JP2020045935A - Tension adjustment device of power transmission belt and grinder having tension adjustment device - Google Patents

Abstract

To provide a tension adjustment device which has durability so that rotation moment is not generated at a support part even when receiving reaction force and is small in the number of part items, low in a cost, and easy in assembling to a power transmission device by an integrated simple constitution, and a grinder having the tension adjustment device.SOLUTION: A tension adjustment device 50 comprises a fixing member 51, an energization pulley 55, a slide member 56 and an elastic member 57. A center position of an energization reaction force which the energization pulley receives from a power transmission belt 42 is defined as a first center position D1, a center position of an energization force by which the elastic member energizes the slide member 56 is defined as a second center position D2, a position in which a guide member 53 of the fixing member 51 guides the slide member is defined as a guide position G, and a first distance L1 between the first center position and the second position is shorter than a second distance L2 between the first center position D1 and the guide position G.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power transmission belt tension adjusting device and a grinding machine including the tension adjusting device.

  Conventionally, there is a driving force transmission device that transmits a rotational driving force from one axis to another axis. In such a driving force transmission device, for example, a rubber belt is stretched between a driving pulley fixed to a driving force shaft and a driven pulley fixed to a driven shaft for transmitting power. Thus, when the driving force shaft is rotationally driven, the rotational driving force is transmitted to the driven shaft via the belt and the driven pulley.

  However, at this time, a large tension is always applied to the belt. For this reason, the rubber belt may elongate by a predetermined amount, and the tension of the belt may decrease. When the tension of the belt decreases, if the belt is, for example, a flat belt, slippage occurs between the belt and each pulley, and the transmission efficiency of the driving force may be reduced. Further, if the elongation is further increased, the belt may be detached from each pulley.

  Therefore, there is a tension adjusting device that applies an urging force in the direction of increasing the tension to the belt in response to such a decrease in the tension of the belt (see Patent Documents 1-3). In the tension adjusting device of Patent Literature 1, the belt is urged by manually moving an urging pulley provided at the end of the bracket to increase the belt tension. Further, in the tension adjusting device of Patent Literature 2, an urging pulley is moved in the direction of the belt by an elastic member to urge the belt, and the tension of the belt is automatically increased.

  However, in the tension adjusting device of Patent Document 1, in the axial direction of the driving pulley, a position where the urging pulley urges the belt, that is, a position where the belt tension applies a reaction force to the urging pulley, The position of the support point of the bracket on which the biasing pulley is provided is offset. Further, the brackets are arranged in a cantilever state with the support point position as a fulcrum. For this reason, the bracket receives the rotational moment due to the reaction force based on the tension of the belt, and when the received rotational moment is large, the bracket may be deformed.

  Also, in the tension adjusting device of Patent Document 2, in the axial direction of the driving pulley (crank pulley), the position where the belt tension applies a reaction force to the urging pulley, and the elastic member includes the urging pulley ( The center of the load that urges the tension pulley in the direction of the belt is offset from the center of the load. Further, the biasing pulley is supported in a cantilever manner by a support member that supports the elastic member. For this reason, the biasing pulley receives a rotational moment due to a reaction force based on the tension of the belt, and the support member is tilted, which may cause wear between the member supporting the support member and the support member.

  However, as a configuration capable of coping with these problems, in the tension adjusting device described in Patent Document 3, in the axial direction of the driving pulley, the position where the belt tension applies a reaction force to the biasing pulley, and the elastic member The load center position for urging the urging pulley in the direction of the belt substantially coincides. For this reason, even if the urging pulley is supported by the fixed member via the supporting member in a one-sided state, the tension of the opposing belt is offset by the urging force of the elastic member. As described above, the possibility that the support member of the biasing pulley receives a rotational moment is low.

Japanese Utility Model Publication No. 50-25905 Japanese Utility Model Publication No. 62-44188 Japanese Patent No. 5479351

  However, the tension adjusting device of Patent Literature 3 is not originally a configuration for solving the problems described in the descriptions of Patent Literatures 1 and 2. According to the description of Patent Document 3, the tension adjusting device is a device configured to satisfy good maintainability (exchangeability). For this reason, the urging portion 4a is formed completely separate from the portion provided with the urging pulley so that it can be easily replaced with a new elastic member (compression spring). Further, the urging portion 4a includes a retainer which is a cylindrical member for accommodating an elastic member (compression spring). The retainer includes a spring holding member that supports both ends of the compression spring, and an insertion piece that supports the compression spring and manages the compression amount of the compression spring. Further, a monitoring window for monitoring the compression amount of the compression spring, which is an index for determining the replacement time of the compression spring, is provided on a side surface of the retainer. For this reason, the tension adjusting device of Patent Document 3 has a very complicated and expensive configuration.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problem, and even if a biasing pulley receives a reaction force corresponding to the tension of a power transmission belt from a belt, a rotational moment is applied to a supporting portion of the biasing pulley. The tension adjusting device and the tension adjusting device for the power transmission belt are low in cost and easy to assemble to the power transmission device because of the durability, the small number of parts, and the simple structure integrated. It is an object of the present invention to provide a grinding machine having the same.

(1. Power transmission belt tension adjustment device)
The power transmission belt tension adjusting device according to the present invention includes a fixing member, a biasing pulley that biases the power transmission belt to change the tension of the power transmission belt, and a rotatable rotation of the biasing pulley. A sliding member that supports, and is engaged with a guide member included in the fixing member, and is guided to be reciprocally movable with respect to the fixing member in a direction of urging the power transmission belt by the urging pulley; An elastic member that is disposed between the fixed member and the slide member and that urges the slide member in a direction in which the urging pulley urges the power transmission belt.

  In the rotation axis direction of the biasing pulley, a center position of the biasing reaction force received by the biasing pulley from the power transmission belt is defined as a first center position, and the elastic member attaches the slide member. The center position of the urging force to be urged is defined as a second center position, a position at which the guide member of the fixed member guides the slide member is defined as a guide position, and the first center position and the second center are defined. A first distance between the positions is shorter than a second distance between the first center position and the guide position.

