JP5033709B2 - Power transmission device - Google Patents

Description

  The present invention relates to an improvement in a power transmission device.

As a conventional power transmission device, one in which a transmission is connected to an engine via a travel clutch is known (for example, see Patent Document 1).
JP 63-223207 A

  As shown in FIGS. 1 and 7 of Patent Document 1, a drive pulley 17 is attached to the output shaft 5 of the engine 4 mounted on the small snowplow, and the driven pulley 16 of the input shaft 15 of the transmission 14 is attached. A V-belt 18 is stretched around the drive pulley 17 and the driven pulley 16.

A travel clutch 45 is provided on the side of the V-belt 18 in order to interrupt power transmitted from the engine 4 to the transmission 14.
The traveling clutch 45 includes a roller 46 that can press the V-belt 18.

  Since the V-belt 18 is hung on the driving pulley 17 and the driven pulley 16 in a slack state, power is not transmitted from the output shaft 5 of the engine 4 to the input shaft 15 of the transmission 14 in this state, but the roller 46 Is pressed against the V belt 18, the V belt 18 is stretched and power is transmitted from the drive pulley 17 to the driven pulley 16.

  In the transmission 14, by operating the shift lever 33, it is possible to select the forward, reverse, and neutral by switching the meshing of the transmission gear. Except for selecting neutral, the transmission 14 is interlocked with the operation of the shift lever 33. Thus, the engagement of the predetermined transmission gear and the connection of the traveling clutch 45 are simultaneously performed.

  In a small snowplow as disclosed in Patent Document 1, it is particularly difficult to employ a transmission 14 that is required to reduce costs, has a plurality of gears, and requires high precision in parts, and has a simple structure. Desired. For example, a simple mechanism for switching the forward / reverse movement of the transmission is desirable, but it is also necessary that the forward / backward movement can be switched smoothly. Further, the traveling clutch 45 can be further reduced in cost by adopting a simple structure.

In addition, for example, depending on the state of the snow removal site, there is a case where the small snow remover is pushed and pulled by human power without using the power of the small snow remover to change the direction or move. From the viewpoint of ease of use, it is desirable to be able to set and maintain the neutral state of the transmission with a simple structure so that the direction can be changed and moved.
An object of the present invention is to provide a power transmission device which can smoothly switch between forward and backward movement with a simple structure and can set and maintain a neutral state.

The invention according to claim 1 is a power transmission device capable of switching the rotation direction of the drive shaft between forward rotation and reverse rotation when power is transmitted from the drive source to the drive shaft via the power transmission device. A forward drive pulley and a reverse drive pulley connected to the output shaft, a forward drive shaft connected to the drive shaft via a forward gear train, a forward driven pulley attached to the forward drive shaft, and A forward rotation belt stretched over each of the forward rotation drive pulley and the forward rotation driven pulley, a reverse rotation shaft connected to the drive shaft via a reverse rotation gear train, and a reverse rotation driven pulley attached to the reverse rotation shaft; A reverse rotation belt stretched around each of the reverse rotation drive pulley and the reverse rotation driven pulley, and only one of the forward rotation belt and the reverse rotation belt is stretched to stretch the forward rotation belt and the reverse rotation bell. Among them, the belt switching means for switching the belt for transmitting the power and the neutral state in which the transmission of the power in both the forward rotation belt and the reverse rotation belt is cut off by loosening both the forward rotation belt and the reverse rotation belt. An upper transmission unit including a neutral holding unit, the upper transmission unit is rotatably attached to the vertically extending drive shaft provided in the lower transmission unit, and the neutral holding unit extends downward from the upper transmission unit. The upper transmission portion positioning pin provided in this manner, the holding position pin provided so as to extend upward from the lower transmission portion, and one end portion are rotatably attached to the upper transmission portion, and the other end portion is the upper transmission portion It comprises a pair of left and right holding plates that sandwich the positioning pin and the holding position pin, and a tension coil spring that is stretched over the holding plate .

  In order to rotate the drive shaft in the forward direction, only the forward rotation belt is stretched by the belt switching means. As a result, power is transmitted from the forward drive pulley connected to the output shaft of the drive source to the forward driven pulley via the forward belt, and further from the forward shaft attached to the forward driven pulley to the forward gear. Power is transmitted to the drive shaft through the row, and the drive shaft rotates forward.

  In order to reversely rotate the drive shaft, only the reverse rotation belt is stretched by the belt switching means. As a result, power is transmitted from the reverse drive pulley connected to the output shaft of the drive source to the reverse driven pulley via the reverse belt, and from the reverse shaft attached to the reverse driven pulley via the reverse gear train. Power is transmitted to the drive shaft, and the drive shaft reverses.

