JP4250645B2 - Belleville spring device, guide shaft and disc spring used therefor - Google Patents

Description

  The present invention relates to a disc spring device having a plurality of disc springs and a guide shaft that is inserted through a central hole of each disc spring and guides the disc springs coaxially, and a guide shaft and disc spring used therefor. .

  Conventionally, a disc spring apparatus having a plurality of disc springs and a guide shaft that is inserted through a central hole of each disc spring and guides the plurality of disc springs coaxially is used as a tool holding device of a machine tool or the like. It is known to be used. FIG. 16 is a cross-sectional view showing the configuration of the spindle 101 of a machine tool provided with such a tool holding device 105. As shown in this figure, the main shaft 101 is rotatably supported in a housing (not shown). A tool holding device 105 for mounting the tool holder 103 on the front end (left side in FIG. 16) of the main shaft 101 is provided in a through hole 102 formed in the shaft center of the main shaft 101. The tool holding device 105 includes a lifting shaft 106 (corresponding to the guide shaft) accommodated in the through hole 102 so as to be movable back and forth in the axial direction, a collet 107 as a gripping mechanism provided at the tip of the lifting shaft 106, and a lifting A plurality of disc springs 108 are loosely inserted into the shaft 106. The disc spring 108 is provided so as to be aligned in the axial direction between the first stopper 110 that contacts the step 109 of the through hole 102 and the second stopper 111 that is integrally provided behind the lifting shaft 106. 106 is urged in the backward direction (right side in FIG. 16). Further, the collet 107 retracts and contracts together with the lifting shaft 106 at the retracted position of the lifting shaft 106 and grips the pull stud 104 protruding from the rear end of the tool holder 103. On the other hand, when the pulling shaft 106 moves forward against the bias of the disc spring 108 by a drive mechanism (not shown) provided behind the main shaft 101, the collet 107 expands while moving forward to release the pull stud 104. .

  In the tool holding device 105, in order to extend the life of the disc spring 108, disc springs 108 having different spring constants are used on the front side and the rear side. Specifically, based on the difference in the deflection amount depending on the position of the plurality of disc springs 108, a rear disc spring 108 having a large deflection amount is used with a large spring constant, and the front side having a relatively small deflection amount is used. A disc spring 108 having a small spring constant is used. As a result, the deflection amount of the whole of the plurality of disc springs 108 arranged in the axial direction of the pulling shaft 106 is made uniform, thereby extending the life of the disc spring 108 as a whole apparatus.

JP 2003-145323 A (2nd page, FIG. 2)

  As described above, in order to extend the life of the disc spring, it is effective to eliminate unevenness in the amount of deflection of the disc spring, but according to the study by the present inventors, the disc spring, the guide shaft, Operation failure due to clogging of wear powder generated by sliding between the sliding springs, sliding resistance due to twisted disc springs, etc., and poor lubrication due to grease deterioration when using grease, etc. It was found that the amount of deflection was non-uniform, causing the disc spring to break. That is, when malfunction or twisting occurs, only a part of the disc springs are compressed, the amount of deflection becomes non-uniform, and an excessive load is partially applied, and the disc springs are easily damaged. In particular, in applications where the disc spring and guide shaft rotate, such as the main shaft of a machine tool, the outer peripheral surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring are used to prevent the disc spring from being biased during rotation. It is necessary to reduce the clearance between the two. For this reason, it has been found that wear powder is clogged and the disc spring is apt to be distorted, which is a major cause of the disc spring breakage.

  The present invention has been made in view of the above problems, and its object is to prevent clogging or twisting of wear powder between the disc spring and the guide shaft, thereby further extending the life of the disc spring. DISCLOSURE OF THE INVENTION An object of the present invention is to provide a disc spring device that can perform the above operation, and a guide shaft and disc spring used therefor.

In order to achieve the above object, a disc spring device according to the present invention has a plurality of disc springs and a guide shaft that is inserted through a central hole of each disc spring and guides the disc springs coaxially. configuration, the guide shaft, on the outer peripheral surface thereof, a guide surface for guiding the disc springs in contact with the inner peripheral surface of the central hole, as well as organic and recess retracted radially inward from the guiding surface The grease is not interposed between the outer peripheral surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring .

  According to this characteristic configuration, a space due to the concave portion is formed between the outer peripheral surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring. Therefore, the wear powder generated by sliding between the disc spring and the guide shaft can move to the recess. Therefore, it is possible to suppress the occurrence of malfunction due to clogging of wear powder between the guide surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring. Further, by providing the recess, the contact area between the guide surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring can be reduced. Therefore, the sliding resistance of the disc spring with respect to the guide shaft can be reduced, and the occurrence of twisting can be suppressed. As a result, it has become possible to extend the life of the disc spring.

  Here, it is preferable that the concave portion is provided continuously over the entire region for guiding the disc spring in the axial direction of the guide shaft.

  If comprised in this way, it will become possible for the abrasion powder which moved to the recessed part to move to the axial direction of a guide shaft. Therefore, it is possible to prevent the wear powder from being unevenly distributed. For example, when a large amount of wear powder is generated, such as when a solid lubricant film is provided on the disc spring or the guide shaft, the operation is caused by clogging of the wear powder. It becomes possible to suppress the occurrence of defects.

In addition, it is preferable that the concave portion is provided by forming a chamfer or a groove on the outer peripheral surface of the guide shaft.
If comprised in this way, a recessed part can be formed in the outer peripheral surface of a guide shaft by simple process.

  Further, it is preferable that the concave portion is provided in a spiral shape along the outer peripheral surface of the guide shaft.

