Hoist

Abstract

Provided is a hoist with which it is possible to improve a drive shaft structure and a manufacturing process, with respect to the surrounding configuration of the drive shaft.　The hoist is for lifting and lowering a load by means of a load sheave 84 on which a load chain C2 for lifting the load is wound. The hoist comprises: a drive shaft 40 for transmitting a driving force for lifting and lowering the load to the load sheave 84; a brake receiving part 42 provided unrotatably on the drive shaft 40; and a brake plate 52 that slides relative to the brake receiving part 42, wherein the drive shaft 40 and the brake receiving part 42 are integrally formed.

Description

hoisting machine

[0001] The present invention relates to a hoist.

[0002] As shown in Patent Documents 1 and 2, for example, a chain block includes a drive shaft (also called a pinion shaft) to which driving force from a hand wheel is transmitted, and a brake pad is disposed on the outer periphery of the drive shaft adjacent to the hand wheel. This brake pad supports a brake plate and a ratchet wheel, and includes a cylindrical portion that runs along the drive shaft and a flange portion that protrudes toward the outer periphery of the drive shaft.

[0003] The brake retainer is usually configured to be screwed onto the male thread portion of the drive shaft, as disclosed in Patent Document 2, but there are also configurations in which the drive shaft and brake retainer are spline-connected, as disclosed in Patent Document 1.

[0004] Patent No. 6467407 Patent No. 5550410

[0005] In the configurations disclosed in the above-mentioned Patent Documents 1 and 2, the diameter of the base end of the drive shaft where the brake retainer is located is slightly smaller than the portion where the male thread, spline, etc. are formed. Therefore, when a strong impact is applied to the drive shaft from the hand wheel side, there is a risk that the drive shaft will break at its base end. In addition, because different manufacturing methods are used for the drive shaft and the brake retainer, there is a problem of increased man-hours.

[0006] Therefore, in the structure including the drive shaft and the brake receiver, there is room for further improvement in the structure and manufacturing process.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a hoist that allows improvements to be made to the configuration and manufacturing process of the drive shaft in relation to the configuration in the vicinity of the drive shaft.

[0008] In order to solve the above problems, according to a first aspect of the present invention, there is provided a hoist for raising and lowering a load via a load sheave around which a load chain for hoisting the load is wound, the hoist comprising: a drive shaft for transmitting the driving force for raising and lowering the load to the load sheave; a brake receiving portion non-rotatably attached to the drive shaft; and a brake plate that slides against the brake receiving portion, wherein the drive shaft and the brake receiving portion are integrally molded.

[0009] According to the present invention, it is possible to provide a chain block that allows improvements to be made to the configuration of the drive shaft and the manufacturing process in relation to the configuration in the vicinity of the drive shaft.

[0010] 5 is a perspective view showing the configuration of a chain block according to an embodiment of the present invention. FIG. 5 is an exploded perspective view showing the configuration of the chain block shown in FIG. 1. FIG. 6 is a cross-sectional view showing the chain block shown in FIG. 1 cut to include the drive shaft and the load sheave shaft. FIG. 6 is a cross-sectional view showing the chain block shown in FIG. 1 cut along a plane including the drive shaft and the reduction gear member. FIG. 7 is a perspective view showing the configuration of the drive shaft included in the chain block shown in FIG. 1, as seen from the pinion gear side. FIG. 7 is a perspective view showing the configuration of the drive shaft included in the chain block shown in FIG. 1, as seen from the male thread portion opposite to that in FIG. 5. FIG. 8 is a perspective view showing the configuration of a drive shaft according to a comparative example, where (A) shows the state as seen from the pinion gear side and (B) shows the state as seen from the male thread portion. FIG. 9 is a diagram showing a drive shaft according to a comparative example and a brake plate and a ratchet wheel of a brake mechanism. FIG. 10 is a schematic view showing an image of carburizing treatment on the drive shaft included in the chain block shown in FIG. 1, where (A) shows a state in which a carburized treatment layer is formed on the large diameter portion of the shaft-shaped portion, and (B) shows a state in which a carburized treatment layer is formed on the flange portion.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A chain block 10 as a hoist according to an embodiment of the present invention will now be described with reference to the drawings.

[0012] In the following description, the X direction is the axial direction of the drive shaft 40, the X1 side is the side where the wheel cover 15 is located in Figure 2, and the X2 side is the opposite side where the third die-cast frame 13 is located. The Z direction is the vertical direction (hanging direction; hoisting / lowering direction) when the chain block 10 is suspended, the Z1 side is the upper side in the suspended state, and the Z2 side is the lower side in the suspended state. The Y direction is the direction perpendicular to the X and Z directions, the Y1 side is the lower right side in Figure 2, and the Y2 side is the opposite upper left side.