By means of belt switching means, the normal rotation belt is changed from the slackened state to the tensioned state, and at the same time the reverse rotation belt is tensioned to the slackened state, or the normal rotation belt is changed from the tensioned state to the slackened state, and at the same time for reverse rotation. The belt can be changed from the slack state to the tension state, and the forward / reverse rotation of the drive shaft can be smoothly switched, and the clutch engagement / disengagement operation can be performed at the time of such forward / reverse switching.
Therefore, there is no need for a transmission that includes a plurality of gears and requires high precision in parts, a traveling clutch that includes many parts, and the like.

  In addition, it is possible to set the neutral state in which the connection between the output shaft side of the drive source and the drive shaft side is cut off by slackening both the forward rotation belt and the reverse rotation belt during the forward / reverse rotation of the drive shaft. Further, the neutral state can be maintained by the neutral holding means, and the drive shaft can be rotated without being constrained by the output shaft of the drive source. When a general-purpose machine such as a small snowplow to which a traveling means such as a belt is attached is pushed and pulled manually, the traveling means easily rotates, so that the general-purpose machine can be easily pushed and pulled.

According to the first aspect of the present invention, in the power transmission device capable of switching the rotation direction of the drive shaft between normal rotation and reverse rotation when transmitting power from the drive source to the drive shaft via the power transmission device, A forward drive pulley and a reverse drive pulley connected to the output shaft, a forward drive shaft connected to the drive shaft via a forward gear train, a forward driven pulley attached to the forward drive shaft, and A forward rotation belt stretched over each of the forward rotation drive pulley and the forward rotation driven pulley, a reverse rotation shaft connected to the drive shaft via a reverse rotation gear train, and a reverse rotation driven pulley attached to the reverse rotation shaft; The reverse rotation belts and the reverse rotation belts stretched around the reverse rotation drive pulley and the reverse rotation driven pulley, and only one of the normal rotation belt and the reverse rotation belt is stretched. The belt switching means that switches the belt that transmits power and the forward rotation belt and the reverse rotation belt are both loosened to maintain the neutral state in which the transmission of power in both the forward rotation belt and the reverse rotation belt is cut off. And an upper transmission unit that is pivotally attached to the vertically extending drive shaft provided in the lower transmission unit, and the neutral holding unit is disposed downward from the upper transmission unit. An upper transmission portion positioning pin provided to extend, a holding position pin provided to extend upward from the lower transmission portion, and one end portion rotatably attached to the upper transmission portion, and the other end portion to the upper transmission a pair of left and right holding plates sandwiching the part positioning pin and the holding position pin, since composed of a tension coil spring stretched over the holding plate, as in the prior art transmissions, With a simple structure such as a row clutch, the drive shaft can be smoothly switched between forward and reverse rotation, and the drive shaft can be set to a neutral state separated from the output shaft of the drive source. Can be held by the neutral holding means.For example, it is possible to easily push and pull a general-purpose machine provided with traveling means such as wheels and crawler belts on the drive shaft side. Can be changed or moved.
In the power transmission device of the present invention, the belt is stretched or loosened to transmit power, or the power transmission is cut off, and the upper transmission unit is simply rotated around the drive shaft. Cost can be reduced.
In the present invention, the holding mechanism can hold the neutral state, and the drive shaft can be rotated without being constrained by the output shaft (crankshaft) of the engine. When a general-purpose machine (for example, a small snowplow) to which a traveling means such as a crawler belt is attached is pushed and pulled manually, the crawler running part easily rotates, so that the small snowplow can be pushed and pulled easily. .
Thus, in the power transmission device of the present invention, the forward and reverse rotations of the drive shaft can be smoothly switched as a simple structure, and the drive shaft can be set to a neutral state separated from the output shaft of the engine. In addition, since this neutral state can be held by a holding mechanism, it can be easily pushed and pulled by a general-purpose machine such as a small snow remover provided with a crawler traveling part, and can be easily used. Can be changed or moved.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a perspective view showing a small snowplow having a power transmission device according to the present invention. The small snowplow 10 transmits an engine 12 and power of the engine 12 to a machine body 11 and a small snowplow 10. A transmission 13 that constitutes a main part that switches between forward and backward travel, a pair of left and right crawler travel units 14 and 16 connected to the output side of the transmission 13, and a pair of left and right swings provided on the body 11 so as to be swingable Pipes 17 and 18, a snow removal plate 21 attached to the front ends of the swing pipes 17 and 18 for snow removal, and a pair of left and right handles 22 and 23 attached to the rear ends of the swing pipes 17 and 18. The power transmission device 25 is a device that transmits power from the engine 12 to the left and right crawler travel units 14 and 16. Reference numeral 26 denotes a cover that covers the transmission 13.

