JP2013019106A - Bucket tooth of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bucket tooth capable of securing breaking strength of a bush and the bucket tooth in such a well-balanced manner.SOLUTION: For a tooth 2, when a hole inner dimension of a through-hole 2a, which is formed at a sidewall part 2b and is made to pass through to a cavity part V1 and to which an attachment pin unit 11 for fixation and bushes 14a and 14b are inserted, is defined as A, an inner dimension in a vertical direction of the cavity part V1 in the vertical direction including a center of the through-hole 2a in a side view is defined as B, an inner dimension in a width direction of the cavity part V1 including the through-hole 2a in a top view is defined as C, and the maximum width dimension of a pair of sidewall parts 2b at a position including the through-hole 2a in the top view is defined as D, A, B, C and D satisfy the relational expression: 0.61≤A/B≤0.73, 1.62≤D/C≤1.92.

Description

  The present invention relates to a bucket tooth that is mounted in a replaceable state on a front end portion of a lower surface of a bucket of a construction machine.

  Various excavating tools are attached to a work machine mounted on a work vehicle such as a hydraulic excavator. For example, in a bucket (work machine) mounted on a hydraulic excavator, a plurality of bucket teeth (excavating tools) are attached to a tip portion on the excavation side so as to protrude from the tip portion. And during excavation, these bucket teeth function as cutting edges, so that they are penetrated into the excavation target to increase excavation force.

  The bucket tooth attached to the tip portion of the bucket on the excavation side penetrates into the excavation target during excavation work, and therefore, the degree of wear is significant compared to other parts. For this reason, the bucket tooth is attached in a state where it can be exchanged with respect to the bucket, and is exchanged as necessary in, for example, about 1000 hours of excavation work time. That is, since the bucket tooth has a high replacement frequency, it is required to have high workability at the time of replacement work.

  In Patent Document 1, in order to attach the bucket tooth to the adapter of the bucket, the movement of the bucket tooth is caused by a pin that is partially press-fitted into the insertion hole on the side surface of the adapter in the through hole provided on the side surface of the bucket tooth. A configuration is disclosed that is stopped and secures the bucket tooth to the adapter. In the bucket tooth fixed by this configuration, the workability of the tooth replacement may be deteriorated due to the deformation of the pin due to the load during the work.

  In order to solve this problem, a configuration has been proposed in which a bucket tooth is fixed to an adapter by inserting a bush loaded with a pin into a through hole provided in a side surface of the bucket tooth. In the bucket tooth that conforms to this configuration, the load during operation is not directly applied to the pin, so that deformation of the pin can be prevented.

Japanese Patent Laid-Open No. 51-090701 (published on August 9, 1976)

However, the conventional bucket tooth has the following problems.
That is, in the configuration of the above-described bucket tooth, when the bushing moves in a direction in which it is removed from the adapter of the bucket tooth, it is worn by receiving a load due to contact with the bucket tooth, so that the required breaking strength of the bushing is ensured. For this purpose, a sufficient cross-sectional area is required.

On the other hand, the bucket tooth has a limitation on the outer size because a predetermined space is required around the adapter when the adapter is attached or detached. For this reason, when the bush becomes large, the portion around the through hole in the bucket tooth becomes thin, and the breaking strength of the bucket tooth itself may be reduced.
The subject of this invention is providing the bucket tooth which can ensure the fracture strength of a bush and a bucket tooth with sufficient balance.

The bucket tooth according to the first aspect of the present invention is a bucket tooth of a construction machine that is attached to the tip portion of the bucket, and has a tip that connects the upper surface, the lower surface connected at the upper surface and the tip portion, and the upper surface and the lower surface. A pair of side surfaces formed on the side including the portion, a rear end opening formed on the upper surface, the lower surface, the rear side of the pair of side surfaces and into which the tip of the bucket is inserted, and provided on one rear side of the pair of side surfaces. A convex side wall portion formed therein, a cavity portion provided in the bucket tooth from the rear end opening portion, a through hole formed in the side wall portion and penetrating to the cavity portion, and a fixing pin and a bush are inserted therein It is equipped with. The inside dimension of the through hole is A, the inside height dimension of the cavity in the vertical direction including the center of the through hole in the side view is B, and the inner dimension in the width direction of the cavity including the through hole in the top view. When the dimension is C and the maximum width dimension of the pair of side wall portions at the position including the through hole in the top view is D, A, B, C, and D satisfy the following relational expression.
0.61 ≦ A / B ≦ 0.73
1.62 ≦ D / C ≦ 1.92

Here, in order to ensure a good balance of the breaking strength of the bushing inserted into the bucket tooth and the through hole of the bucket tooth, the relationship of dimensions around the through hole formed in the bucket tooth is defined.
As a result, by making the relationship of the dimensions around the through hole of the bucket tooth within an appropriate range, the break strength of the bucket tooth and the bush is avoided from being extremely reduced, and the break strength of the bucket tooth and the bush is balanced. Can be secured.

The bucket tooth according to the second invention is the bucket tooth according to the first invention, and A / B and D / C satisfy the following relational expressions.
0.61 ≦ A / B ≦ 0.67
1.66 ≦ D / C ≦ 1.82

Here, a more preferable range is specified for the above-described numerical ranges of A / B and D / C.
As a result, by making the relationship of the dimensions around the through hole of the bucket tooth within an appropriate range, the break strength of the bucket tooth and the bush is avoided from being extremely reduced, and the break strength of the bucket tooth and the bush is balanced. Can be secured.

  According to the bucket tooth according to the present invention, by making the relationship of dimensions around the through-hole of the bucket tooth within an appropriate range, it is possible to avoid that the breaking strength of the bucket tooth and the bush is extremely reduced, The breaking strength of the bush can be secured in a well-balanced manner.

The perspective view which shows the attachment structure of the tooth of the bucket which concerns on one Embodiment of this invention. The disassembled perspective view which expanded the attachment structure vicinity of the tooth of FIG. (A) is a side view which shows the structure of the attachment pin contained in the attachment structure of FIG. (B) is a side view showing a configuration of a bolt. (C) is a side view showing a configuration of a washer. (D) is a side view which shows the structure of a bush. (A), (b) is the side surface schematic diagram which shows the structure of the attachment structure of the tooth of FIG. 2, and sectional drawing in the front-back direction of a tooth. (A), (b) is a graph which shows the relationship between a tooth hole ratio (A / B) and a tooth width ratio (D / C), and a cross-sectional area of a bush and a tooth rear part.

The bucket tooth according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5B.
[Mounting structure of the tooth 2 to the bucket 1]
The tooth (bucket tooth) 2 of the bucket (work machine) 1 according to the present embodiment is a structure for attaching the tooth 2 to the bucket 1 as shown in FIG. The mounting pin assembly 4 is provided.

