JP4690752B2 - Lubrication structure of work equipment - Google Patents

Description

  The present invention relates to a lubrication structure for a working device including a transmission mechanism that converts a rotary motion of a handheld work machine, particularly a hedge trimmer, a mower, a brush cutter, etc. into a reciprocating motion.

  A hand-held work machine, such as a hedge trimmer, includes a transmission mechanism that converts rotational motion into reciprocating motion. Grease is generally used for lubrication of the transmission mechanism, but if the grease supply to the drive parts in the transmission mechanism is insufficient, seizure, wear, etc. occur and the transmission mechanism is damaged. There is a fear. Therefore, it is sufficient to periodically replenish the grease so that the supply of the grease does not become insufficient, but this replenishment work is troublesome for the operator.

  On the other hand, a ball bearing or needle bearing is attached to the rotating part in the transmission mechanism to reduce grease supply, or a recess or notch is provided in the driven gear that transmits power to the transmission mechanism to accept grease. A hand-held work device has been developed that facilitates improvement of lubricity (see Patent Document 1).

  In this hand-held work device described in Patent Document 1, a rotating portion (ring in the literature) is slidably fitted to an eccentric cam (eccentricator in the literature) attached to a side surface of a driven gear (gear in the literature). The rotating portion is provided with a plurality of blades extending therefrom. For this reason, when the driven gear rotates, the eccentric cam rotates in conjunction with the driven gear, and the rotating portion and the blade reciprocate. At this time, since the side surface of the rotating portion is in sliding contact with the side surface of the driven gear, these side surfaces may be seized or worn. Therefore, a seizure or the like is prevented by providing a recess (in the literature, a recess) capable of receiving the lubricating oil on the side surface of the driven gear.

JP-A-10-136784

  In the hand-held work device described in Patent Document 1, even if lubricating oil is received in the recess, the clearance between the housing that accommodates the driven gear and the transmission mechanism and the driven gear and the transmission mechanism is large. Depending on the posture, the lubricating oil received in the recess may flow out, and sufficient lubricating performance may not be exhibited.

  On the other hand, in a hand-held work device equipped with a ball bearing or a needle bearing, there is a problem that the cost increases due to an increase in the number of parts.

  An object of the present invention is to provide a lubrication structure for a work device that suppresses an increase in the cost of a hand-held work device and has good lubricity, and meets the demand.

In order to solve such a problem, the present invention provides a driven gear that rotates by receiving power from a drive source, and a transmission mechanism that transmits power from the driven gear in conjunction with power from the driven gear. A working part that performs a predetermined work by receiving power from the transmission mechanism part, and a gear case that rotatably supports at least the driven gear and the transmission mechanism part and accommodates a lubricant (for example, grease in the embodiment). In the working device (for example, the hedge trimmer 1 in the embodiment), the transmission mechanism portion has a rod rotatably connected between an eccentric cam provided on the driven gear and the working portion. A lubricating structure for a working device, wherein an inner side surface portion of a gear case surrounding a rotating portion (for example, the large rotating portion 27 in the embodiment) that is rotatably connected to an eccentric cam of a rod is provided close to the rotating portion. , Gear case Configure the space within, the space portion and the space portion of the side to be expanded and the space portion of the side to be reduced by the movement of the eccentric cam and the rod is formed, a space portion of said reduced the side the eccentric cam communicating passage that communicates the sliding surface of the rotating portion to be fitted is provided, by using the compression of the lubricant caused by the volume reduction of the space of the reduced by side, the communicating passage The lubricant is supplied to the rotating portion by the following.

  According to the present invention, the rotating portion is rotatably connected to an eccentric cam provided on the driven gear, the inner side surface portion of the gear case is provided at a position close to the rotating portion, and the eccentric cam and the rod are moved. By utilizing the pressure fluctuation of the lubricant, it is possible to give the transmission mechanism a pump function of the lubricant, and lubricate the rotating part without increasing the cost with few design changes without intervention of the bearing. It is possible to improve the performance.

Said communicating passage or, if the volume of the space of the reduced the side are substantially minimized, the sliding surface of the pivot portion fitted into the space between the eccentric cam on the side that is the reduction It is characterized by communicating with.

