JP2000170788A - Overload slip device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overload slip device which reduces the number of part components, and does not require the time and the labor to the assembly work and the dissolution work. SOLUTION: In an overload slip device which transmits the motive power by locking an inside and an outside rotary members 1 and 2 rotatable each other by making the same axial line as the rotary shafts, by a locking member 4 sprung by a springing member 5, the springing member 5 is formed in a circular form, while a locking member holding groove 22 to hold the locking member 4, and a springing member housing groove 23 to house the springing member 5, are formed to either one side of the inside and the outside rotary members 1 and 2, and an engaging recess 12 the locking member 4 is engaged is formed to the other side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a power tool such as a hammer drill and transmits a torque less than an allowable value.
The present invention relates to an overload slip device for preventing an overload from being applied to a power transmission mechanism of a power tool.

[0002]

2. Description of the Related Art Heretofore, an inner rotating member, an outer rotating member rotatably provided outside the inner rotating member, and a mutual power of the inner rotating member and the outer rotating member have been prevented to prevent power. A plurality of engaging members for transmitting, and a plurality of engaging portions in which the engaging member is engaged with the opposing peripheral surfaces of the inner rotating member and the outer rotating member are formed so as to face each other,
An overload slip device is known in which when a predetermined torque is applied, these locking members are disengaged from a plurality of engagement portions, and the outer rotating member rotates with respect to the inner rotating member to prevent overload.

In such an overload slip device, one rotating member is provided with the same number of pockets as the locking member, a coil spring is housed therein, and the locking member is pressed against the engaging portion of the other rotating member. (For example, see Japanese Patent Publication No. 48-41484 and Japanese Utility Model Laid-Open Publication No. 7-22135).

[0004]

However, in the overload slip devices described in these prior art documents, it is necessary to provide one coil spring for each locking member, which causes an increase in the number of parts. I was Further, at the time of assembling, it is necessary to install the locking member while compressing the coil springs one by one and maintaining the compressed state, which requires a lot of work. Further, during operation, the coil spring may unexpectedly expand and the locking member may be scattered.

Accordingly, the present invention provides an overload slip device that reduces the number of parts and does not require assembling and disassembling operations.

[0006]

According to the first aspect of the present invention, the inner and outer rotating members (1, 7, 2, 8) rotatable about the same axis as the rotation axis and the resilient member (5). , 9), said inner and outer rotating members (1, 7,
And a locking member (4) for transmitting power while preventing mutual rotation of (2, 8), the annular resilient member (5, 51, 52, 9). And one of the inner and outer rotating members (2, 7) is formed in an annular shape along the circumferential direction, and the resilient member (5, 51, 5) is formed.
Resilient member accommodating grooves (23, 73) for accommodating 2, 9);
A locking member holding groove (22, 72) formed on the rotating member (2, 7) having the resilient member housing groove (23, 73) formed therein for holding the locking member; The locking member (4) formed on the other of the members (1, 8).
And a position holding member (P) abutting on end faces of the inner and outer rotating members (1, 7, 2, 8).

[0007]

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

FIGS. 1 to 4 show an embodiment of an overload slip device according to the present invention. The overload slip device includes a power transmission shaft 3 serving as a central axis of the device, and a substantially annular inner rotating member 1 attached to the outer periphery of the power transmission shaft 3 and rotating integrally with the power transmission shaft 3. A substantially annular outer rotating member 2 provided on an outer peripheral portion of the inner rotating member 1.
And a locking member 4 # 4 formed in a columnar shape and locking the outer rotating member 2 and the inner rotating member 1 to transmit power (see FIGS. 1 and 2).

The power transmission shaft 3 is formed in a round bar shape, and a central portion 31 in the axial direction has a large diameter.
A pinion gear 32 having a truncated cone shape is formed on an upper portion of the power transmission shaft 3 in the axial direction (upper side in FIG. 1). On the other hand, the lower portion 33 in the axial direction (the lower side in FIG. 1) is formed to have a smaller diameter than the central portion. Bearings B1 and B2 for supporting the overload slip device on a casing or the like of a power tool (not shown) are fitted to the lower portion 33 and an end of the central portion 32 on the pinion gear 32 side. A key groove 34 is formed on the peripheral surface of the central portion 31 so as to extend downward in the axial direction from the position of the lower end surface of the bearing B1.

A keyway 100 is formed on the inner peripheral surface of the inner rotating member 1 provided on the outer periphery of the power transmission shaft 3 along the axial direction. The position of the inner rotating member 1 is aligned with the key groove 100 facing the key groove 34 of the power transmission shaft 3, and the key 6 is inserted into the key grooves 100 and 34 and attached. Further, the inner rotating member 1 is mounted with its upper surface in contact with the bearing B1, and the movement in the axial direction is restricted.