The engine 12 is a vertical engine including a crankshaft 27 arranged vertically.
The left crawler traveling unit 14 includes a drive wheel 31 provided behind the snow discharge plate 21, an idler wheel 32 provided behind the drive wheel 31, and each of the drive wheel 31 and the idler wheel 32. A crawler belt 33 wound around, a travel shaft 34 connected to the transmission 13 and attached to the drive wheel 31, and a driven shaft 36 that rotatably supports the idler wheel 32.
The right crawler traveling unit 16 is symmetrical to the left crawler traveling unit 14 and has the same basic structure as the left crawler traveling unit 14 and will not be described in detail.

  Each of the handles 22 and 23 includes a grip 41 at the end, and the right handle 23 includes a forward / reverse switching lever 42 for switching forward / backward movement of the small snowplow 10 and a lock lever 43 for locking the forward / backward switching lever 42. Is provided. Reference numerals 45 and 46 denote a first cable and a second cable that are passed between the transmission 13 and the forward / reverse switching lever 42 in order to switch forward / reverse.

  FIG. 2 is a perspective view showing a power transmission device according to the present invention (the arrow (FRONT in the figure represents the front of the small snowplow. The same applies hereinafter)), and the power transmission device 25 is the engine 12 (FIG. 1), a drive pulley 51 attached to the lower end of the crankshaft 27, two V belts 52, 53 hung on the drive pulley 51, and the drive pulley 51 via these V belts 52, 53. The transmission 13 is connected.

The transmission 13 includes an upper transmission 55 connected to the V-belts 52 and 53, and a lower transmission 56 disposed below the upper connection 55.
The upper transmission 55 is rotatably attached to a vertically extending drive shaft (not shown; details will be described later) provided in the lower transmission 56.
The lower transmission unit 56 is attached to the body 11 (see FIG. 1) and is connected to the travel shaft 34.
The drive pulley 51 is a component in which a first drive pulley 51A on which the V belt 52 is hung and a second drive pulley 51B on which the V belt 53 is hung are integrally formed.

The upper transmission unit 55 includes two first input shafts 61 and second input shafts 62 that are rotatably and vertically attached to the upper transmission unit case 63, and the first input shaft 61 and the second input shaft 62 are connected to each other. A first pulley 64 and a second pulley 66 are respectively attached to the upper end portions by nuts 67, the V belt 52 is hung on the first pulley 64, and the V belt 53 is hung on the second pulley 66.
A holding mechanism 70 is provided in front of the upper transmission unit 55 to hold the position of the upper transmission unit 55 in the rotational direction with respect to the lower transmission unit 56 at a predetermined position.

  The holding mechanism 70 includes a bracket 76 attached to the front part of the upper transmission part case 63 with bolts 75, 75, an upper transmission part positioning pin 77 attached to the front end part of the bracket 76 so as to extend downward, and a lower part. A holding position pin 81 attached to the front part of the lower transmission part case 78 of the transmission part 56 so as to extend upward, and one end part are rotatably attached to the lower part of the upper transmission part 55 and the other end part is respectively provided. A pair of left and right holding plates 82 and 83 sandwiching the upper transmission portion positioning pin 77 and the holding position pin 81 and a tension coil spring 84 attached to the holding plates 82 and 83 are attached.

  The predetermined position held by the holding mechanism 70 is a position where both of the V-belts 52 and 53 are loosened and cannot transmit power. When the upper transmission 55 is rotated, the upper speed change is performed by the elastic force of the tension coil spring 84. The portion 55 is returned to a predetermined position and held at that position.

  A turning mechanism 90 for turning the upper transmission 55 is provided with a pair of left and right turning pins 91 and 92 attached to the left and right ends of the upper transmission case 63 (only the reference numeral 91 on the front side is shown). Mounting pieces 93 and 93 (only the front side symbol 93 is shown), tension coil springs 94 and 94 (only the front side symbol 94 is shown), and wire ends, which are sequentially connected to the pivot pins 91 and 92. Member 96, 96 (only front side 96 is indicated), first and second cables 45, 46 (only front side 45 is shown), forward / reverse switching lever 42 (see FIG. 1) and lock lever 43 (see FIG. 1).

  The first cable 45 includes an outer cable 101 whose one end is supported by a cable support stay 98 provided in the machine body 11 (see FIG. 1), and is movably inserted into the outer cable 101 and has a wire end member at one end. And an inner wire 102 to which 96 is attached. The second cable 46 has the same structure as the first cable 45, and detailed description thereof is omitted.

  The upper transmission case 63 has a flat plate 112 attached to the upper portion thereof with a plurality of bolts 111, and a belt detachment prevention pin that prevents the V belts 52 and 53 from being detached from the first pulley 64 and the second pulley 66 on the flat plate 112. 113, 113, 114, 116, 116 are set up. In detail, the locking pin 114 is attached to the flat plate 112 via an auxiliary plate 118.