  According to the present invention, the high pressure lubricant can be supplied to the sliding surface by connecting the space portion and the sliding surface by the communication path in the vicinity where the space portion is substantially minimized. The lubricity of the moving part can be improved.

Further, the present invention is characterized in that a communication path is provided in the rod , the driven gear or the gear case .

  According to the present invention, by providing the communication path in the rod, the sliding surface and the space are always communicated by the communication path, so that the lubricity of the rotating part can be further improved.

  Furthermore, the present invention is characterized in that a concave portion is provided on the sliding surface, and one end side of the communication path is connected to the concave portion to communicate the space portion in the concave portion with the reduced space portion.

  According to the present invention, since the concave portion provided on the sliding surface is connected to one end side of the communication path, the lubricant is directly guided to the concave section, so that the reception of the lubricant becomes more advantageous, and the Coupled with the supply of the lubricant, the lubricity of the rotating part can be further improved.

  According to the present invention, the gear case is provided with a receiving portion for receiving the lubricant, and the receiving portion is arranged without straddling two space portions in the gear case partitioned by the movement of the rod.

According to this invention, by providing the receiving part of the lubricant without straddling the two space parts partitioned by the movement of the rod, the effect of the invention of any one of claims 1 to 6 is not reduced, The amount of lubricant contained in the gear case can be increased, and the lubricity of the rotating part can be further improved.
According to the present invention, the driven gear is rotated by a drive gear that rotates by receiving power from a drive source, and an inner side surface portion of the gear case that surrounds the drive gear is provided close to the drive gear. The inner side surface portion surrounding the driven gear and the inner side surface portion surrounding the driven gear are opened and communicated with each other, and the drive gear and the toothed portion of the driven gear are arranged to mesh with each other at the opened portion.

  According to the lubricating structure of the working device according to the present invention, the rotating part is rotatably connected to an eccentric cam provided on the driven gear, and the inner side surface part of the gear case is provided at a position close to the rotating part, By utilizing the pressure variation of the lubricant due to the movement of the eccentric cam and the rod, it is possible to provide a lubrication structure for a working device that suppresses an increase in cost and has good lubricity.

  A preferred embodiment of a lubricating structure for a working device according to the present invention will be described below with reference to FIGS. In the present embodiment, a lubricating structure of a hedge trimmer that cuts branches and leaves will be described. 1A and 1B show a bottom view and a cross-sectional view of the power transmission device 10 of the hedge trimmer 1. FIG. The power transmission device 10 receives a power from an engine (not shown) via a drive gear 11 and rotates. The power transmission device 10 is attached to a side surface of the driven gear 13 and interlocked with the driven gear 13 from the driven gear 13. The transmission mechanism 20 that transmits the power of the power, the working unit 50 that cuts branches and leaves by receiving the power from the transmission mechanism 20, the drive gear 11, the driven gear 13, and the transmission mechanism 20 are rotatably supported. And a gear case 60 for containing grease as a lubricant.

  As shown in FIG. 2 (component development view), the drive gear 11 includes a shaft portion 11a and a tooth portion 11b formed at the tip of the shaft portion 11a, and a bearing 61 mounted in the gear case 60. It is supported so that it can rotate freely. The driven gear 13 is larger in diameter than the pitch circle diameter of the drive gear 11, and circular eccentric cams 21, 21 ′ eccentric to the outside of the rotation center axis S of the driven gear 13 are integrally formed on both side surfaces of the driven gear 13. Is provided. These eccentric cams 21, 21 ′ have a smaller diameter than the driven gear 13 and are arranged in a straight line.

  The transmission mechanism unit 20 includes the pair of eccentric cams 21 and 21 'described above and rods 25 and 25' that are rotatably fitted to the eccentric cams 21 and 21 '. The rods 25 and 25 ′ are plate-like, and are formed on one end side of the connecting rod 26 and the connecting rod 26 and fitted with the eccentric cams 21 and 21 ′. It is formed on the end side and is rotatably fitted to the base of the working unit 50 and has an annular small rotating part 28 having a smaller diameter than the large rotating part 27. When the large rotating portion 27 is fitted to the eccentric cams 21 and 21 ′, the side surface on the front side of the large rotating portion 27 and the end surfaces of the eccentric cams 21 and 21 ′ are arranged on substantially the same plane.