  Thus, in the tension adjusting device according to the present invention, the first distance between the first center position and the second center position is shorter than the second distance between the first center position and the guide position. Be composed. Therefore, even if the urging pulley receives a reaction force corresponding to the tension of the power transmission belt, the reaction force is generated by the urging force by which the elastic member urges the slide member according to the position of the second center position. As a result, the rotational moment applied to the guide member of the slide member can be satisfactorily suppressed. Further, since the wear of the guide shaft is suppressed well, high durability is provided.

  At this time, the elastic member is significantly different from the configuration of the urging portion (4a) of Patent Document 3, and is formed as an urging portion only by being disposed between the fixed member and the sliding member. For this reason, the assembling is simple and the number of parts is greatly reduced, so that the manufacturing can be performed at low cost. Further, the tension adjusting device is formed by integrating (uniting) a fixing member, an elastic member, a biasing pulley, a slide member, and a guide member for guiding the slide member. Therefore, as in Patent Document 3, the urging portion (4a) and the urging pulley (14) are formed separately from each other, and then separately engaged with the supporting portion of the driving force transmission device while being engaged with each other. There is no need to assemble them. Therefore, it is possible to reduce the number of assembling steps to the driving force transmission device, and further reduce the cost.

(2. Grinding machine)
Further, the grinding machine according to the present invention is a grinding wheel, a shaft member connected to the grinding wheel and rotatably supporting the grinding wheel around an axis, a motor having an output shaft, and a motor having an output shaft, the shaft member and the motor A power transmission belt that is wound around the output shaft and transmits the rotational force of the motor to the grinding wheel via the shaft member; and the tension described above that adjusts the tension of the power transmission belt to a predetermined tension. An adjusting device. As described above, when a workpiece is ground, a grinding machine having high durability can be obtained by applying the invention to a grinding machine in which the tension of the power transmission belt fluctuates due to the vibration of the grinding wheel. It also contributes to the cost reduction of the grinding machine.

1 is a schematic plan view of a grinding machine to which a power transmission belt tension adjusting device according to an embodiment is applied. FIG. 2 is a view as viewed in a direction K in FIG. 1, in which a tension adjusting device is mounted on a driving force transmission device. It is a perspective view of a tension adjusting device. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2. FIG. 5 is a Q view of only the fixing member main body in FIG. 4. FIG. 5 is an R view of FIG. 4. FIG. 7 is a view corresponding to FIG. 6 and illustrating a first modification. FIG. 13 is a diagram corresponding to FIG. 4 for explaining Modification 2;

<1. First embodiment>
(1-1. Overview)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a grinding machine 1 to which a tension adjusting device 50 (see FIG. 2) for a power transmission belt 42 according to the present invention is applied. The grinder 1 is, for example, a grindstone traverse grinder. FIG. 1 shows an example of a plan view of the grinding machine 1, and FIG. 2 shows a K view in FIG. In all the drawings in which the X axis, the Y axis, and the Z axis are described, the X axis, the Y axis, and the Z axis are orthogonal to each other. The Y axis indicates a vertical upward direction, and the Z axis and the X axis indicate a horizontal direction. The Z axis indicates the direction of the workpiece rotation axis, and the X axis direction indicates the direction in which the grinding wheel 15 cuts into the workpiece W.

(1-2. Overall Configuration of Grinding Machine 1)
As shown in FIG. 1, the grinding machine 1 includes a bed 11 fixed on a floor, a headstock 12 rotatably supporting both ends of a work W fixed to the bed 11, a tailstock device 13, The wheel head 14 is capable of moving in a Z-axis direction and an X-axis direction, and a control device 18 is provided.

  The grindstone head 14 includes a grindstone wheel 15 rotatably supported by the grindstone wheel 14, a driving force transmitting device 40 for rotatingly driving the grindstone wheel 15, and a tension adjusting device 50 according to the present invention described in detail below. . The control device 18 drives the headstock 12 and the grinding wheel 15, controls the position of the grinding wheel 15 with respect to the work W, and controls the grinding of the work W by the grinding wheel 15.

  The grinding machine 1 grinds the workpiece W rotating around the workpiece rotation axis WZ by the grinding wheel 15. The grinding wheel 15 is formed in a substantially disk shape. The grinding wheel 15 rotates around a grinding wheel rotation axis TZ, and is configured to be relatively movable with respect to the workpiece W in the Z-axis and X-axis directions. The work rotation axis WZ and the grindstone rotation axis TZ are both parallel to the Z axis.

  As shown in FIG. 1, the headstock 12 includes a base 12a, a spindle housing 12b, and a spindle 12c. The base 12a is placed on the bed 11. The main shaft housing 12b is configured to be able to reciprocate in the Z-axis direction with respect to the base 12a. The main shaft 12c is supported rotatably around the work rotation axis WZ in the main shaft housing 12b. A center member 12d is provided at one end of the main shaft 12c. The main shaft 12c is provided with a drive motor (not shown), and the control device 18 can rotate the main shaft 12c at an arbitrary angular velocity to an arbitrary angle around the work rotation axis WZ passing through the tip of the center member 12d.

  The tailstock 13 includes a base 13a, a tailstock housing 13b, a tailstock 13c, and a center member 13d. The base 13a is placed on the bed 11. The tailstock housing 13b is configured to be movable in the Z-axis direction with respect to the base 13a. The tail shaft 13c is rotatably or non-rotatably supported around the work rotation axis WZ within the tail shaft housing 13b, and is provided coaxially with the main shaft 12c. The work W is supported at both ends (or near both ends) by the headstock 12 having the center member 12d and the tailstock 13 having the center member 13d. Note that the center member 12d may be a chuck.