  The transmission 13 described above includes an upper transmission unit 55, a lower transmission unit 56, and a rotation mechanism 90 that rotates the upper transmission unit 55 to switch between a state in which the V belts 52 and 53 are stretched and a state in which the V belts 52 and 53 are loosened. By holding both the V-belts 52 and 53 in a slack state, the V-belts 52 and 53 are both provided with a holding mechanism 70 that is in a neutral state in which no power is transmitted.

  FIG. 3 is a plan view showing a power transmission device according to the present invention, which passes through the axis 27a of the crankshaft 27 of the engine and the axis 121a of the drive shaft 121 provided in the lower transmission unit 56 (see FIG. 2). The first input shaft 61 is located on the left side, the second input shaft 62 is located on the right side, and the first pulley 64 attached to the first input shaft 61 with respect to the center line 122 extending in the front-rear direction of the snowplow. With the second pulley 66 attached to the second input shaft 62, the outer diameter D2 of the second pulley 66 is larger than the outer diameter D1 of the first pulley 64 when the outer diameters are D1 and D2, respectively. Has been. Reference numeral 123 denotes a reference line that passes through the axis 121 a of the drive shaft 121 and is orthogonal to the center line 122.

  The second pulley 66 is a component that transmits power for reverse travel, and the second pulley 66 has a larger diameter than the first pulley 64 that transmits power for forward travel because the reduction ratio is larger than that of the first pulley 64. This is because the traveling speed of the small snowplow when traveling backward is smaller than the traveling speed when traveling forward.

  The upper transmission portion positioning pin 77 and the holding position pin 81 constituting the holding mechanism 70 are arranged side by side along the center line 122, and the elastic force of the tension coil spring 84 on the holding surfaces 82 a and 83 a of the holding plates 82 and 83. It is sandwiched between.

  Since the holding position pin 81 is fixed on the center line 122, when the upper transmission portion positioning pin 77 is rotated with the rotation of the upper transmission portion 55, the upper transmission portion positioning pin 77 is The elastic force returns to the center line 122 and is held on the center line 122.

FIG. 4 is an explanatory view showing a power transmission path of the power transmission device according to the present invention. The first input shaft 61, the second input shaft 62, and the drive shaft 121 are respectively a first drive gear 131 and a second drive gear 132. A driven gear 133 is attached.
Here, the first drive gear 131 and the second drive gear 132 have the same number of teeth.

The first drive gear 131 meshes directly with the driven gear 133, the second drive gear 132 meshes with the idle gear 136 that is rotatably attached to the idle shaft 134, and the idle gear 136 meshes with the driven gear 133. Here, the number of teeth of the idle gear 136 is the same as the number of teeth of the first drive gear 131 and the second drive gear 132.
The idle shaft 134 is attached to the upper transmission case 63 (see FIG. 3), and is disposed in front of the second input shaft 62 and rearward of the drive shaft 121.

  The first drive gear 131 and the driven gear 133 are components constituting a first gear train 137 that rotates the drive shaft 121 in the forward direction, and the second drive gear 132, idle gear 134, and driven gear 133 are the drive shaft 121. This is a part constituting the second gear train 138 that reverses the rotation.

  When the small snowplow advances, the engine power is (crankshaft 27, drive pulley 51) → V belt 52 → (first pulley 64, first input shaft 61, first drive gear 131) → (driven gear 133) in this order. , And the drive shaft 121). That is, it is transmitted from the first input shaft 61 to the drive shaft 121 via the first gear train 137.

  When the small snowplow reverses, the engine power is (crankshaft 27, drive pulley 51) → V belt 53 → (second pulley 66, second input shaft 62, second drive gear 132) → idle gear 136 in this order. → (Driven gear 133, drive shaft 121) That is, the signal is transmitted from the second input shaft 62 to the drive shaft 121 via the second gear train 138.

5 is a cross-sectional view taken along line 5-5 of FIG. 3, and the power transmission device 25 includes a drive pulley 51, V belts 52 and 53, and a transmission 13 driven by these V belts 52 and 53. .
The transmission 13 includes an upper transmission unit 55, a lower transmission unit 56, a holding mechanism 70, and a rotation mechanism 90 (see FIG. 2). The transmission 13 switches the small snowplow forward and backward and is in a neutral state (drive shaft). 121 (a state in which no power is transmitted to 121).

