Torque clutch mechanism and power tool

Abstract

To provide a torque clutch mechanism which can vary the magnitude of load torque when idling between forward rotational drive and reverse rotational drive, and to provide a power tool including the torque clutch mechanism.SOLUTION: A torque clutch mechanism 1 includes: a base member 2 rotatable around an axis L1; a clutch member 3 having a through hole 33; an engaging element 4; and a pressing member 5. A base side opposing surface 22 has an engaging protrusion 23. In the torque clutch mechanism 1, the base member 2 rotates while the engaging protrusion 23 is in an engagement state with the engaging element 4 to cause the clutch member 3 to rotate. When load torque applied to the clutch member 3 becomes a predetermined value or more, the engaging protrusion 23 rides over the engaging element 4, causing the base member 2 to idle. The through hole 33 has: a first inner surface 330 against which the engaging element 4 abuts during forward rotation of the base member 2; and a second inner surface 331 against which the engaging element 4 abuts during reverse rotation thereof. Angles α, β that the inner surfaces 330, 331 form with respect to a clutch side opposing surface 34 differ from each other.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a torque clutch mechanism and a power tool. [Background technology]

[0002] Patent Document 1 describes a torque clutch mechanism for a tightening tool, which includes a locking body biased by a clutch spring and a rotatable ring gear provided with a locking protrusion that the locking body can lock onto or overcome. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-113944 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the tightening tool described in Patent Document 1, the shape of the locking protrusion is a line-symmetrical mountain shape in the rotation direction of the ring gear. Therefore, in this tightening tool, when a load torque is applied to the output shaft at the tip of the tool, the locking protrusion overcomes the locking body and the ring gear rotates freely, the magnitude of the load torque is approximately equal during forward rotation driving and reverse rotation driving.

[0005] When loosening a screw that has been tightened by using the torque clutch mechanism of this tightening tool, if the ring gear spins freely during reverse rotation with the same load torque as during forward rotation, the tightened screw cannot be removed. Therefore, with this tightening tool, there is a risk that the torque clutch mechanism must be disabled or that a separate tool must be prepared.

[0006] In view of the above circumstances, an object of the present disclosure is to provide a torque clutch mechanism and an electric tool equipped with the same, which can change the magnitude of the load torque when idling between forward rotation driving and reverse rotation driving. [Means for solving the problem]

[0007] A torque clutch mechanism according to one aspect of the present disclosure includes a base member rotatable around an axis extending in one direction, a clutch member aligned in the one direction with respect to the base member and having a through hole penetrating in the one direction, and a locking body movably accommodated in the through hole. The torque clutch mechanism further includes a pressing member that elastically presses the locking body against the base member. A base-side facing surface of the base member that faces the clutch member has a locking protrusion that protrudes toward the clutch member. The torque clutch mechanism is configured such that the clutch member rotates integrally with the base member by the base member rotating with the locking protrusion engaged with the locking body. The torque clutch mechanism is configured such that when a load torque applied to the clutch member reaches or exceeds a predetermined value, the locking body is pressed by the locking protrusion to move toward the pressing member, and the locking protrusion overcomes the locking body, causing the base member to rotate freely. The through hole has a first inner surface with which the engaging body comes into contact when the base member rotates forward, and a second inner surface with which the engaging body comes into contact when the base member rotates reversely. A first angle formed by the first inner surface with respect to a clutch-side opposing surface of the clutch member that faces the base member, and a second angle formed by the second inner surface with respect to the clutch-side opposing surface are different from each other.

[0008] An electric power tool of one aspect of the present disclosure includes a motor having a rotating shaft, a reduction mechanism connected to the rotating shaft, the torque clutch mechanism connected to the reduction mechanism, and an output shaft connected to the torque clutch mechanism. Effect of the Invention

