Portable cutting machine

Abstract

To provide a portable cutter capable of preventing a belt from slipping with a pulley of a belt while maintaining preferable assemblability and maintainability.SOLUTION: According to an aspect of the present invention, provided is a portable cutter. This portable cutter includes: a cutting part including a disc-shaped cutting blade that rotates to cut an object to be cut and a first rotation shaft serving as a rotation center of the cutting blade; a drive part including a drive source and a second rotation shaft that rotates by driving of the drive source; a transmission part including a first pulley fixed to the first rotation shaft, a second pulley fixed to the second rotation shaft, and a belt extending across the first pulley and the second pulley, the transmission part being configured to transmit a rotation force by the drive part to the cutting part; and a case including a storage space storing the transmission part, and at least one communication part communicating with the storage space and opened to the outside. The storage space is configured to allow entering of liquid and liquid that has entered the storage space is discharged to the outside via the communication part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a portable cutting machine.

Background Art

[0002] Conventionally, when using a portable cutting machine to cut, for example, concrete or asphalt, water may be sprayed onto the cutting blade for the purpose of preventing the scattering of generated dust. In this case, if the sealing performance is low, water may accumulate in the belt chamber, and the belt may slip relative to the pulley, resulting in a case where cutting cannot be performed. Therefore, in Patent Document 1, a structure for enhancing the sealing performance of the belt chamber and preventing the intrusion of water has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, enhancing the sealing performance of the belt chamber reduces the assemblability and maintainability of the portable cutting machine, and as a result, there is a problem of cost increase. Therefore, in view of the above circumstances, the present invention aims to provide a portable cutting machine that can prevent the belt from slipping relative to the pulley while maintaining good assemblability and maintainability.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a portable cutting machine is provided. The portable cutting machine includes a cutting unit having a disk-shaped cutting blade that cuts an object to be cut by rotating and a first rotating shaft that serves as the rotation center of the cutting blade, a drive source, a drive unit having a second rotating shaft that rotates by the drive of the drive source, a first pulley fixed to the first rotating shaft, a second pulley fixed to the second rotating shaft, and a belt wound around the first pulley and the second pulley, a transmission unit that transmits the rotational force from the drive unit to the cutting unit, a storage space that houses the transmission unit, and a case having at least one communication portion that communicates with the storage space and is open to the outside. The storage space is configured to allow the intrusion of liquid and to discharge the liquid that has intruded into the storage space to the outside through the communication portion.

[0006] According to such an aspect, it is possible to provide a portable cutting machine that can prevent or suppress the storage of liquid in the belt chamber (the storage space of the transmission unit) without reducing the assemblability and maintainability.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various characteristic matters shown in the following embodiments can be combined with each other.

[0009] Incidentally, the program for realizing the software that appears in this embodiment may be provided as a non-transitory computer-readable medium readable by a computer, may be provided so as to be downloadable from an external server, or may be provided such that the program is started on an external computer to realize its functions on a client terminal (so-called cloud computing).

[0010] Also, in this embodiment, the “section” may include, for example, a combination of hardware resources implemented by a circuit in a broad sense and information processing of software that can be specifically realized by these hardware resources. Further, in this embodiment, various types of information are handled, and these types of information are represented, for example, by physical values of signal values representing voltage and current, the high and low of signal values as a set of binary bits composed of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculation can be executed on a circuit in a broad sense.

[0011] Also, a circuit in a broad sense is a circuit realized by appropriately combining at least a circuit, circuitry, a processor, a memory, etc. That is, it includes an application specific integrated circuit (ASIC), programmable logic devices (for example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc.

[0012] FIG. 1 is a perspective view of the portable cutting machine as seen from the right side. FIG. 2 is a perspective view of the portable cutting machine as seen from the left side. FIG. 3 is a side view showing the state where the belt cover is removed (shown with a slight inclination). FIG. 4 is a cross-sectional view of the case ((a) partial cross-sectional view, (b) enlarged cross-sectional view). FIG. 5 is a cross-sectional view showing an enlarged area near the second pulley. FIG. 6 is a side view showing another configuration of the communication part. Note that hereinafter, as shown in each figure, the front-back direction and the left-right direction will be defined and described. The portable cutting machine of the present invention is a device having a cutting blade, and this cutting blade cuts an object to be cut such as concrete or asphalt.