  A traverse base 19 is placed on the bed 11. The traverse base 19 is positioned and controlled at an arbitrary position in the Z-axis direction along the V-shaped guide 23 according to the rotation angle of the ball screw 22 controlled by the Z-axis drive motor 21. The control device 18 outputs a control signal to the Z-axis drive motor 21 while detecting a signal from position detection means such as an encoder (not shown), and positions the traverse base 19 in the Z-axis direction.

  On the traverse base 19, a grinding wheel base 14 for moving the grinding wheel 15 forward and backward is mounted. The grinding wheel head 14 is positioned at an arbitrary position in the X-axis direction along guides 16 and 17 integrally provided on the upper surface of the traverse base 19 according to the rotation angle of the ball screw 30 controlled by the X-axis drive motor 25. Is positioned. The control device 18 outputs a control signal to the X-axis drive motor 25 while detecting a signal from the position detection means, and positions the position of the grinding wheel head 14 in the X-axis direction.

  Further, for example, it is assumed that the grinding wheel rotation axis TZ and the workpiece rotation axis WZ are located on the same horizontal plane. In this state, the grinding wheel 15 is relatively approached to the workpiece W, and a point on the grinding wheel 15 side at a position where the workpiece W contacts the grinding wheel 15 is set as a processing point. At this time, the grinding machine 1 is provided with a coolant nozzle for supplying coolant near the processing point, but is not shown.

  As shown in FIG. 1, the grindstone table 14 includes a slide table 26, a grindstone wheel 15, a grindstone bearing 27, a grindstone drive motor 28 (a servomotor, corresponding to a motor), and an X-axis drive motor 25. , A driving force transmitting device 40 (see FIG. 2) for rotating and driving the grinding wheel 15, a tension adjusting device 50 (see FIG. 2) and the like. The rotational driving force (rotating force) of the grinding wheel drive motor 28 is transmitted to the grinding wheel 15 via the driving force transmission device 40. In the present embodiment, an example of the structure in which the wheel head 14 is moved forward and backward by the X-axis drive motor 25 and the ball screw 30 has been described, but a linear motor may be used, for example. The drive device for moving the grindstone head 14 forward and backward is not particularly limited.

(1-3. Driving force transmission device 40)
As shown in FIG. 2, the driving force transmission device 40 includes a driving pulley 41, a power transmission belt 42, and a driven pulley 43. The cylindrical drive pulley 41 is fixed to a tip of a rotary shaft 28a (corresponding to an output shaft) provided in the grindstone drive motor 28 so as to be integrally rotatable with the rotary shaft 28a. At both ends of the outer peripheral surface of the drive pulley 41 in the axial direction of the rotating shaft 28a, flanges (not shown) are provided to protrude. In the present embodiment, the cylindrical driven pulley 43 has a smaller cylindrical diameter than the driving pulley 41, and is provided at the tip of a rotating shaft 15a (corresponding to a shaft member) that supports the grinding wheel 15 rotatably around the axis. It is fixed so as to be integrally rotatable with the rotating shaft 15a. A flange (not shown) protrudes from both ends of the outer peripheral surface of the driven pulley 43 in the axial direction of the rotating shaft 15a.

  The power transmission belt 42 (hereinafter, referred to as the belt 42 only) is hung with tension T between the flanges on the outer peripheral surface of the driving pulley 41 and between the flanges on the outer peripheral surface of the driven pulley 43. (See the two-dot chain line in FIG. 2). At this time, the tension T may be smaller than a predetermined tension T1 to be set between the drive pulley 41 and the driven pulley 43 when the grindstone drive motor 28 is operated (T ≦ T1). The predetermined tension T1 is a value set to have a predetermined width (range).

  When the tension T of the belt 42 between the drive pulley 41 and the driven pulley 43 is a predetermined tension T1, the rotational force of the grinding wheel drive motor 28 is reduced by the rotation shaft 28a, the drive pulley 41, the belt 42, and the driven pulley 43. , The rotating shaft 15a in this order, and the grinding wheel 15 is driven to rotate. That is, the rotational force of the grinding wheel drive motor 28 is transmitted to the grinding wheel 15 via the rotating shaft 15a (shaft member).

  In the above description, the belt 42 is a so-called flat belt, and is, for example, a unitary flat belt formed only of urethane rubber which is rubber. However, the belt 42 is not limited to a simple flat belt. For example, a film core flat belt using a stretched polyamide film or the like as a core, a cord flat belt using a polyester cord or the like as a core, or a laminate in which a relatively strong core such as polyester and a cover layer having a high friction coefficient are laminated. A flat belt may be used.

(1-4. Tension adjusting device 50)
The tension adjusting device 50 is a device that adjusts the tension T of the belt 42 included in the driving force transmission device 40 to a predetermined tension T1 set in advance. As shown in FIG. 2, the tension adjusting device 50 is unitized and fixed to the slide table 26 of the grindstone table 14. As shown in FIGS. 2 to 4, the tension adjusting device 50 includes a fixing member 51, a biasing pulley 55, a slide member 56, two compression coil springs 57, 57 (corresponding to elastic members). , Is provided.

(1-4-1. Fixing member 51)
The fixing member 51 includes a fixing member main body 52, two guide shafts 53, 53 (corresponding to guide members), and two support shafts 54, 54. The fixing member main body 52 is formed of, for example, an iron-based plate member such as SPCC. As shown in FIGS. 2 to 4, the fixing member main body 52 includes a first support portion 52 a and a second support portion 52 b formed by bending both ends in the longitudinal direction of a rectangular plate member at right angles, respectively. A connection portion 52c for connecting the first support portion 52a and the second support portion 52b; As a result, the inner surfaces 52a1 and 52b1 of the first support 52a and the second support 52b face each other.