[0013] (1. Configuration of Chain Block 10) Fig. 1 is a perspective view showing the appearance of a chain block 10 according to this embodiment. Fig. 2 is an exploded perspective view showing the configuration of the chain block 10 shown in Fig. 1. Fig. 3 is a cross-sectional view showing the chain block 10 shown in Fig. 1 cut along a plane including the drive shaft 40 and the load sheave shaft 80. Fig. 4 is a cross-sectional view showing the chain block 10 shown in Fig. 1 cut along a plane including the drive shaft 40 and the reduction gear member 60.

[0014] 1 to 4, the chain block 10 includes a first die-cast frame 11, a second die-cast frame 12, a third die-cast frame 13, an upper hook 20, a hand wheel assembly 30, a drive shaft 40, a brake mechanism 50, a load sheave shaft 80 having a load sheave 84, a hand chain C1, a load chain C2, etc. These components are assembled to form a chain block main body CB1.

[0015] (1-1. Overview of the First Die-Casting Frame 11, the Second Die-Casting Frame 12, and the Third Die-Casting Frame 13) The first die-casting frame 11, the second die-casting frame 12, and the third die-casting frame 13 are formed by light alloy die-casting, such as aluminum die-casting, which uses an aluminum-based metal. Other examples of light alloy die-casting include magnesium die-casting, which uses a magnesium-based alloy. The first die-casting frame 11, the second die-casting frame 12, and the third die-casting frame 13 may also be formed by light alloy die-casting, using a light metal such as magnesium, other than light alloy die-casting.

[0016] In the following description, for the sake of simplicity, the first die-casting frame 11 will be referred to as the first frame 11, the second die-casting frame 12 as the second frame 12, and the third die-casting frame 13 as the third frame 13.

[0017] The first frame 11, second frame 12, and third frame 13 support the various components of the chain block 10. The first frame 11, second frame 12, and third frame 13 are fastened together with bolts BT and nuts N1. A connecting shaft 14 is attached to the first frame 11 and the third frame 13. An upper hook 20 for hanging the chain block on, for example, a ceiling is pivotally attached to the connecting shaft 14. The tension of the load applied to the load chain C2 is transmitted to the load sheave shaft 80 via a load sheave 84 (described later), and then to the upper hook 20 via the first frame 11 and the third frame 13, which pivotally support the load sheave shaft 80.

[0018] A lower hook 100 for hanging a load is connected to the lower end of the load chain C2.

[0019] (1-2. Regarding the Wheel Cover 15) A wheel cover 15 that houses the hand wheel assembly 30 is attached to one side (X1 side) in the axial direction (X direction) of the first frame 11. This wheel cover 15 is a part that covers the hand wheel assembly 30 to prevent the hand chain C1 from falling off and to protect it from the outside, and is provided in the shape of a cylinder with a bottom.

[0020] The wheel cover 15 is assembled so that its folded portion 15a fits into a groove (reference numeral omitted) of the first frame 11. The support plate 16 is screwed to the first frame 11 so that the folded portion 15a of the wheel cover 15 does not slip out of the groove of the first frame 11, thereby preventing the wheel cover 15 from coming off. Therefore, the wheel cover 15 is rotatably provided between the first frame 11 and the support plate 16.

[0021] Furthermore, a pair of openings in the wheel cover 15 through which the hand chain C1 passes is fitted with a protective member 17. The protective member 17 guides the hand chain C1 so that the hand chain C1 is wound around the hand wheel 31 and protects the hand chain C1 and the wheel cover 15 from damage caused by contact between the hand chain C1 and the wheel cover 15, and is made of, for example, resin (see FIG. 2).

[0022] (1-3. Hand Wheel Assembly 30) Next, we will explain the hand wheel assembly 30. As shown in Figures 3 and 4, the hand wheel assembly 30 includes a hand wheel 31, which has an insertion hole 31a on the central side of the hand wheel 31. In addition, a wheel plate portion 31b is provided around the insertion hole 31a.

[0023] An overload prevention mechanism 33 including a pair of clutch plates 33a, 33b and a drive member 33c is disposed in the insertion hole 31a. Furthermore, a female thread portion 33c1 having a female thread is provided at the radial center of the drive member 33c. The rotational force from the hand wheel 31 is transmitted to the drive shaft 40 via the overload prevention mechanism 33, and in the event of an overload, slippage occurs between the wheel plate portion 31b and the clutch plates 33a, 33b, protecting the suspended load and the chain block 10 from the overload.

[0024] (1-4. Regarding the drive shaft 40) Next, the drive shaft 40 will be described. As shown in FIGS. 2 to 4, the drive shaft 40 is a member extending in the X direction from the second frame 12 to the hand wheel 31. The drive shaft 40 is provided with a male thread portion 41. The male thread portion 41 is the portion into which the female thread portion 33c1 of the drive member 33c described above is screwed. In this embodiment, the male thread portion 41 is a multiple-start thread with multiple threads.