  The working unit 50 includes a pair of blades 51 and 51 ′ extending from the power transmission device 10. The blades 51 and 51 'are plate-like, and a plurality of blades (not shown) are arranged on the tip side along the extending direction of the blades 51 and 51'. The pair of blades 51, 51 ′ are arranged so that the side surfaces face each other, one blade 51 is connected to the rod 25 fitted to one eccentric cam 21, and the other blade 51 ′ is the other eccentric cam 21. It is connected to a 'rod 25 fitted in'. For this reason, when the drive gear 11 rotates, the pair of blades 51 and 51 ′ reciprocate in different directions via the transmission mechanism 20.

  The gear case 60 that accommodates the base of the drive gear 11, the driven gear 13, the transmission mechanism 20, and the working unit 50 configured as described above includes a main body 63 and a lid 70 that covers the main body 63. As shown in FIGS. 1A, 1 </ b> B, and 2, the main body 63 has a substantially rectangular shape in plan view, and on the surface side of the main body 63, the drive gear 11, the driven gear 13, and the transmission mechanism unit. 20 and the main body side accommodation recessed part 64 which accommodates the base part of the working part 50 are formed. The main body side accommodating recess 64 accommodates the main body side cylindrical small concave portion 65 that accommodates the drive gear 11, the main body side cylindrical large concave portion 66 that accommodates the driven gear 13 and the transmission mechanism 20, and the base side of the working unit 50. And a main body side rectangular recess 67.

  On the other hand, a lid-side accommodation recess 71 formed so as to cover the main body-side accommodation recess 64 is formed on the back surface side of the lid 70. The lid-side accommodation recess 71 includes a lid-side cylindrical small recess 72 disposed to face the body-side cylindrical small recess 65, a lid-side cylindrical large recess 73 disposed to face the body-side cylindrical large recess 66, and the body It has the side rectangular recessed part 67 and the lid side rectangular recessed part 74 opposingly arranged.

  When the lid part 70 is fixed to the main body part 63, the main body side cylindrical small concave part 65 and the lid side cylindrical small concave part 72, the main body side cylindrical large concave part 66 and the lid side cylindrical large concave part 73, the main body side rectangular concave part 67. And the lid-side rectangular recess 74 are continuously connected to each other, and a first accommodating portion 81 that accommodates the drive gear 11, a second accommodating portion 82 that accommodates the driven gear 13 and the transmission mechanism portion 20, and a base portion of the working portion 50. A third accommodating portion 83 is formed. The lid part 70 is fastened by a plurality of bolts and fixed to the main body part 63.

  The inner side surface portion 81a of the first housing portion 81 is disposed close to the drive gear 11, and the inner side surface portion 82a of the second housing portion 82 is driven by the driven gear 13 and the transmission mechanism portion 20 (eccentric cams 21, 21 ′, rod 25, 25 ').

  The first accommodating portion 81 and the second accommodating portion 82 intersect with each other, and each intersecting portion opens to communicate the first accommodating portion 81 and the second accommodating portion 82. The teeth of the drive gear 11 and the driven gear 13 protrude and mesh with each other at the intersection.

  A gap between the drive gear 11 accommodated in the first accommodating portion 81 and the first accommodating portion 81, the driven gear 13 and the transmission rear portion 20 accommodated in the second accommodating portion 82, and the second accommodating portion 82. The above-described grease serving as a lubricant is injected into the gap between the base portion of the working unit 50 housed in the third housing portion 83 and the third housing portion 83.

  On the sliding surface 27a of the large rotating portion 27 fitted to the eccentric cams 21 and 21 ', a concave portion 27b that opens to the space portion 82b in the second accommodating portion 82 is formed. The concave portion 27b can receive the grease present in the space portion 82b in the second accommodating portion 82 and efficiently improve the lubricity of the sliding surface 27a. Note that the recess 27b is not limited to the rods 25 and 25 ', and even if the recesses 27b are provided on the eccentric cams 21 and 21', the same effects as those provided on the rods 25 and 25 'can be obtained.