  As shown in FIG. 2, at this time, the length of the second support portion 52b erected from the lower end of the connection portion 52c is the same as the first support portion erected from the upper end of the connection portion 52c. The length is about half of the length of the support portion 52a. The connecting portion 52c is fixed to the slide table 26 of the grindstone table 14 by predetermined fixing means (not shown). As shown in FIG. 5, the first support portion 52a includes four through holes 52a2, 52a3, 52a4, and 52a5. FIG. 5 is a Q view of only the fixing member main body 52 in FIG. As shown in FIG. 5, the four through-holes 52a2-52a5 are arranged such that virtual lines (two-dot chain lines) connecting the centers of the holes form a rectangle Re. The second support 52b has through holes 52b2, 52b3 at positions facing the through holes 52a2, 52a3 of the first support 52a.

  The two guide shafts 53 are provided between the through-hole 52a2 of the first support 52a and the through-hole 52b2 of the second support 52b, and between the through-hole 52a3 of the first support 52a and the second support 52b. It is arranged between the through-hole 52b3 so that each axis position matches the center of each through-hole. At this time, the respective guide shafts 53, 53 are respectively end faces of a first end 53a which is one (upper in FIG. 4) end and a second end 53b which is the other (lower in FIG. 4) end. Are provided with female screws 53a1 and 53b1, respectively.

  Then, as shown in FIG. 4, the four bolts 151 are connected to the through holes 52a2 and 52a3 from the side opposite to the side where the guide shafts 53 and 53 are arranged in the first support portion 52a and the second support portion 52b. The female screws 53a1 and 53b1 are screwed through the through holes 52b2 and 52b3. Thus, the guide shafts 53 are fixed to the fixing member main body 52. At this time, a slide member 56 described later in detail is inserted through the guide shafts 53, 53 so as to be relatively movable in the axial direction with respect to the guide shafts 53, 53. Specifically, the guide shafts 53 are inserted through guide shaft through holes 56a, which are through holes formed in the slide member 56.

  Next, the support shafts 54 will be described. As shown in FIG. 4, the two support shafts 54, 54 are provided with female threads 54a1, 54a1, respectively, on the end surfaces of the first ends 54a, 54a, which are the one (upper in FIG. 4) ends. The support shafts 54, 54 are disposed on the same side as the guide shafts 53, 53 on the first support portion 52a, such that the axes thereof coincide with the centers of the through holes 52a4, 52a5. Then, the two bolts 58 are screwed to the female screws 54a1 and 54a1 via the through holes 52a4 and 52a5 from the side opposite to the side where the support shafts 54 and 54 are arranged in the first support portion 52a. Thus, the support shafts 54, 54 are fixed to the fixing member main body 52 by one-sided support.

  At this time, the slide member 56 described above is inserted into the support shafts 54, 54 so as to be relatively movable in the axial direction with respect to the support shafts 54, 54 and the guide shafts 53, 53, as shown in FIG. You. Specifically, the support shafts 54, 54 are inserted into support shaft holes 56b, 56b, which are through holes formed in the slide member 56. The support shaft holes 56b may be bottomed holes instead of through holes. That is, when the slide member 56 and the support shafts 54, 54 move relatively in the axial direction, the other ends 54b, 54b of the support shafts 54, 54 do not contact the bottom surface of the support shaft hole. What is necessary is just to be formed.

  As shown in FIG. 4, when the tension adjusting device 50 operates, the urging pulley 55 urges the belt 42 of the driving force transmission device 40 by the outer peripheral surface of the urging pulley 55, and the tension T of the belt 42 is increased. Is adjusted (changed) to a predetermined tension T1. As shown in FIG. 4, the urging pulley 55 is formed in a shape similar to the driving pulley 41 and the driven pulley 43.

  That is, the biasing pulley 55 is formed in a cylindrical shape. The urging pulley 55 is provided at the tip of a rotation support shaft 59 that supports the rotation of the urging pulley 55 so as to be rotatable relative to the rotation support shaft 59. The urging pulley 55 includes flanges at both ends of the outer peripheral surface in the rotation axis direction of the urging pulley 55. As will be described later in detail, the end of the rotation support shaft 59 opposite to the side on which the biasing pulley 55 is provided is fixed to the slide member 56.

  As shown in the perspective view of FIG. 3 and the cross-sectional view of FIG. 4, the slide member 56 is a lower part and a front part (left side) in FIG. (See the dashed line portion). For the sake of convenience, in the following description, a member behind (a right side in FIG. 4) of the deleted portion of the block will be described as a first member 56A, and a member above the deleted portion will be described as a second member 56B.

  In the slide member 56, the above-described guide shaft through holes 56a, 56a are formed in the first member 56A. The guide shaft through holes 56a, 56a are formed to penetrate from the upper surface 56c to the lower surface 56d of the first member 56A. The guide shaft through holes 56a, 56a are arranged at the same position in the rotation axis direction of the urging pulley 55 (= the axis direction of the rotation support shaft 59). As described above, the guide shafts 53, 53 (corresponding to guide members) of the fixing member 51 are inserted into and engaged with the guide shaft through holes 56a, 56a. Specifically, dry bearings 152 and 153 are provided between the guide shafts 53 and 53 at both ends (upper and lower ends) of the guide shaft through holes 56a and 56a.

  Thereby, the slide member 56 is guided to be able to reciprocate with high precision with respect to the fixed member 51 in the urging direction (= axial direction of the guide shafts 53, 53) of the belt 42 by the urging pulley 55. In the present embodiment, the guide shafts 53, 53 (corresponding to the guide members) of the fixing member 51 guide the slide member 56 in the rotation axis direction of the urging pulley 55, that is, the guide shafts. The axial positions of the guide shafts 53, 53 (or guide shaft through holes 56a, 56a) are defined as guide positions G. The guide position G will be used later.