  According to this structure, when the relative position of the guide shaft and the disc spring in the axial direction of the guide shaft changes when the disc spring is compressed, the position of the recess with respect to the inner peripheral surface of the central hole of the disc spring is changed in the circumferential direction. Will change. Therefore, the movement of the wear powder generated between the guide surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring can be more efficiently performed. As a result, it is possible to further suppress the occurrence of malfunction due to clogging of wear powder.

According to another aspect of the present invention, there is provided a disc spring device having a plurality of disc springs, and a guide shaft that is inserted through a central hole of each disc spring and guides the disc springs coaxially. disc spring, the inner circumferential surface of the central hole, as well as organic and guided surface that is in contact with the guide on the outer peripheral surface of said guide shaft, and a recess set back radially outward from該被guide surface, wherein The grease is not interposed between the outer peripheral surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring .

  According to this characteristic configuration, a space due to the recess is formed between the inner peripheral surface of the central hole of the disc spring and the outer peripheral surface of the guide shaft. Therefore, the wear powder generated by sliding between the disc spring and the guide shaft can move to the recess. Therefore, it is possible to suppress the occurrence of malfunction due to clogging of wear powder between the guided surface of the disc spring and the outer peripheral surface of the guide shaft. Further, by providing the recess, the contact area between the guided surface of the disc spring and the outer peripheral surface of the guide shaft can be reduced. Therefore, the sliding resistance of the disc spring with respect to the guide shaft can be reduced, and the occurrence of twisting can be suppressed. As a result, it has become possible to extend the life of the disc spring.

  Here, the said recessed part can be provided by making the internal peripheral surface of the said center hole into a polygonal shape. Moreover, the said recessed part can be comprised by the notch part formed in multiple places along the circumferential direction of the said center hole.

  According to these structures, the said recessed part can be formed simultaneously with the punching process by the press etc. for obtaining the shape of a disk spring from a plate-shaped raw material, for example. Therefore, the concave portion can be provided with less effort and cost.

  Moreover, the said recessed part can also be provided by forming thinly the thickness of the one part area | region inside radial direction which contact | connects the said center hole of the said disk spring with respect to the part outside radial direction from the said area | region. At this time, it is preferable that a part of the radially inner part in contact with the central hole of the disc spring is formed in a cross-sectional taper shape whose thickness becomes thinner toward the radially inner side.

  If comprised in this way, the space by the said recessed part can be formed facing the said center hole in the part which the some disc spring piled up in the axial direction of the said guide shaft contact | connects. Moreover, when the said recessed part is made into the same shape over the perimeter of the said disk spring, the said recessed part can be formed only by performing a simple process on at least one of the both surfaces (convex surface and concave surface) of the said disk spring. In addition, although it is suitable to provide the said recessed part over the perimeter of the said disk spring, it is also possible to provide only in the one part area | region of the circumferential direction of the said disk spring. In this case, it is preferable to form at a plurality of locations along the circumferential direction of the central hole.

  Moreover, the said recessed part can be comprised by the ditch | groove formed so that it may continue along the circumferential direction of the said center hole, and it may open to the said center hole side at least. Or the said recessed part can also be comprised by the several recessed hole provided in the internal peripheral surface of the said center hole. Also by these structures, the space by the said recessed part can be formed facing the center hole of the said disk spring.

According to the present invention, the guide shaft that guides the plurality of disc springs coaxially by being inserted into the center holes of the plurality of disc springs is arranged on the outer peripheral surface thereof and on the inner peripheral surface of the central hole. a guide surface for guiding the disc springs in contact, as well as organic and recesses recessed from the guiding surface radially inward, the grease between the inner peripheral surface of the central hole of the disc spring and the outer peripheral surface There is no intervening point.

  According to this characteristic configuration, when a plurality of disc springs are assembled around the guide shaft, a space is formed by a recess between the outer peripheral surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring. become. Therefore, the wear powder generated by sliding between the disc spring and the guide shaft can move to the recess. Therefore, it is possible to suppress the occurrence of malfunction due to clogging of wear powder between the guide surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring. Further, by providing the recess, the contact area between the guide surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring can be reduced. Therefore, the sliding resistance of the disc spring with respect to the guide shaft can be reduced, and the occurrence of twisting can be suppressed. As a result, it has become possible to extend the life of the disc spring assembled to the guide shaft.

According to the present invention, the disc spring having a central hole through which the guide shaft is inserted and guided to the outer peripheral surface of the guide shaft has an inner peripheral surface of the central hole and an outer peripheral surface of the guide shaft. mediated a guided surface that abuts guided, as well as organic and recess receding radially outwardly from該被guide surface, the grease between the inner peripheral surface of the central hole and the outer peripheral surface of the guide shaft It is in the point not to let you .

  According to this characteristic configuration, when the disc spring is assembled around the guide shaft, a space is formed by the recess between the inner peripheral surface of the central hole of the disc spring and the outer peripheral surface of the guide shaft. . Therefore, the wear powder generated by sliding between the disc spring and the guide shaft can move to the recess. Therefore, it is possible to suppress the occurrence of malfunction due to clogging of wear powder between the guided surface of the disc spring and the outer peripheral surface of the guide shaft. Further, by providing the recess, the contact area between the guided surface of the disc spring and the outer peripheral surface of the guide shaft can be reduced. Therefore, the sliding resistance of the disc spring with respect to the guide shaft can be reduced, and the occurrence of twisting can be suppressed. As a result, it has become possible to extend the life of the disc spring.