[0009] In the torque clutch mechanism and the power tool according to one aspect of the present disclosure, the magnitude of the load torque during idling can be changed between when driving in forward rotation and when driving in reverse rotation. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing a power tool according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view of the power tool taken along line AA. [Diagram 3] FIG. 3 is a perspective view showing a torque clutch mechanism included in the power tool. [Figure 4] FIG. 4 is an exploded perspective view showing the torque clutch mechanism of the above. [Diagram 5] 5A and 5B are cross-sectional views showing the operation of the torque clutch mechanism during forward rotation driving. [Figure 6] 6A and 6B are cross-sectional views showing the operation of the torque clutch mechanism during reverse rotation driving. [Figure 7] FIG. 7A is a cross-sectional view showing a first modified example of the torque clutch mechanism of the above embodiment, and FIG. 7B is a cross-sectional view showing a second modified example of the torque clutch mechanism of the above embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (One embodiment) 1. Overview 1 to 6, a torque clutch mechanism 1 according to an embodiment includes a base member 2 rotatable about an axis L1 extending in one direction D1, and a clutch member 3 aligned in the one direction D1 with respect to the base member 2 and having a through hole 33 penetrating in the one direction D1. The torque clutch mechanism 1 further includes a locking body 4 movably accommodated in the through hole 33, and a pressing member 5 that elastically presses the locking body 4 against the base member 2. The base member 2 has a base-side opposing surface 22 that faces the clutch member 3, which has a locking protrusion 23 that protrudes toward the clutch member 3. The torque clutch mechanism 1 is configured such that the clutch member 3 rotates integrally with the base member 2 when the base member 2 rotates with the locking protrusion 23 locked to the locking body 4. The torque clutch mechanism 1 is configured such that, when the load torque applied to the clutch member 3 reaches or exceeds a predetermined value, the locking body 4 is pushed by the locking protrusion 23 to move toward the pressing member 5, and the locking protrusion 23 overcomes the locking body 4, causing the base member 2 to rotate freely. The through hole 33 has a first inner surface 330 with which the locking body 4 comes into contact when the base member 2 rotates forward, and a second inner surface 331 with which the locking body 4 comes into contact when the base member 2 rotates reversely. A first angle α formed by the first inner surface 330 with respect to a clutch-side opposing surface 34 of the clutch member 3 that faces the base member 2, and a second angle β formed by the second inner surface 331 with respect to the clutch-side opposing surface 34 are different from each other.

[0012] In addition, one embodiment of the power tool 100 includes a motor 6 having a rotating shaft 60, a reduction mechanism 7 connected to the rotating shaft 60, the torque clutch mechanism 1 connected to the reduction mechanism 7, and an output shaft 8 connected to the torque clutch mechanism 1.

[0013] In the torque clutch mechanism 1 and the power tool 100 according to one embodiment having the above configuration, it is possible to provide a difference between the frictional resistance generated between the locking body 4 and the first inner surface 330 during forward rotation drive and the frictional resistance generated between the locking body 4 and the second inner surface 331 during reverse rotation drive. Therefore, in the torque clutch mechanism 1 and the power tool 100, the magnitude of the load torque during idling during forward rotation drive and reverse rotation drive can be changed by the difference in the frictional resistance between the locking body 4 and the inner surfaces 330, 331.

[0014] 2.Details Next, the torque clutch mechanism 1 and the power tool 100 according to an embodiment will be described in more detail with reference to the drawings.

[0015] 2-1.Power tools 1 and 2, the power tool 100 includes a motor 6 having a rotating shaft 60, a speed reduction mechanism 7 connected to the rotating shaft 60, a torque clutch mechanism 1 connected to the speed reduction mechanism 7, and an output shaft 8 connected to the torque clutch mechanism 1. The power tool 100 further includes a plurality of operating units 9a, 9b for operating the power tool 100, a housing 10 that forms the outer shell of the power tool 100, a control unit 11 for controlling the power tool 100, and a spring member 12 that elastically presses the pressing member 5 against the locking body 4.

[0016] In this embodiment, the reduction mechanism 7 has a two-stage reduction section. The reduction mechanism 7 is configured with a planetary gear mechanism. The reduction mechanism 7 can appropriately adopt a conventionally known structure.

[0017] The output shaft 8 is provided at its tip with a mounting portion 80 to which a tool tip such as a drill bit, a driver bit, or the like is detachably attached. The output shaft 8 is connected to a rotating shaft 60 of the motor 6 via a torque clutch mechanism 1 and a reduction mechanism 7. The rotation of the rotating shaft 60 of the motor 6 is transmitted to the output shaft 8 via the reduction mechanism 7 and the torque clutch mechanism 1, causing the tool tip attached to the tip of the output shaft 8 to rotate.

[0018] The operating unit 9a is a part for operating to start and stop the power tool 100. In this embodiment, the operating unit 9a is in the shape of a lever. The operating unit 9b is a part for switching between forward rotation drive and reverse rotation drive of the power tool 100. In this embodiment, the operating unit 9b is a switch.

[0019] The housing 10 constitutes the outer shell of the power tool 100. The housing 10 accommodates a motor 6, a reduction mechanism 7, a torque clutch mechanism 1, an output shaft 8, a control unit 11, and a spring member 12.

