JP2014193509A - Power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power tool capable of quickly heating lubricant as compared with a conventional power tool.SOLUTION: A heat transfer portion 16 facing a crankcase 14 in an oil tank 4 is formed of a material such as metal having higher heat conductivity than that of other portions formed of resin including an outer wall portion 19 facing an outside of a chainsaw main body. The heat transfer portion 16 is thinner than the resin portions including the outer wall portion 19. The heat transfer portion 16 is formed, for example, integrally with the other resin portions including the outer wall portion 19 (that is, formed integrally with a casing 15) or welded to each other. If an engine 18 starts operating, then heat generated in a cylinder 13 is transferred to the crankcase 14, the heat transfer portion 16 receives heat of the heated crankcase 14, and chain oil 11 in the oil tank 4 is heated to decrease viscosity.

Description

  The present invention relates to a power tool such as a chain saw provided with an oil tank for containing lubricating oil.

  When a chain saw is used in winter, it is often used in a state where the viscosity of the chain oil is high due to low temperature. When the chain oil is used in a high viscosity state, the pipe resistance in the pipe through which the chain oil passes is large, and the discharge amount of the chain oil tends to be lower than the normal amount. Normally, during use, heat from the engine is gradually transmitted and the chain oil warms up, reducing the viscosity of the chain oil and improving the amount of chain oil discharged. However, it is not preferable that it takes a long time to reach a normal discharge amount. Therefore, a technique is known in which a discharge amount adjusting mechanism is provided in the oil pump and the discharge amount is increased when the discharge amount is lowered.

JP 2012-159026 A

The viscosity of the chain oil changes greatly with changes in temperature, and when the outside air temperature falls below 0 ° C., the viscosity becomes very high. For example, as shown in FIG. 7, as an example of the kinematic viscosity of a general chain oil, it is about 334 mm ² / s at 20 ° C., about 16800 mm ² / s at −20 ° C., and has a difference of about 50 times depending on the temperature. . For this reason, when used in a cold region, it may be difficult to ensure a normal discharge amount even if the discharge amount is adjusted to the maximum by the discharge amount adjusting mechanism. Such a problem is not limited to chain oil in a chain saw, but is common to lubricating oil in other power tools.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a power tool capable of warming the lubricating oil at an early stage as compared with the prior art.

  An aspect of the present invention is a power tool, and includes a high-temperature portion that becomes high temperature during use, an oil tank that contains lubricating oil, and a heat transfer means that transmits heat of the high-temperature portion to the lubricating oil in the oil tank. Prepare. Here, the heat transfer means is a member such as an engine, a motor, a power source / battery unit, etc., whose temperature is higher than that of other parts during use, a means for increasing the temperature of a heater, and an oil tank. This is a region between the heat transfer member and represents the entire configuration intentionally provided for transferring heat, such as a member such as a heat transfer portion, which will be described later, or a high temperature portion and a heat transfer member. It is a superordinate concept that includes a space where heat is transferred between and.

  The heat transfer means may include a heat transfer part that is a part of the oil tank and that conducts heat more easily than other parts of the oil tank.

  The heat transfer part may be present at a position facing the high temperature part side.

  The heat transfer part may be thinner than the other part of the oil tank.

  The heat transfer part may be made of a material having a higher thermal conductivity than the other part of the oil tank.

  The heat transfer part may be integrally molded with the other part of the oil tank or welded to each other.

  Irregularities may be provided on one side or both sides of the heat transfer unit.

  The heat transfer part may be in contact with the high temperature part.

  The power tool may be a chain saw, and the lubricating oil may be a chain oil.

  The high temperature part may be at least a part of the engine.

  A casing for holding the engine may be provided, and the oil tank may be provided inside the casing.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the power tool which can warm lubricating oil early compared with the past can be provided.