(Tooth 2)
The tooth 2 is a claw-like member attached to the tip of the excavation portion of the bucket 1 for excavation by the bucket 1 attached to the tip of the arm of a work machine such as a hydraulic excavator, as shown in FIG. In addition, it has a wedge-shaped outer shape that becomes thinner toward the tip. As shown in FIG. 2, the tooth 2 includes an upper surface 21, a lower surface 22, a pair of left and right side surfaces 23, 23, a rear end opening 24, a cavity V1, and a through hole (through hole) 2a. And a side wall 2b and a contact surface 2c (see FIG. 4B, etc.).

The upper surface 21 is a plane that faces vertically upward in FIG.
The lower surface 22 is a plane that faces vertically downward as opposed to the upper surface 21 in FIG. 2, and is connected to the upper surface 21 at the tip portion of the tooth 2.
The side surfaces 23, 23 are a pair of left and right substantially triangular planes that constitute the left and right side surface portions of the tooth 2, and together with the upper surface 21 and the lower surface 22, configure the outline of the tooth 2.

The rear end opening 24 is an opening formed on the side opposite to the tip portion of the tooth 2.
The cavity V1 is a space formed inside the tooth 2 from the rear end opening 24 formed at the rear end of the tooth 2 toward the front end side. When the tooth 2 is attached to the bucket 1, the insertion portion 3 b of the adapter 3 described later is inserted into the hollow portion V <b> 1.
The through-hole 2a penetrates from the side wall portion 2b of the tooth 2 to the cavity portion V1, and is formed in a columnar shape along a direction orthogonal to the longitudinal direction of the tooth 2 (the direction connecting the rear end and the front end of the tooth 2). It is a hole. A mounting pin assembly 4 to be described later is inserted into the through hole 2a. The through hole 2a has an inner diameter slightly larger than the outer diameter of bushes 14a and 14b of the mounting pin assembly 4 described later.

The side wall portion 2b is a convex portion provided at a position near the rear end of the pair of left and right side surfaces 23, 23, and is formed with a through hole 2a.
As shown in FIG. 4A, the contact surface 2c is an inner wall surface that forms a hollow portion V1 in the tooth 2, and is in contact with a contact surface 3bb on the adapter 3 side described later.
It should be noted that the diameter and width of the through-hole 2a formed in the tooth 2 and the breakage of the rear portions of the bushes 14a, 14b and the tooth 2 are necessary to ensure the balance of the breaking strength of the tooth 2 and the bushes 14a and 14b. The relationship with the area will be described in detail later.

(Adapter 3)
As shown in FIG. 1, a plurality of adapters 3 are provided at one end of the bucket 1, and the above-described tooth 2 is attached to each. And the adapter 3 has the through-hole 3a and the insertion part 3b, as shown in FIG.
The through hole 3a penetrates the adapter 3 in the width direction, and is formed in the side wall portion 3ba of the insertion portion 3b. And the attachment pin assembly 4 is inserted in this through-hole 3a similarly to the said through-hole 2a. The through hole 3 a has an inner diameter larger than the outer diameter of the mounting pin (pin) 11 of the mounting pin assembly 4. For this reason, an internal diameter is small compared with the through-hole 2a mentioned above.

The insertion portion 3 b is formed in accordance with the concave shape of the cavity V <b> 1 formed in the tooth 2, and is inserted into the cavity V <b> 1 of the tooth 2. Moreover, when the insertion part 3b is inserted in the cavity part V1 of the tooth 2, it will contact | abut in the contact surface 3bb with respect to the contact surface 2c provided in the inner wall surface side of the tooth 2 which forms the cavity part V1.
The contact surface 3bb is an outer wall surface of the insertion portion 3b that contacts the contact surface 2c on the tooth 2 side in a state where the tooth 2 is attached to the adapter 3 as shown in FIG.

(Mounting pin assembly 4)
The mounting pin assembly 4 is a member for mounting the tooth 2 so that it does not fall off from the adapter 3, and when the tooth 2 is attached to the adapter 3, as shown in FIG. 3 is inserted into the through hole 2a and the through hole 3a. As shown in FIG. 2, the mounting pin assembly 4 includes a mounting pin 11, bolts 12a and 12b, washers 13a and 13b, and bushings 14a and 14b having a common central axis L. doing.

As shown in FIG. 3A, the mounting pin 11 is a metallic straight pin having a cylindrical shape without a step, and female screws 11a and 11b are formed at both ends. Further, the axial length of the mounting pin 11 is larger than the sum of the length of the through hole 3a of the adapter 3 and the lengths of the two bushes 14a and 14b.
As shown in FIG. 3B, the bolts 12a and 12b are metal fastening members having a general shape, and are male screws relative to the female screws 11a and 11b formed at both ends of the mounting pin 11. The parts are screwed together.

  As shown in FIG. 3C, the washers 13a and 13b have a substantially disk shape in which a through-hole into which the bolts 12a and 12b are inserted is formed at the center and has an outer diameter larger than the outer diameter of the mounting pin 11. It is a metal member. The washers 13a and 13b are fixed to both end surfaces of the mounting pin 11 by bolts 12a and 12b, and are provided so that the bushes 14a and 14b do not come off the mounting pin 11.

  As shown in FIG. 3 (d), the bushes 14a and 14b are substantially cylindrical metal members each having a through-hole into which the mounting pin 11 is inserted at the center, and include bolts 12a and 12b and washers. The mounting pins 11 are provided at both ends by 13a and 13b. The inner diameters of the bushes 14a and 14b are slightly larger than the outer diameter of the mounting pins 11 so that the mounting pins 11 are inserted, and smaller than the outer diameters of the washers 13a and 13b. Therefore, the bushes 14 a and 14 b are rotatable on the outer peripheral surface of the mounting pin 11 and are movable between the washers 13 a and 13 b and the adapter 3.

In the present embodiment, the tooth 2 is fixed to the adapter 3 so as not to drop off by being inserted into the through holes 2a and 3a penetrating the tooth 2 and the adapter 3 by the configuration as described above. .
Here, when a load is applied to the tooth 2 during excavation work using the bucket 1 by a hydraulic excavator or the like, the load acts in a direction of pushing the tooth 2 toward the adapter 3 side. At this time, the load applied to the tooth 2 is received on the outer wall surface (contact surface 3bb) of the insertion portion of the adapter 3 from the contact surface 2c forming the cavity V1 formed in the tooth 2. Therefore, the load applied to the tooth 2 during excavation work or the like does not act on the mounting pin assembly 4 that connects the tooth 2 and the adapter 3. This is because a gap is provided between the outer peripheral surfaces of the bushes 14 a and 14 b and the inner wall surfaces of the first through holes 2 a and 2 a of the tooth 2.

  In other words, in this embodiment, the mounting pin assembly 4 functions only as a retainer for preventing the tooth 2 from falling off the adapter 3 when a force is applied in a direction in which the tooth 2 is separated from the adapter 3.