[0025] A brake receiving portion 42 is provided on the drive shaft 40 on the other side (X2 side) of the male thread portion 41 in the axial direction (X direction), and this brake receiving portion 42 can receive a brake plate 52 (described later) and support a ratchet wheel 53.

[0026] Furthermore, a nut threading portion 43 is provided on the drive shaft 40 on one side (X1 side) in the axial direction (X direction) of the male thread portion 41. The nut threading portion 43 is a portion that prevents the retaining nut N2, which prevents the hand wheel assembly 30 from coming off the drive shaft 40, from coming off, and is formed with a male thread.

[0027] Unlike the male threads of the male threaded portion 41, the male threads of the nut screwing portion 43 are single-start threads with a single multiplier. The orientation of the male threads of the male threaded portion 41 and the orientation of the male threads of the nut screwing portion 43 are opposite to each other. Therefore, when the drive member 33c and the retaining nut N2 are in strong contact with each other, if the drive member 33c attempts to advance along the male threaded portion 41 in the direction of removal from the drive shaft 40 (direction X1), the retaining nut N2 advances in the direction of tightening (direction X2). This prevents the drive member 33c from coming off the drive shaft 40.

[0028] The nut screwing portion 43 is also provided with a pin insertion hole 43a. The pin insertion hole 43a is a hole into which a retaining pin P1 that prevents the retaining nut N2 from coming off the nut screwing portion 43 is inserted.

[0029] Furthermore, a first bearing attachment portion 44 is provided on the drive shaft 40 on the other side (X2 side) in the axial direction (X direction) of the brake receiving portion 42. The first bearing attachment portion 44 is a portion for supporting the drive shaft 40 relative to the first frame 11 via a bearing B1.

[0030] A second bearing attachment portion 45 is provided at the other axial end (X-direction) (the end on the X2 side) of the drive shaft 40. The second bearing attachment portion 45 is a portion for supporting the drive shaft 40 relative to the second frame 12 via a bearing B2.

[0031] A pinion gear 46 is provided on the drive shaft 40 between the first bearing attachment portion 44 and the second bearing attachment portion 45. This pinion gear 46 is the portion that meshes with a large-diameter gear 63 (described later) of the first reduction gear section G1. Therefore, the drive shaft 40 is the shaft of the hand wheel assembly 30, and is the input shaft of the first reduction gear section G1 (reduction gear mechanism) to which the rotational driving force of the hand wheel 31 is input.

[0032] The configuration of the drive shaft 40 will be described in detail later.

[0033] (1-5. Brake Mechanism 50) A brake mechanism 50 is also attached to the drive shaft 40. The brake mechanism 50 primarily comprises brake plates 51 and 52, a ratchet wheel 53, and a pawl member 54. The ratchet wheel 53 is disposed between the brake plates 51 and 52, and the brake plates 51 and 52, ratchet wheel 53, and bushing 55 are disposed between the drive member 33c and the brake receiving portion 42. When the hand wheel assembly 30 is rotated in the winding direction by pulling the hand chain C1 in the winding direction, the rotation in the winding direction causes the drive member 33c to move in a direction that presses against the brake plate 52 due to the action of the female thread portion 33c1 and the male thread portion 41. The rotational force of the hand wheel assembly 30 is transmitted to the brake receiving portion 42 via the brake plate 52, ratchet wheel 53, and brake plate 51. As the hand wheel assembly 30 rotates, the drive shaft 40 also rotates integrally with it.

[0034] The bushing 55 is annular and can rotate relative to the large diameter portion 42a of the drive shaft 40 in the radial direction of the ratchet wheel 53, and is provided between the brake plates 51 and 52 in the axial direction (X direction). The bushing 55 is made of, for example, a sintered material and is impregnated with lubricating oil. This reduces wear at the contact points between the ratchet wheel 53, the large diameter portion 42a, and the bushing 55.

[0035] The ratchet wheel 53 is axially supported via a bushing 55 so as to be relatively rotatable with respect to the drive shaft 40. The tip of a pawl member 54 shown in Figure 2 engages with the ratchet teeth of the ratchet wheel 53, and this engagement forms a ratchet mechanism that prevents the ratchet wheel 53 from rotating in the reverse direction (rotating in the winding-down direction).

[0036] On the other hand, when the hand wheel assembly 30 is rotated in the lowering direction by pulling the hand chain C1 in the lowering direction, the rotation in the lowering direction causes the drive member 33c to move in a direction that loosens the pressure on the brake plate 51. Then, even if the ratchet wheel 53 cannot rotate in the lowering direction, the pressure between the ratchet wheel 53 and the brake plates 51 and 52 is loosened, allowing the load sheave shaft 80, load gear 70, reduction gear member 60, and drive shaft 40, which will be described later, to rotate. If the pulling of the hand chain C1 in the lowering direction is stopped while a load is suspended, the load weight immediately causes the drive member 33c to press the brake plate 51 of the brake mechanism 50 against the ratchet wheel 53, thereby activating the brake and holding the load.