The right view which made the cross section a part of the chain saw which concerns on Embodiment 1 of this invention. The left view which made the cross section a part of the chain saw shown in FIG. The left view which made the cross section a part of the chain saw which concerns on Embodiment 2 of this invention. The left view which made the cross section a part of the chain saw which concerns on Embodiment 3 of this invention. The left view which made the cross section a part of the chain saw which concerns on Embodiment 4 of this invention. The left view which made the cross section a part of the chain saw which concerns on Embodiment 5 of this invention. Temperature characteristic diagram of kinematic viscosity of a chain oil.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

Embodiment 1 FIG. 1 is a right side view, partly in section, of a chain saw according to Embodiment 1 of the present invention. FIG. 2 is a left side view, partly in section, of the chain saw shown in FIG. As shown in these drawings, the main body 1 of the chain saw includes an engine 18 as a prime mover and its accessory parts, and a casing 15 for housing them. A chain bar 2 and a saw chain 3 for cutting a material to be cut such as wood are provided in front of the main body 1. A handle portion 22 (rear handle) is provided above the main body 1 so as to extend forward and backward, and a throttle lever 23 is provided on the handle portion 22. Note that the front handle is not shown in FIGS. 1 and 2. An oil pump 8 that is actuated by the rotational movement of the drive shaft 6 and the worm gear 7 of the engine 18 is disposed on the right side surface of the main body 1. A suction pipe 9 is connected between the oil pump 8 and the oil tank 4, and a discharge pipe 10 is connected between the oil pump 8 and the discharge port 12.

  The engine 18 (engine body) including the cylinder 13 and the crankcase 14 is an example of a high temperature part, and is held by a casing 15 formed of, for example, resin. An oil tank 4 and a fuel tank 5 are provided (comparted) in the casing 15. The oil tank 4 contains chain oil 11 and the fuel tank 5 contains fuel 21. The heat transfer portion 16 facing the crankcase 14 side of the oil tank 4 is an example of heat transfer means, and includes, for example, other portions made of resin including an outer wall portion 19 that faces the outside of the chain saw body (contacts outside air). In comparison, it is made of a material having a high thermal conductivity, preferably a material such as a metal. For example, aluminum or copper is suitable for the heat transfer section 16. Alternatively, the heat transfer section 16 is thinner than other portions including the outer wall section 19. The heat transfer part 16 is molded integrally with other parts including the outer wall part 19 (that is, molded integrally with the casing 15) or welded to each other. The heat transfer section 16 is exemplified by a plate shape that is curved so as to be substantially parallel to the crankcase 14 that faces the heat transfer portion 16, but may have another shape such as a flat plate shape.

  The operation of this embodiment will be described. When the engine 18 is operated, the saw chain 3 is guided and driven by the chain bar 2 by the power of the engine 18. Further, the chain oil 11 is led from the oil tank 4 to the oil pump 8 through the suction pipe 9, and further led from the oil pump 8 to the discharge port 12 through the discharge pipe 10, and is attached near the discharge port 12. Chain oil 11 is supplied to the chain bar 2 and the saw chain 3. When the engine 18 is operated, the heat generated in the cylinder 13 is transmitted to the crankcase 14, the heat transfer section 16 receives the heat of the crankcase 14, the chain oil 11 in the oil tank 4 is warmed, and the viscosity is lowered.

  According to the present embodiment, the following effects can be achieved.

  Since the heat transfer part 16 facing the crankcase 14 side (high temperature part side) of the oil tank 4 is made of a material having higher thermal conductivity than other resin parts including the outer wall part 19, the heat transfer part 16 is the other. The heat from the crankcase 14 can be efficiently transmitted to the chain oil 11 in the oil tank 4 as compared with the case where the same material (made of resin) is used. For this reason, even when the chain saw is used in a cold region, if the engine 18 is operated, the chain oil 11 can be warmed early and the viscosity can be reduced. Here, if the structure including the outer wall portion 19 including the outer wall portion 19 has a high thermal conductivity, for example, a material such as a metal, the heat is increased from the chain oil 11 through the outer wall portion 19 in addition to an increase in cost and weight. There is a problem that it becomes easy to escape and the speed at which the chain oil 11 warms is slowed down. In this respect, in the present embodiment, the heat transfer part 16 facing the high temperature part side is made of a material having high thermal conductivity such as metal, while the outer wall part 19 is made of resin (a material having low heat conductivity, light weight and low cost). By doing, cost increase and weight increase can be suppressed, and the heating speed of the chain oil 11 can be suitably increased.

  As described above, even when the chain saw is used in a cold region, the chain oil 11 can be warmed early and the viscosity can be lowered. The burden on the user can be reduced.