<Tooth 2 mounting structure>
Here, it will be as follows if the attachment structure of the tooth 2 using each member mentioned above is demonstrated in detail.
That is, as shown in FIG. 4B, in the state where the insertion portion 3b of the adapter 3 is inserted into the cavity V1 formed inside the tooth 2, the mounting pin assembly 4 is connected to the tooth 2 and the adapter. 3 is inserted into a through-hole 2a and a through-hole 3a penetrating in the width direction.
The attachment procedure of the attachment pin assembly 4 is as follows.
First, after the mounting pin 11 is inserted into the central hole of the bush 14b, the bolt 12b is fixed to one end of the mounting pin 11 via a washer 13b. At this time, the bolt 12 b is screwed into a female screw 11 b formed at one end of the mounting pin 11.

Next, the mounting pin 11 is inserted into the through hole 2a on the tooth 2 side and the through hole 3a on the adapter 3 side from the other end side.
Next, the other end side of the mounting pin 11 coming out from the side opposite to the insertion side of the tooth 2 is inserted into the central hole of the bush 14a. The bushes 14a and 14b are provided so as to be rotatable with respect to the mounting pin 11, respectively. And the volt | bolt 12a is fixed to the other end side of the attachment pin 11 via the washer 13a. At this time, the bolt 12 a is screwed into a female screw 11 a formed at the other end of the mounting pin 11.

As a result, the bushes 14 a and 14 b are disposed in the through hole 2 a on the tooth 2 side and are disposed outside the side wall portions 3 ba on both sides of the adapter 3 as shown in FIG. As a result, it is possible to avoid the mounting pin assembly 4 for preventing the tooth 2 from dropping out of the through holes 2a and 3a.
On the other hand, when a force is applied in a direction for separating the tooth 2 from the adapter 3 for some reason, the inner peripheral surface of the through hole 2a of the tooth 2 is attached by the relative movement of the tooth 2 with respect to the adapter 3. It contacts the outer peripheral surfaces of the bushes 14a, 14b of the pin assembly 4. At this time, part of the force applied from the tooth 2 to the bushes 14a and 14b is effectively released by the rotation of the bushes 14a and 14b. Therefore, even when a force is transmitted from the tooth 2 to the outer peripheral surfaces of the bushes 14a and 14b, a large load is not applied to the mounting pin 11.

  In the present embodiment, as described above, in the mounting structure of the tooth 2 using the mounting pin assembly 4 inserted into the through holes 2a and 3a passing through the tooth 2 and the adapter 3, the tooth 2 is attached to the adapter 3. As a member constituting the mounting pin assembly 4 for fixing the tooth 2 so as not to drop off against the force acting in the direction of separating, a straight metal pin (mounting pin 11) having no step is used. . Metal members are all used as the bushes 14a and 14b, the bolts 12a and 12b, and the washers 13a and 13b for preventing the mounting pin 11 from falling off the through holes 2a and 3a. Further, the bushes 14 a and 14 b can move in the axial direction between the washers 13 a and 13 b and the adapter 3 along the attachment pin 11, and can rotate about the axis of the attachment pin 11.

As a result, a large load applied to the tooth 2 during excavation work or the like is not applied to the mounting pin assembly 4, and the mounting pin 11 is locally compared to the conventional mounting pin assembly. Since the shape of the straight pin does not include a step portion where stress is concentrated on the mounting pin 11, the mounting pin 11 can be prevented from being broken.
In addition, since the mounting pin assembly 4 does not include a member such as an elastic member that is greatly deteriorated over time, the life of the mounting pin assembly 4 can be extended as compared with the conventional case and can be used for a long time. .

[Diameter ratio and width ratio of through hole 2a of tooth 2]
In the tooth 2 of the present embodiment, by setting the dimensional relationship around the through hole of the tooth 2 within an appropriate range, the rupture strength of the tooth 2 and the bushes 14a and 14b is maintained while maintaining the workability of the tooth 2 replacement work. In order to avoid that the balance is extremely lowered, the tooth 2 is formed so as to maintain the following relationship.

Specifically, as shown in FIGS. 4 (a) and 4 (b), the inner diameter of the through hole 2a is A, and the center of the through hole 2a in a side view (FIG. 4 (a)). B is the inner dimension of the cavity V1 in the vertical direction (left-right direction in FIG. 4A), and the width direction of the cavity V1 including the through hole 2a in the top view (FIG. 4B) (FIG. 4B). ) Where C is the inner dimension in the left-right direction), and D is the maximum width dimension of the pair of left and right side wall portions 2b at the position including the through hole 2a when viewed from above, A, B, C, D satisfy the following relational expression: .
0.61 ≦ A / B ≦ 0.73
1.62 ≦ D / C ≦ 1.92

  Here, the central axis L of the through hole 2 a of the tooth 2 is the same as the central axis of the through hole 3 a of the adapter 3. The width direction and the vertical direction described above are based on the central axis L of the through hole 2a of the tooth 2, and the direction of the central axis L is the width direction, and the direction perpendicular to the plane including the central axis and the front-back direction of the tooth 2 is vertical. The direction. Even when the central axis L is arranged in parallel with the central axis of the through hole 3a of the adapter 3 at a position away from the distal end of the tooth 2, the mounting pin described in the description of the mounting structure of the tooth 2 is used. There is no problem if the positional relationship between the assembly 4 and the through hole 2a is satisfied.

  The tooth 2 molded so as to satisfy these conditions can sufficiently secure the breaking strength of the bushes 14a and 14b inserted into the through hole 2a while sufficiently securing the exceptional strength in the vicinity of the through hole 2a. . At the same time, since the interval between the teeth 2 can be sufficiently secured when the adapter 3 is mounted, it is possible to avoid deterioration in workability of the tooth 2 replacement work regardless of the presence of the side wall 2b.

  The minimum values of the hole ratio A / B and the width ratio D / C are determined as follows. In the case of the conventional structure in which the bucket tooth is attached to the adapter using only the pins without using the bush, the hole ratio A / B is 0.40 to 0.50. In this embodiment, since the bushes 14a and 14b are loosely fitted on the outer periphery of the mounting pin 11, the hole ratio A / B is increased by the minimum thickness required for the bushes 14a and 14b. 0.61 or more.

Further, in the conventional structure without bushes, the width ratio D / C is 1.20 to 1.40.
In this embodiment, there are bushes 14a and 14b, bolts 12a and 12b for attaching the bushes 14a and 14b to the mounting pin 11, and the heads of the bolts 12a and 12b need to be completely in the insertion hole 2a. Therefore, the width ratio D / C is set to a numerical value of 1.62 or more, which is larger than the above range. The reason why B and C are used here is that the dimensions relating to the adapter 3 (that is, the dimensions of the cavity portion V1 of the tooth 2) are the same as those in the prior art.

The maximum value of the hole ratio A / B is determined as follows.
The cross-sectional area in the central axis direction of the bush 14a (the area of the bush cross-section (filled portion) in FIG. 4B) is the dimension A, and the through hole 2a of the tooth 2 in the cross-section in the longitudinal direction of the tooth including the central axis C of the bushes 14a and 14b. The cross-sectional area of the rear part (the area of the tooth-filled portion in FIG. 4B) is related to the dimension B, respectively. The breaking strengths of the bushes 14a and 14b and the rear part of the tooth 2 are approximately proportional to the cross-sectional area of the bush and the rear part of the tooth, respectively.