1. First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the overall configuration of a disc spring device 1 according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. As shown in these drawings, the disc spring device 1 includes a plurality of disc springs 3 and a guide shaft 2 that is inserted into the central hole 3a of each disc spring 3 and guides the disc springs 3 coaxially. Have. In the vicinity of the end on one side (left side in FIG. 1) of the guide shaft 2, a male screw portion 2a is provided, and a stopper 5 is screwed together. Further, a stepped portion 2b is provided in the vicinity of the end portion on the other side (right side in FIG. 1) of the guide shaft 2, and an end plate 6 is provided on an end surface on one side (left side in FIG. 1) of the stepped portion 2b. Are in contact. The stopper 5 and the end plate 6 have an outer diameter larger than the outer diameter of the disc spring 3. The plurality of disc springs 3 are accommodated between the stopper 5 and the end plate 6 in a state compressed from a free length. The end plate 6 moves relative to the guide shaft 2 on one side (left side in FIG. 1) of the stepped portion 2b, so that the plurality of disc springs 3 guided by the guide shaft 2 are compressed or expanded. To do.

1-1. Guide shaft 2
The guide shaft 2 has a guide surface 2c and a chamfered portion 2d on the outer peripheral surface of the region between the male screw portion 2a and the stepped portion 2b. The step portion 2b is formed in a cylindrical shape having an outer diameter larger than that of the guide surface 2c of the guide shaft 2, and forms a step with respect to the guide surface 2c. The step 2b is formed integrally with or separate from the main body of the guide shaft 2. As shown in FIG. 2, the chamfered portion 2d is a plane parallel to the tangential direction of the outer peripheral surface of the guide shaft 2, and here, at eight positions in the circumferential direction on the outer peripheral surface of the guide shaft 2 at regular intervals. They are spaced apart. As well shown in FIG. 1, the chamfered portion 2d is provided over the entire region between the male screw portion 2a and the stepped portion 2b. That is, the chamfered portion 2 d is provided continuously over the entire region for guiding the disc spring 3 in the axial direction of the guide shaft 2. The guide surface 2c is a circular arc-shaped surface formed by the outer peripheral surface of the guide shaft 2 that is not provided with the chamfered portion 2d, as well shown in FIG. The guide surface 2 c abuts on a guided surface 3 b constituted by the inner peripheral surface of the central hole 3 a of the disc spring 3 and guides the disc spring 3. The surface of the guide shaft 2 is subjected to a surface treatment such as a solid lubricant film or plating. In the present embodiment, the chamfered portion 2d corresponds to the concave portion 4 in the present invention. The number of chamfered portions 2d in the circumferential direction and the interval between them can be arbitrarily changed.

1-2. Belleville spring 3
The disc spring 3 is a disc-shaped spring that is formed in a truncated conical shape and is provided with a central hole 3a in the central portion in the radial direction. In the present embodiment, the central hole 3a is circular. The inner peripheral surface of the central hole 3 a becomes a guided surface 3 b that comes into contact with the guide surface 2 c of the guide shaft 2. The inner diameter of the central hole 3a is slightly larger than the outer diameter of the guide surface 2c of the guide shaft 2 so that the disc spring 3 can slide with respect to the guide shaft 2. Here, as shown in FIG. 1, a plurality of the same size disc springs 3 are overlapped in the same direction (three in the embodiment described later) as one set, and the axial direction is set for each set. A plurality of alternating pairs (42 pairs in the embodiment described later) are arranged coaxially around the guide shaft 2. The surface of the disc spring 3 is subjected to a surface treatment such as a solid lubricating film or plating. In addition, the number of sets and the number of sets of the disc springs 3 can be arbitrarily changed.

1-3. Stopper 5 and end plate 6
The stopper 5 is a cylindrical member having an outer diameter that is slightly larger than the outer diameter of the disc spring 3, and is provided with a female screw portion in the vicinity of the central portion in the length direction in the central portion in the radial direction, and the other side of the female screw portion. A large-diameter circular hole is provided in the guide surface 2c of the guide shaft 2 (on the right side in FIG. 1). The stopper 5 also has a function as a nut that is screwed into the male screw portion 2a of the guide shaft 2. In this state, the circular hole is on one side of the guide shaft 2 (the left side in FIG. 1). ) To cover a part of the guide surface 2c.
The end plate 6 is a disk-shaped member having an outer diameter slightly larger than the outer diameter of the disc spring 3. A circular hole through which the guide shaft 2 is inserted is provided in the central portion in the radial direction, and is slidable with respect to the guide shaft 2. The end plate 6 is in contact with the stepped portion 2 b of the guide shaft 2, so that movement of the end plate 6 to the other side (the right side in FIG. 1) of the guide shaft 2 is restricted.

1-4. Example Next, the result of the endurance test performed regarding the Example and comparative example of the disc spring apparatus 1 which concerns on this embodiment is demonstrated. FIG. 3 is a table showing the results of endurance tests for the examples and comparative examples of the disc spring apparatus 1 according to the present embodiment. In the disc spring device 1 according to the embodiment, as the disc spring 3, the plate thickness is 2.00 [mm], the outer diameter is 40.00 [mm], the inner diameter is 20.40 [mm], and the free height is 3.10 [mm]. The size of was used. The diameter of the guide surface 2c of the guide shaft 2 was 20.38 [mm]. On the outer peripheral surface of the guide shaft 2, chamfered portions 2 d are provided at regular intervals at eight locations in the circumferential direction as described above. Both the guide shaft 2 and the disc spring 3 are coated with a fluorine-based solid lubricant film. Then, 42 sets, each of which is a set of three stacked disc springs 3, are arranged coaxially around the guide shaft 2 by alternately changing the axial direction of each set. The total length of 42 sets 126 disc springs 3 having a free length of 298.2 [mm] is stored between the stopper 5 and the end plate 6 in a state of being contracted to 277.4 [mm]. The disc spring apparatus 1 according to the comparative example has the same configuration as that of the above-described embodiment except that the guide shaft 2 uses a shaft having a circular cross section where the chamfered portion 2d is not provided.