[0013] The portable cutting machine 1 shown in FIG. 1 etc. includes a cutting machine main body 10, a front handle 20, and a rear handle 30. The front handle 20 extends in the left-right direction and is located above the front side of the cutting machine main body 10. It has a gripping bar 20a, a first support bar 20b that extends obliquely downward from the right end of the gripping bar 20a to the lower part of the cutting machine main body 10, and a second support bar 20c that extends obliquely downward from the left end of the gripping bar 20a to the lower part of the cutting machine main body 10. An operator can lift the cutting machine main body 10 by gripping the gripping bar 20a.

[0014] The rear handle 30 has a U shape and is fixed to the rear side of the cutting machine main body 10 at both ends. A throttle lever 30a for adjusting the rotational speed of the cutting blade is provided on this rear handle 30. The cutting machine main body 10 includes a cutting part 2, a motor (driving part) 3, a transmission part 4, and a case 5. As shown in FIGS. 1 and 2, the cutting part 2 has a disk-shaped cutting blade 21 that cuts an object to be cut by rotating, and a first rotating shaft 22 that is the center of rotation of this cutting blade 21. The cutting blade 21 can cut an object to be cut that comes into contact with it by rotating around the first rotating shaft 22.

[0015] As shown in FIGS. 4 and 5, the motor 3 has a drive source 31 including a magnet and a coil, and a second rotating shaft 32 that rotates by driving of the drive source 31. By adjusting the degree of gripping of the throttle lever 30a, the rotational speed of the motor 3 (second rotating shaft 32) can be controlled. As shown in FIG. 3, the transmission part 4 has a first pulley 41 fixed to the first rotating shaft 22, a second pulley 42 fixed to the second rotating shaft 32, and a belt 43 wound around the first pulley 41 and the second pulley 42. This transmission part 4 rotates the belt 43 via the second pulley 42 by the rotation of the motor 3 (second rotating shaft 32). By the rotation of this belt 43, the first pulley 41 is rotated, and the cutting blade 21 is rotated via the first rotating shaft 22. That is, the transmission part 4 transmits the rotational force by the motor 3 to the cutting blade 21 (cutting part 2).

[0016] The motor 3 and the transmission part 4 are housed in the case 5. This case 5 has a housing 51 and a belt cover (first cover) 52 detachably attached to the housing 51. The housing 51 houses the motor (drive part) 3. The belt cover 52 is attached to the housing 51 so as to cover the transmission part 4, and a belt chamber (accommodation space) 520 is formed between the belt cover 52 and the housing 51. The transmission part 4 is housed in this belt chamber 520.

[0017] Here, when cutting an object to be cut such as concrete or asphalt with the portable cutting machine 1, in order to reduce the generation of dust, the cutting operation is performed while supplying water (liquid) to the cutting blade 21. In the present embodiment, the housing 51 and the belt cover 52 are in direct contact. In other words, no sealing member (such as a liquid seal) is arranged between the housing 51 and the belt cover 52. In addition, the belt cover 52 is fixed to the housing 51 by a plurality (three in this embodiment) of fixing bolts (fixing portions) 53. Note that the number of the fixing bolts 53 may be other than three, preferably five or less, and more preferably three or less.

[0018] According to such a configuration, water intrusion into the belt chamber 520 is allowed. That is, the sealing property (liquid tightness) of the belt chamber 520 is low. In this case, although there is a concern that water accumulates in the belt chamber 520 and the belt 43 slips with respect to the second pulley 42, on the other hand, there is an advantage that the assemblability and maintainability of the portable cutting machine 1 can be improved. Therefore, in the present invention, in order to eliminate the above-mentioned concerns, a communication portion 54 that communicates with the belt chamber 520 and opens to the outside of the portable cutting machine 1 (belt chamber 520) is provided. Water that has entered the belt chamber 520 through the communication portion 54 can be discharged to the outside of the portable cutting machine 1. Thereby, while maintaining good assemblability and maintainability of the portable cutting machine 1, it is possible to prevent the belt 43 from idling (slipping) and making it difficult to cut an object to be cut.