On the other hand, the outer circumferential surface of the inner rotating member 1 has a locking groove 12 # 12 as a shallow engaging recess extending from the lower end surface (the lower surface in FIG. 1) to a substantially central portion in the axial direction. They are formed at equal intervals in the circumferential direction. A flange 13 is formed on an upper portion (upper side in FIG. 1) of the inner rotating member 1 so as to protrude outward in the radial direction.

An outer rotating member 2 disposed outside the inner rotating member 1 is formed in a substantially annular shape, and a groove is formed in one end surface thereof at a substantially central portion of a radial member width along a circumferential direction. It is a formed member (see FIG. 3). The outer peripheral surface of the outer rotating member 2 is formed with a gear 24 over the entire circumference, and meshes with another gear such as a power tool (not shown). The outer rotating member makes the inner peripheral edge portion of the upper end surface on which the groove is not formed abut against the flange portion 13 of the inner rotating member 1,
The lower end surface on the side where the groove is formed is mounted substantially flush with the lower end surface of the inner rotating member 1 (see FIG. 1).

The groove formed in the outer rotating member 2 along the circumferential direction is a part that serves as a spring accommodating groove 23 for accommodating the ring spring 5 as a resilient member. The spring accommodating groove 23 is formed with the groove width kept at a constant interval, and is provided while leaving only a part in the circular direction as the rib 25. The rib 25 is formed so as to connect the radially inner portion 20 and the outer portion 21 of the spring accommodating groove 23 (see FIGS. 2 and 3). The spring accommodating groove 23 is formed from the lower end surface of the outer rotating member 2 to the position of the axial end of the locking groove 12 # 12 (see FIG. 1).

The ring spring 5 as a resilient member is a ring-shaped member having an elastic force, and has a cutout 51 in a part in the circumferential direction for discontinuing the member.
When the ring spring is compressed so as to reduce the gap between the notches 51, the ring spring stores a resilient force in a radially outward direction. Conversely, if the ring spring is pulled to increase the gap between the notches 51, the ring spring moves toward the center in the radial direction. Power is stored. This ring spring 5
Is formed to be slightly smaller than the outer diameter of the inner side wall of the spring accommodating groove 23.

The diameter of the ring spring 5 is increased so as to widen the gap between the notches 51, and the notches match the positions of the ribs 25 so that the spring receiving grooves 23 are formed from the axially lower portions of the rotating members 1 and 2. It is provided to be inserted into. The member width of the ring spring 5 is formed to be smaller than the groove width of the spring accommodating groove 23, and a gap is formed between the outer peripheral surface of the ring spring 5 and the inner wall outside the spring accommodating groove 23. (See FIG. 2).

A retaining member retaining groove for retaining the retaining members 4 # 4 in the inner portion 20 of the spring accommodating groove 23 of the outer rotating member 2 so as to extend along the axial direction from the lower end surface at eight locations in the circumferential direction. 2
2 ‥ 22 is formed. This locking member holding groove 22 #
22 is a locking groove 1 formed on the outer peripheral surface of the inner rotating member 1.
The same number as 2 ‥ 12 is provided so that the positions of the locking grooves 12 ‥ 12 in the circumferential direction coincide with each other. Further, the spring receiving groove 23 is formed so as to communicate with the inner peripheral surface (see FIGS. 1 and 2). The length of the locking member holding groove 22 # 22 from the lower end face is equal to the length of the locking groove 12 # 12 and the spring accommodating groove 23.
Are formed in the same size as the length in the axial direction, and the positions of the end portions are matched with each other. Note that the locking grooves 12 # 12 and the locking member holding grooves 22 # 22 are not limited to being formed at eight locations, and it is sufficient if there is at least one.

The locking member holding grooves 22 # 22 have
The cylindrical locking members 4 # 4 are disposed so that their longitudinal directions coincide with the axial direction of the overload slip device (see FIG. 1). The locking member holding groove 22 #
The space between the opposing surfaces 22 is slightly larger than the diameter of the locking members 4 # 4, and a slight gap is formed between them. On the other hand, the length L (see FIG. 1) from the inner peripheral surface of the resilient member 5 to the locking groove 12 of the inner rotating member 1 is determined before the locking members 4 # 4 are disposed. Is formed so as to be smaller than or equal to the diameter.