[0020] Based on the operation of the operation units 9a and 9b, the control unit 11 controls the rotation of the motor 6. The control unit 11 is a device mainly composed of a computer system such as a microcomputer.

[0021] The spring member 12 is indirectly connected to the pressing member 5 of the torque clutch mechanism 1, and applies a biasing force to the pressing member 5 toward the locking body 4.

[0022] An AC adapter (not shown) connected to a commercial power source is detachably attached to the end of the power tool 100 opposite to the output shaft 8. The power tool 100 can drive the motor 6 by power supplied from the commercial power source to rotate the tool tip attached to the attachment portion 80 at the tip of the output shaft 8.

[0023] 2-2. Torque clutch mechanism Next, a detailed description will be given of the torque clutch mechanism 1 shown in Figures 2 to 6. The torque clutch mechanism 1 is a mechanism that prevents the power of the motor 6 from being transmitted to the output shaft 8 when a load torque of a predetermined value or more is applied to the tip tool of the power tool 100.

[0024] As shown in FIGS. 3, 4 and 5A, the torque clutch mechanism 1 includes a base member 2, a clutch member 3, a locking body 4, and a pressing member 5.

[0025] The base member 2 is rotatable about an axis L1. In this embodiment, the base member 2 has a disk-shaped base plate 20 and a cylindrical connecting portion 21 protruding from the center of the base plate 20 to one side in a direction D1 (the side opposite to the clutch member 3). The base plate 20 and the connecting portion 21 are concentrically arranged. As shown in FIG. 2, a tip portion 210 of the connecting portion 21 is connected to the reduction mechanism 7.

[0026] 3, 4 and 5A, the base plate 20 has a base-side opposing surface 22 that faces the clutch member 3. The base-side opposing surface 22 has a locking protrusion 23 that protrudes toward the clutch member 3 side.

[0027] A slide groove 24 into which a part of the locking body 4 fits is provided on the base-side opposing surface 22. The slide groove 24 is an annular groove when viewed in one direction D1. As shown in Fig. 2, the slide groove 24 has a cross-sectional shape perpendicular to the circumferential direction that fits into (in other words, matches) a part of the locking body 4.

[0028] 4, the base member 2 has a recess 25 in a part of the base-side opposing surface 22. In this embodiment, the recess 25 is located in a part of the circumferential direction of the slide groove 24 and is provided so as to cross the slide groove 24 in the radial direction of the base plate 20.

[0029] That is, the recess 25 is longer in the radial direction of the base plate 20 than a portion of the circumferential direction of the sliding groove 24. The cylinder 13 is attached to the recess 25. The cylinder 13 is rotatably attached to the recess 25. In this embodiment, the cylinder 13 is attached to the recess 25 so that the central axis of the cylinder 13 is parallel to the radial direction of the base plate 20. A portion of the cylinder 13 is housed in the recess 25, and the remaining portion protrudes from the recess 25. The outer peripheral surface of the portion of the cylinder 13 protruding from the recess 25 is the locking protrusion 23.

[0030] In this embodiment, two recesses 25 are provided in the base-side opposing surface 22. The two recesses 25 are arranged at an interval of 180 degrees in the circumferential direction of the slide groove 24. In each of the two recesses 25, one cylindrical body 13 is rotatably accommodated.

[0031] Therefore, two locking protrusions 23 are formed on the base-side opposing surface 22, and these two locking protrusions 23 are arranged at an interval of 180 degrees in the circumferential direction of the base plate 20. The central axes of the two cylindrical bodies 13 that fit into the two recesses 25 are positioned on the same straight line.

[0032] A circular bearing hole 26 is provided in the center of the base-side opposing surface 22 when viewed in one direction D1.

[0033] The clutch member 3 is arranged in one direction D1 relative to the base member 2. The clutch member 3 has a through hole 33 penetrating therethrough in the one direction D1.

[0034] The clutch member 3 has a disk-shaped main body 30, a cylindrical first shaft portion 31 protruding from the center of the main body 30 to one side in the direction D1 (the base member 2 side), and a second shaft portion 32 protruding from the center of the main body 30 to the other side in the direction D1 (the side opposite to the base member 2). The first shaft portion 31, the main body 30, and the second shaft portion 32 are arranged concentrically. The first shaft portion 31 is inserted into the bearing hole 26 of the base member 2. As a result, the base member 2 and the clutch member 3 are combined concentrically and rotatably.

[0035] 2, the second shaft portion 32 has a tip portion 320 fixed to the output shaft 8. This causes the clutch member 3 and the output shaft 8 to rotate integrally.