  By the way, in order to stop the movement of the tooth 2 from the adapter 3 by the pin assembly 4, the bushes 14 a and 14 b come into contact with the rear part of the tooth 2. At this time, the breaking strength of the bushes 14a and 14b need not be larger than the breaking strength of the rear portion of the tooth 2. The hole ratio A / B is approximately 0.73 to 0.77 when the fracture strengths of the bushes 14a and 14b and the rear part of the tooth 2 are equal, that is, the bush cross-sectional area and the tooth rear part cross-sectional area are equal. For this reason, in this embodiment, the maximum value of the hole ratio A / B is set to 0.73.

Next, the maximum value of the width ratio D / C is determined as follows.
In this embodiment, the bucket 1 main body to which the tooth 2 is attached is the same as before. Accordingly, the plurality of adapters 3 at the tip of the bucket 1 and the dimensions between the adapters 3 are the same as before.
On the other hand, the tooth 2 which concerns on this embodiment has the side wall part 2b which protrudes in the direction between the adapters 3. FIG. Therefore, when the protrusion of the side wall 2b becomes large, the interval between the plurality of teeth 2 attached to the adapter 3 is narrowed. Since the distance between the teeth 2 has a minimum dimension required for the replacement operation of the tooth 2, a corresponding maximum dimension is derived for the dimension D. In the present embodiment, the maximum value of the width ratio D / C is set to 1.92 from the maximum dimension of the dimension D.

  FIG. 5 shows the relationship between the hole ratio A / B and the width ratio D / C and the cross-sectional areas of the bush and the tooth rear part in the tooth 2 used for the hydraulic excavator having a certain vehicle body weight. In FIG. 5A, the horizontal axis represents the hole ratio A / B, and the vertical axis represents the cross-sectional area. In FIG. 5A, the solid line graph shows the bush cross-sectional area, and the broken line graph shows the tooth rear part cross-sectional area. In FIG. 5B, the horizontal axis indicates the width ratio D / C, and the others indicate the same items as in FIG.

Here, the dimensions and geometric shapes of the adapter 3 of the bucket are the same as the conventional one including the through hole 3a. In other words, the dimension / geometric shape of the cavity portion V1 of the tooth 2 is the same as the conventional one.
As described above, the tooth hole ratio A / B is set to 0.61 or more and 0.73 or less. In the graph of FIG. 5A, A / B is 0.73, and the cross-sectional areas of the rear portions of the bushes 14 a and 14 b and the tooth 2 are equal. That is, A / B is 0.73, and the breaking strengths of the bushes 14a and 14b and the rear part of the tooth 2 corresponding thereto are balanced. However, since the breaking strength of the bushes 14a and 14b is preferably smaller than the breaking strength of the rear portion of the tooth 2, the tooth hole ratio A / B is set to be in the range of 0.61 to 0.67. It is desirable that

As described above, the tooth width ratio D / C is set to 1.62 or more and 1.92 or less. However, the maximum value 1.92 of the tooth width ratio D / C is a value for securing only the minimum interval between the teeth 2 that is indispensable for the replacement work of the tooth 2, so that the replacement work can be easily performed. The maximum value is preferably 1.82 or less, which is smaller than the above-mentioned 1.92.
Further, the minimum value 1.62 of the tooth width ratio is a minimum value for the head of the bolt 12a to be accommodated in the through hole 2a of the tooth 2, but is 1.66 which is a larger value for safety. Preferably there is.

In summary, the tooth hole ratio A / B is more preferably 0.61 to 0.67, and the tooth width ratio D / C is more preferably 1.66 to 1.82. That is, it is more preferable that the tooth 2 satisfies the following relational expression.
0.61 ≦ A / B ≦ 0.67
1.66 ≦ D / C ≦ 1.82

[Other Embodiments]
In the said embodiment, the through-hole 2a of the tooth 2 gave and demonstrated the example by which the cross section was made into the columnar hole of a circle | round | yen. However, the present invention is not limited to this.
For example, the cross-section of the through hole 2a may be an irregular shape that is not a circle, for example, an elliptical shape.
Moreover, shapes other than the through-hole 2a are the same as the above-mentioned embodiment. The in-hole dimension A in the relational expression means the inner dimension of the through-hole 2a in the vertical direction including the center of the through-hole 3a of the adapter 3 corresponding to the attachment in the side view of the tooth. Relational expressions B, C, and D are synonymous with the above-described embodiment, and the relational expressions are the same.

(Summary)
As described above, the tooth 2 has a tooth hole ratio A / B, which is a ratio of the inside dimension of the through hole in the tooth height direction and the inside dimension of the cavity, with the center axis L at the time of tooth attachment, and the tooth outside dimension in the tooth width direction. The range of the tooth width ratio D / C, which is the ratio of the inner dimensions, preferably satisfies the following relational expression.
0.61 ≦ A / B ≦ 0.73
1.62 ≦ D / C ≦ 1.92

Further, the tooth 2 satisfying the following relational expression is a tooth 2 attached to the adapter 3 by inserting bushes 14a and 14b loaded with attachment pins 11 into through holes 2a provided on the side surface of the tooth 2. It is more preferable.
0.61 ≦ A / B ≦ 0.67
1.66 ≦ D / C ≦ 1.82
As a result, the tooth 2 is designed so that the tooth hole ratio A / B and the tooth width ratio D / C are within the above ranges, so that the fracture strength of the tooth 2 and the bushes 14a and 14b is sufficiently secured. A good tooth 2 can be obtained. Moreover, the tooth shape can be optimized by designing the tooth 2 so as to be within the above range.

  The bucket tooth of the present invention has the effect of ensuring the bushing and the breaking strength of the bucket tooth in a well-balanced manner, and thus can be widely applied to the bucket tooth mounted in a replaceable state on the bucket of a construction machine. It is.

1 bucket (work machine)
2 tooth (bucket tooth)
2a Through hole (through hole)
2b Side wall portion 2c Contact surface 3 Adapter 3a Through hole 3b Insertion portion 3ba Side wall portion 3bb Contact surface 4 Mounting pin assembly 11 Mounting pin (pin)
11a, 11b Female screws 12a, 12b Bolts 13a, 13b Washers 14a, 14b Bush 21 Upper surface 22 Lower surface 23 Side surface 24 Rear end opening V1 Cavity

  The present invention relates to a bucket tooth that is mounted in a replaceable state on a front end portion of a lower surface of a bucket of a construction machine.

  Various excavating tools are attached to a work machine mounted on a work vehicle such as a hydraulic excavator. For example, in a bucket (work machine) mounted on a hydraulic excavator, a plurality of bucket teeth (excavating tools) are attached to a tip portion on the excavation side so as to protrude from the tip portion. And during excavation, these bucket teeth function as cutting edges, so that they are penetrated into the excavation target to increase excavation force.