[0037] (1-6. Reduction Gear Member 60 and Load Gear 70) Next, the reduction gear member 60 will be described. As shown in Fig. 4, the reduction gear member 60 has a first bearing attachment portion 61, a second bearing attachment portion 62, a large diameter gear 63, and a small diameter gear 64. Of these, the first bearing attachment portion 61 is a portion located on one end side (X1 side) of the reduction gear member 60 in the axial direction (X direction), and is a portion for supporting the reduction gear member 60 on the first frame 11 via a bearing B3.

[0038] In addition, the second bearing mounting portion 62 is a portion located on the other end side (X2 side) of the reduction gear member 60 in the axial direction (X direction), and is a portion for supporting the reduction gear member 60 relative to the third frame 13 via a bearing B4.

[0039] The large diameter gear 63 is a gear portion that meshes with the pinion gear 46, and constitutes the first reduction gear portion G1. The large diameter gear 63 and the pinion gear 46 are set to reduce the speed at a predetermined reduction ratio.

[0040] The small diameter gear 64 is a part that meshes with the load gear 70, and this meshing is set so that the small diameter gear 64 and the load gear 70 are reduced in speed at a predetermined reduction ratio.

[0041] Furthermore, the load gear 70 with which the small diameter gear 64 meshes has a center hole (reference numeral omitted), and this center hole and a gear mounting portion 81 of the load sheave shaft 80 described later are connected, for example, by a spline connection or other torque-transmitting connection structure, so that the two rotate integrally.

[0042] The small diameter gear 64 and the load gear 70 constitute a second reduction gear section G2.

[0043] (1-7. Regarding the Load Sheave Shaft 80) Next, the load sheave shaft 80 will be described. The load sheave shaft 80 has a gear mounting portion 81, a first bearing mounting portion 82, a second bearing mounting portion 83, and a load sheave 84. The gear mounting portion 81 is the portion that is coupled to the center hole of the load gear 70, thereby allowing the load gear 70 and the load sheave shaft 80 to rotate integrally.

[0044] The first bearing attachment portion 82 is a portion located on one end side (X1 side) in the axial direction (X direction) of the load sheave shaft 80. The first bearing attachment portion 82 is a portion for supporting the load sheave shaft 80 relative to the first frame 11 via a bearing B5.

[0045] A second bearing attachment portion 83 is provided at the other end (X2 side end) in the axial direction (X direction) of the load sheave shaft 80. The second bearing attachment portion 83 is a portion for supporting the load sheave shaft 80 relative to the third frame 13 via a bearing B6.

[0046] The load sheave 84 is a portion around which the load chain C2 is looped, and has chain pockets (horizontal pockets and vertical pockets (not shown)) around its entire circumference into which the load chain C2 fits.

[0047] (2. Details of the Configuration of the Drive Shaft 40) Next, details of the configuration of the drive shaft 40 will be described. Fig. 5 is a perspective view showing the configuration of the drive shaft 40, as seen from the pinion gear 46 side. Fig. 6 is a perspective view showing the configuration of the drive shaft 40, as seen from the male thread portion 41, which is opposite to Fig. 5.

[0048] As described above, the drive shaft 40 shown in Figures 5 and 6 has the male thread portion 41, the brake receiving portion 42, the first bearing mounting portion 44, the second bearing mounting portion 45, and the pinion gear 46.

[0049] The brake receiving portion 42 includes a large diameter portion 42a and a flange portion 42b. The large diameter portion 42a is the portion to which the ratchet wheel 53 is attached via a bushing 55. Therefore, the large diameter portion 42a has a larger diameter than the rest of the drive shaft 40 except for the flange portion 42b. The flange portion 42b is a disk-shaped portion on which the brake plate 52 slides. Therefore, the flange portion 42b has a larger diameter than the large diameter portion 42a. The thickness of the flange portion 42b is determined so that it does not undergo plastic deformation even when pressed by the brake plate 52 during winding.

[0050] This drive shaft 40 is integrally formed by cold forging. More specifically, current drive shafts have a shaft-shaped portion and a flange portion provided separately. The configuration of such a current drive shaft (referred to as drive shaft 40B according to a comparative example) is shown in FIG. 7. Also, FIG. 8 shows a configuration in which brake plates 51B and 52B and a ratchet wheel 53B of a brake mechanism (referred to as brake mechanism 50B) are arranged on the outer periphery of drive shaft 40B.