  Further, the slide member 56 supports the urging pulley 55 via the rotation support shaft 59 as described above. The urging pulley 55 is supported by the rotation support shaft 59 so as to be rotatable relative to the rotation support shaft 59. At this time, the rotation axis direction of the urging pulley 55 (the axis direction of the rotation support shaft 59) is set in an assembled state in which the tension adjusting device 50 is assembled to the driving force transmission device 40 (in the following description, an assembled state is set). Are described only in some cases) and the driving pulley 41 and the driven pulley 43 are arranged in parallel with each other.

  The rotation support shaft 59 is fixed by projecting a predetermined amount from the front surface 56e of the first member 56A. As described above, the rotation support shaft 59 is provided so as to penetrate from the front surface 56e (the left surface in FIG. 4) of the first member 56A to the rear surface 56f (the right surface in FIG. 4) of the first member 56A. The end is press-fitted into the support hole and fixed.

  At this time, as shown in FIG. 4 when viewed from the left in FIG. 4, that is, when the tension adjusting device 50 is viewed from the rotation axis direction of the urging pulley 55 in FIG. Are respectively arranged equally on both sides of the rotation axis O across the rotation axis O of the urging pulley 55 (= the axis of the rotation support shaft 59). The biasing pulley 55 is provided at the tip of the rotation support shaft 59 so as to be rotatable relative to the rotation support shaft 59 via a bearing (not shown) such as a ball bearing or a needle bearing.

  In addition, the biasing pulley 55 is disposed such that the right end surface in FIG. 4 is slightly separated from the front surface 56e of the first member 56A. Further, the biasing pulley 55 has a large portion around the rotation support shaft 59 housed in a space S formed by the front of the front surface of the first member 56A and below the lower surface 56g of the second member 56B. You. The lower portion of the urging pulley 55 is open to the external space V. Accordingly, in the state of being assembled to the driving force transmission device 40 described above, the outer surface of the belt 42 provided in the driving force transmission device 40 located in the external space V below the urging pulley 55, and the urging pulley 55 A part of the outer peripheral surface located below can be satisfactorily contacted.

  As described above, the slide member 56 includes the support shaft holes 56b through which the two support shafts 54 are inserted into the second member 56B. The support shaft holes 56b are formed to penetrate from the upper surface 56c to the lower surface 56g of the second member 56B. The upper surface 56c of the second member 56B is flush with the upper surface 56c of the first member 56A. The support shaft holes 56b are arranged at the same position in the rotation axis direction of the biasing pulley 55 (the axis direction of the rotation support shaft 59).

  Then, as shown in FIG. 4, the support shafts 54, 54 of the fixing member 51 are inserted into the support shaft holes 56b, 56b as described above. Therefore, it can be said that the positions of the axes of the support shaft holes 56b, 56b and the axes of the support shafts 54, 54 coincide. At this time, the position of the lower end surface of each of the support shafts 54, 54 is such that the lower surface 56g of the second member 56B of the slide member 56 can be moved even if the slide member 56 is moved upward relative to the support shafts 54 at the maximum. And is formed to have a length that does not abut (collide) with the outer peripheral surface of the urging pulley 55.

  In the above-described configuration, the first support portion 52a of the fixed member main body 52 is provided with the two compression coil springs 57, 57 (elastic members) having the support shafts 54, 54 respectively inserted into the inner diameter side. A predetermined amount of compression is provided between the surface 52a1 on the side of the slide member 56 and the upper surface 56c of the slide member 56. Thus, the compression coil springs 57 urge the slide member 56 in the direction in which the urging pulley 55 urges the power transmission belt 42 in the above-described assembled state.

  Here, as shown in FIG. 4, in the rotation axis direction of the biasing pulley 55, the center position of the biasing force P that biases the slide member 56 by the two compression coil springs 57, 57 (elastic member), that is, The load center position of the urging force P is defined as a second center position D2. Further, in the rotation axis direction of the urging pulley 55, the center position of the urging reaction force (-P) received from the belt 42 by the urging pulley 55, that is, the load center position of the urging reaction force (-P) is referred to as the fourth position. Defined as one center position D1. In the present embodiment, the first center position D1 of the urging pulley 55 in the rotation axis direction is assumed to coincide with the center position of the width Wi of the belt 42.

  At this time, the center position of the width Wi of the belt 42 coincides with the second center position D2 of the urging force for urging the slide member 56 by the compression coil springs 57, 57 in the rotation axis direction of the urging pulley 55. The position of the biasing pulley 55 is set in advance. That is, in the above embodiment, the first distance L1 (not shown) between the first center position D1 and the second center position D2 in the rotation axis direction of the biasing pulley 55 is “0”. Therefore, the first distance L1 is shorter than the second distance L2 between the first center position D1 and the guide position G.

  When the slide member 56 is viewed from the rotation axis direction (R direction) of the urging pulley 55, as shown in FIG. 6, the support shafts 54, 54 (or the support shafts through which the support shafts 54, 54 are inserted). Extensions of the axes 54A, 54A of the holes 56b, 56b) have a uniform distance a on both sides of the rotation axis O across the rotation axis O of the urging pulley 55 (= the axis of the rotation support shaft 59). Placed.

  At this time, the compression coil springs 57, 57 are biased by the two compression coil springs 57, 57 at the center position D3 (corresponding to the second center position D2) of the biasing force for biasing the slide member 56. Is the center between the axes of the compression coil springs 57, 57. That is, when viewed from the R direction, at the center position D3, the extension line of the urging force P for urging the slide member 56 by the two compression coil springs 57 is the same as the rotation axis O of the urging pulley 55. Intersect.

(1-5. Action)
Next, the operation in the assembled state (see FIG. 2) in which the tension adjusting device 50 is assembled to the driving force transmitting device 40 will be described. Since the operation of the grinding machine 1 is known, a detailed description is omitted. For example, FIG. 2 shows that, in the initial state, when the tension adjusting device 50 is assembled to the driving force transmitting device 40, the two compression coil springs 57, 57 apply an urging force P for urging the slide member 56; This shows a state in which the biasing reaction force (-P) received by the biasing pulley 55 from the belt 42 is balanced. It is assumed that the tension of the belt 42 at this time is a predetermined tension T1 having a width (range).