Further, as shown in FIGS. 3 (a) and 3 (b), it changes in the vicinity of the connecting rod 26 side of the large rotation portion 27 of the rod 25 ′, more specifically, by the movement of the eccentric cam 21 ′ and the rod 25 ′. The sliding surface of the space portion 82b ₂ to be reduced and the large rotation portion 27 is located near the position where the volume of the space portion 82b ₂ to be reduced among the space portions 82b in the second accommodating portion 82 is substantially minimized. A communication path 30 that communicates with 27a is provided. In addition, a recessed portion 31 that communicates with the space portion 82 b ₂ in the second accommodating portion 82 is formed in the opening portion on the sliding surface 27 a side of the communication passage 30.

For this reason, as shown in FIGS. 4A to 4H, the space portion 82b shown by hatching has two spaces due to the movement of the eccentric cam 21 ′ (21) and the rod 25 ′ (25) in the direction of arrow A. It is partitioned into parts 82b ₁ and 82b ₂ . And these spaces _82b 1, 82b ₂ are eccentric cam 21 '(21) and the rod 25' volume by movement varies (25), two volumes of the space portion _82b 1, 82b ₂ is reduced space 82b ₂ of that side, briefly volume is reduced by movement of the eccentric cam 21 '(21) and the rod 25' (25) as shown in FIG. 4 (b) ~ (f). When the FIG. 4 (g) an eccentric cam 21 to the position shown in '(21) and the rod 25' (25) moves, the volume of the space portion 82b ₂ is substantially minimized. As a result, grease is supplied to the sliding surface 27a is received in the recess 31 flows into the communicating path 30 by boosting compressed existing in the space portion 82b _2. That is, the transmission mechanism unit 20 has a pump function for feeding grease. For this reason, the lubricity of the sliding surface 27a can be improved efficiently without increasing the cost by a small design change in which the communication passage 30 is provided in the large rotation portion 27 without mounting a bearing on the sliding surface 27a. Can be aimed at. Note that the recess 31 is not limited to the rod 25 ′ (25), and even when the recess 31 is provided on the eccentric cam 21 ′ (21), the same effect as that provided on the rod 25 ′ (25) can be obtained. Further, the communication path 30 may be provided in the gear case 60 or the driven gear 13 if the above-described principle is applied, without being provided in the rod 25.

In the embodiment described above, the grease is gradually consumed with the operation of the power transmission device 10, but there is a risk that insufficient lubrication of each drive component due to insufficient grease will occur. For this reason, in order to prevent grease shortage, a receiving portion 85 that receives grease may be provided on the bottom surface of the second storage portion 82 as shown in FIG. As shown in FIGS. 6A and 6H, the receiving portion 85 includes a space portion 82b in the second accommodating portion 82 partitioned by the rod 25 ′ (25), as shown in FIGS. as shown in f), it is arranged on one side of the rod 25 '(25 two partitioned by movement of the) space _82b 1, 82b _2. In the present embodiment, the receiving portion 85 is provided in the space portion 82b ₂ located on the downstream side in the rod rotation direction (arrow A direction).

The shape of the receiving portion 85 is formed in a substantially semicircular shape that does not extend over the _two space portions 82b ₁ and 82b ₂ , and the compression of the space portion 82b ₂ shown in FIGS. In the process, it is difficult for the grease to leak from the space portion 82b ₂ to the other space portion 82b ₁ . In the compression process of the space 82b ₂ shown in FIG. 6 (b) ~ (e) , the space portion 82b ₂ is filled with grease, if there is room to receive grease into the receiving portion 85, receiving from the space portion 82b ₂ The grease flows into the portion 85. Further, as shown in FIGS. 6 (f) and (g), in the vicinity where the compression of the space portion 82 b ₂ is highest, the receiving portion 85 is formed so as not to open into the space portion 82 b ₂ , and the rod 25. communicating passage 30 '(25) is in communication with the space portion 82b _2. Therefore, in the process shown in FIG. 6 (f) and (g), the grease filled in the space portion 82b _2, lubricates and flows to the sliding surface 27a of the communication passage 30. The compressed volume of the space portion 82b ₂ in the process shown in FIG. 6 (f) and (g) is such that greater than summed volume of the connecting passage 30 and the recess 31, by disposing the receiving portion 85, Since grease flows densely through the communication passage 30 and the grease is sufficiently received in the recess 31, it is more effective. 5 and 6, the receiving portion 85 is provided on the space portion 82b ₂ side, but may of course be provided on the space portion 82b ₁ side, or provided on each of the space portion 82b ₂ and the space portion 82b _1. good.