[0051] 7 and 8, the drive shaft 40B according to the comparative example is provided with a male thread portion 41B and a pinion gear 46B, just like the drive shaft 40 according to the present embodiment. However, as shown in FIG. 8, a brake receiver 140B corresponding to the brake receiver portion 42 is separate from the drive shaft 40B. Therefore, the drive shaft 40B and the brake receiver 140B must be manufactured separately, and when assembling the chain block, the drive shaft 40B is passed through a center hole in the brake receiver 140B, and in that state, other components are attached to the drive shaft 40B or to other components.

[0052] Furthermore, the drive shaft 40B is subjected to a carburizing treatment followed by quenching and tempering to harden the surface, while the brake pad 140B is quenched without carburizing, which requires separate processes for each.

[0053] In contrast, in this embodiment, the drive shaft 40 is formed by cold forging to include the brake receiving portion 42, and then carburized to form the carburized layer CT1. An image of the carburizing process is shown in FIG. 9 . FIG. 9 is a schematic diagram showing the carburizing process of the drive shaft 40. (A) shows the carburized layer CT1 formed on the large diameter portion 42a of the shaft-shaped portion 47, and (B) shows the carburized layer CT1 formed on the flange portion 42b. While FIG. 9 shows the carburized layer CT1 formed on the large diameter portion 42a and the flange portion 42b, the carburized layer CT1 is also formed on portions of the drive shaft 40 other than the large diameter portion 42a and the flange portion 42b. However, partial carburizing may be performed on only a portion of the drive shaft 40, such as the large diameter portion 42a and the flange portion 42b.

[0054] That is, if the shaft-like portion including the male thread portion 41 and the pinion gear 46 is referred to as shaft-like portion 47, then both shaft-like portion 47 and brake receiving portion 42 are carburized. As a result, a continuous carburized layer CT1 is formed over the entire surface of drive shaft 40. This improves the hardness of the surfaces of drive shaft 40, particularly brake receiving portion 42 and large diameter portion 42a, thereby enabling improved wear resistance.

[0055] Furthermore, by providing the drive shaft 40 with the brake receiving portion 42, it is possible to improve the strength of the entire drive shaft 40. That is, in the drive shaft 40B according to the comparative example, as shown in FIG. 7, a step portion 43B for receiving the brake receiving portion 140B is provided on the other axial side (X2 side) of the male thread portion 41B. Then, between this step portion 43B and the male thread portion 41B (i.e., on the base side where the brake receiving portion 140B is located), a small diameter portion 42B having a smaller diameter than the male thread portion 41B is provided. The brake receiving portion 140B is located in this small diameter portion 42B.

[0056] However, the small diameter portion 42B is the smallest diameter portion between the stepped portion 43B and the male thread portion 41B. Therefore, for example, if the chain block 10 falls and an external force from the hand wheel assembly 30 or the like acts on the drive shaft 40B, there is a risk that the drive shaft 40B will break at the small diameter portion 42B due to a bending moment or shear load caused by the distance from the hand wheel assembly 30 to the small diameter portion 42B.

[0057] In contrast, in this embodiment, the brake receiving portion 42 is integrated with the drive shaft 40. Therefore, the brake receiving portion 42 is present in the area corresponding to the small diameter portion 42B, and the brake receiving portion 42 has a larger diameter than the shaft portion 47. Therefore, even if an external force from, for example, the hand wheel assembly 30 acts on the drive shaft 40, the brake receiving portion 42 can prevent the drive shaft 40 from breaking. Furthermore, the male threaded shaft portion 41a, which is provided between the male threaded portion 41 and the large diameter portion 42a, is close to the hand wheel assembly 30, and therefore the bending moment is small. Therefore, the male threaded shaft portion 41a can prevent the drive shaft 40 from breaking.

[0058] 5 and 6 , the drive shaft 40 is provided with a brake relief groove 48. This brake relief groove 48 is provided in the surface of the flange portion 42b on the male thread portion 41 side, by recessing the base portion of the flange portion 42b relative to the large diameter portion 42a. Therefore, the sliding surface 42b1 of the flange portion 42b that comes into contact with the brake plate 52 is not directly adjacent to the large diameter portion 42a of the drive shaft 40.

[0059] That is, by integrating the large diameter portion 42a and the brake receiving portion 42, the sliding surface 42b1 of the flange portion 42b that comes into contact with the brake plate 52 is also integrated with the drive shaft 40. In this case, when the brake plate 52 slides on the sliding surface 42b1, the brake plate 52 wears, and wear powder of the brake plate 52 gets in between the brake plate 52 and the sliding surface 42b1, which may result in a decrease in braking performance.

[0060] However, when the brake relief groove 48 is provided, wear powder can enter the groove portion, preventing it from getting between the brake plate 52 and the sliding surface 42b1, which has the effect of preventing a deterioration in braking performance.