  At this time, as shown in FIG. 4, in the rotation axis direction of the biasing pulley 55, the compression coil springs 57, 57 move the second central position D <b> 2 of the biasing force P for biasing the slide member 56 and the biasing pulley 55. The pulley 55 is at the same position as the first center position D1 of the urging reaction force (-P) received from the belt 42. Thus, the biasing force P and the biasing reaction force (-P) are offset in the rotation axis direction of the biasing pulley 55.

  Accordingly, the slide member 56 to which the biasing pulley 55 is fixed is rotated about any point of the guide position G by the biasing reaction force (-P) received by the biasing pulley 55 from the belt 42. Moment is unlikely to occur. For this reason, there is a low possibility that the generated rotational moment causes a tilt between the bearing 152 provided in the slide member 56 and the guide shafts 53 supported by the bearing 153 to cause abrasion.

  At this time, as shown in FIG. 6, when the tension adjusting device 50 is viewed from the rotation axis direction (R direction) of the urging pulley 55, the tension adjusting device 50 is compressed at the center position D3 corresponding to the second center position D2. An extension line of the urging force P for urging the slide member 56 by the coil springs 57, 57 intersects the rotation axis of the urging pulley 55. Further, at a center position D4 corresponding to the first center position D1, the extension line of the biasing reaction force (-P) received by the biasing pulley 55 from the belt 42 intersects with the rotation axis of the biasing pulley 55.

  That is, in the left-right direction in FIG. 6, the compression coil springs 57, 57 are biased by the biasing pulley 55 received from the belt 42 by the center position D <b> 3 (load center position) of the biasing force P for biasing the slide member 56. The center position D4 of the reaction force (-P) (the center position of the load) coincides with the center position D4.

  As a result, the slide member 56 generates a biasing reaction force (−P) that the biasing pulley 55 receives from the belt 42 and a biasing force P that biases the slide member 56 by the two compression coil springs 57. They face each other at the same position in the horizontal direction in FIG. Therefore, a rotational moment for rotating the slide member 56 in the state shown in FIG. For this reason, there is a low possibility that the generated rotational moment causes an inclination between the bearing 152 provided in the slide member 56 and the guide shafts 53 supported by the bearing 153, resulting in wear.

  Thereafter, when the grinding machine 1 operates for a long time and the belt 42 of the driving force transmission device 40 is extended, the tension T1 of the belt 42 decreases. Thereby, the transmission efficiency of the rotational force of the grinding wheel drive motor 28 transmitted between the drive pulley 41 and the driven pulley 43 is reduced. If the tension T1 further decreases, the belt 42 may fall off the driving pulley 41 and the driven pulley 43.

  However, in the present embodiment, the tension adjusting device 50 is provided, and the urging pulley 55 always urges the belt 42 in a well-balanced manner as described above. When the tension T1 decreases, the urging pulley 55 advances toward the belt 42 by the urging of the compression coil springs 57, 57 while maintaining the state of being urged in a well-balanced state, and reduces the tension of the belt 42 by the tension. Adjust to T1.

(1-6. Effect in First Embodiment)
According to the tension adjusting device 50 of the power transmission belt 42 according to the first embodiment, the tension adjusting device 50 includes the fixing member 51, the urging pulley 55, the slide member 56, and the compression coil springs 57, 57 (elastic members). Is done. Then, in the rotation axis direction of the biasing pulley 55, the center position of the biasing reaction force (-P) received by the biasing pulley 55 from the power transmission belt 42 is defined as a first center position D1. , 57 (elastic member) define the center position of the urging force P for urging the slide member 56 as the second center position D2, and the guide shafts 53, 53 (guide member) of the fixed member 51 guide the slide member 56. The position is defined as a guide position G. Then, a first distance L1 between the first center position D1 and the second center position D2 is shorter than a second distance L2 between the first center position D1 and the guide position G.

  Thus, in the tension adjusting device 50, the first distance L1 between the first center position D1 and the second center position D2 is shorter than the second distance L2 between the first center position D1 and the guide position G. It is configured to be. For this reason, even if the urging pulley 55 receives a reaction force (-P) corresponding to the tension T of the power transmission belt 42, the reaction force is not changed according to the position of the second center position D2. 57 (elastic member) is offset correspondingly by the urging force for urging the slide member 56. For this reason, the rotational moment received by the guide shafts 53, 53 (guide members) of the slide member 56 can be favorably suppressed. Therefore, the slide member 56 is satisfactorily guided by the guide shafts 53 and 53 (guide member), and can be accurately moved relative to the guide shafts 53 and 53 in the axial direction. In addition, the tension adjusting device 50 has high durability because the abrasion of the guide shafts 53 is well suppressed.

  At this time, the compression coil springs 57, 57 (elastic members) are greatly different from the configuration of the urging portion 4a in the related art (Patent Document 3), and the fixed member 51 (fixed member main body 52) and the slide member 56 It is established as an urging portion simply by arranging it between. For this reason, assembling is simple and the number of parts is greatly reduced, so that the tension adjusting device 50 can be manufactured at low cost.

  Further, in the tension adjusting device 50, the fixing member 51, the compression coil springs 57, 57, the biasing pulley 55, the slide member 56, and the guide shafts 53, 53 (guide members) for guiding the slide member 56 are integrated (unit). Is formed. Therefore, as in the prior art (Patent Literature 3), the urging portion (4a) and the pulley (14) for urging are formed separately from each other, and thereafter, while being engaged with each other, the driving force transmission device is provided. There is no need to separately assemble the support. For this reason, the number of steps for assembling to the driving force transmission device 40 can be reduced, and the cost can be reduced.