  The durability test is performed between the stopper 5 and the end plate 6 of the disc spring apparatus 1 according to the example and the comparative example by using a hydraulic cylinder equivalent to that used for the machine tool described as the background art. This was performed by repeatedly applying a load to the plurality of disc springs 3. Here, a plurality of disc springs 3 having a total length of 277.4 [mm] in an initial tightening state in which the female thread portion of the stopper 5 is screwed to the male thread portion 2a of the guide shaft 2 are set to 269.8 [mm]. The compression operation was repeated once per second. And the presence or absence of the breakage of the disc spring 3 was confirmed from the appearance about every 1 million times, and the load at the time of extension generated by the plurality of disc springs 3 was measured. The results of this durability test are shown in the table of FIG. In the “Appearance” column of the table, “◯” indicates no breakage and “x” indicates breakage. As shown in this table, in the comparative example using the guide shaft 2 having a circular cross section, the disc spring 3 was broken after 4 million times, whereas in the example, the disc spring 3 was not exceeded even after exceeding 10 million times. The result that it did not break was obtained. From this, it was proved that the life of the disc spring 3 can be greatly extended by providing the outer peripheral surface of the guide shaft 2 with the concave portion 4 such as the chamfered portion 2d that is retracted radially inward from the guide surface 2c. In addition, although the dispersion | variation in the measurement result of the load at the time of expansion | extension exists, the remarkable difference was not seen between the Example and the comparative example.

When the state of the disc spring apparatus 1 according to the example and the comparative example was observed after the test, the following was found.
(1) Wear powder is clogged in the gap between the guide shaft 2 and the disc spring 3 of the disc spring device 1 according to the comparative example, and sliding of some disc springs 3 is prevented. On the other hand, in the disc spring apparatus 1 according to the embodiment, wear powder such as a solid lubricating film adheres to the chamfered portion 2d of the guide shaft 2, and the guide surface 2c of the guide shaft and the guided surface of the disc spring 3 It was found that clogging of wear powder in the gap with 3b did not occur, and malfunction could be prevented.
(2) The guide shaft 2 of the disc spring apparatus 1 according to the comparative example had a large amount of wear in the axial direction, and the disc spring 3 was broken in the vicinity thereof. On the other hand, the partial wear was not seen in the guide shaft 2 of the disc spring apparatus 1 which concerns on an Example. From this, it was found that in the disc spring device 1 according to the example, the occurrence of twisting of the disc spring 3 with respect to the guide shaft 2 could be suppressed.
(3) In the disc spring apparatus 1 according to the comparative example, a large amount of wear of the guided surface 3 b occurs in a part of the disc spring 3 in the axial direction of the guide shaft 2, and a large sliding between the guide shaft 2 and the guide shaft 2. It can be seen that there was dynamic resistance. On the other hand, in the disc spring apparatus 1 according to the embodiment, the guided surface 3b of the disc spring 3 is partially worn only at the portion that contacts the guide surface 2c of the guide shaft 2, and the wear amount is small. It was. From this, it was found that in the disc spring device 1 according to the example, the sliding resistance of the disc spring 3 relative to the guide shaft 2 could be reduced.

2. Second Embodiment Next, a second embodiment of the present invention will be described with reference to the drawings. 4 is a cross-sectional view showing the overall configuration of the disc spring device 1 according to the present embodiment, and FIG. 5 is a cross-sectional view taken along the line AA of FIG. As shown in these drawings, the Belleville spring device 1 according to the present embodiment has the above-described chamfered portion 2d provided in the guide shaft 2 with a spiral groove 2e along the outer peripheral surface as the recess 4. It differs from one embodiment. Other configurations are the same as those in the first embodiment.

  In the present embodiment, the guide shaft 2 has a guide surface 2c and a groove portion 2e on the outer peripheral surface of the region between the male screw portion 2a and the stepped portion 2b. In this example, the groove 2e is a U-shaped groove as shown in FIG. Further, as the groove portion 2e, a plurality of (four in this example) grooves are arranged at regular intervals in the circumferential direction on the outer peripheral surface of the guide shaft 2. The inclination angle of the groove portion 2e with respect to the axial direction of the guide shaft 2 is not preferably a large angle in order to prevent the central hole 3a of the disc spring 3 from being caught by the groove portion 2e. Is preferred. As well shown in FIG. 1, the groove 2e is provided over the entire area between the male screw 2a and the step 2b. That is, the groove portion 2 e is provided continuously over the entire region for guiding the disc spring 3 in the axial direction of the guide shaft 2. The guide surface 2c is configured by an outer peripheral surface of the guide shaft 2 that is not provided with the groove 2e.

  When the spiral groove 2e is provided on the outer peripheral surface of the guide shaft 2 as in the present embodiment, the guide shaft 2 in the axial direction of the guide shaft 2 and the entire length of the plurality of disc springs 3 are compressed. When the relative position to each disc spring 3 changes, the position of the groove 2e with respect to the guided surface 3b of each disc spring 3 changes in the circumferential direction. Therefore, the wear powder generated between the guide surface 2c of the guide shaft 2 and the guided surface 3b of the disc spring 3 can be efficiently guided into the groove 2e. As a result, the occurrence of malfunction due to clogging of wear powder can be further suppressed.

  In the present embodiment, the groove 2e corresponds to the recess 4 in the present invention. In addition, the cross-sectional shape, arrangement | positioning, etc. of the groove part 2e can be changed arbitrarily. Therefore, for example, the cross-sectional shape of the groove 2e may be an arc shape or a V shape. Moreover, the space | interval and the number of the groove parts 2e can also be determined arbitrarily according to the quantity of the abrasion powder to generate | occur | produce. For example, changing the interval of the spiral groove 2e according to the position of the guide shaft 2 in the axial direction is also one preferred embodiment. That is, for example, when the amount of movement of the disc spring 3 on the end plate 6 side is larger than that of the disc spring 3 on the stopper 5 side, the interval between the groove portions 2e on the end plate 6 side is increased, and from there the stopper 5 side It is also possible to arrange the groove 2e so that the interval becomes narrower as it goes toward. Further, in another preferred embodiment, the shape of the groove portion 2e is other than a spiral shape, for example, a straight line shape parallel to the axial direction of the guide shaft 2.