[0061] The drive shaft 40 is also provided with an inner ring abutment portion 49 as shown in Figure 5. The inner ring abutment portion 49 is a portion that prevents the outer ring of the bearing B1, which is disposed in the first bearing attachment portion 44, from contacting the back surface 42b2 of the flange portion 42b, which is opposite the sliding surface 42b1. In other words, the inner ring abutment portion 49 is formed with an outer diameter that allows it to contact the inner ring of the bearing B1 but not the outer ring of the bearing B1. This configuration does not impede the rotation of the bearing B1.

[0062] Therefore, it is possible to adopt a configuration in which the first bearing mounting portion 44 is provided adjacent to the flange portion 42b and the bearing B1 is brought into close contact with the inner ring abutment portion 49. This makes it possible to reduce the length of the chain block 10 in the axial direction (X direction). It also becomes possible to position the drive shaft 40 on the other side (X2 side) in the axial direction (X direction).

[0063] A curved portion 48R is provided at the boundary between the brake relief groove 48 and the large diameter portion 42a. This curved portion 48R prevents stress concentration from occurring at the boundary between the brake relief groove 48 and the shaft-like portion 47. A curved portion 49R is also provided at the boundary between the inner ring abutment portion 49 and the shaft-like portion 47. Like the curved portion 48R described above, this curved portion 49R also prevents stress concentration from occurring at the boundary between the inner ring abutment portion 49 and the flange portion 42b.

[0064] (3. Modifications) Although one embodiment of the present invention has been described above, the present invention can be modified in various other ways, which will be described below.

[0065] In the above embodiment, the chain block 10 is described as a hoist. However, the hoist is not limited to the chain block 10. For example, the present invention may be applied to a lever hoist.

[0066] In the above embodiment, the chain block body CB1 is described as being made up of the first to third die-cast frames 11 to 13. However, the chain block body may be made up of four or more die-cast frames.

[0067] In the above embodiment, the brake receiving portion 42 includes the large diameter portion 42 a and the flange portion 42 b. However, the brake receiving portion 42 may include only the flange portion 42 b or only the large diameter portion 42 a.

[0068] Further, the drive shaft 40 of the above-described embodiment may be configured to omit the brake relief groove 48. Further, the drive shaft 40 of the above-described embodiment may be configured to omit the inner ring abutment portion 49.

[0069] Furthermore, the hand wheel 31 in the above-described embodiment has an insertion hole 31a through which the overload prevention mechanism 33 is inserted, and the male threaded portion 41 of the drive shaft 40 is screwed into the female threaded portion 33c1 of the overload prevention mechanism 33. However, instead of the insertion hole 31a, a configuration may be adopted in which the female threaded portion 33c1 is directly provided on the hand wheel 31, and the male threaded portion 41 of the drive shaft 40 is screwed into the female threaded portion 33c1 without going through the overload prevention mechanism 33.

[0070] In the above embodiment, the ratchet wheel 53 is supported by the bushing 55 so as to be rotatable relative to the large diameter portion 42a of the drive shaft 40. However, the ratchet wheel 53 may be supported by the bushing 55 so as to be rotatable relative to the large diameter portion 42a of the drive shaft 40 without the bushing 55.

[0071] (4. Supplementary Note) The contents described in the above-described embodiment can be understood, for example, as follows: [1] That is, a chain block 10 (hoist) for raising and lowering a load via a load sheave 84 around which a load chain C2 for hoisting the load is wound, comprising: a drive shaft 40 of the above-described embodiment that transmits the driving force for raising and lowering the load to the load sheave 84; a brake receiving portion 42 that is non-rotatably provided on the drive shaft 40; and a brake plate 52 that slides relative to the brake receiving portion 42, wherein the drive shaft 40 and the brake receiving portion 42 are integrally molded.

[0072] This configuration makes it possible to improve the configuration and manufacturing process of the drive shaft 40. Specifically, in the current drive shaft 40B, as shown in Figure 8, the brake retainer 140B is separate from the drive shaft 40B. This means that the drive shaft 40B and the brake retainer 140B must be manufactured separately, and when assembling the chain block, the drive shaft 40B must be passed through the center hole of the brake retainer 140B, and in that state, other components can be attached to the drive shaft 40B or to other components.

[0073] Furthermore, the diameter of the base side of the drive shaft 40B where the brake receiver is located is smaller than that of the male thread portion 41B, etc., and a small diameter portion 42B where the brake receiver 140B is located is provided. Therefore, when a strong impact is applied to the drive shaft 40B from, for example, the hand wheel assembly 30, the drive shaft 40B may break at the small diameter portion 42B. Furthermore, different manufacturing methods are used for the drive shaft 40B and the brake receiver 140B, which increases the number of manufacturing steps.