Embodiment 2 FIG. 3 is a left side view, partly in section, of a chain saw according to Embodiment 2 of the present invention. This chain saw is different from the first embodiment shown in FIG. 1 and FIG. 2 in that the surface of the heat transfer section 16 is provided with irregularities, and is identical in other points. According to the present embodiment, since the unevenness is provided on the surface of the heat transfer section 16, the heat transfer area (surface area) of the heat transfer section 16 is increased, and the heat from the crankcase 14 is more efficiently transferred to the oil tank. 4 can be transmitted to the chain oil 11 in the cylinder 4. In the example of FIG. 3, unevenness is provided on both surfaces of the heat transfer section 16, but a structure in which unevenness is provided only on one surface may be used, and so-called “fins” may be used as long as the heat transfer area (surface area) is widened. Arbitrary structures such as a mold or feather structure can be used on both sides or one side. In this case, since an effect of increasing the heat transfer efficiency according to the adopted structure is obtained, a structure having a large heat transfer area (surface area) is more preferable.

Embodiment 3 FIG. 4 is a left side view, partly in section, of a chain saw according to Embodiment 3 of the present invention. This chain saw is different from that of the first embodiment shown in FIGS. 1 and 2 in that a connection portion 17 that is thermally connected to the transmission portion 16 is provided in the crankcase 14. Matches in other respects. The connecting portion 17 is a convex portion that rises from the outer peripheral surface of the crankcase 14 toward the heat transfer portion 16 and is preferably fixed in contact with the heat transfer portion 16. According to the present embodiment, the connection portion 17 (for example, the same metal as the crankcase 14) can transfer heat from the crankcase 14 to the heat transfer portion 16 without air (that is, the connection portion that becomes a high temperature portion). 17 is in direct contact with the heat transfer section 16), so that heat from the crankcase 14 can be more efficiently transferred to the chain oil 11 in the oil tank 4. The invention described in the present embodiment illustrates the connection portion 17 as an example of forming a heat transfer path between the heat source such as the crankcase 14 and the transmission portion 16, such as air. As long as a heat transfer path higher than a structure in which heat is transmitted through a simple space is formed, the connecting portion 17 does not need to be physically connected or contacted. Further, as in the second embodiment, irregularities or the like may be provided on the surface of the heat transfer section 16. Further, the connecting portion 17 may be provided on the transmission portion 16 side instead of the structure provided on the crankcase 14, or may be provided on both the crankcase 14 and the transmission portion 16 so that both are in contact with each other. The connection portion 17 may be provided in a heat source other than the crankcase 14 exemplified in the following embodiment.

Embodiment 4 FIG. 5 is a left side view, partly in section, of a chain saw according to Embodiment 4 of the present invention. This embodiment is an exemplification of an embodiment in which the cylinder 13 is used as a heat source. This chain saw has an oil tank 4 as compared with that of the first embodiment shown in FIGS. 1 and 2. The difference is that it is provided behind the casing 15 and in the vicinity of the cylinder 13 of the engine, and the other points coincide. In this case, the heat transfer section 16 faces the cylinder 13 side (high temperature section side). This embodiment can achieve the same effects as those of the first embodiment. In addition, the modification added to Embodiment 1 in Embodiment 2 and 3 is applicable also to this Embodiment. Further, as long as the oil tank 4 can be placed in the vicinity of the cylinder 13, the structure is not limited to the chain saw having the structure exemplified in the present embodiment, and the structures exemplified in the above or below embodiments. It is possible to apply to any structure.

Embodiment 5 FIG. 6 is a left side view, partly in section, of a chain saw according to Embodiment 5 of the present invention. This chain saw has a handle 22 (rear handle) behind the main body 1 and an oil tank 4 provided in the vicinity of the muffler 20 as compared with the first embodiment shown in FIGS. Are different in other points, and are identical in other points. This embodiment is an example of an embodiment in which the muffler 20 is used as a heat source, and the heat transfer section 16 faces the muffler 20 side (high temperature section side). This embodiment can achieve the same effects as those of the first embodiment. In addition, the modification added to Embodiment 1 in Embodiment 2 and 3 is applicable also to this Embodiment. Further, as long as the oil tank 4 can be placed in the vicinity of the muffler 20, the structure is not limited to the chain saw illustrated in the present embodiment, and any structure such as the structure illustrated in each of the above embodiments may be used. It is possible to apply to the structure of