[0019] In particular, the communication portion 54 is configured such that water that has entered the belt chamber 520 is discharged in the upright state of the portable cutting machine 1. Here, the "upright state of the portable cutting machine 1" refers to a state in which the front handle 20 is upward and the cutting machine main body 10 is placed on the ground or a mounting table. Therefore, the communication portion 54 is preferably provided below the case 5. In this embodiment, the communication portion 54 is located below the belt 43 in the upright state of the portable cutting machine 1. Thereby, as shown by the arrow in FIG. 3, water that has entered the belt chamber 520 can be smoothly discharged to the outside of the portable cutting machine 1.

[0020] In addition, in the present embodiment, in the upright state of the portable cutting machine 1, the second pulley 42 is configured to be located below the first pulley 41. That is, the belt cover 52 (belt chamber 520) is inclined so as to be located downward on the rear side from the front side in the upright state of the portable cutting machine 1. Therefore, the water that has entered the belt chamber 520 tends to collect and accumulate on the second pulley 42 side. Therefore, in particular, the communication portion 54 is provided so as to be located below the second pulley 42 in the upright state of the portable cutting machine 1. With such a configuration, the water that has entered the belt chamber 520 can be smoothly collected toward the communication portion 54 and discharged to the outside of the portable cutting machine 1.

[0021] Specifically, the communication portion 54 is configured by a groove recessed from the outer surface of the housing 51 to the side opposite to the belt chamber 520. According to such a configuration, the communication portion 54 can be formed relatively simply without reducing the mechanical strength of the case 5. As shown in FIG. 4(b), this groove includes a first bottom surface 541 extending along the vertical direction in the upright state of the portable cutting machine 1, and a second bottom surface 542 that is continuous with the first bottom surface 541 and slopes downward from the inside to the outside of the portable cutting machine 1. Thereby, the water that has entered the belt chamber 520 is more likely to move smoothly along the second bottom surface 542 (inclined surface) as indicated by the two-dot chain line arrow in FIG. 4(b).

[0022] In addition, as shown in FIG. 4(b), the belt cover 52 has a lower side wall 521 located downward in the upright state of the portable cutting machine 1. And this lower side wall 521 is provided with an inner surface 521a that slopes downward from the outside to the inside of the portable cutting machine 1. Thereby, the water that has entered the belt chamber 520 can be moved and collected toward the communication portion 54. Note that both the inner surface 521a and the outer surface 521b of the lower side wall 521 slope downward from the outside to the inside of the portable cutting machine 1, but only the inner surface 521a may slope. The opening area of the communication part 54 (the area of the region 543 defined by the first bottom surface 541 and the side surface that define the communication part 54 and the left end surface of the lower side wall 521) is preferably set to a size that allows water that has entered the belt chamber 520 to pass through, but blocks the passage of water containing dust generated from the object to be cut.

[0023] As shown in FIG. 5, the second pulley 42 has an annular recess 421 formed along the circumferential direction around the second rotation shaft 32. And the housing 51 has an annular convex part 511 that is inserted into the recess 421 in a spaced-apart state. With such a configuration, the length of the gap formed between the second pulley 42 and the housing 51 can be increased. Therefore, it is possible to suitably prevent water (or water containing dust) that has entered the belt chamber 520 from entering the motor 3 side and causing the motor 3 to malfunction. Also, in the present embodiment, the separation distance between the recess 421 and the convex part 511 is larger on the inner side (W2 in the figure) than on the outer side (W1 in the figure) in the radial direction. In this case, even if water enters between the recess 421 and the convex part 511, the space becomes larger on the inner side than on the outer side in the radial direction, so the capillary phenomenon is inhibited and further movement inward is restricted (limited).