  The upper transmission unit 55 includes an upper transmission unit case 63 (a lower case 143 and an upper case 144 mounted on the upper part of the lower case 143) that is rotatably attached to the drive shaft 121 via two bearings 141 and 142. ), A second input shaft 62 rotatably mounted on the upper transmission case 63 via two bearings 146 and 147, and two bearings 146 and 147 (not shown) on the upper transmission case 63. A first input shaft 61 (see FIG. 3) mounted rotatably, and an idle shaft 134 inserted into insertion holes 143a and 144a formed in the lower case 143 and the upper case 144 of the upper transmission case 63, respectively. The first input shaft 61, the second input shaft 62, and the drive shaft 121 are spline-coupled to each other and are connected to the upper transmission unit. A first drive gear 131 (not shown), a second drive gear 132, a driven gear 133, and an idle gear 136 rotatably mounted on the idle shaft 134 via a bush 149; A first pulley 64 (see FIG. 3) and a second pulley 66 are spline-coupled to the first input shaft 61 and the second input shaft 62, respectively.

  Here, reference numeral 151 is a cap for closing the opening 144b opened in the upper case 144 above the drive shaft 121, and 152 is a seal member provided between the second input shaft 62 and the opening 144c on the upper case 144 side. , 153 is a collar for positioning the lower case 143 and the upper case 144, and 154 is a bolt for fastening the lower case 143 and the upper case 144 together.

  The lower transmission unit 56 includes a lower transmission unit case 161 (consisting of a case main body 162 and a cover member 163 that closes an opening provided in the lower portion of the case main body 162), and two bearings 164 in the lower transmission unit case 161. , 166, a drive shaft 121 that is rotatably mounted, a worm wheel 167 that meshes with a worm 121 </ b> A formed at a lower portion of the drive shaft 121, an upper opening 162 a of the case main body 162, and a lower case of the upper transmission portion 55. The worm wheel 167 is attached to a travel shaft 34 that is rotatably attached to the case main body 162. The seal member 168 is provided between the lower end portion of the cylinder 143 and the cylindrical portion 143b. Reference numeral 169 denotes a nut screwed to the upper end portion of the drive shaft 121 to prevent the bearing 142 from coming off from the drive shaft 121.

  Here, reference numeral 171 denotes a collar for positioning the case main body 162 and the cover member 163, 172 denotes a bolt for fastening the case main body 162 and the cover member 163, and 173 attaches the case main body 162 to the body 11 (see FIG. 1). Bolts 174 are spaces in the lower transmission case 161, 176 is lubricating oil stored in a space 177 formed by a space 148 in the upper transmission 55 and a space 174 in the lower transmission 56, and 176a is lubrication. This is the oil level of the working oil 176.

  As described above, the transmission 13 rotatably attaches the upper transmission unit 55 to the lower transmission unit 56, and connects the upper transmission unit 55 and the lower transmission unit 56 to the upper opening 162a of the lower transmission unit 56. The cylinder portion 143b of the upper transmission portion 55 is inserted into the inner opening portion 162a and the space between the upper opening 162a and the cylinder portion 143b is sealed by the seal member 168. For example, the upper transmission portion and the lower transmission portion are moved up and down. The number of parts of the transmission 13 can be reduced and the structure of the transmission 13 can be simplified compared to the structure in which the seal members are provided in the upper transmission unit and the lower transmission unit.

  Also, the upper transmission portion 55 and the lower transmission portion 56 are brought closer together by overlapping the upper opening 162a of the lower transmission portion 56 and the cylindrical portion 143b of the upper transmission portion 55 in the axial direction of the drive shaft 121. Thus, the height H of the transmission 13 can be further reduced.

  In the holding mechanism 70, the upper transmission portion positioning pin 77 extends below the lower holding plate 82, and the holding position pin 81 is press-fitted into a mounting hole 162c provided in the case main body 162 of the lower transmission portion 56. The holding plates 82 and 83 extend upward from the upper holding plate 83, and are rotatably attached to the lower cylindrical portion 143 c of the lower case 143 of the upper transmission portion 55 via plate receiving members 181 and 182. In addition, 184 is a washer and 185 is a retaining ring.

  6 is a cross-sectional view taken along line 6-6 of FIG. 3, and is located inside the upper end portion of the upper case 144 of the upper transmission unit 55, that is, the opening 144b of the upper case 144, the drive shaft 121, the bearing 142, and the nut. 169 and the cap 151 form a breather chamber 191, and one end of an L-shaped breather pipe 192 is press-fitted into a vertical hole 144 e opened in the upper case 144. A breather hose 193 is connected to the end, and a breather passage 194 is formed by the breather pipe 192 and the breather hose 193.

  Since the breather chamber 191 is adjacent to the upper side of the bearing 142, the temperature increases as the temperature of the bearing 142 increases while the drive shaft 121 rotates, and the pressure increases. However, the breather chamber 191 is connected to the breather chamber 191. By communicating with the outside of the transmission 13, the temperature in the breather chamber 191 can be lowered and the pressure can be lowered.