The axial position of the inner rotating member 1, the outer rotating member 2, the locking members 4 # 4, and the ring spring 5 described above is maintained by the slip-off preventing plate P as a donut-shaped position holding member. ing. The detachment preventing plate P is fitted to the power transmission shaft 3 such that the upper surface thereof is in contact with the lower end surfaces of the inner rotating member 1 and the outer rotating member 2, and the lower portion thereof is positioned by the stop ring S ( (See FIG. 1).

When the torque input to the overload slip device is equal to or less than a predetermined value, the engaging members 4 # 4 are formed on the inner rotating member 1 by the ring spring 5 as shown in FIGS. The retaining groove 12 # 1 is repelled by the retaining groove 12 # 12.
2 and the inner rotating member 1 and the outer rotating member 2
Means that the power transmission shaft 3 rotates around the shaft. But,
When the power transmission shaft 3 is locked or the like and the torque exceeds a certain value, as shown in FIG. 4, the elastic force of the ring spring 5 is overcome, and the locking members 4 # 4 move the ring spring 5 outward in the radial direction. To get over the locking grooves 12 # 12 and the engagement state is released. And the outer rotating member 2 is the inner rotating member 2
Independently rotate the outer peripheral surface. Until a predetermined torque is applied, the inner rotary member 1 and the outer rotary member 2 rotate together, but when the input torque exceeds a predetermined value, the locking of the locking members 4 # 4 is released. The rotation of the outer rotating member 2 with respect to the inner rotating member 1 prevents application of a torque exceeding an allowable value, thereby preventing breakage.

Since the notch 51 of the ring spring 5 is accommodated in the rib 25 of the outer rotating member 2 so as to be aligned, the ring spring 10 does not move in the circumferential direction.
The lacking portion 51 does not catch on the locking members 4 # 4 to cause malfunction.

The ring spring 5 as a resilient member is
The invention is not limited to the one provided with one member, and two ring springs 52 and 53 having different diameters may be provided to be overlapped in the radial direction as shown in FIG. In this embodiment, a power transmission shaft 3 serving as a rotation shaft provided at the center of the overload slip device, an inner rotation member 1 attached to the outer peripheral surface of the power transmission shaft 3 via a key 6, and An outer rotating member 2 is provided on the outer side thereof, and the inner rotating member 1 and the outer rotating member 2 are locked by locking members 4 # 4.

The spring accommodating groove 23 formed along the circumferential direction of the outer rotating member 2 is formed over substantially the entire circumference, leaving a part on the circumference as a rib 25. The two ring springs 52 and 53 are overlapped in the radial direction,
The two notches 51, 51 are inserted into the spring accommodating grooves 23 so as to match the positions of the ribs 25.

Further, the spring accommodating groove is not limited to the form provided on the outer rotating member, but may be provided on the inner rotating member 7 as shown in FIG. In the embodiment shown in FIG. 6, an inner rotating member 7 having a spring housing groove 73 and locking member holding grooves 72 # 72 is provided on the outer peripheral surface of the power transmission shaft 3 via a key 6. Also, the outer rotating member 8 having locking grooves 82 # 82 as engagement recesses on the outer periphery of the inner rotating member 7.
Is provided.

At substantially the center of the radial width of the member of the inner rotary member 7, there is formed a spring receiving groove 73 formed along the circumferential direction for receiving the annular ring spring 9 as a resilient member. Is formed. The spring receiving groove 73 is provided with a rib 75 for connecting the radially inner portion 71 and the outer portion 70 of the spring receiving groove 73 to one portion in the circumferential direction. The spring receiving groove 73 is formed from the lower end surface of the inner rotating member 7 to a position substantially at the center of the axial member of the inner rotating member 7.

The ring spring 9 accommodated in the spring accommodating groove 73 is formed in an annular shape, and has a notch 91 on a part of the circumference thereof for discontinuing the members. Further, the diameter of the outer peripheral portion of the ring spring 9 is formed to be slightly larger than the diameter of the inner wall outside the spring receiving groove 73. When the ring spring 9 is accommodated in the spring accommodating groove 73, the notch 91
Is compressed to reduce the diameter of the ring spring 9 so as to reduce the gap, and the notch 91 is accommodated so as to match the position of the rib 75. The member width of the accommodated ring spring 9 is formed smaller than the groove width of the spring accommodating groove 73, and the outer peripheral surface of the ring spring 9 and the inner wall outside the spring accommodating groove 73 have
A gap is formed.