[0024] From the viewpoint of preventing water from entering between the recess 421 and the convex part 511, for example, a liquid repellent treatment may be applied to the inner surface of the recess 421 and / or the outer surface of the convex part 511. Such a portable cutting machine 1 further includes a protective cover (second cover) 6 provided so as to cover a part of the cutting blade 21. As shown in FIGS. 1 and 2, the protective cover 6 has a semi-circular first side wall part 6a and a second side wall part 6b located on both sides of the cutting blade 21, and a curved third side wall part 6c that connects the first side wall part 6a and the second side wall part 6b at the rear side.

[0025] The portion surrounded by the first side wall portion 6a, the second side wall portion 6b, and the third side wall portion 6c forms a storage recess that opens to the front side of the portable cutting machine 1, and this storage recess is configured to store approximately the rear half of the cutting blade 21. That is, the protective cover 6 is configured to cover approximately the rear half of the cutting blade 21. By providing such a protective cover 6, the opportunity for the operator to directly contact the cutting blade 21 can be more reliably reduced. Also, the scattering of the water supplied to the cutting blade 21 to unnecessary locations can be reduced.

[0026] Also, the water supplied when cutting the object to be cut may be supplied from a water supply mechanism (liquid supply mechanism) provided separately from the portable cutting machine 1, but the portable cutting machine 1 of the present embodiment includes a water supply mechanism (liquid supply mechanism) 7 for supplying water (liquid) to the cutting blade 21. By the portable cutting machine 1 including such a water supply mechanism 7, it becomes possible for one operator to cut the object to be cut while preventing the scattering of dust. Specifically, the water supply mechanism 7 has a connection portion 71 connectable to an external water supply source, a water supply port 72 provided in the first side wall portion 6a of the protective cover 6, and a connection tube 73 connecting the connection portion 71 and the water supply port 72. A valve 711 for adjusting the water supply amount is provided in the middle of the connection portion 71.

[0027] The portable cutting machine 1 also includes a baffle plate 8 provided at the lower front of the case 5. This baffle plate 8 has a protruding portion 81 that protrudes from the lower part of the case 5 toward the lower part of the protective cover 6 in the upright state of the portable cutting machine 1. The baffle plate 8 has a function of preventing water from reaching the case 5 when cutting the object to be cut. Thereby, it is possible to more preferably prevent water from entering the belt chamber 520. On the upper part of the case 5, a power switch portion (not shown) for turning on and off the power supply to the portable cutting machine 1, a condition setting portion (not shown) for setting the operating conditions of the portable cutting machine 1, etc. are provided. Also, inside the case 5, a control board (not shown) for controlling the operation of the motor 3 is built in. An arithmetic element and a storage element are mounted on this control board.

[0028] The arithmetic element is composed of, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), etc. By reading a predetermined program stored in the storage element, the arithmetic element realizes various functions related to the portable cutting machine 1. That is, the information processing by software stored in the storage element is specifically realized by the arithmetic element. Note that the arithmetic element is not limited to being single, and a plurality of arithmetic elements may be provided for each function. Or, a combination thereof may be used.

[0029] The storage element stores various information defined by the above description. This can be implemented as a storage device such as a solid state drive (SSD) that stores various programs related to the portable cutting machine 1 executed by the arithmetic element, or as a memory such as a random access memory (RAM) that stores temporarily necessary information (arguments, arrays, etc.) related to the operation of the program. Also, the storage element stores various programs, variables, etc. related to the portable cutting machine 1 executed by the arithmetic element.

[0030] In such a portable cutting machine 1, an operator holds the handle bar 20a with one hand to lift the cutting machine body 10, position the cutting blade 21 downward, hold the rear handle 30 with the other hand, and operate the throttle lever 30a. Then, while controlling the rotational speed of the cutting blade 21 and pressing it against the object to be cut, the object to be cut can be cut.