  The bearing 142 is a shield type, a shield plate 142b is fixed to the outer ring 142a, and a labyrinth gap is formed by the shield plate 142b and a groove formed on the seal surface of the inner ring 142c. Intrusion of dust and the like is prevented.

  FIG. 7 is a perspective view showing a main part of the holding plate support structure of the holding mechanism according to the present invention. The holding plates 82 and 83 are provided with plate holes 82b and 83b, respectively, and the plate receiving members 181 and 182 are respectively large. Diameter portions 181a and 182a, small diameter portions 181b and 182b, and step portions 181c and 182c provided between the large diameter portions 181a and 182a and the small diameter portions 181b and 182b, respectively.

  The holding plate 82 is placed on the stepped portion 181c of the plate receiving member 181, and the plate hole portion 82b is rotatably fitted to the small diameter portion 181a of the plate receiving member 181. Similarly, the holding plate 83 is a plate receiving member. The plate 18 is mounted on the step portion 182c of the member 182, and the plate hole 83b is rotatably fitted to the small diameter portion 182a of the plate receiving member 182, and the washer 184 is in contact with the upper surface of the holding plate 83. 83 slides with the plate receiving members 181 and 182 and the washer 184 having the function of a bush that promotes sliding, and does not contact the lower case 143 of the upper transmission 55 shown in FIG.

  FIG. 8 is a rear view of the transmission according to the present invention, in which the first pulley 64 is disposed at a position higher than the second pulley 66, and the upper transmission unit case 63, specifically, the rotation pins 91 on the left and right of the lower case 143. , 92 are provided, and a tip end portion 193a of a breather hose 193 forming a breather passage 194 is inserted into a hose fixing hole 143e provided in a rear portion of the lower case 143 and opens downward. Therefore, there is no fear that rainwater or the like is sucked into the breather passage 194.

  FIG. 9 is a side view of the main part showing the periphery of the handle of the rotating mechanism according to the present invention. A rear bracket 201 is attached to the rear side of the right handle 23, and a rear support shaft 202 provided on the rear bracket 201 is attached. When the bearing member 203 provided on the forward / reverse switching lever 42 is fitted, the forward / reverse switching lever 42 is rotatably attached to the rear bracket 201, and the rear part of the forward / reverse switching lever 42, specifically, the rear end (rear part) The first cable 45 is connected to the rear of the support shaft 202, and the second cable 46 is connected to the center of the forward / reverse switching lever 42 (the front of the rear support shaft 202). The front bracket 204 is connected to the front side of the handle 23. The lock lever 43 is rotatably attached to a front support shaft 206 provided on the front bracket 204.

  The forward / reverse switching lever 42 includes a locked piece 207 that is restrained when the rotation is locked by the lock lever 43 at the upper center portion. Reference numerals 211 and 212 denote connecting pins provided on the rear side surface of the forward / reverse switching lever 42 in order to connect the first cable 45 and the second cable 46 to the forward / reverse switching lever 42.

  The lock lever 43 is a component in which a shaft support portion 43a supported by the front support shaft 206 and a grip portion 43b elongated from the shaft support portion 43a are integrally formed, and is moved forward and backward on the side surface of the shaft support portion 43a. Two lock pieces 214 and 215 having L-shape in side view that can be engaged with the locked piece 207 of the switching lever 42 are provided.

  In the first cable 45 and the second cable 46, each outer cable 101 is attached to a cable bracket 217 provided on the handle 23 with a nut 218, and an end fitting 221 attached to the tip of each inner wire 102 is switched back and forth. The lever 42 is rotatably connected to the connecting pins 211 and 212 of the lever 42.

Next, the operation of the power transmission device 25 described above will be described.
FIGS. 10A and 10B are first operation diagrams showing the operation of the power transmission device according to the present invention.
In (a), when the forward / reverse switching lever 42 is in the position of the two-dot chain line, both the V belts 52 and 53 shown in FIG. Since power is not transmitted from the crankshaft 27 of the engine to the first input shaft 61 and the second input shaft 62, the traveling shaft 34 does not rotate, and the crawler traveling portions 14 and 16 shown in FIG. The machine 10 is in a stopped state. That is, the transmission 13 is in a neutral (so-called “neutral”) state.

  Returning to FIG. 10 (a), in order to move the small snowplow forward, the forward / reverse switching lever 42 is tilted forward as shown by the arrow A (falling from the position of the two-dot chain line to the position of the solid line) The inner wire 102 of the first cable 45 is pulled as indicated by an arrow B. (At this time, the inner wire 102 of the second cable 46 is drawn into the outer cable 101 of the second cable 46.)