3. Third Embodiment Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a cross-sectional view corresponding to the AA cross section of FIG. 1 in the disc spring device 1 according to the present embodiment. As shown in this figure, the disc spring apparatus 1 according to the present embodiment has the above-described first structure in that the guide shaft 2 does not have the chamfered portion 2d as the concave portion 4 and the concave portion 4 is provided on the disc spring 3 side. This is different from the embodiment. Other configurations are the same as those in the first embodiment.

  In the present embodiment, the guide shaft 2 has a circular outer peripheral surface in a region between the male screw portion 2a and the stepped portion 2b, and the entire outer peripheral surface constitutes the guide surface 2c. On the other hand, the disc spring 3 has a guided surface 3b guided on the inner peripheral surface of the central hole 3a in contact with the guide surface 2c (outer peripheral surface) of the guide shaft 2, and radially outward from the guided surface 3b. And a recessed portion 4 that is retracted. Specifically, as shown in FIG. 6, the central hole 3 a of the disc spring 3 is formed in a polygonal shape (an octagon in this example), and the vicinity of each corner 3 c is a recess 4. That is, in this embodiment, the recessed part 4 is provided by making the internal peripheral surface of the center hole 3a polygonal. Further, the central portion of each side of the central hole 3 a that contacts the guide surface 2 c of the guide shaft 2 becomes the guided surface 3 b of the disc spring 3. The shape of the central hole 3a is not limited to an octagon as shown in the figure, and may be various polygonal shapes such as a pentagon, a hexagon, and a decagon.

  Even when the recess 4 is provided on the disc spring 3 side as in this embodiment, the recess 4 is provided between the inner peripheral surface of the central hole 3 a of the disc spring 3 and the guide surface 2 c of the guide shaft 2. A space will be formed. Therefore, the wear powder generated by sliding between the disc spring 3 and the guide shaft 2 moves to the recess 4, and the wear powder is between the guided surface 3 b of the disc spring 3 and the guide surface 2 c of the guide shaft 2. It is possible to suppress the occurrence of malfunction due to clogging. Further, by providing the concave portion 4, the contact area between the guided surface 3b of the disc spring 3 and the guide surface 2c of the guide shaft 2 can be reduced. Therefore, the sliding resistance of the disc spring 3 with respect to the guide shaft 2 can be reduced, and the occurrence of twisting can be suppressed. As a result, the life of the disc spring 3 can be extended.

4). Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a cross-sectional view corresponding to the AA cross section of FIG. 1 in the disc spring device 1 according to the present embodiment. As shown in this figure, the disc spring apparatus 1 according to the present embodiment includes the recess 4 by notches 3d formed at a plurality of locations along the circumferential direction of the central hole 3a of the disc spring 3. In the point, it differs from the structure which provided the recessed part 4 by making the internal peripheral surface of the center hole 3a in said 3rd embodiment into a polygonal shape. Other configurations are the same as those of the third embodiment.

  In other words, in the present embodiment, the guide shaft 2 has a circular outer peripheral surface in the region between the male screw portion 2a and the stepped portion 2b, and the entire outer peripheral surface constitutes the guide surface 2c. On the other hand, as shown in FIG. 7, the disc spring 3 has a configuration in which notched portions 3 d that are spaced apart at regular intervals are provided at a plurality of locations in the circumferential direction of the central hole 3 a. In this example, each notch 3d has an arcuate shape (substantially semicircular shape), and is provided at six positions in the circumferential direction of the central hole 3a so as to be spaced apart at regular intervals. Each of these notches 3 d becomes a recess 4. Further, a portion other than the cutout portion 3 d of the inner peripheral surface of the central hole 3 a that contacts the guide surface 2 c of the guide shaft 2 becomes the guided surface 3 b of the disc spring 3. In addition, the shape of the notch 3d, the number in the circumferential direction, the interval thereof, and the like can be arbitrarily changed. Further, it is not necessary that the intervals between the plurality of notches 3d are constant.

  The same effects as those of the third embodiment can be obtained by the configuration of the present embodiment. In the third embodiment and the fourth embodiment described above, the concave portion 4 is formed by changing the planar shape of the central hole 3 a of the disc spring 3. However, the configuration for forming the recess 4 in the disc spring 3 is not limited to this. Therefore, various embodiments for providing the concave portion 4 in the disc spring 3 will be further described below.

5. Fifth Embodiment Next, a fifth embodiment of the present invention will be described based on the drawings. In the disc spring device 1 according to the present embodiment, the thickness of a partial region (hereinafter referred to as “thin region”) 3e in the radial direction in contact with the central hole 3a of the disc spring 3 is set to be more radial than the thin region 3e. The recessed part 4 is provided by forming thinly with respect to an outer part. FIG. 8 is a partial cross-sectional perspective view showing the configuration of the disc spring 3 of the disc spring device 1 according to the present embodiment. FIG. 9 is a diagram illustrating details of a contact portion (a guide portion between the guide surface 2c and the guided surface 3b) between the guide shaft 2 and the disc spring 3 of the disc spring device 1 according to the present embodiment. FIG. 2 is a diagram corresponding to an enlarged view of a main part of FIG. 1. As shown in these drawings, in the present embodiment, the thin region 3e is formed in a tapered cross-section that becomes thinner as it goes inward in the radial direction of the disc spring 3. At this time, the thin-walled region 3 e, that is, a region on the radially inner side in contact with the central hole 3 a of the disc spring 3 is a region having a constant width from the inner peripheral surface of the central hole 3 a of the disc spring 3. Here, the thin region 3e is continuously formed over the entire circumference of the disc spring 3 (central hole 3a). Furthermore, in the present embodiment, the thin region 3 e is formed on both surfaces of the disc spring 3.