  The bucket tooth attached to the tip portion of the bucket on the excavation side penetrates into the excavation target during excavation work, and therefore, the degree of wear is significant compared to other parts. For this reason, the bucket tooth is attached in a state where it can be exchanged with respect to the bucket, and is exchanged as necessary in, for example, about 1000 hours of excavation work time. That is, since the bucket tooth has a high replacement frequency, it is required to have high workability at the time of replacement work.

  In Patent Document 1, in order to attach the bucket tooth to the adapter of the bucket, the movement of the bucket tooth is caused by a pin that is partially press-fitted into the insertion hole on the side surface of the adapter in the through hole provided on the side surface of the bucket tooth. A configuration is disclosed that is stopped and secures the bucket tooth to the adapter. In the bucket tooth fixed by this configuration, the workability of the tooth replacement may be deteriorated due to the deformation of the pin due to the load during the work.

  In order to solve this problem, a configuration has been proposed in which a bucket tooth is fixed to an adapter by inserting a bush loaded with a pin into a through hole provided in a side surface of the bucket tooth. In the bucket tooth that conforms to this configuration, the load during operation is not directly applied to the pin, so that deformation of the pin can be prevented.

Japanese Patent Laid-Open No. 51-090701 (published on August 9, 1976)

However, the conventional bucket tooth has the following problems.
That is, in the configuration of the above-described bucket tooth, when the bushing moves in a direction in which it is removed from the adapter of the bucket tooth, it is worn by receiving a load due to contact with the bucket tooth, so that the required breaking strength of the bushing is ensured. For this purpose, a sufficient cross-sectional area is required.

  On the other hand, the bucket tooth has a limitation on the outer size because a predetermined space is required around the adapter when the adapter is attached or detached. For this reason, when the bush becomes large, the portion around the through hole in the bucket tooth becomes thin, and the breaking strength of the bucket tooth itself may be reduced.

  The subject of this invention is providing the bucket tooth which can ensure the fracture strength of a bush and a bucket tooth with sufficient balance.

The bucket tooth according to the first aspect of the present invention is a bucket tooth of a construction machine that is attached to the tip portion of the bucket, and has a tip that connects the upper surface, the lower surface connected at the upper surface and the tip portion, and the upper surface and the lower surface. A pair of side surfaces formed on the side including the portion, a rear end opening formed on the upper surface, the lower surface, the rear side of the pair of side surfaces and into which the tip of the bucket is inserted, and provided on one rear side of the pair of side surfaces. A convex side wall portion formed therein, a cavity portion provided in the bucket tooth from the rear end opening portion, a through hole formed in the side wall portion and penetrating to the cavity portion, and a fixing pin and a bush are inserted therein It is equipped with. Then, assuming that the inner dimension of the through hole is A and the inner height dimension of the cavity in the vertical direction including the center of the through hole in a side view is B , A and B satisfy the following relational expression.
0.61 ≦ A / B ≦ 0.7 3

Here, in order to ensure a good balance of the breaking strength of the bushing inserted into the bucket tooth and the through hole of the bucket tooth, the relationship of dimensions around the through hole formed in the bucket tooth is defined.

  As a result, by making the relationship of the dimensions around the through hole of the bucket tooth within an appropriate range, the break strength of the bucket tooth and the bush is avoided from being extremely reduced, and the break strength of the bucket tooth and the bush is balanced. Can be secured.

The bucket tooth according to the second invention is the bucket tooth according to the first invention, and A / B satisfies the following relational expression.
0.61 ≦ A / B ≦ 0.6 7

Here, a more preferable range is specified for the above-described numerical ranges of A / B and D / C.
As a result, by making the relationship of the dimensions around the through hole of the bucket tooth within an appropriate range, the break strength of the bucket tooth and the bush is avoided from being extremely reduced, and the break strength of the bucket tooth and the bush is balanced. Can be secured.

  A bucket tooth according to a third aspect is the bucket tooth according to the first or second aspect, wherein the inner dimension in the width direction of the cavity including the through hole in the top view is C, and the through hole is included in the top view. When the maximum width dimension of the pair of side wall portions at the position is D, C and D satisfy the following relational expression.
      1.62 ≦ D / C ≦ 1.92

  The bucket tooth according to the fourth invention is the bucket tooth according to the third invention, and D / C satisfies the following relational expression.

      1.66 ≦ D / C ≦ 1.82

  According to the bucket tooth according to the present invention, by making the relationship of dimensions around the through-hole of the bucket tooth within an appropriate range, it is possible to avoid that the breaking strength of the bucket tooth and the bush is extremely reduced, The breaking strength of the bush can be secured in a well-balanced manner.

The perspective view which shows the attachment structure of the tooth of the bucket which concerns on one Embodiment of this invention. The disassembled perspective view which expanded the attachment structure vicinity of the tooth of FIG. (A) is a side view which shows the structure of the attachment pin contained in the attachment structure of FIG. (B) is a side view showing a configuration of a bolt. (C) is a side view showing a configuration of a washer. (D) is a side view which shows the structure of a bush. (A), (b) is the side surface schematic diagram which shows the structure of the attachment structure of the tooth of FIG. 2, and sectional drawing in the front-back direction of a tooth. (A), (b) is a graph which shows the relationship between a tooth hole ratio (A / B) and a tooth width ratio (D / C), and a cross-sectional area of a bush and a tooth rear part.

The bucket tooth according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5B.
[Mounting structure of the tooth 2 to the bucket 1]
The tooth (bucket tooth) 2 of the bucket (work machine) 1 according to the present embodiment is a structure for attaching the tooth 2 to the bucket 1 as shown in FIG. The mounting pin assembly 4 is provided.

(Tooth 2)
The tooth 2 is a claw-like member attached to the tip of the excavation portion of the bucket 1 for excavation by the bucket 1 attached to the tip of the arm of a work machine such as a hydraulic excavator, as shown in FIG. In addition, it has a wedge-shaped outer shape that becomes thinner toward the tip. As shown in FIG. 2, the tooth 2 includes an upper surface 21, a lower surface 22, a pair of left and right side surfaces 23, 23, a rear end opening 24, a cavity V1, and a through hole (through hole) 2a. And a side wall 2b and a contact surface 2c (see FIG. 4B, etc.).

The upper surface 21 is a plane that faces vertically upward in FIG.
The lower surface 22 is a plane that faces vertically downward as opposed to the upper surface 21 in FIG. 2, and is connected to the upper surface 21 at the tip portion of the tooth 2.

The side surfaces 23, 23 are a pair of left and right substantially triangular planes that constitute the left and right side surface portions of the tooth 2, and together with the upper surface 21 and the lower surface 22, configure the outline of the tooth 2.
The rear end opening 24 is an opening formed on the side opposite to the tip portion of the tooth 2.