[0036] 4, the main body 30 is provided with a through hole 33 penetrating in one direction D1. In this embodiment, the main body 30 is provided with two through holes 33. Each of the two through holes 33 has a first inner surface 330 with which the locking body 4 comes into contact during forward rotation driving, and a second inner surface 331 with which the locking body 4 comes into contact during reverse rotation driving. The two through holes 33 are disposed at an interval of 180 degrees in the circumferential direction of the main body 30.

[0037] Of the inner circumferential surface of the through hole 33, half in the circumferential direction of the main body portion 30 is a first inner surface 330, and the remaining half is a second inner surface 331. The first inner surface 330 and the second inner surface 331 face each other in the circumferential direction of the main body portion 30.

[0038] As shown in FIG. 5A, in the main body 30, a first angle α formed by the clutch side facing surface 34 facing the base plate 20 of the base member 2 and the first inner surface 330 is different from a second angle β formed by the clutch side facing surface 34 and the second inner surface 331. In this embodiment, the second angle β is larger than the first angle α. In this embodiment, the first angle α is 90 degrees, and the second angle β is 95 degrees. The difference between the first angle α and the second angle β is preferably 3 degrees or more and 10 degrees or less. In addition, the second angle β is preferably 93 degrees or more and 100 degrees or less.

[0039] Of the openings at both ends of the through hole 33 in the one direction D1, the opening 332 located on the clutch side facing surface 34 is elliptical. The opening 333 on the opposite side is circular. The opening 332 has an elliptical shape that extends slightly in the reverse rotation direction (i.e., counterclockwise direction) from the opening 332 when viewed from the base member 2 side in the one direction D1.

[0040] Both openings 332, 333 are provided with a size and shape that allows the locking body 4 to pass through. The circular opening 333 has approximately the same size and shape as a cross section passing through the center of the locking body 4. In the circumferential direction of the clutch member 3, the length of the elliptical opening 332 is longer than the length of the opening 333. In the radial direction of the disk-shaped main body 30, the length of the opening 332 is the same as the length of the opening 333. The opening 332 has a larger opening area than the opening 333.

[0041] The locking body 4 has a circular cross section perpendicular to a radial direction perpendicular to the axis L1 of the base member 2. In this embodiment, the locking body 4 is a steel sphere. The locking body 4 is movably accommodated in the through hole 33. The locking body 4 is always in contact with the base side opposing surface 22 of the base member 2. In other words, the locking body 4 is in contact with the sliding groove 24 or the locking protrusion 23.

[0042] The pressing member 5 is a member that elastically presses the locking body 4 against the base member 2. As shown in Fig. 4, the pressing member 5 has a main body portion 50 that is a circular plate when viewed in one direction D1, and a cylindrical tube portion 51 that protrudes from the main body portion 50 to one side in the one direction D1 (the side opposite to the base member 2). The main body portion 50 and the tube portion 51 are arranged concentrically.

[0043] The pressing member 5 is attached to the clutch member 3 such that the main body portion 50 overlaps the main body portion 30 of the clutch member 3 and the second shaft portion 32 of the clutch member 3 fits inside the tubular portion 51. A biasing force is applied to the main body portion 50 of the pressing member 5 from the spring member 12 (see FIG. 2 ), and the main body portion 50 is biased toward the main body portion 30 of the clutch member 3. The pressing member 5 is attached to the clutch member 3 so as to be movable in one direction D1. The biasing force applied from the spring member 12 to the pressing member 5 toward the base member 2 causes the pressing member 5 to elastically press the locking body 4 against the base member 2.

[0044] The torque clutch mechanism 1 shown in Fig. 3 and Fig. 5A is formed by combining the above-described base member 2, clutch member 3, locking body 4, and pressing member 5. The torque clutch mechanism 1 is disposed in a housing 10 of a power tool 100 as shown in Fig. 2.

[0045] As shown in Fig. 5A, in the torque clutch mechanism 1, when the base member 2 rotates with the locking protrusion 23 locked to the locking body 4, the clutch member 3 rotates integrally with the base member 2. When the load torque applied to the clutch member 3 reaches or exceeds a predetermined value, as shown in Fig. 5B, the locking body 4 pressed by the locking protrusion 23 moves toward the pressing member 5, and the locking protrusion 23 overcomes the locking body 4, causing the base member 2 to rotate freely. As the base member 2 rotates freely, the power transmission from the rotating shaft 60 of the motor 6 to the output shaft 8 is interrupted.