  According to the configuration of the present embodiment, as shown in FIG. 9, even when a plurality of disc springs 3 are superposed in the same direction along the axial direction of the guide shaft 2, the superposition is performed. A space defined by the recess 4 surrounded by the thin region 3e of the adjacent disc spring 3 is formed facing the central hole 3a on the radially inner side of the portion where the plurality of disc springs 3 are in contact. Therefore, the wear powder generated by sliding between the disc spring 3 and the guide shaft 2 moves to the recess 4, and the wear powder is between the guided surface 3 b of the disc spring 3 and the guide surface 2 c of the guide shaft 2. It is possible to suppress the occurrence of malfunction due to clogging. Accordingly, it is possible to extend the life of the disc spring 3. Moreover, in this embodiment, since the thin area | region 3e for comprising the recessed part 4 is continuously formed over the perimeter of the disk spring 3 (central hole 3a), it is easy to cut on both surfaces of the disk spring 3 The thin region 3e (recessed portion 4) can be formed only by performing the above and the like.

5-1. Example FIG. 10 is a table showing the results of endurance tests for examples and comparative examples of the disc spring apparatus 1 according to the present embodiment. The basic conditions in this durability test are the same as in the case of the first embodiment described above. That is, the disc spring device 1 according to the embodiment has a plate thickness of 2.00 [mm], an outer diameter of 40.00 [mm], an inner diameter of 20.40 [mm], and a free height of 3.10 [disc] as the disc spring 3. mm] dimensions were used. The disc spring 3 is provided with a thin region 3e having a tapered cross section as shown in FIGS. The radial direction length of the thin region 3e was 1.0 [mm], and the plate thickness at the position facing the central hole 3a was 1.0 [mm]. The diameter of the guide surface 2c of the guide shaft 2 was 20.38 [mm]. Both the guide shaft 2 and the disc spring 3 are coated with a fluorine-based solid lubricant film. Then, 42 sets, each of which is a set of three stacked disc springs 3, are arranged coaxially around the guide shaft 2 by alternately changing the axial direction for each set. The total length of 42 sets 126 disc springs 3 having a free length of 298.2 [mm] is stored between the stopper 5 and the end plate 6 in a state of being contracted to 277.4 [mm]. The disc spring apparatus 1 according to the comparative example has the same configuration as that of the above-described embodiment except that a general disc spring 3 in which the thin region 3e is not used is used.

  The durability test is performed between the stopper 5 and the end plate 6 of the disc spring apparatus 1 according to the example and the comparative example by using a hydraulic cylinder equivalent to that used for the machine tool described as the background art. This was performed by repeatedly applying a load to the plurality of disc springs 3. Here, a plurality of disc springs 3 having a total length of 277.4 [mm] in an initial tightening state in which the female thread portion of the stopper 5 is screwed to the male thread portion 2a of the guide shaft 2 are set to 269.8 [mm]. The compression operation was repeated once per second. And the presence or absence of the breakage of the disc spring 3 was confirmed from the appearance about every 1 million times, and the load at the time of extension generated by the plurality of disc springs 3 was measured. The results of this durability test are shown in the table of FIG. In the “Appearance” column of the table, “◯” indicates no breakage and “x” indicates breakage. As shown in this table, in the comparative example using a general disc spring 3, the disc spring 3 broke down after 4 million times, whereas in the example, the disc spring 3 even when it reached nearly 8 million times. Results in no breakage. From this, it was demonstrated that the life of the disc spring 3 can be greatly extended by providing the concave portion 4 with the thin region 3e in a part on the radially inner side in contact with the central hole 3a of the disc spring 3. In addition, although the dispersion | variation in the measurement result of the load at the time of expansion | extension exists, the remarkable difference was not seen between the Example and the comparative example.

5-2. Other Configuration Examples The configuration of the thin region 3e of the disc spring 3 is not limited to the configuration illustrated in FIGS. Specifically, the shape of the thin region 3e is not limited to the cross-sectional taper shape as described above, and can be various shapes. Therefore, for example, as shown in FIG. 11, it is also one preferred embodiment to form a thin-walled region 3 e having a substantially arc-shaped cross section in a part on the radially inner side in contact with the central hole 3 a of the disc spring 3. is there. Also in the example shown in FIG. 11, the thin regions 3e are continuously formed on both surfaces of the disc spring 3 over the entire circumference of the disc spring 3 (central hole 3a). Note that the cross-sectional shape of the thin region 3e shown in FIG. 11 is merely an example, and various other shapes can be employed.

  Further, the thin region 3e is not necessarily formed on both surfaces of the disc spring 3 as described above. For example, as shown in FIG. 12, the thin region 3e is preferably formed only on one surface of the disc spring 3. This is one of the embodiments. 11 shows a configuration in which the thin region 3e is formed only on the convex surface side of the disc spring 3, but a configuration in which the thin region 3e is formed only on the concave surface side of the disc spring 3 may be employed. In addition, the cross-sectional shape of the thin region 3e at this time is not limited to the cross-sectional taper shape, and can be various shapes as described above.