  According to the first embodiment, when the tension adjusting device 50 is viewed from the rotation axis direction (R direction) of the urging pulley 55, the tension adjusting device 50 corresponds to the second center position D2, and the compression coil springs 57, 57 are provided. An extension line extending in the direction of the biasing force P from the center position D3 (load center position) of the biasing force P for biasing the slide member 56 by the (elastic member) intersects the rotation axis O of the biasing pulley 55. Thus, when viewed from the R direction, the urging force P and the urging reaction force (-P) received by the urging pulley 55 from the power transmission belt 42 are applied at the same position in the left-right direction in FIG. The momentum is offset. Therefore, no rotational moment is generated on the slide member 56 in FIG. Therefore, the slide member 56 is more appropriately guided by the guide shafts 53, 53 (guide member), and can be relatively accurately moved relative to the guide shafts 53, 53 in the axial direction.

  Further, according to the first embodiment, the elastic members are the compression coil springs 57, 57, and the fixed member 51 has the fixed member main body 52 and the first and second end portions 53a, 53b have the fixed member main body 52. , The guide shafts 53, 53 serving as guide members whose axis position is the guide position G, the first end 54 a is fixed to the fixed member main body 52, and is inserted through the inner diameter side of the compression coil springs 57, 57. And support shafts 54, 54 whose axial position matches the second center position D2. The slide member 56 includes guide shaft through-holes 56a, 56a through which the guide shafts 53, 53 are axially movable relative to the slide member 56, and support shafts 54, 54, respectively. And supporting shaft holes 56b, 56b inserted so as to be relatively movable in the axial direction with respect to the member 56.

  Thus, the compression coil springs 57, 57 are provided as elastic members. Thus, the fixing member 51, the compression coil springs 57, 57, the biasing pulley 55, the slide member 56, and the guide shafts 53, 53 (guide members) for guiding the slide member 56 are integrated easily and at low cost. (Unitized).

  Further, according to the first embodiment, in the fixing member 51, the extension of the axis of the guide shafts 53, 53 and the extension of the axis of the support shafts 54, 54 are respectively the rotation axis O (= rotation) of the biasing pulley 55. Two guide shafts 53, 53 and two support shafts 54, 54 are provided so as to be evenly arranged on both sides of the rotation axis O across the support shaft 59). Two compression coil springs 57, 57 (elastic members) are arranged between the fixed member 51 and the slide member 56 such that their respective axes coincide with the axes of the two support shafts 54, 54, respectively.

  With such a configuration, the two compression coil springs 57, 57 can urge the slide member 56 in a wide range and stably, and the two compression coil springs 57, 57 urge the slide member 56. The center position (center of load) can be easily matched with the position of the urging reaction force (-P) received by the urging pulley 55 from the power transmission belt 42. Accordingly, when viewed from the R direction, the urging force P by the compression coil springs 57, 57 and the urging reaction force (-P) received by the urging pulley 55 from the power transmission belt 42 correspond to the left-right direction in FIG. In, they are urged and offset at the same position. Accordingly, since no rotational moment is generated in the slide member 56, the slide member 56 can stably move relative to the fixed member 51 in the axial direction.

  Further, according to the first embodiment, the grinding machine 1 includes the grinding wheel 15 and the rotating shaft 15a (corresponding to a shaft member) that is connected to the grinding wheel 15 and rotatably supports the grinding wheel 15 around the axis. , A grinding wheel drive motor 28 (motor) having a rotating shaft 28a (output shaft), a rotating shaft 15a and a rotating shaft 28a of the motor 28, and the rotating force of the grinding wheel drive motor 28 is applied to the grinding wheel via the rotating shaft 15a. A power transmission belt 42 for transmitting to the vehicle 15 and a tension adjusting device 50 for adjusting the tension T of the power transmission belt 42 to a predetermined tension are provided. As described above, when the workpiece W (workpiece) is ground, the tension adjusting device 50 is applied to the grinding machine 1 in which the tension T of the power transmission belt 42 fluctuates due to the vibration of the grinding wheel 15 at all times. The board 1 also has high durability. In addition, by applying the low-cost tension adjusting device 50, the cost of the grinding machine 1 can be reduced.

(1-7. Modification of First Embodiment)
(1-7-1. Modification 1)
In the first embodiment, two support shafts 54, 54 and two compression coil springs 57, 57 (elastic members) are provided. However, it is not limited to this mode. As a first modification of the first embodiment, each of the support shaft 54 and the compression coil spring 57 (elastic member) may be one. In this case, as shown in FIG. 7, the support shaft 54 and the compression coil spring 57 are arranged such that each axis crosses the rotation axis of the biasing pulley 55 when the tension adjusting device 50 is viewed from the R direction. Preferably. Thereby, the same effect as in the first embodiment can be expected. The present invention is not limited to the mode of the first modification, and the axes of the support shaft 54 and the compression coil spring 57 may be arranged so as not to intersect with the rotation axis of the biasing pulley 55. This can be expected to have a corresponding effect.

(1-7-2. Modification 2)
Further, in the first embodiment, the first center position D1 which is the center position of the biasing reaction force (-P) for biasing the biasing pulley 55 by the belt 42 in the rotation axis direction of the biasing pulley 55. The aspect in which the compression coil springs 57 and 57 match the second center position D2 which is the center position of the urging force P for urging the slide member 56 has been described.

  However, it is not limited to this mode. As a second modification of the first embodiment (see FIG. 8), the second center position D2 only needs to be located within the range of the width Wi of the power transmission belt 42 in the rotation axis direction of the biasing pulley 55. Even with such an arrangement, the rotational moment to be generated for the slide member 56 can be changed according to the magnitude of the second center position D2, as compared with the case where the second center position D2 is arranged to coincide with the guide position. Is suppressed. Further, the second center position D2 may not be located within the range of the width Wi of the power transmission belt 42 in the rotation axis direction of the urging pulley 55. In this case, the first distance L1 may be smaller than the second distance L2. This can be expected to have a corresponding effect.