[0046] 3. Operation of the Torque Clutch Mechanism Next, the operation of the torque clutch mechanism 1 will be described.

[0047] The power tool 100 shown in Figures 1 and 2 can perform forward rotation driving in which the tip tool attached to the mounting portion 80 at the tip of the output shaft 8 rotates clockwise and reverse rotation driving in which the tip tool rotates counterclockwise when viewed from the base member 2 toward the clutch member 3 in one direction D1.

[0048] During forward rotation drive, the rotating shaft 60 of the motor 6 rotates in the forward direction (i.e. clockwise), and the rotation of the rotating shaft 60 is transmitted to the base member 2 via the reduction mechanism 7, causing the base member 2 to rotate forward. At this time, the base member 2 rotates in a state in which each of the two locking protrusions 23 of the base member 2 is locked in the forward direction with the two locking bodies 4 in the two through holes 33 of the clutch member 3, causing the clutch member 3 to rotate forward integrally with the base member 2. The forward rotation of the clutch member 3 causes the output shaft 8 to rotate forward, and the tip tool attached to the mounting portion 80 at the tip of the output shaft 8 to rotate forward.

[0049] During forward rotation drive, when the load torque received by the tool bit is less than a predetermined value, the above state is maintained. The load torque received by the tool bit is transmitted to the locking body 4 via the output shaft 8 and the clutch member 3, and as a result, the load torque is applied from the locking body 4 to the locking protrusion 23. When the load torque applied from the locking body 4 to the locking protrusion 23 is less than a predetermined value, the state in which the locking body 4 is locked to the locking protrusion 23 is maintained, and the base member 2 is prevented from rotating idly (the base member 2 rotates with a movement separate from the clutch member 3).

[0050] When the load torque received by the tool tip during forward rotation (i.e., the load torque applied from the locking body 4 to the locking protrusion 23) reaches or exceeds a predetermined value, the above state is released. In detail, each of the two locking protrusions 23 of the base member 2 climbs over the two locking bodies 4 in the two through holes 33 of the clutch member 3, and the state of being locked to the two locking bodies 4 is released, and the base member 2 rotates freely. As a result, the power transmission from the base member 2 (i.e., from the rotating shaft 60 of the motor 6) to the tool tip connected to the clutch member 3 is interrupted.

[0051] During reverse rotation driving, the torque clutch mechanism 1 operates in a similar state to that during the forward rotation driving described above, except that the rotation direction is reversed.

[0052] In the power tool 100 of this embodiment, the torque clutch mechanism 1 has inner surfaces 330, 331 with different angles α, β relative to the clutch side opposing surface 34. Therefore, in the power tool 100 of this embodiment, when the load torque received by the tool tip is equal to or greater than a predetermined value, the power tool 100 performs different operations as described below depending on whether the tool tip is driven in forward rotation or reverse rotation.

[0053] During forward rotation driving, as shown in Figures 5A and 5B, the locking body 4 is pushed in the forward rotation direction by the locking protrusion 23, and while contacting the first inner surface 330, moves toward the pressing member 5 against the biasing force from the pressing member 5, causing the locking protrusion 23 to overcome the locking body 4.

[0054] During reverse rotation driving, as shown in Figures 6A and 6B, the locking body 4 is pushed in the reverse rotation direction by the locking protrusion 23, and while hitting the second inner surface 331, moves toward the pressing member 5 against the biasing force from the pressing member 5, causing the locking protrusion 23 to climb over the locking body 4.

[0055] Here, the second angle β of the second inner surface 331 relative to the clutch side opposing surface 34 is larger than the first angle α of the first inner surface 330 relative to the clutch side opposing surface 34. Therefore, the frictional resistance generated between the second inner surface 331 and the locking body 4 is larger than the frictional resistance generated between the first inner surface 330 and the locking body 4. By the amount of this difference in frictional resistance, it becomes more difficult for the locking protrusion 23 to overcome the locking body 4 during reverse rotation driving, and the load torque during idling during reverse rotation driving is larger than that during forward rotation driving.

[0056] 4. Effects In the power tool 100 of the present embodiment described above, the frictional resistance occurring between the locking body 4 and the second inner surface 331 during reverse driving is set to be larger than the frictional resistance occurring between the locking body 4 and the first inner surface 330 during forward driving. Therefore, due to the difference in frictional resistance, it becomes more difficult for the locking protrusion 23 to overcome the locking body 4 during reverse driving, and the load torque during idling during reverse driving is larger than that during forward driving.