  Further, the thin region 3e is not necessarily formed continuously over the entire circumference of the disc spring 3 (central hole 3a) as described above. For example, as shown in FIG. It is also possible to form the region only. In this example, the thin region 3e is provided at a predetermined interval at a plurality of locations in the circumferential direction of the central hole 3a. In this case, each of the plurality of thin regions 3 e becomes the recess 4. In addition, the shape of the thin area | region 3e, the number of the circumferential direction, its space | interval, etc. can be changed arbitrarily. Further, it is not necessary that the intervals between the plurality of thin regions 3e are constant.

6). Sixth Embodiment Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 14 is a partial cross-sectional perspective view showing the configuration of the disc spring 3 of the disc spring device 1 according to the present embodiment. As shown in this figure, the disc spring device 1 according to the present embodiment is formed so that the recess 4 is continuous along the circumferential direction of the central hole 3a of the disc spring 3 and opens at least toward the central hole 3a. It is constituted by a concave groove 3f. Other configurations are the same as those of the fifth embodiment. Specifically, here, the groove 3f has a substantially V-shaped cross section, and is continuously formed over the entire circumference of the disc spring 3 (central hole 3a). Further, here, the concave groove 3 f is formed at a substantially central portion in the thickness direction in the central hole 3 a of the disc spring 3. The recessed groove 3f can also be formed in a spiral shape with respect to the central hole 3a of the disc spring 3. Further, the shape of the groove 3f is not limited to the substantially V-shaped cross section as described above, and may be other shapes such as a substantially U-shaped cross section and a substantially U-shaped cross section. It is.

7). Seventh Embodiment Next, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 15 is a partial cross-sectional perspective view showing the configuration of the disc spring 3 of the disc spring device 1 according to the present embodiment. As shown in this figure, in the disc spring device 1 according to this embodiment, the concave portion 4 is constituted by a plurality of concave holes 3 g provided on the inner peripheral surface of the central hole 3 a of the disc spring 3. Other configurations are the same as those of the fifth embodiment. Specifically, the recessed hole 3g is a round hole having a certain depth in the radial direction of the disc spring 3 here. In this example, the concave holes 3g are provided at a predetermined interval at a plurality of locations in the circumferential direction of the central hole 3a. In this case, each of the plurality of recessed holes 3 g becomes the recessed portion 4. It should be noted that the shape of the concave holes 3g, the number in the circumferential direction, and the interval thereof can be arbitrarily changed. Further, it is not necessary that the intervals between the plurality of concave holes 3g are constant.

8). Other Embodiments (1) The configuration of the recess 4 provided in the guide shaft 2 is not limited to that described in the first and second embodiments. For example, it is one of the preferred embodiments that a spiral chamfered portion 2d corresponding to a twisted guide shaft 2 provided with the chamfered portion 2d according to the first embodiment is provided, and this is used as a recess 4. It is. Moreover, the recessed part 4 does not necessarily need to be continuing in the axial direction of the guide shaft 2, and may have a discontinuous part. That is, even if the concave portion 4 has a discontinuous portion, a space can be formed between the guide surface 2c of the guide shaft 2 and the guided surface 3b of the disc spring 3, and similarly, the effect of the present invention. It is possible to play. Moreover, the recessed part 4 provided in the guide shaft 2 can also be made into shapes other than chamfering or a groove | channel. For example, a plurality of round holes provided to a predetermined depth in the radial direction of the guide shaft 2 can be used. In this case, it is preferable to have a configuration in which round holes and the like are arranged on the average in both the circumferential direction and the axial direction of the guide shaft 2.

(2) In the first and second embodiments described above, the case where the concave portion 4 is provided over the entire region for guiding the disc spring 3 in the axial direction of the guide shaft 2 has been described. The configuration is not limited to this. That is, it is one of the preferred embodiments that the recess 4 is provided in a part of a region for guiding the disc spring 3 in the axial direction of the guide shaft 2. In this case, it is desirable to provide the recess 4 at least in a region where the wear powder is easily clogged or twisted between the disc spring 3 and the guide shaft 2. For example, in the disc spring device 1 shown in FIG. 1, the disc spring 3 on the side close to the stopper 5 has a small relative movement amount with respect to the guide shaft 2, and in particular, the entire region for guiding the disc spring 3 in the axial direction of the guide shaft 2. Among them, wear powder clogging and twisting are likely to occur in a third region on the stopper 5 side. Therefore, it is preferable to provide the recess 4 at least in this region. Thereby, a space can be formed between the guide surface 2c of the guide shaft 2 and the guided surface 3b of the disc spring 3 at least in a region where wear powder is clogged or twisted easily, and the effect of the present invention can be achieved. It becomes possible to play.

(3) In each of the above embodiments, the configuration in which the concave portion 4 is provided in either the guide shaft 2 or the disc spring 3 has been described. However, the scope of application of the present invention is not limited to this, and it is one of preferred embodiments of the present invention to provide the recess 4 in both the guide shaft 2 and the disc spring 3. For example, the disc springs 3 according to the fifth to seventh embodiments described above all have the guide hole 2 provided with the chamfered portion 2d, the groove portion 2e, and the like because the planar shape of the central hole 3a is circular. Even when the disc spring device 1 is configured in combination, the disc spring 3 is not eccentric and is not particularly caught in the circumferential direction.

(4) In the above-described embodiment, the disc springs 3 are a plurality of sets (implemented in the embodiment, 3 pieces), and a plurality of sets (implementation) in which the axial direction is alternately changed for each set. In the example, 42 sets) are arranged around the guide shaft 2 on the same axis. However, the arrangement configuration of the disc spring 3 can be arbitrarily determined according to the required spring load. Therefore, it is naturally possible to change the direction of the disc springs 3 one by one, or to arrange all the disc springs 3 in the same direction.