  The cavity V1 is a space formed inside the tooth 2 from the rear end opening 24 formed at the rear end of the tooth 2 toward the front end side. When the tooth 2 is attached to the bucket 1, the insertion portion 3 b of the adapter 3 described later is inserted into the hollow portion V <b> 1.

  The through-hole 2a penetrates from the side wall portion 2b of the tooth 2 to the cavity portion V1, and is formed in a columnar shape along a direction orthogonal to the longitudinal direction of the tooth 2 (the direction connecting the rear end and the front end of the tooth 2). It is a hole. A mounting pin assembly 4 to be described later is inserted into the through hole 2a. The through hole 2a has an inner diameter slightly larger than the outer diameter of bushes 14a and 14b of the mounting pin assembly 4 to be described later.

The side wall portion 2b is a convex portion provided at a position near the rear end of the pair of left and right side surfaces 23, 23, and is formed with a through hole 2a.
As shown in FIG. 4A, the contact surface 2c is an inner wall surface that forms a hollow portion V1 in the tooth 2, and is in contact with a contact surface 3bb on the adapter 3 side described later.

  It should be noted that the diameter and width of the through-hole 2a formed in the tooth 2 and the breakage of the rear portions of the bushes 14a, 14b and the tooth 2 are necessary to ensure the balance of the breaking strength of the tooth 2 and the bushes 14a and 14b. The relationship with the area will be described in detail later.

(Adapter 3)
As shown in FIG. 1, a plurality of adapters 3 are provided at one end of the bucket 1, and the above-described tooth 2 is attached to each. And the adapter 3 has the through-hole 3a and the insertion part 3b, as shown in FIG.

  The through hole 3a penetrates the adapter 3 in the width direction, and is formed in the side wall portion 3ba of the insertion portion 3b. And the attachment pin assembly 4 is inserted in this through-hole 3a similarly to the said through-hole 2a. The through hole 3 a has an inner diameter larger than the outer diameter of the mounting pin (pin) 11 of the mounting pin assembly 4. For this reason, an internal diameter is small compared with the through-hole 2a mentioned above.

The insertion portion 3 b is formed in accordance with the concave shape of the cavity V <b> 1 formed in the tooth 2, and is inserted into the cavity V <b> 1 of the tooth 2. Moreover, when the insertion part 3b is inserted in the cavity part V1 of the tooth 2, it will contact | abut in the contact surface 3bb with respect to the contact surface 2c provided in the inner wall surface side of the tooth 2 which forms the cavity part V1.
The contact surface 3bb is an outer wall surface of the insertion portion 3b that contacts the contact surface 2c on the tooth 2 side in a state where the tooth 2 is attached to the adapter 3 as shown in FIG.

(Mounting pin assembly 4)
The mounting pin assembly 4 is a member for mounting the tooth 2 so that it does not fall off from the adapter 3, and when the tooth 2 is attached to the adapter 3, as shown in FIG. 3 is inserted into the through hole 2a and the through hole 3a. As shown in FIG. 2, the mounting pin assembly 4 includes a mounting pin 11, bolts 12a and 12b, washers 13a and 13b, and bushings 14a and 14b having a common central axis L. doing.

  As shown in FIG. 3A, the mounting pin 11 is a metallic straight pin having a cylindrical shape without a step, and has female threads 11a and 11b formed at both ends. Further, the axial length of the mounting pin 11 is larger than the sum of the length of the through hole 3a of the adapter 3 and the lengths of the two bushes 14a and 14b.

  As shown in FIG. 3B, the bolts 12a and 12b are metal fastening members having a general shape, and are male screws relative to the female screws 11a and 11b formed at both ends of the mounting pin 11. The parts are screwed together.

  As shown in FIG. 3C, the washers 13a and 13b have a substantially disk shape in which a through-hole into which the bolts 12a and 12b are inserted is formed at the center and has an outer diameter larger than the outer diameter of the mounting pin 11. It is a metal member. The washers 13a and 13b are fixed to both end surfaces of the mounting pin 11 by bolts 12a and 12b, and are provided so that the bushes 14a and 14b do not come off the mounting pin 11.

  As shown in FIG. 3 (d), the bushes 14a and 14b are substantially cylindrical metal members each having a through-hole into which the mounting pin 11 is inserted at the center, and include bolts 12a and 12b and washers. The mounting pins 11 are provided at both ends by 13a and 13b. The inner diameters of the bushes 14a and 14b are slightly larger than the outer diameter of the mounting pins 11 so that the mounting pins 11 are inserted, and smaller than the outer diameters of the washers 13a and 13b. Therefore, the bushes 14 a and 14 b are rotatable on the outer peripheral surface of the mounting pin 11 and are movable between the washers 13 a and 13 b and the adapter 3.

  In the present embodiment, the tooth 2 is fixed to the adapter 3 so as not to drop off by being inserted into the through holes 2a and 3a penetrating the tooth 2 and the adapter 3 by the configuration as described above. .

  Here, when a load is applied to the tooth 2 during excavation work using the bucket 1 by a hydraulic excavator or the like, the load acts in a direction of pushing the tooth 2 toward the adapter 3 side. At this time, the load applied to the tooth 2 is received on the outer wall surface (contact surface 3bb) of the insertion portion of the adapter 3 from the contact surface 2c forming the cavity V1 formed in the tooth 2. Therefore, the load applied to the tooth 2 during excavation work or the like does not act on the mounting pin assembly 4 that connects the tooth 2 and the adapter 3. This is because a gap is provided between the outer peripheral surfaces of the bushes 14 a and 14 b and the inner wall surfaces of the first through holes 2 a and 2 a of the tooth 2.

  In other words, in this embodiment, the mounting pin assembly 4 functions only as a retainer for preventing the tooth 2 from falling off the adapter 3 when a force is applied in a direction in which the tooth 2 is separated from the adapter 3.

<Tooth 2 mounting structure>
Here, it will be as follows if the attachment structure of the tooth 2 using each member mentioned above is demonstrated in detail.

  That is, as shown in FIG. 4B, in the state where the insertion portion 3b of the adapter 3 is inserted into the cavity V1 formed inside the tooth 2, the mounting pin assembly 4 is connected to the tooth 2 and the adapter. 3 is inserted into a through-hole 2a and a through-hole 3a penetrating in the width direction.

The attachment procedure of the attachment pin assembly 4 is as follows.
First, after the mounting pin 11 is inserted into the central hole of the bush 14b, the bolt 12b is fixed to one end of the mounting pin 11 via a washer 13b. At this time, the bolt 12 b is screwed into a female screw 11 b formed at one end of the mounting pin 11.

Next, the mounting pin 11 is inserted into the through hole 2a on the tooth 2 side and the through hole 3a on the adapter 3 side from the other end side.
Next, the other end side of the mounting pin 11 coming out from the side opposite to the insertion side of the tooth 2 is inserted into the central hole of the bush 14a. The bushes 14a and 14b are provided so as to be rotatable with respect to the mounting pin 11, respectively. And the volt | bolt 12a is fixed to the other end side of the attachment pin 11 via the washer 13a. At this time, the bolt 12 a is screwed into a female screw 11 a formed at the other end of the mounting pin 11.