[0031] According to the portable cutting machine 1, while allowing water to enter the belt chamber 520, the water that has entered the belt chamber 520 can be discharged to the outside of the portable cutting machine 1 through the communication part 54. Therefore, it is possible to prevent the assemblability and maintainability of the portable cutting machine 1 from deteriorating, and to prevent the cutting of the object to be cut from becoming difficult due to the belt 43 idling (slipping).

[0032] In the portable cutting machine 1, although the configuration in which one communication part 54 is provided in the case 5 is shown, as shown in FIG. 6, two (a plurality of) communication parts 54 may be provided in the case 5. Further, the communication part 54 may be provided so as to penetrate the belt cover 52, and the arrangement position is not limited to the location shown in the figure.

[0033] Furthermore, it may be provided in each of the aspects described below. In the portable cutting machine, the communication part is configured such that the liquid that has entered the storage space is discharged in a vertically upright state of the portable cutting machine. Portable cutting machine. In the portable cutting machine, the communication part is located below the belt in a vertically upright state of the portable cutting machine. Portable cutting machine. In the portable cutting machine, the case has a plurality of the communication parts. Portable cutting machine. In the portable cutting machine, in a vertically upright state of the portable cutting machine, the second pulley is located below the first pulley. Portable cutting machine. In the portable cutting machine, the communication part is located below the second pulley in a vertically upright state of the portable cutting machine. Portable cutting machine. In the portable cutting machine, the case has a housing that houses the drive part and a first cover that forms the storage space between the housing and the communication part. The communication part has a groove formed by being recessed from the outer surface of the housing to the side opposite to the storage space. Portable cutting machine. In the portable cutting machine, the groove includes a first bottom surface extending along the vertical direction in the upright state of the portable cutting machine, and a second bottom surface continuous with the first bottom surface and inclined downward from the inside to the outside of the portable cutting machine. Portable cutting machine. In the portable cutting machine, the first cover has a lower side wall located below in the upright state of the portable cutting machine, and the lower side wall has an inner surface inclined downward from the outside to the inside of the portable cutting machine. Portable cutting machine. In the portable cutting machine, the housing and the first cover are in direct contact. Portable cutting machine. In the portable cutting machine, the case further has a plurality of fixing parts for fixing the first cover to the housing, and the number of installed fixing parts is five or less. Portable cutting machine. In the portable cutting machine, the second pulley has an annular recess formed along the circumferential direction around the second rotating shaft, and the housing has an annular protrusion inserted in a spaced state in the recess. Portable cutting machine. In the portable cutting machine, the separation distance between the recess and the protrusion is larger on the inner side than on the outer side in the radial direction. Portable cutting machine. In the portable cutting machine, the drive unit is a motor. Portable cutting machine. In the portable cutting machine, it further includes a liquid supply mechanism for supplying the liquid to the cutting blade. Portable cutting machine. In the portable cutting machine, it further includes a second cover provided to cover a part of the cutting blade, and in the upright state of the portable cutting machine, a part protruding from the lower part of the case toward the lower part of the second cover, and a baffle plate for preventing the liquid from reaching the case. Portable cutting machine. Of course, this is not the limit.

[0034] As described above, various embodiments of the present invention have been explained. However, these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. Such embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

[0035] For example, when the object to be cut (workpiece) by the portable cutting machine 1 is a metal product such as a metal paver, the liquid supplied to the cutting blade 21 may be oil or the like. In this case, the friction generated during cutting of the metal product can be reduced, and heat generation can be suppressed. Also, the drive unit may be configured by an engine.