[0057] Therefore, in the power tool 100 of this embodiment, when a screw that has been tightened by applying the torque clutch mechanism 1 is rotated in the reverse direction to loosen it, it is possible to prevent the base member 2 from spinning freely. Therefore, the power tool 100 of this embodiment is easy to use because it does not require the operation of disabling the torque clutch mechanism 1 or the trouble of preparing a separate power tool.

[0058] Furthermore, in the power tool 100 of this embodiment, the frictional resistance generated between the locking body 4 and the second inner surface 331 can be adjusted by appropriately adjusting the second angle β of the second inner surface 331 relative to the clutch side opposing surface 34, making it easy to adjust the load torque during idling.

[0059] In the power tool 100 of this embodiment, the locking body 4 has a circular cross section, and therefore the portions of the locking body 4 that come into contact with the locking protrusions 23 and the inner surfaces 330, 331 tend to change, making the locking body 4 less susceptible to wear.

[0060] In addition, in the power tool 100 of this embodiment, the locking protrusion 23 is composed of a cylindrical body 13 rotatably attached to the recess 25, so that the part of the locking protrusion 23 that comes into contact with the locking body 4 is easily changed, and the locking protrusion 23 is less likely to wear out.

[0061] In addition, in the power tool 100 of this embodiment, since the locking body 4 is spherical, even if the angles α, β of the inner surfaces 330, 331 relative to the clutch side opposing surface 34 are adjusted, the locking body 4 easily moves while contacting the first inner surface 330 or the second inner surface 331.

[0062] 5. Variations Next, a description will be given of modified examples of the torque clutch mechanism 1 and the power tool 100 according to the above-described embodiment. The modified examples described below can be appropriately combined.

[0063] The first angle α and the second angle β may be different from each other, and the second angle β may be smaller than the first angle α.

[0064] The locking body 4 is not limited to a sphere as long as the cross section perpendicular to the radial direction perpendicular to the axis L1 of the base member 2 is circular. For example, the locking body 4 may be cylindrical with a central axis extending in the radial direction. The cross section of the locking body 4 is not limited to a circular shape and may be another shape.

[0065] Furthermore, the material of the locking body 4 is not limited to steel, and it may be made of other materials.

[0066] Moreover, the base member 2 does not necessarily have to have the recessed portion 25, and the locking protrusion 23 may be molded integrally with the base member 2.

[0067] Furthermore, the cylindrical body 13 may be fixed in the recess 25 and may not be rotatable. In this case, the member constituting the locking protrusion 23 is not limited to a cylindrical shape and may have other shapes.

[0068] Further, the locking protrusion 23 is not limited to a semicircular cross section, and may have other shapes. For example, the locking protrusion 23 may have a trapezoidal cross section having two inclined surfaces 230, 231, as in Modification 1 shown in Fig. 7A. In Modification 1, the two inclined surfaces 230, 231 are provided symmetrically with respect to a line.

[0069] Furthermore, the two inclined surfaces 230, 231 may be provided asymmetrically, that is, at different angles to each other, as in the second modification shown in FIG. 7B.

[0070] The torque clutch mechanism 1 is not limited to being applied to the power tool 100 having the structure shown in FIG. 1, but may be applied to power tools having other structures.

[0071] (summary) As described above in the embodiment and its modified example, the torque clutch mechanism (1) of the first aspect has the following configuration.

[0072] That is, the torque clutch mechanism (1) of the first embodiment includes a base member (2) rotatable about an axis (L1) extending in one direction (D1), and a clutch member (3) arranged in one direction (D1) with respect to the base member (2) and having a through hole (33) penetrating in the one direction (D1). The torque clutch mechanism (1) of the first embodiment further includes a locking body (4) movably accommodated in the through hole (33), and a pressing member (5) that elastically presses the locking body (4) against the base member (2). The base member (2) has a base-side opposing surface (22) that faces the clutch member (3) and has a locking protrusion (23) that protrudes toward the clutch member (3). The torque clutch mechanism (1) is configured such that the clutch member (3) rotates integrally with the base member (2) when the base member (2) rotates with the locking protrusion (23) locked to the locking body (4). The torque clutch mechanism (1) is configured such that, when the load torque applied to the clutch member (3) reaches or exceeds a predetermined value, the locking body (4) is pushed by the locking protrusion (23) to move toward the pressing member (5), and the locking protrusion (23) overcomes the locking body (4), causing the base member (2) to rotate freely. The through hole (33) has a first inner surface (330) with which the locking body (4) comes into contact when the base member (2) rotates forward, and a second inner surface (331) with which the locking body (4) comes into contact when the base member (2) rotates backward. A first angle (α) formed by the first inner surface (330) with respect to a clutch-side facing surface (34) of the clutch member (3) facing the base member (2) and a second angle (β) formed by the second inner surface (331) with respect to the clutch-side facing surface (34) are different from each other.