  In FIG. 10 (b), while maintaining the state of being tilted in front of the forward / reverse switching lever 42, the lock lever 43 is now tilted toward the grip 41 as shown by the arrow C, and the gripping portion of the lock lever 43 is 43b is gripped with the grip 41 by hand.

  As a result, one lock piece 214 of the two lock pieces 214 and 215 of the lock lever 43 hits the locked piece 207 of the forward / reverse switching lever 42 as shown by an arrow D, and the return / forward switching lever 42 returns. That is, clockwise rotation is restricted. This is the locked state of the forward / reverse switching lever 42.

FIGS. 11A and 11B are second operation diagrams showing the operation of the power transmission device according to the present invention.
In (a), when the inner wire 102 (see also FIGS. 10A and 10B) of the first cable 45 is pulled as shown by an arrow E, the right rotation pin 92 is pulled. The upper transmission 55 is rotated about the drive shaft 121 as indicated by an arrow F, and the V belt 52 is in a tensioned state (the V belt 53 is in a slack state).

  At this time, the upper transmission portion positioning pin 77 presses the right holding plate 83 as the upper transmission portion 55 rotates, so that the holding plate 83 rotates as indicated by an arrow G. As a result, the tension coil spring 84 is stretched, and the elastic force of the tension coil spring 84 that attempts to return the holding plate 83 to the original position (on the center line 122) gradually increases.

  In (b), when the V-belt 52 is in a tensioned state, the rotation of the drive pulley 51, for example, the rotation in the direction of arrow H is transmitted to the first pulley 64 via the V-belt 52 and attached to the first input shaft 61. The first drive gear 131 rotates in the arrow H direction, and the driven gear 133 that meshes with the first drive gear 131 rotates (forward rotation) in the arrow J direction. Thereby, a small snowplow advances.

  Returning to FIG. 10B, in order to stop and stop the small snowplow, the lock lever 43 may be released to release the forward / reverse switching lever 42. As a result, the restraint of the forward / reverse switching lever 42 by the lock lever 42 is released, and the forward / reverse switching lever 42 is moved by the elastic force of the compression coil springs 84 and 94 shown in FIG. Return to position and become neutral.

12 (a) and 12 (b) are third operation diagrams showing the operation of the power transmission device according to the present invention.
In (a), in order to reverse the small snowplow, when the forward / reverse switching lever 42 is tilted backward from the neutral position as shown by the arrow M (from the position of the two-dot chain line to the position of the solid line), The inner wire 102 of the two cables 46 is pulled as indicated by an arrow N. (At this time, the inner wire 102 of the first cable 45 is drawn into the outer cable 101 of the first cable 45.)

  In (b), while maintaining the state of being tilted after the forward / reverse switching lever 42, the lock lever 43 is tilted toward the grip 41 as shown by the arrow P, and the grip 43b of the lock lever 43 is gripped. Hold with 41.

  As a result, one lock piece 215 of the two lock pieces 214 and 215 of the lock lever 43 hits the locked piece 207 of the forward / reverse switching lever 42 as indicated by the arrow Q, and the return of the forward / reverse switching lever 42 returns. That is, the counterclockwise rotation is restricted. This is the locked state of the forward / reverse switching lever 42.

FIGS. 13A and 13B are fourth operation diagrams showing the operation of the power transmission device according to the present invention.
In (a), when the inner wire 102 (see also FIGS. 12A and 12B) of the second cable 46 is pulled as indicated by an arrow R, the left rotation pin 91 is pulled, and therefore the transmission 13 The upper transmission 55 is rotated about the drive shaft 121 as indicated by an arrow S, and the V belt 53 is tensioned accordingly. At this time, the upper transmission portion positioning pin 77 pushes the left holding plate 82, so that the holding plate 82 rotates as indicated by an arrow T.
As a result, the tension coil spring 84 is extended, and the elastic force of the tension coil spring 84 that attempts to return the holding plate 82 to the original position (on the center line 122) gradually increases.

  In (b), when the V belt 53 is in a tensioned state, the rotation of the drive pulley 51, for example, the rotation in the direction of arrow H is transmitted to the second pulley 66 via the V belt 53 and attached to the second input shaft 62. The second drive gear 132 rotates in the arrow H direction, the idle gear 134 meshed with the second drive gear 132 rotates in the arrow U direction, and the driven gear 133 meshed with the idle gear 134 rotates (reverses) in the arrow H direction. Thereby, a small snowplow reverses.

  Returning to FIG. 12B, in order to stop and stop the reverse movement of the small snowplow, the lock lever 43 may be released to release the lock of the forward / reverse switching lever 42. As a result, the restraint of the forward / reverse switching lever 42 by the lock lever 42 is released, and the forward / reverse switching lever 42 is moved along the two-dot chain line in FIG. 12A by the elastic force of the compression coil springs 84 and 94 shown in FIG. Return to position and become neutral.