Explanation of Reference Numerals

[0036] 1: Portable cutting machine 10: Cutting machine main body 20: Front handle 20a: Grip bar 20b: First support bar 20c: Second support bar 30: Rear handle 30a: Throttle lever 2: Cutting part 21: Cutting blade 22: First rotating shaft 3: Motor 31: Drive source 32: Second rotating shaft 4: Transmission part 41: First pulley 42: Second pulley 421: Concave part 43: Belt 5: Case 51: Housing 511: Convex part 52: Belt cover 520: Belt chamber 521: Lower side wall 521a: Inner surface 521b: Outer surface 53: Fixing bolt 54: Communication part 541: First bottom surface 542: Second bottom surface 543: Region 6: Protection cover 6a: First side wall part 6b: Second side wall part 6c: Third side wall part 7: Water supply mechanism 71: Connection part 711: Valve 72: Water supply port 73: Connection tube 8: Baffle plate 81: Part W1: Width W2: Width

Claims

1. A portable cutting machine, comprising a disc-shaped cutting blade that cuts an object to be cut by rotating, and a cutting unit having a first rotating shaft that is the center of rotation of the cutting blade; a drive source, and a drive unit having a second rotating shaft that rotates by driving of the drive source; a first pulley fixed to the first rotating shaft, a second pulley fixed to the second rotating shaft, and a belt wound around the first pulley and the second pulley, and a transmission unit that transmits the rotational force from the drive unit to the cutting unit; a case having a storage space for housing the transmission unit, and at least one communication part that communicates with the storage space and opens to the outside; the storage space is configured to allow intrusion of liquid, and the liquid that has intruded into the storage space is discharged to the outside through the communication part; the case has a housing that houses the drive unit and a first cover that forms the storage space between the housing and the communication part is configured by a groove recessed from the outer surface of the housing to the side opposite to the storage space, a portable cutting machine.

2. In the portable cutting machine according to Claim 1, the communication part is configured such that the liquid that has intruded into the storage space is discharged in an upright state of the portable cutting machine, a portable cutting machine.

3. In the portable cutting machine according to Claim 1 or Claim 2, the communication part is located below the belt in an upright state of the portable cutting machine, a portable cutting machine.

4. In the portable cutting machine according to any one of Claims 1 to 3, the case has a plurality of the communication parts, a portable cutting machine.

5. In the portable cutting machine according to any one of Claims 1 to 4, in an upright state of the portable cutting machine, the second pulley is located below the first pulley, a portable cutting machine.

6. In the portable cutting machine according to Claim 5, the communication part is located below the second pulley in an upright state of the portable cutting machine, a portable cutting machine.

7. In the portable cutting machine according to any one of Claims 1 to 6, the groove includes a first bottom surface that extends along the vertical direction in an upright state of the portable cutting machine, and a second bottom surface that is continuous with the first bottom surface and slopes downward from the inside to the outside of the portable cutting machine, a portable cutting machine.

8. In the portable cutting machine according to any one of Claims 1 to 7, the first cover has a lower wall that is positioned downward in the upright state of the portable cutting machine, the lower wall has an inner surface that slopes downward from the outside to the inside of the portable cutting machine. A portable cutting machine.

9. In the portable cutting machine according to any one of Claims 1 to 8, the housing and the first cover are in direct contact. A portable cutting machine.

10. In the portable cutting machine according to any one of Claims 1 to 9, the case further has a plurality of fixing parts for fixing the first cover to the housing, the number of the installed fixing parts is five or less. A portable cutting machine.

11. In the portable cutting machine according to any one of Claims 1 to 10, the second pulley has an annular recess formed along the circumferential direction around the second rotating shaft, the housing has an annular convex part that is inserted into the recess in a spaced-apart state. A portable cutting machine.

12. In the portable cutting machine according to Claim 11, the separation distance between the recess and the convex part is larger on the inner side than on the outer side in the radial direction. A portable cutting machine.

13. In the portable cutting machine according to any one of Claims 1 to 12, the drive part is a motor. A portable cutting machine.

14. In the portable cutting machine according to any one of Claims 1 to 13, furthermore, it is provided with a liquid supply mechanism for supplying the liquid to the cutting blade. A portable cutting machine.

15. In the portable cutting machine according to any one of Claims 1 to 14, furthermore, a second cover provided so as to cover a part of the cutting blade, in the upright state of the portable cutting machine, it has a part that protrudes from the lower part of the case toward the lower part of the second cover, and a baffle plate that prevents the liquid from reaching the case. A portable cutting machine.

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