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  The heat transfer portion 16 facing the high temperature portion of the oil tank 4 can adopt an arbitrary structure that has better heat conduction than the other portions of the oil tank 4. For example, a material (resin) having the same thermal conductivity as that of the other resin parts including the outer wall part 19 and a structure in which the heat transfer part 16 is made thinner than the other part, or the outer wall part 19 is heated. A structure that causes a difference in heat transfer between the heat transfer section 16 and the outer wall section 19, such as attaching a cover made of resin or the like having low transferability, is exemplified. Even in this case, the heat from the high temperature portion can be efficiently transferred to the chain oil 11 in the oil tank 4 as compared with the case where the heat transfer portion 16 has the same heat transfer (thickness or the like) as the other portions. For this reason, even when the chain saw is used in a cold region, the chain oil 11 can be warmed early to reduce the viscosity. Here, when the oil tank 4 is made thin as a whole, in addition to a decrease in strength, since the outer wall portion 19 is thin, heat easily escapes from the oil tank 4 to the outside air, and the speed at which the chain oil 11 is warmed is reduced. . In this regard, in the present embodiment, the heat transfer portion 16 facing the high temperature portion side is thinned while the other portions including the outer wall portion 19 are thickened to suppress the strength reduction and the heating speed of the chain oil 11 Can be suitably increased. On the other hand, when the heat transfer section 16 is made of a material having high thermal conductivity, the thickness may be equal to or greater than that of other resin parts including the outer wall section 19. The heat transfer section 16 may extend to a position other than the position facing the high temperature section, but the influence of cooling by the outside air can be ignored, or the influence can be kept at a position and size that is sufficiently small in practice. desirable. More preferably, it should be within the range excluding the portion facing the outside of the chain saw body (in contact with the outside air).

  The power tool is not limited to an engine tool, and may be a structure using another power source such as an electric tool. In other words, the prime mover in the power tool is not limited to the engine, and may be an electric motor or the like. In this case, the high temperature part may be an electric motor, a battery (a lithium battery or a fuel cell), a catalyst part, or the like. Alternatively, instead of a heat source such as an engine, an electric motor, or a battery, or in addition to these high temperature parts, a high temperature part is separately provided in the same position as the above exemplified high temperature part by a heater, that is, in the vicinity of the oil tank 4. It is good also as a structure. The power tool of the present invention is not limited to a chain saw, and the oil to be heated is not limited to chain oil. The present invention is an invention that can be applied to all power tools in which the viscosity of lubricating oil is a problem in cold regions, and the above embodiment is merely an example of the preferred embodiment.

1: main body, 2: chain bar, 3: saw chain, 4: oil tank, 5: fuel tank, 6: drive shaft, 7: worm gear, 8: oil pump, 9: suction pipe, 10: discharge pipe, 11: chain Oil: 12: Discharge port, 13: Cylinder, 14: Crankcase, 15: Casing, 16: Heat transfer part, 17: Connection part, 18: Engine, 19: Outer wall part, 20: Muffler, 21: Fuel

Claims (11)

  A power tool comprising: a high-temperature part that becomes high temperature during use; an oil tank that contains lubricating oil; and a heat transfer means that transfers heat from the high-temperature part to the lubricating oil in the oil tank.   2. The power tool according to claim 1, wherein the heat transfer means includes a heat transfer portion that is a part of the oil tank and that conducts heat more easily than another part of the oil tank.   The power tool according to claim 2, wherein the heat transfer part is present at a position facing the high temperature part side.   The power tool according to claim 3, wherein the heat transfer portion is thinner than the other portion of the oil tank.   The power tool according to claim 3 or 4, wherein the heat transfer part is made of a material having a higher thermal conductivity than the other part of the oil tank.   The power tool according to claim 5, wherein the heat transfer portion is integrally molded with or welded to the other portion of the oil tank.   The power tool according to any one of claims 2 to 6, wherein unevenness is provided on one side or both sides of the heat transfer unit.   The power tool according to any one of claims 2 to 7, wherein the heat transfer section is in contact with the high temperature section.   The power tool according to any one of claims 1 to 8, wherein the power tool is a chain saw and the lubricating oil is a chain oil.   The power tool according to any one of claims 1 to 9, wherein the high temperature part is at least a part of an engine.   The power tool according to claim 10, further comprising a casing that holds the engine, wherein the oil tank is provided inside the casing.

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