[0074] However, in the drive shaft 40 of this embodiment, the drive shaft 40 and the brake receiving portion 42 are integrally molded. Therefore, the brake receiving portion 42 is provided in a portion corresponding to the small diameter portion 42B, eliminating the small diameter portion 42B, which would otherwise be a weak point against external impact. Therefore, even if an external force from, for example, the hand wheel assembly 30, acts on the drive shaft 40, the drive shaft 40 can be prevented from breaking at the brake receiving portion 42. Furthermore, because the male threaded shaft portion 41a can be formed at a short distance from the hand wheel assembly 30, the bending moment due to the external force applied to the hand wheel assembly 30 is reduced, preventing the male threaded shaft portion 41a from breaking.

[0075] Furthermore, because the brake receiving portion 42 is integrally molded with the drive shaft 40, there is no need to create a separate brake receiving portion 140B. This also reduces the number of steps required to assemble the brake receiving portion 140B, which is a separate body, to the drive shaft 40. This allows for cost reductions in the manufacture of the chain block 10 (hoist).

[0076] Furthermore, if the brake receiver 140B were made separately, the diameter of the portion that slides against the bushing 55B would need to be increased to ensure the strength of the brake receiver 140B. However, by integrally molding the brake receiver 42 with the drive shaft 40, the diameter of the large diameter portion 42a can be reduced while still maintaining the necessary strength. This makes it possible to reduce the size of the drive shaft 40 and the chain block 10 equipped with the drive shaft 40.

[0077] [2] Furthermore, in the above embodiment, in addition to the contents described in [1] above, the drive shaft 40 may be configured to include a drive member 33c that screws into a male thread portion 41 provided on the outer periphery of the drive shaft 40, and a ratchet wheel 53 that has ratchet teeth on the outer periphery to restrict the direction of rotation to one direction and presses against the brake plates 51, 52, and the brake receiving portion 42 may include a flange portion 42b that protrudes outward from the axial portion of the drive shaft 40 and has a sliding surface 42b1 that slides against the brake plates 51, 52, and a large diameter portion 42a that is formed integrally with the flange portion 42b and supports the ratchet wheel 53.

[0078] As described above, the brake receiving portion 42 includes the large diameter portion 42a and the flange portion 42b. Therefore, the large diameter portion 42a can adequately support the ratchet wheel 53, and the flange portion 42b allows the sliding surface 42b1 of the ratchet wheel 53 to slide against the brake plate 52, thereby providing sufficient braking force.

[0079] Furthermore, by integrating the brake receiving portion 42 with the drive shaft 40, it is possible to prevent delays in the braking process due to play or gaps between the drive shaft 40B and the brake receiving portion 140B, which may occur when the drive shaft 40B and the brake receiving portion 140B are separate components. Therefore, in the unlikely event that the load falls, the timing at which the braking process begins between the sliding surface 42b1 and the brake plate 52 is accelerated, making it possible to slow down the load's falling speed while it is still low.

[0080] [3] Furthermore, in the above embodiment, in addition to the contents described in the above [1] and [2], or a combination thereof, the drive shaft 40 may be provided with a brake relief groove 48, and the brake relief groove 48 may be provided in the surface of the flange portion 42 b on the side where the brake plate 52 is arranged, so as to recess the base portion of the flange portion 42 b relative to the large diameter portion 42 a.

[0081] The brake plate 52 wears as it slides against the sliding surface 42b1, and this wear powder accumulates between the brake plate 52 and the sliding surface 42b1, preventing uniform contact between the brake plate 52 and the sliding surface 42b1, which could result in a deterioration of braking performance. Therefore, by providing the brake relief groove 48, which is a recess in the base of the flange portion 42b relative to the large diameter portion 42a, the wear powder enters the brake relief groove 48. This makes it possible to prevent wear powder from accumulating between the brake plate 52 and the sliding surface 42b1. This makes it possible to prevent a deterioration in braking performance and maintain a maintenance-free state over a long period of time.

[0082] [4] Furthermore, in the above embodiment, in addition to the contents described in any one of the above [1] to [3] or a combination thereof, the drive shaft 40 may be provided with an inner ring abutment portion 49, and the inner ring abutment portion 49 may be provided with an outer diameter that makes contact with the inner ring of the adjacently arranged bearing B1 but does not make contact with the outer ring of the bearing B1.

[0083] When this configuration is adopted, even if the bearing B1 is brought into close contact with the inner ring abutment portion 49, the inner ring abutment portion 49 abuts the inner ring of the bearing B1, but the inner ring abutment portion 49 does not abut the outer ring of the bearing B1. This makes it possible to achieve a configuration in which rotation of the bearing B1 is not hindered. This makes it possible to adopt a configuration in which the first bearing mounting portion 44 is provided adjacent to the flange portion 42b and the bearing B1 is brought into close contact with the inner ring abutment portion 49. This makes it possible to reduce the length of the chain block 10 in the axial direction (X direction). It also makes it possible to position the other side (X2 side) of the drive shaft 40 in the axial direction (X direction).

