected to the drive shaft 3 via the chuck 112, the alignment bearing 104 and the alignment mechanism 116 cooperate even if an axial misalignment occurs between the forward / reverse shaft 106 and the drive shaft 3. Then, the axial misalignment is absorbed, and the forward / reverse drive motor 110 can smoothly forward / reverse the forward / reverse rotation shaft 106 and the drive shaft 3 to contribute to accurate measurement of backlash.

  Furthermore, in the forward / reverse drive mechanism 45, a friction mechanism 126 is provided between the support base 101 and the forward / reverse shaft 106 to provide friction resistance to the rotation of the forward / reverse shaft 106. Therefore, when measuring the backlash, Since the rotation of the rotation 106 is changed from normal rotation to reverse rotation, when the normal rotation of the normal / reverse rotation shaft 106 is stopped, the over rotation can be prevented by the action of the friction mechanism 126 due to the inertia of the normal / reverse rotation shaft 106. Backlash can be measured accurately.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, the present invention can also be applied to measurement of gear backlash in a gear case of a device other than an outboard motor. Further, when the gear case 1 is positioned and held on the work holder 40, the propeller shaft 10 can be in a horizontal posture and the drive shaft 3 can be in a vertical posture. The gear backlash can also be calculated from the rotation delay of the driven gears 17 and 18 when the drive gear 16 rotates in the reverse direction after the forward rotation. In an outboard motor, an angular contact ball bearing may be used instead of the angular contact roller bearing 20.

1 ... Gear case 3 ... First transmission shaft (drive shaft)
10 .... Second transmission shaft (propeller shaft)
14 .... Propeller 15 .... Switching device (forward / reverse switching device)
16... First gear (drive gear)
17 ··· Second gear (forward driven gear)
18... 2nd gear (reverse driven gear)
20. Angular contact bearing (angular contact roller bearing)
23 ··· Radial bearing ( ball bearing)
35 ··· Backlash measuring device 40 ··· Work holder 43 ··· Thrust load applying mechanism 44 · · · Switching drive mechanism 45 · · · Forward / reverse drive mechanism 46 · · · Electronic control Unit 51a, 51b ... positioning means (positioning hole)
99 ··· Rotation status sensor
DESCRIPTION OF SYMBOLS 101 ... Support stand 104 ... Alignment bearing 106 ... Forward / reverse shaft 107 ... Rotation condition sensor (torque sensor)
110: Forward / reverse drive motor 111 ... Support cylinder 112 ... Chuck 116 ... Alignment mechanism 126 ... Friction mechanism

Claims (8)

The first gear (16) connected to the first transmission shaft (3) supported on the gear case (1) and the second transmission shaft (10) supported on the gear case (1) are connected to or connectable. A backlash measuring device for measuring backlash between the second gear (17, 18) meshing with the first gear (16),
The workpiece holding body (40) that holds the gear case (1) in a predetermined position, and the first transmission shaft (3) in a state where the second gear (17, 18) is rotatable, the assumed back Rotation state sensors (99, 107) for detecting the rotation state of the first transmission shaft (3), which can be reversely rotated more than the angle corresponding to the assumed backlash after being forwardly rotated more than the angle corresponding to the rush. And the first transmission shaft (3) is assumed by the operation of the forward / reverse drive mechanism (45) in a state where the second gear (17, 18) is rotatable. When the forward rotation is more than the angle corresponding to the backlash, and the reverse rotation is more than the angle corresponding to the assumed backlash, from the start of the reverse rotation of the first transmission shaft (3) to the time when the torque suddenly increases. The first transmission shaft 3) the signal of the rotational angle wherein received from rotation state sensor (99,107) for calculating the backlash value, characterized in that it comprises an electronic control unit (46) for determining the appropriateness of the value back Rush measuring device. The backlash measuring device according to claim 1,
The rotational state sensor is a rotational position sensor (99) for detecting a rotational position of the first transmission shaft (3) and a torque sensor (107) for detecting rotational torque of the first transmission shaft (3), The electronic control unit (46) receives the detection signals of the rotational position sensor (99) and the torque sensor (107) and calculates the backlash value. The backlash measuring device according to claim 1 or 2,
The first transmission shaft (3) and the second transmission shaft (10) are supported by the gear case (1) so as to be orthogonal to each other, the first gear (16) is a bevel-type drive gear, Two gears (17, 18) are a pair of bevel type driven gears meshing with both side portions of the drive gear (16), and between these driven gears (17, 18) and the second transmission shaft (10). In this case, each driven gear (17, 18) is selectively connected to the second transmission shaft (10), or both driven gears (17, 18) are released from the connection to the second transmission shaft (10). And a switching drive mechanism (44) capable of switching the switching device (15), and one driven member by applying a thrust load to the second transmission shaft (10). A thrust load applying mechanism (43) capable of applying a load to the gear (17); Backlash measurement device comprising and. The backlash measuring device according to claim 3,
The gear case (1) constitutes the lower part of the casing of the outboard motor, the first transmission shaft is a drive shaft (3) driven by the engine (2), and the second transmission shaft is A propeller shaft (10) to which a propeller (14) is mounted at a rear end, the switching device is a forward / reverse switching device (15), and the one driven gear is a forward driven gear (17); , Supported by the gear case (1) via an angular contact bearing (20), and the other driven gear is a reverse driven gear (18), and the gear case (1) via a radial bearing (23). When the backlash between the drive gear (16) and the forward driven gear (17) is measured, both driven gears (17, 18) are moved by the operation of the switching drive mechanism (44). It controls the forward-reverse switching device to release the neutral state from the connection (15) between the propeller shaft (10), by the operation of the thrust load applying mechanism (43), the angular contact through the propeller shaft (10) A backlash measuring device, wherein a thrust load is applied to the bearing (20) to apply a load to the forward driven gear (17). The backlash measuring device according to claim 3,
The gear case of (1), the first transmission shaft (3) and the vertical position of one of the second transmission shaft (10), also a work holder capable of retaining position-decided Me their other in a horizontal position (40) A backlash measuring device comprising: The backlash measuring device according to claim 1 or 5,
A backlash measuring device, wherein the work holder (40) is provided with a plurality of positioning means (51a, 51b) corresponding to a plurality of types of the gear cases (1). The backlash measuring device according to claim 1,
The forward / reverse drive mechanism (45) is supported by a support base (101) and an alignment bearing (104) on the support base (101), and connected to the first transmission shaft (3) at the tip. A forward / reverse shaft (106) having a chuck (112) that can be operated, a forward / reverse drive motor (110) connected to the rear end of the forward / reverse shaft (106), and a centering mechanism on the support base (101) A backlash measuring device comprising: a support cylinder (111) that is supported non-rotatably via (116) and supports the forward / reverse drive motor (110). The backlash measuring device according to claim 1 or 7,
The forward / reverse drive mechanism (45) is supported by a support base (101) and an alignment bearing (104) on the support base (101), and connected to the first transmission shaft (3) at the tip. A forward / reverse shaft (106) having a chuck (112) that can be operated, a forward / reverse drive motor (110) coupled to the rear end of the forward / reverse shaft (106), the support base (101) and the forward / reverse shaft (106) A backlash measuring device provided with a friction mechanism (126) provided between the two and (106) and providing frictional resistance to rotation of the forward / reverse rotation shaft (106).

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