  As a result, the bushes 14 a and 14 b are disposed in the through hole 2 a on the tooth 2 side and are disposed outside the side wall portions 3 ba on both sides of the adapter 3 as shown in FIG. As a result, it is possible to avoid the mounting pin assembly 4 for preventing the tooth 2 from dropping out of the through holes 2a and 3a.

  On the other hand, when a force is applied in a direction for separating the tooth 2 from the adapter 3 for some reason, the inner peripheral surface of the through hole 2a of the tooth 2 is attached by the relative movement of the tooth 2 with respect to the adapter 3. It contacts the outer peripheral surfaces of the bushes 14a, 14b of the pin assembly 4. At this time, part of the force applied from the tooth 2 to the bushes 14a and 14b is effectively released by the rotation of the bushes 14a and 14b. Therefore, even when a force is transmitted from the tooth 2 to the outer peripheral surfaces of the bushes 14a and 14b, a large load is not applied to the mounting pin 11.

  In the present embodiment, as described above, in the mounting structure of the tooth 2 using the mounting pin assembly 4 inserted into the through holes 2a and 3a passing through the tooth 2 and the adapter 3, the tooth 2 is attached to the adapter 3. As a member constituting the mounting pin assembly 4 for fixing the tooth 2 so as not to drop off against the force acting in the direction of separating, a straight metal pin (mounting pin 11) having no step is used. . Metal members are all used as the bushes 14a and 14b, the bolts 12a and 12b, and the washers 13a and 13b for preventing the mounting pin 11 from falling off the through holes 2a and 3a. Further, the bushes 14 a and 14 b can move in the axial direction between the washers 13 a and 13 b and the adapter 3 along the attachment pin 11, and can rotate about the axis of the attachment pin 11.

  As a result, a large load applied to the tooth 2 during excavation work or the like is not applied to the mounting pin assembly 4, and the mounting pin 11 is locally compared to the conventional mounting pin assembly. Since the shape of the straight pin does not include a step portion where stress is concentrated on the mounting pin 11, the mounting pin 11 can be prevented from being broken.

  In addition, since the mounting pin assembly 4 does not include a member such as an elastic member that is greatly deteriorated over time, the life of the mounting pin assembly 4 can be extended as compared with the conventional case and can be used for a long time. .

[Diameter ratio and width ratio of through hole 2a of tooth 2]
In the tooth 2 of the present embodiment, by setting the dimensional relationship around the through hole of the tooth 2 within an appropriate range, the rupture strength of the tooth 2 and the bushes 14a and 14b is maintained while maintaining the workability of the tooth 2 replacement work. In order to avoid that the balance is extremely lowered, the tooth 2 is formed so as to maintain the following relationship.

Specifically, as shown in FIGS. 4 (a) and 4 (b), the inner diameter of the through hole 2a is A, and the center of the through hole 2a in a side view (FIG. 4 (a)). B is the inner dimension of the cavity V1 in the vertical direction (left-right direction in FIG. 4A), and the width direction of the cavity V1 including the through hole 2a in the top view (FIG. 4B) (FIG. 4B). ) Where C is the inner dimension in the left-right direction), and D is the maximum width dimension of the pair of left and right side wall portions 2b at the position including the through hole 2a when viewed from above, A, B, C, D satisfy the following relational expression: .
0.61 ≦ A / B ≦ 0.73
1.62 ≦ D / C ≦ 1.92

  Here, the central axis L of the through hole 2 a of the tooth 2 is the same as the central axis of the through hole 3 a of the adapter 3. The width direction and the vertical direction described above are based on the central axis L of the through hole 2a of the tooth 2, and the direction of the central axis L is the width direction, and the direction perpendicular to the plane including the central axis and the front-back direction of the tooth 2 is vertical. The direction. Even when the central axis L is arranged in parallel with the central axis of the through hole 3a of the adapter 3 at a position away from the distal end of the tooth 2, the mounting pin described in the description of the mounting structure of the tooth 2 is used. There is no problem if the positional relationship between the assembly 4 and the through hole 2a is satisfied.

  The tooth 2 molded so as to satisfy these conditions can sufficiently secure the breaking strength of the bushes 14a and 14b inserted into the through hole 2a while sufficiently securing the exceptional strength in the vicinity of the through hole 2a. . At the same time, since the interval between the teeth 2 can be sufficiently secured when the adapter 3 is mounted, it is possible to avoid deterioration in workability of the tooth 2 replacement work regardless of the presence of the side wall 2b.

  The minimum values of the hole ratio A / B and the width ratio D / C are determined as follows. In the case of the conventional structure in which the bucket tooth is attached to the adapter using only the pins without using the bush, the hole ratio A / B is 0.40 to 0.50. In this embodiment, since the bushes 14a and 14b are loosely fitted on the outer periphery of the mounting pin 11, the hole ratio A / B is increased by the minimum thickness required for the bushes 14a and 14b. 0.61 or more.

Further, in the conventional structure without bushes, the width ratio D / C is 1.20 to 1.40.
In this embodiment, there are bushes 14a and 14b, bolts 12a and 12b for attaching the bushes 14a and 14b to the mounting pin 11, and the heads of the bolts 12a and 12b need to be completely in the insertion hole 2a. Therefore, the width ratio D / C is set to a numerical value of 1.62 or more, which is larger than the above range. The reason why B and C are used here is that the dimensions relating to the adapter 3 (that is, the dimensions of the cavity portion V1 of the tooth 2) are the same as those in the prior art.

The maximum value of the hole ratio A / B is determined as follows.
The cross-sectional area in the central axis direction of the bush 14a (the area of the bush cross-section (filled portion) in FIG. 4B) is the dimension A, and the through hole 2a of the tooth 2 in the cross-section in the longitudinal direction of the tooth including the central axis C of the bushes 14a and 14b. The cross-sectional area of the rear part (the area of the tooth-filled portion in FIG. 4B) is related to the dimension B, respectively. The breaking strengths of the bushes 14a and 14b and the rear part of the tooth 2 are approximately proportional to the cross-sectional area of the bush and the rear part of the tooth, respectively.

  By the way, in order to stop the movement of the tooth 2 from the adapter 3 by the pin assembly 4, the bushes 14 a and 14 b come into contact with the rear part of the tooth 2. At this time, the breaking strength of the bushes 14a and 14b need not be larger than the breaking strength of the rear portion of the tooth 2. The hole ratio A / B is approximately 0.73 to 0.77 when the fracture strengths of the bushes 14a and 14b and the rear part of the tooth 2 are equal, that is, the bush cross-sectional area and the tooth rear part cross-sectional area are equal. For this reason, in this embodiment, the maximum value of the hole ratio A / B is set to 0.73.