  In the embodiment described so far, as shown in FIG. 1, there is a possibility that the gear case 60 and the driving components (the driving gear 11, the driven gear 13, and the transmission mechanism unit 20) are in direct contact. In addition, in order to protect the lid portion 70, a protective member (not shown) may be interposed, and the first to third storage portions 81 to 83, the receiving portion 85, and the like described above may be similarly formed on the protective member. Further, the driven gear 13 may be provided with a receiving portion 85 to have the same effect.

1 shows a power transmission device of a hedge trimmer according to an embodiment of the present invention, in which FIG. (A) is a bottom view of the power transmission device, and (b) in FIG. It is sectional drawing of the part which corresponds. The partial expanded view of this power transmission device is shown. The communication path provided in the power transmission device is shown, wherein FIG. (A) is a bottom view of the power transmission device, and (b) is a cross-section of the portion corresponding to the III-III arrow in FIG. FIG. An explanatory view for explaining supply of grease by volume change of a space part is shown. The bottom view of the power transmission device which provided the receiving part is shown. An explanatory view for explaining supply of grease by a receiving part is shown.

Explanation of symbols

1 Hedge trimmer (working equipment)
13 Driven gear 20 Transmission mechanism 21, 21 ′ Eccentric cam 25, 25 ′ Rod 27 Large turning part (turning part)
27a Sliding surface 30 Communication path 31 Recessed portion 50 Working portion 60 Gear case 82a Inner side surface portion 82b ₂ Space portion 85 Receiving portion

Claims (8)

A driven gear that rotates by receiving power from a drive source, a transmission mechanism that transmits power from the driven gear in conjunction with power from the driven gear, and receives power from the transmission mechanism A working unit that performs a predetermined work and a gear case that rotatably supports at least the driven gear and the transmission mechanism unit and accommodates a lubricant, wherein the transmission mechanism unit is connected to the driven gear. A lubricating structure for a working device having a rod rotatably connected between an eccentric cam provided and the working portion,
An inner side surface portion of the gear case that surrounds a rotating portion that is rotatably connected to the eccentric cam of the rod is provided close to the rotating portion to form a space portion in the gear case, and the space portion is the eccentric portion. A sliding surface of a rotating portion that is formed with a space portion that is reduced by the movement of the cam and the rod and a space portion that is enlarged and that fits into the space portion that is reduced and the eccentric cam. A communication passage that communicates with the space, and the compression of the lubricant generated by the volume reduction of the space portion on the reduced side is utilized to supply the lubricant to the rotating portion through the communication passage. Lubricating structure for working equipment. The communication path includes a space portion on the reduced side and a sliding surface of a rotating portion fitted to the eccentric cam when the volume of the space portion on the reduced side is substantially minimum. The lubricating structure for a working device according to claim 1 , wherein the lubricating structure is in communication. Lubricating structure of the working apparatus according to claim 1 or 2, characterized in that a said communication passage to said rod. The lubricating structure for a working device according to claim 1 or 2 , wherein the communication path is provided in the driven gear. Lubricating structure of the working apparatus according to claim 1 or 2, characterized in that a said communication passage to said gear case. A recess provided in the sliding surface, by connecting one end of the communicating passage to the recess, according to claim 3, characterized in that for communicating the space portion and the reduced space of the recess The lubrication structure of the work equipment. A receiving unit for receiving the lubricant in the gear case is provided, the receiving portion, claim 1, characterized in that arranged without spanning two spaces in the gear case partitioned by movement of the rod 6 The lubricating structure of the working device according to any one of the above.   The driven gear is rotated by a drive gear that rotates by receiving power from a drive source, and an inner side surface portion of the gear case that surrounds the drive gear is provided close to the drive gear, and an inner side surface portion that surrounds the drive gear; The lubrication of the working device according to claim 1, wherein inner side surfaces surrounding the driven gear are opened and communicated with each other, and the drive gear and the driven gear teeth are meshed with each other at the opened portion. Construction.

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