On the outer portion 70 of the inner rotating member 7, locking member holding grooves 72 # 72 formed integrally with the spring receiving groove 73 so as to extend along the axial direction are uniformly arranged at eight circumferential positions. Have been. The retaining member retaining grooves 72 # 72 communicate the spring receiving groove 73 with the outer peripheral surface. The locking member holding grooves 72 # 72 are formed from the lower end surface (the front side of the paper surface of FIG. 6) of the outer portion 70 to substantially the center of the inner rotating member 7 in the axial direction. In the axial direction. Further, the locking member holding portion 7
The spacing between the facing surfaces of 2 面 72 is formed slightly larger than the diameter of the locking members 4 ‥ 4, and a slight gap is formed between them. On the other hand, the length from the outer peripheral surface of the resilient member 9 to the locking groove 82 of the outer rotating member 8 is equal to the length of the locking member 4 ‥ 4.
Before the disposition, is formed so as to be smaller than or equal to the diameter of the locking members 4 # 4. Note that also in the present embodiment, it is sufficient that at least one locking member holding groove is provided.

On the other hand, on the inner peripheral surface of the outer rotating member 8, there is provided a locking recess having a shallow depth extending along the axial direction at a position corresponding to the locking member holding grooves 72 # 72 in the circumferential direction. Stop grooves 82 # 82 are formed. The lengths of the locking grooves 82 # 82 are formed to have the same dimensions as the axial lengths of the spring receiving groove 73 and the locking member holding grooves 72 # 72, and are formed so that the end positions thereof are matched.

The portions surrounded by the locking member holding grooves 72 # 72 of the inner rotating member 7, the locking grooves 82 # 82 of the outer rotating member 8 and the ring spring 9 are formed by cylindrical locking members. The members 4 # 4 are inserted with their axial directions aligned with the axial direction of the inner rotating member 7. Although not shown in the drawings, also in this embodiment, the axial position of the inner rotating member, the outer rotating member, the locking member, and the ring spring is controlled by a slip-off preventing plate as a donut-shaped position holding member. Has been maintained.

The overload slip device according to the present embodiment, when the torque applied to the device is equal to or less than a predetermined value, the outer rotating member 8
The engaging members 4 # 4 are engaged with the engaging grooves 82 # 82, and the outer rotating member 8 and the inner rotating member 7 rotate together. On the other hand, when the torque exceeds a predetermined value, the locking members 4 # 4 are disengaged from the locking grooves 82 # 82 and overcome the elastic force of the ring spring 9 to push the ring spring 9 radially inward. The outer rotating member 8 rotates independently of the inner rotating member 7 to avoid an overload state.

In the above embodiment, the locking member is described as having a cylindrical shape. However, the present invention is not limited to this.
The locking member may be ball-shaped.

[0031]

As described above, according to the present invention,
Since all the locking members are repelled by one resilient member, the number of parts can be reduced. In addition, it is not necessary to incorporate a resilient member for each locking member, so that work efficiency can be improved. Further, when assembling the outer rotating member to the inner rotating portion, it is not necessary to hold each resilient member in a compressed state, so that not only a troublesome operation can be omitted, but also the locking member is scattered during the operation. There is no need to bother workers.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an overload slip device according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where the torque applied to the overload slip device of FIG. 1 is equal to or less than a predetermined value.

FIG. 3 is a perspective view of an outer rotating member of the overload slip device according to the embodiment of FIG. 1;

FIG. 4 is a cross-sectional view showing a state where a torque equal to or more than a predetermined value is applied to the overload slip device shown in FIG. 2;

FIG. 5 is a cross-sectional view of an overload slip device showing another embodiment different from FIG. 2;

FIG. 6 is a cross-sectional view of an overload prevention device according to another embodiment different from FIG. 1;

[Explanation of symbols]

 1,7 Inner rotating member 12,82 Engaging concave portion (locking groove) 2,8 Outer rotating member 22,72 Locking member holding groove 23,73 Resilient member accommodating groove (spring accommodating groove) 3 Power transmission shaft 4 Stop member 5, 51, 52, 9 Resilient member (ring spring)

Claims (1)

[Claims] 1. A reciprocally rotatable inner and outer rotatable member and a resilient member on the same axis as a rotation axis to prevent the inner and outer rotatable members from rotating relative to each other to transmit power. An annular resilient member, and an annular resilient member formed in one of the inner and outer rotating members along the circumferential direction to accommodate the resilient member. A resilient member accommodating groove formed on the rotating member having the resilient member accommodating groove formed thereon,
A locking member holding groove for holding the locking member; an engagement recess formed on the other of the inner or outer rotating member to engage with the locking member; and an end surface of the inner and outer rotating member. An overload slip device, comprising: a position holding member.