Next, the maximum value of the width ratio D / C is determined as follows.
In this embodiment, the bucket 1 main body to which the tooth 2 is attached is the same as before. Accordingly, the plurality of adapters 3 at the tip of the bucket 1 and the dimensions between the adapters 3 are the same as before.

  On the other hand, the tooth 2 which concerns on this embodiment has the side wall part 2b which protrudes in the direction between the adapters 3. FIG. Therefore, when the protrusion of the side wall 2b becomes large, the interval between the plurality of teeth 2 attached to the adapter 3 is narrowed. Since the distance between the teeth 2 has a minimum dimension required for the replacement operation of the tooth 2, a corresponding maximum dimension is derived for the dimension D. In the present embodiment, the maximum value of the width ratio D / C is set to 1.92 from the maximum dimension of the dimension D.

  FIG. 5 shows the relationship between the hole ratio A / B and the width ratio D / C and the cross-sectional areas of the bush and the tooth rear part in the tooth 2 used for the hydraulic excavator having a certain vehicle body weight. In FIG. 5A, the horizontal axis represents the hole ratio A / B, and the vertical axis represents the cross-sectional area. In FIG. 5A, the solid line graph shows the bush cross-sectional area, and the broken line graph shows the tooth rear part cross-sectional area. In FIG. 5B, the horizontal axis indicates the width ratio D / C, and the others indicate the same items as in FIG.

  Here, the dimensions and geometric shapes of the adapter 3 of the bucket are the same as the conventional one including the through hole 3a. In other words, the dimension / geometric shape of the cavity portion V1 of the tooth 2 is the same as the conventional one.

  As described above, the tooth hole ratio A / B is set to 0.61 or more and 0.73 or less. In the graph of FIG. 5A, A / B is 0.73, and the cross-sectional areas of the rear portions of the bushes 14 a and 14 b and the tooth 2 are equal. That is, A / B is 0.73, and the breaking strengths of the bushes 14a and 14b and the rear part of the tooth 2 corresponding thereto are balanced. However, since the breaking strength of the bushes 14a and 14b is preferably smaller than the breaking strength of the rear portion of the tooth 2, the tooth hole ratio A / B is set to be in the range of 0.61 to 0.67. It is desirable that

  As described above, the tooth width ratio D / C is set to 1.62 or more and 1.92 or less. However, the maximum value 1.92 of the tooth width ratio D / C is a value for securing only the minimum interval between the teeth 2 that is indispensable for the replacement work of the tooth 2, so that the replacement work can be easily performed. The maximum value is preferably 1.82 or less, which is smaller than the above-mentioned 1.92.

  Further, the minimum value 1.62 of the tooth width ratio is a minimum value for the head of the bolt 12a to be accommodated in the through hole 2a of the tooth 2, but is 1.66 which is a larger value for safety. Preferably there is.

In summary, the tooth hole ratio A / B is more preferably 0.61 to 0.67, and the tooth width ratio D / C is more preferably 1.66 to 1.82. That is, it is more preferable that the tooth 2 satisfies the following relational expression.
0.61 ≦ A / B ≦ 0.67
1.66 ≦ D / C ≦ 1.82

[Other Embodiments]
In the said embodiment, the through-hole 2a of the tooth 2 gave and demonstrated the example by which the cross section was made into the columnar hole of a circle | round | yen. However, the present invention is not limited to this.

For example, the cross-section of the through hole 2a may be an irregular shape that is not a circle, for example, an elliptical shape.
Moreover, shapes other than the through-hole 2a are the same as the above-mentioned embodiment. The in-hole dimension A in the relational expression means the inner dimension of the through-hole 2a in the vertical direction including the center of the through-hole 3a of the adapter 3 corresponding to the attachment in the side view of the tooth. Relational expressions B, C, and D are synonymous with the above-described embodiment, and the relational expressions are the same.

(Summary)
As described above, the tooth 2 has a tooth hole ratio A / B, which is a ratio of the inside dimension of the through hole in the tooth height direction and the inside dimension of the cavity, with the center axis L at the time of tooth attachment, and the tooth outside dimension in the tooth width direction. The range of the tooth width ratio D / C, which is the ratio of the inner dimensions, preferably satisfies the following relational expression.
0.61 ≦ A / B ≦ 0.73
1.62 ≦ D / C ≦ 1.92

Further, the tooth 2 satisfying the following relational expression is a tooth 2 attached to the adapter 3 by inserting bushes 14a and 14b loaded with attachment pins 11 into through holes 2a provided on the side surface of the tooth 2. It is more preferable.
0.61 ≦ A / B ≦ 0.67
1.66 ≦ D / C ≦ 1.82

  As a result, the tooth 2 is designed so that the tooth hole ratio A / B and the tooth width ratio D / C are within the above ranges, so that the fracture strength of the tooth 2 and the bushes 14a and 14b is sufficiently secured. A good tooth 2 can be obtained. Moreover, the tooth shape can be optimized by designing the tooth 2 so as to be within the above range.

  The bucket tooth of the present invention has the effect of ensuring the bushing and the breaking strength of the bucket tooth in a well-balanced manner, and thus can be widely applied to the bucket tooth mounted in a replaceable state on the bucket of a construction machine. It is.

1 bucket (work machine)
2 tooth (bucket tooth)
2a Through hole (through hole)
2b Side wall portion 2c Contact surface 3 Adapter 3a Through hole 3b Insertion portion 3ba Side wall portion 3bb Contact surface 4 Mounting pin assembly 11 Mounting pin (pin)
11a, 11b Female screws 12a, 12b Bolts 13a, 13b Washers 14a, 14b Bush 21 Upper surface 22 Lower surface 23 Side surface 24 Rear end opening V1 Cavity

Claims (2)

A bucket tooth of a construction machine to be attached to the tip of the bucket,
The top surface;
A lower surface connected at the upper surface and the tip, and
A pair of side surfaces formed on the side including the tip so as to connect the upper surface and the lower surface;
A rear end opening formed on the rear surface of the upper surface, the lower surface, and the pair of side surfaces, into which the front end of the bucket is inserted;
Convex side wall portions provided at positions closer to the rear of the pair of side surfaces;
A cavity provided in the bucket tooth from the rear end opening;
A through hole formed in the side wall portion and penetrating to the cavity portion, and a pin and a bush for fixing are inserted;
With
The inside dimension of the through hole is A, the inside dimension in the vertical direction of the cavity part in the vertical direction including the center of the through hole in a side view is B, and the width part of the cavity part in the width direction including the through hole in a top view. When the inner dimension is C, and the maximum width dimension of the pair of side wall portions at the position including the through hole in a top view is D, the A, B, C, and D satisfy the following relational expression.
Construction machine bucket tooth.
0.61 ≦ A / B ≦ 0.73
1.62 ≦ D / C ≦ 1.92 The A / B and the D / C satisfy the following relational expression:
The bucket tooth of the construction machine according to claim 1.
0.61 ≦ A / B ≦ 0.67
1.66 ≦ D / C ≦ 1.82

Images