[0073] In the torque clutch mechanism (1) of the first embodiment having the above configuration, it is possible to make a difference between the frictional resistance generated between the locking body (4) and the first inner surface (330) during forward rotation drive and the frictional resistance generated between the locking body (4) and the second inner surface (331) during reverse rotation drive. Therefore, in the torque clutch mechanism (1) of the first embodiment, it is possible to change the magnitude of the load torque during idling between forward rotation drive and reverse rotation drive by the amount of the difference in the frictional resistance between the locking body (4) and the inner surfaces (330, 331).

[0074] As in the embodiment and its modified example described above, the torque clutch mechanism (1) of the second aspect additionally includes the following configuration in addition to the configuration of the first aspect.

[0075] That is, in the torque clutch mechanism (1) of the second embodiment, the second angle (β) is greater than the first angle (α).

[0076] In the torque clutch mechanism (1) of the second embodiment having the above configuration, the frictional resistance generated between the locking body (4) and the second inner surface (331) is greater than the frictional resistance generated between the locking body (4) and the first inner surface (330). Therefore, in the torque clutch mechanism (1) of the second embodiment, the load torque during idling can be made greater during reverse rotation drive than during forward rotation drive. As a result, in the torque clutch mechanism (1) of the second embodiment, it is possible to prevent the base member (2) from idling when a screw that has been tightened by applying the torque clutch mechanism (1) is loosened by reverse rotation drive.

[0077] As in the embodiment and its modified example described above, the torque clutch mechanism (1) of the third aspect additionally includes the following configuration in addition to the configuration of the first or second aspect.

[0078] That is, in the torque clutch mechanism (1) of the third embodiment, the locking body (4) has a circular cross section perpendicular to the radial direction perpendicular to the axis (L1) of the base member (2).

[0079] In the torque clutch mechanism (1) of the third aspect having the above configuration, the locking body (4) movable within the through hole (33) has a circular cross section, and therefore the locking body (4) is likely to come into point or line contact with the first inner surface (330) or the second inner surface (331). Therefore, in the torque clutch mechanism (1) of the third aspect, the frictional resistance generated between the locking body (4) and the inner surfaces (330, 331) is likely to be stable, and the load torque during idling can be easily set to a desired magnitude.

[0080] As in the embodiment and its modified example described above, the torque clutch mechanism (1) of the fourth aspect additionally includes the following configuration in addition to the configuration of the third aspect.

[0081] That is, in the torque clutch mechanism (1) of the fourth embodiment, the locking body (4) is a steel ball.

[0082] In the torque clutch mechanism (1) of the fourth aspect having the above configuration, the locking body (4) movable within the through hole (33) is spherical, so that the manner in which the locking body (4) contacts the first inner surface (330) or the second inner surface (331) is more likely to be stable. Therefore, in the torque clutch mechanism (1) of the fourth aspect, the frictional resistance generated between the locking body (4) and the inner surfaces (330, 331) is more likely to be stable, and the load torque during idling can be easily set to a desired value. In addition, in the torque clutch mechanism (1) of the fourth aspect, the locking body (4) is a steel sphere, so that the locking body (4) is less likely to wear, and since commercially available steel spheres can be used, the manufacturing cost can be reduced.

[0083] As in the embodiment and its modified example described above, the torque clutch mechanism (1) of the fifth aspect additionally includes the following configuration in addition to the configuration of any one of the first to fourth aspects.

[0084] That is, in the torque clutch mechanism (1) of the fifth aspect, the base member (2) has a recess (25) in a part of the base-side opposing surface (22). The locking protrusion (23) is formed of a cylindrical body (13) attached to the recess (25) so that a cross section perpendicular to a radial direction perpendicular to the axis (L1) of the base member (2) has a circular shape.

[0085] In the torque clutch mechanism (1) of the fifth aspect having the above configuration, the locking protrusions (23) have an arc-shaped surface in the rotation direction of the base member (2), so that the locking body (4) easily rides up onto the locking protrusions (23) in the same manner in both reverse and forward rotation driving. Therefore, in the torque clutch mechanism (1) of the fifth aspect, when a load torque of a predetermined value or more is applied, the locking body (4) that is pushed by the locking protrusions (23) and moves toward the pressing member (5) is likely to hit the first inner surface (330) or the second inner surface (331). In addition, in the torque clutch mechanism (1) of the fifth aspect, when the cylindrical body (13) is worn due to contact with the locking body (4) or the like, it is only necessary to replace the cylindrical body (13), so that the material cost at the time of replacement can be reduced.