(5) In each of the first to third embodiments described above, it is one of preferred embodiments that grease is interposed between the outer peripheral surface of the guide shaft 2 and the inner peripheral surface of the disc spring 3. is there. That is, in the above embodiment, the solid lubricating film is used as the lubrication between the guide shaft 2 and the disc spring 3, but when the surface of the guide shaft 2 and the disc spring 3 is plated, Lubrication with grease may be appropriate. Even in this case, according to the configuration of the present invention, since a large amount of grease can be held in the recess 4, deterioration of the grease can be delayed, and lubrication between the disc spring 3 and the guide shaft 2 can be delayed. Can be carried out well over a longer period of time.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a disc spring device used for an urging mechanism of a tool holding device of a machine tool or an urging mechanism of various devices such as a valve opening / closing device.

Sectional drawing which shows the whole structure of the disc spring apparatus which concerns on 1st embodiment of this invention. AA sectional view of FIG. The table | surface which shows the result of the endurance test about the Example and comparative example of the disc spring apparatus which concern on 1st embodiment of this invention. Sectional drawing which shows the whole structure of the disc spring apparatus which concerns on 2nd embodiment of this invention. AA sectional view of FIG. Sectional drawing equivalent to the AA cross section of FIG. 1 in the disc spring apparatus which concerns on 3rd embodiment of this invention. Sectional drawing equivalent to the AA cross section of FIG. 1 in the disc spring apparatus which concerns on 4th embodiment of this invention. The fragmentary sectional perspective view which shows the structure of the disk spring of the disk spring apparatus which concerns on 5th embodiment of this invention. The figure which shows the detail of the contact part of the guide shaft and disc spring of the disc spring apparatus which concerns on 5th embodiment of this invention. The table | surface which shows the result of the endurance test about the Example and comparative example of the disc spring apparatus which concern on 5th embodiment of this invention. The figure (1) which shows the other example of the disc spring apparatus which concerns on 5th embodiment of this invention. The figure (2) which shows the other example of the disc spring apparatus which concerns on 5th embodiment of this invention. The figure which shows the other example of the disc spring apparatus which concerns on 5th embodiment of this invention (3) The fragmentary sectional perspective view which shows the structure of the disk spring of the disk spring apparatus which concerns on 6th embodiment of this invention. The fragmentary sectional perspective view which shows the structure of the disk spring of the disk spring apparatus which concerns on 7th embodiment of this invention. Sectional drawing of the tool holding apparatus provided with the disc spring apparatus which concerns on background art

Explanation of symbols

1: disc spring device 2: guide shaft 2c: guide surface 2d: chamfered portion 2e: groove portion 3: disc spring 3a: center hole 3b: guided surface 3c: corner portion 3d: notch portion 3e: thin wall region 3f: concave groove 4: Recess

Claims (13)

A disc spring device having a plurality of disc springs and a guide shaft that is inserted through a central hole of each disc spring and guides the disc springs coaxially;
Said guide shaft, on the outer peripheral surface, as well as organic and guide surfaces for guiding the disc springs in contact with the inner peripheral surface of said central bore, and a recess which is retracted radially inward from the guiding surface, the guide A disc spring device in which grease is not interposed between the outer peripheral surface of the shaft and the inner peripheral surface of the central hole of the disc spring.   The disc spring device according to claim 1, wherein the concave portion is provided continuously over the entire region for guiding the disc spring in the axial direction of the guide shaft.   The disc spring apparatus according to claim 1 or 2, wherein the concave portion is provided by forming a chamfer or a groove on an outer peripheral surface of the guide shaft.   The disc spring device according to any one of claims 1 to 3, wherein the concave portion is provided in a spiral shape along an outer peripheral surface of the guide shaft. A disc spring device having a plurality of disc springs and a guide shaft that is inserted through a central hole of each disc spring and guides the disc springs coaxially;
The disc spring, the inner circumferential surface of the central hole, as well as organic and guided surface that is in contact with the guide on the outer peripheral surface of said guide shaft, and a recess set back radially outward from該被guide surface, A disc spring device in which grease is not interposed between the outer peripheral surface of the guide shaft and the inner peripheral surface of the central hole of the disc spring.   The disc spring apparatus according to claim 5, wherein the concave portion is provided by making an inner peripheral surface of the central hole into a polygonal shape.   The disc spring apparatus according to claim 5, wherein the concave portion is constituted by a notch portion formed at a plurality of locations along a circumferential direction of the central hole.   The said recessed part is provided by forming the thickness of the one part area | region inside radial direction which contact | connects the said center hole of the said disk spring thinly with respect to the part outside radial direction from the said area | region. Disc spring device as described.   The disc spring device according to claim 8, wherein a part of the radially inner part of the disc spring that is in contact with the central hole is formed in a cross-sectional taper shape such that a thickness thereof decreases toward the radially inner side.   The disc spring device according to claim 5, wherein the concave portion is constituted by a concave groove that is continuous along the circumferential direction of the central hole and is formed to open at least to the central hole side.   The disc spring apparatus according to claim 5, wherein the concave portion includes a plurality of concave holes provided on an inner peripheral surface of the central hole. A guide shaft that coaxially guides the plurality of disc springs by being inserted through a central hole of the plurality of disc springs,
On its outer peripheral surface, wherein a guide surface for guiding the disc spring at the inner circumferential surface of the central hole abuts, while organic and recesses recessed from the guiding surface radially inwardly, the disc spring and the outer peripheral surface A guide shaft that does not interpose grease with the inner peripheral surface of the center hole . A disc spring having a central hole through which the guide shaft is inserted and guided to the outer peripheral surface of the guide shaft,
Wherein the inner peripheral surface of the central hole, and the guide surfaces are guided in contact with the outer peripheral surface of said guide shaft, as well as organic and recess receding radially outwardly from該被guide surface, the outer periphery of the guide shaft A disc spring in which grease is not interposed between the surface and the inner peripheral surface of the central hole .

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