(1-7-3. Modification 3)
In the first embodiment, the power transmission belt 42 is described as a rubber flat belt. However, it is not limited to this mode. As a third modification (not shown) of the first embodiment, any material may be used as long as the power transmission belt 42 is formed of a material that may be elongated during operation of the driving force transmission device 40 and the tension T may be reduced. May be formed. For example, it may be formed of resin, metal, or the like. With this, a corresponding effect can be expected.

<2. Others>
In the first embodiment, the rotation support shaft 59 is fixed to the slide member 56 so as not to rotate relatively. However, the present invention is not limited to this mode. The rotation support shaft 59 may be configured such that the end opposite to the end on which the biasing pulley 55 is disposed is rotated relative to the slide member 56 via a ball bearing or the like. It may be supported as possible. In this case, the urging pulley 55 is fixed to the other end of the rotation support shaft 59. With this, the same effect as in the first embodiment can be expected.

  In the first embodiment, as the guide portions of the slide member 56, the guide shaft through holes 56a formed in the slide member 56, and the guide shaft 53 inserted through the guide shaft through holes 56a, 56a. , 53 are engaged. However, the present invention is not limited to this mode, and the guide section may be formed by any method. For example, a guide unit using a rail system as disclosed in the related art (Japanese Patent No. 5479351) may be used. Alternatively, a known LM guide may be applied to form the guide portion. With these, the same effects as in the above embodiment can be expected.

  In the first embodiment, the elastic member is the compression coil spring 57, but is not limited to this mode. The elastic member may be any material such as rubber, a leaf spring, and a wave washer. However, it is preferable that the elastic member can be satisfactorily held between the upper surface of the slide member 56 and the first support portion 52a of the fixed member main body 52 by the support shaft or a member replacing the support shaft. This can be expected to have a corresponding effect.

  Further, in the first embodiment, the mode in which the tension adjusting device 50 for the power transmission belt is provided in the grinding machine has been described, but the present invention is not limited to this mode. The present invention may be applied to any device provided with a driving force transmission device including a driving pulley, a driven pulley, and a belt.

  Reference Signs List 1: grinding machine, 15: grinding wheel, 15a: rotating shaft (shaft member), 28: grinding wheel driving motor (motor), 28a: rotating shaft (output shaft), 40: driving force transmission device, 41: driving pulley, 42 Power transmission belt, 43; driven pulley, 50: tension adjusting device, 51: fixing member, 52: fixing member main body, 52a: first supporting portion, 52b; second supporting portion, 52c; connecting portion, 53; , 54; support shaft, 55; biasing pulley, 56; slide member, 56a; guide shaft through hole, 56b; support shaft hole, 59; rotary support shaft, D1: first center position, D2; Center position, G: guide position, L1: first distance, L2: second distance.

Claims (8)

In the power transmission belt tension adjustment device,
A fixing member,
An urging pulley for urging the power transmission belt to change the tension of the power transmission belt,
The biasing pulley is rotatably supported, and is engaged with a guide member included in the fixing member, and reciprocates with respect to the fixing member in a direction of biasing the power transmission belt by the biasing pulley. A sliding member guided as possible,
An elastic member that is disposed between the fixed member and the slide member and that urges the slide member in a direction in which the urging pulley urges the power transmission belt;
With
In the rotation axis direction of the biasing pulley, a center position of the biasing reaction force received by the biasing pulley from the power transmission belt is defined as a first center position, and the elastic member biases the slide member. The center position of the urging force is defined as a second center position, and the position where the guide member of the fixed member guides the slide member is defined as a guide position,
A tension adjusting device for a power transmission belt, wherein a first distance between the first center position and the second center position is shorter than a second distance between the first center position and the guide position.   When the tension adjusting device is viewed from the rotation axis direction of the urging pulley, the elastic member at the second central position is an extension of the central position of the urging force for urging the slide member, The tension adjusting device for a power transmission belt according to claim 1, wherein the tension adjusting device intersects the rotation axis of the urging pulley. The elastic member is a compression coil spring,
The fixing member,
A fixing member body,
A first and second end portions are fixed to the fixing member main body, and a guide shaft as the guide member whose axial position is the guide position,
A first end portion is fixed to the fixing member main body and is inserted through the inner diameter side of the compression coil spring, and a support shaft having an axial position coinciding with the second center position,
The slide member,
The guide shaft, a guide shaft through-hole that is inserted so as to be relatively movable in the axial direction with respect to the slide member,
3. The power transmission belt tension adjusting device according to claim 1, wherein the support shaft includes a support shaft hole that is inserted so as to be relatively movable in the axial direction with respect to the slide member. 4. The fixing member,
The guide shaft and the support so that the axis of the guide shaft and the extension of the axis of the support shaft are equally arranged on both sides of the rotation axis while straddling the rotation axis of the urging pulley. Equipped with two axes,
The compression coil spring,
The tension adjusting device for a power transmission belt according to claim 3, wherein two axes are arranged between the fixed member and the slide member so that the axes coincide with the axes of the two support shafts, respectively.   The tension adjustment of the power transmission belt according to any one of claims 1 to 4, wherein the second center position is located within a range of a width of the power transmission belt in the rotation axis direction of the biasing pulley. apparatus.   The tension adjusting device for a power transmission belt according to claim 1, wherein the second center position matches the first center position.   The tension adjusting device for a power transmission belt according to any one of claims 1 to 6, wherein the power transmission belt is a rubber flat belt. With a grinding wheel
A shaft member connected to the grinding wheel and supporting the grinding wheel so as to be rotatable around an axis;
A motor having an output shaft;
The power transmission belt that is wound around the shaft member and the output shaft of the motor, and that transmits the rotational force of the motor to the grinding wheel via the shaft member;
A grinding machine comprising: the tension adjusting device according to claim 1, wherein the tension of the power transmission belt is adjusted to a predetermined tension.

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