[0084] [5] In addition to the above-mentioned embodiments described in any one of [1] to [4] or a combination thereof, a carburized layer CT1 is formed on the large diameter portion 42a and the flange portion 42b of the drive shaft 40.

[0085] Forming such a carburized layer CT1 increases the surface hardness of the large diameter portion 42a and the flange portion 42b. Therefore, when the drive shaft 40 is rotated by operating the hand wheel 31, the large diameter portion 42a slides against the bushing 55, which prevents wear on the large diameter portion 42a. The flange portion 42b also prevents wear due to sliding with the brake plate 52. Furthermore, because the pinion gear 46, the large diameter portion 42a, and the flange portion 42b of the drive shaft 40 are integrally molded, the carburization process is performed simultaneously with the carburization process performed to improve the strength of the pinion gear 46. This eliminates the need for separate carburization processes, thereby reducing costs.

[0086] [6] In addition to the above-mentioned [5], in the above embodiment, the drive shaft 40 is integrally formed by cold forging.

[0087] This eliminates the need to separately manufacture the drive shaft 40 and the brake receiving portion 42, and also eliminates the need for processing, for example, splines to connect the drive shaft 40 and the brake receiving portion 42, thereby reducing costs. Furthermore, because a continuous metal flow is formed by cold forging, the strength of the drive shaft 40 can be improved and damage such as fatigue and breakage can be suppressed.

[0088] 10... Chain block (an example of a hoist), 11... First die-cast frame, 12... Second die-cast frame, 13... Third die-cast frame, 14... Connecting shaft, 15... Wheel cover, 15a... Turn-back portion, 16... Support plate, 17... Protective member, 20... Upper hook, 30... Hand wheel assembly, 31... Hand wheel, 31a... Insertion hole, 31b... Wheel plate portion, 33... Overload prevention mechanism, 33a, 33b... Clutch Latch plate, 33c... driving member, 33c1... female thread portion, 40, 40B... drive shaft, 41, 41B... male thread portion, 42... brake receiving portion, 42a... large diameter portion, 42b... flange portion, 42b1... sliding surface, 42b2... back surface, 42B... small diameter portion, 43... nut screwing portion, 44... first bearing mounting portion, 45... second bearing mounting portion, 46, 46B... pinion gear, 47... shaft-shaped portion, 48... brake relief groove, 48R, 49R... curved portion, 4 9...inner ring abutment portion, 50, 50B...brake mechanism, 51, 52, 51B, 52B...brake plate, 53, 53B...ratchet wheel, 54...pawl member, 55...bush, 60...reduction gear member, 61...first bearing mounting portion, 62...second bearing mounting portion, 63...large diameter gear, 64...small diameter gear, 70...load gear, 80...load sheave shaft, 81...gear mounting portion, 82...first bearing mounting portion, 83...second bearing mounting portion, 84...load sheave, 100 ...Lower hook, 140B...Brake receiver, B1 to B6...Bearings, BT...Bolt, C1...Hand chain, C2...Load chain, CB1...Chain block body, CT1...Carburized treatment layer, G1...First reduction gear section (corresponding to part of the reduction gear mechanism), G2...Second reduction gear section (corresponding to part of the reduction gear mechanism), GB1, GB2...Gear box, N1...Nut, N2...Retaining nut, P1...Retaining pin

Claims

1. A hoist for raising and lowering a load via a load sheave around which a load chain for hoisting the load is wound, comprising: a drive shaft that transmits the driving force for raising and lowering the load to the load sheave; a brake receiving portion that is non-rotatably attached to the drive shaft; and a brake plate that slides relative to the brake receiving portion, wherein the drive shaft and the brake receiving portion are integrally molded.

2. A hoist as claimed in claim 1, comprising: a drive member that screws into a male threaded portion provided on the outer periphery of the drive shaft; and a ratchet wheel that has ratchet teeth on the outer periphery to restrict the direction of rotation to one direction and presses against the brake plate; wherein the brake receiving portion comprises a flange portion that protrudes outward from the axial portion of the drive shaft and has a sliding surface that slides against the brake plate; and a large diameter portion that is formed integrally with the flange portion and supports the ratchet wheel.

3. A hoist as claimed in claim 2, characterized in that the drive shaft is provided with a brake relief groove, and the brake relief groove is provided in a surface of the flange portion on the side where the brake plate is arranged, so as to recess the base portion of the flange portion relative to the large diameter portion.

4. A hoist as claimed in claim 2 or 3, characterized in that the drive shaft is provided with an inner ring abutment portion, and the inner ring abutment portion is provided with an outer diameter such that it comes into contact with the inner ring of an adjacently arranged bearing but does not come into contact with the outer ring of said bearing.

5. A hoist according to claim 2 or 3, characterized in that a carburized layer is formed on the large diameter portion and the flange portion of the drive shaft.

6. A hoist as claimed in claim 5, characterized in that the drive shaft is integrally formed by cold forging.

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