[0086] As in the embodiment and its modified example described above, the torque clutch mechanism (1) of the sixth aspect additionally includes the following configuration in addition to the configuration of the fifth aspect.

[0087] That is, in the torque clutch mechanism (1) of the sixth embodiment, the cylindrical body (13) is rotatably attached to the recess (25).

[0088] In the torque clutch mechanism (1) of the sixth aspect having the above-mentioned configuration, the cylindrical body (13) rotates within the recess (25), so that the portion of the cylindrical body (13) that contacts the locking body (4) is unlikely to be constant, and the cylindrical body (13) is unlikely to wear out.

[0089] As in the above-described embodiment and its modified example, the power tool (100) of the seventh aspect has the following configuration.

[0090] That is, the power tool (100) of the seventh embodiment includes a motor (6) having a rotating shaft (60), a speed reduction mechanism (7) connected to the rotating shaft (60), and the torque clutch mechanism (1) of any one of the first to sixth embodiments connected to the speed reduction mechanism (7). The power tool (100) further includes an output shaft (8) connected to the torque clutch mechanism (1).

[0091] In the power tool (100) of the seventh aspect having the above configuration, it is possible to make a difference between the frictional resistance generated between the locking body (4) and the first inner surface (330) during forward driving and the frictional resistance generated between the locking body (4) and the second inner surface (331) during reverse driving. Therefore, in this power tool (100), it is possible to change the magnitude of the load torque during idling between forward driving and reverse driving by the amount of the difference in the frictional resistance between the locking body (4) and the inner surfaces (330, 331).

[0092] The present disclosure has been described above based on the embodiments shown in the attached drawings, but the present disclosure is not limited to the above embodiments, and appropriate design changes are possible within the intended scope of the present disclosure. [Explanation of symbols]

[0093] 1 Torque clutch mechanism 2 Base material 22 Base side facing surface 23 Locking protrusion 25 Recess 3 Clutch parts 33 Through hole 330 First inner surface 331 Second inner surface 34 Clutch side facing surface 4 Locking body 5 Pressing member 6 Motor 60 Rotational Axis 7 Reduction mechanism 8 Output shaft 13 Cylinder 100 Power tools D1 One direction L1 axis α first angle β second angle

Claims

1. A base member rotatable around an axis extending in one direction; a clutch member having a through hole aligned in the one direction with respect to the base member and penetrating in the one direction; A locking body movably received in the through hole; a pressing member that elastically presses the engaging body against the base member; Equipped with The base member has a base-side facing surface facing the clutch member, the base side facing surface having a locking protrusion protruding toward the clutch member, When the base member rotates with the locking protrusion locked to the locking body, the clutch member rotates integrally with the base member, a torque clutch mechanism configured such that, when a load torque applied to the clutch member reaches or exceeds a predetermined value, the locking body is pushed by the locking protrusion to move toward the pressing member, the locking protrusion overcomes the locking body, and the base member rotates freely; the through hole has a first inner surface with which the locking body comes into contact when the base member rotates forward, and a second inner surface with which the locking body comes into contact when the base member rotates backward, a first angle formed by the first inner surface with respect to a clutch-side opposing surface of the clutch member that faces the base member, and a second angle formed by the second inner surface with respect to the clutch-side opposing surface of the clutch member are different from each other; Torque clutch mechanism.

2. The second angle is greater than the first angle.

2. The torque clutch mechanism of claim 1.

3. The locking body has a circular cross section perpendicular to a radial direction perpendicular to the axis of the base member.

2. The torque clutch mechanism of claim 1.

4. The locking body is a steel sphere.

4. The torque clutch mechanism of claim 3.

5. The base member has a recess in a part of the base-side facing surface, The locking protrusion is formed of a cylindrical body attached to the recess so that a cross section perpendicular to a radial direction perpendicular to the axis of the base member is circular.

2. The torque clutch mechanism of claim 1.

6. The cylindrical body is rotatably mounted in the recess.

6. The torque clutch mechanism of claim 5.

7. A motor having a rotating shaft; A reduction mechanism connected to the rotating shaft; A torque clutch mechanism according to any one of claims 1 to 6, which is coupled to the reduction mechanism; an output shaft coupled to the torque clutch mechanism; Power tools.

Images