  1, 2, and 4, when power is transmitted from the drive source (engine 12) to the drive shaft 121 via the power transmission device 25, the rotation direction of the drive shaft 121 is rotated forward. In the power transmission device 25 that can be switched between forward and reverse rotation, a forward drive pulley (first drive pulley 51A) and a reverse drive pulley (second drive pulley pulley 51B) connected to the output shaft (crankshaft 27) of the engine 12 A forward rotation shaft (first input shaft 61) coupled to the drive shaft 121 via a forward rotation gear train (first gear train 137), and a forward rotation driven pulley attached to the first input shaft 61 ( A first pulley 64), a forward rotation belt (V belt 52) stretched over each of the first drive pulley 51 A and the first pulley 64, and a reverse gear train (second gear) on the drive shaft 121. A reverse rotation shaft (second input shaft 62) connected via a row 138), a reverse driven pulley (second pulley 66) attached to the second input shaft 62, and the second drive pulley 51B and the second drive pulley 51B. A belt for reverse rotation (V belt 53) stretched around each of the two pulleys 66 and a belt for switching a belt for transmitting power among the V belts 52, 53 by stretching only one of the V belts 52, 53. A switching means (rotating mechanism 90) and a neutral holding means (holding mechanism 70) for holding a neutral state in which transmission of power in both the V belts 52 and 53 is cut off by loosening both the V belts 52 and 53. With the rotation mechanism 90, the V-belt 52 is changed from the loosened state to the tensioned state, and at the same time the V-belt 53 is changed to the slackened state, or the V-belt 52 is tensioned. It allows to taut the slack of the V-belt 53 at the same time as the loose state al, it can be switched smoothly forward and reverse drive shaft 121.

Moreover, it is also possible to set the neutral state in which the connection between the crankshaft 27 side of the engine 12 and the drive shaft 121 side is cut off, with both the V belts 52 and 53 being slackened during the forward / reverse switching of the drive shaft 121. it can.
Accordingly, there is no need for a conventional transmission having a plurality of gears and high precision required for parts, a traveling clutch composed of many parts, and the like, and the power transmission device 25, more specifically, the transmission 13 can be simplified. Structure.

  The power transmission device 25 according to the present invention does not include a conventional traveling clutch, but has a structure in which power is transmitted by stretching or loosening the V belts 52 and 53 or the power transmission is cut off. The mechanism 90 can be said to be a kind of clutch. This clutch has a simple structure that simply rotates the upper transmission 55 around the drive shaft 121, and the cost can be reduced.

  Furthermore, the neutral state can be held by the holding mechanism 70, and the drive shaft 121 can be rotated without being constrained by the crankshaft 27 of the engine 12. When the general-purpose machine (small snowplow 10) to which the traveling means (crawler traveling units 14, 16) such as a crawler belt is attached is manually pushed and pulled, the crawler traveling units 14, 16 are easily rotated. The snowplow 10 can be pushed and pulled easily.

  Thus, in the power transmission device 25 of the present invention, the forward rotation and the reverse rotation of the drive shaft 121 can be smoothly switched as a simple structure, and the drive shaft 121 is separated from the crankshaft 27 of the engine 12 in a neutral state. Furthermore, since this neutral state can be held by the holding mechanism 70, it is possible to easily push and pull the small snowplow 10 provided with the crawler running portions 14 and 16 with human power. The direction of the small snowplow 10 can be changed or moved.

  In the present embodiment, the power transmission device 25 is mounted on the small snowplow 10 as shown in FIG. 1, but the present invention is not limited to this and may be applied to a general-purpose machine such as a tillage machine.

  The power transmission device of the present invention is suitable for a small snowplow.

It is a perspective view which shows the small snowplow provided with the power transmission device which concerns on this invention. It is a perspective view which shows the power transmission device which concerns on this invention. It is a top view which shows the power transmission device which concerns on this invention. It is explanatory drawing which shows the power transmission path | route of the power transmission device which concerns on this invention. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is a principal part perspective view which shows the holding plate support structure of the holding mechanism which concerns on this invention. It is a rear view of the transmission which concerns on this invention. It is a principal part side view which shows the steering wheel periphery of the rotation mechanism which concerns on this invention. It is the 1st operation figure showing an operation of the power transmission device concerning the present invention. It is a 2nd operation | movement figure which shows the effect | action of the power transmission device which concerns on this invention. It is a 3rd operation | movement figure which shows the effect | action of the power transmission device which concerns on this invention. It is the 4th operation figure showing operation of the power transmission device concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Drive source (engine), 25 ... Power transmission device, 27 ... Output shaft (crankshaft), 51A ... Forward drive pulley (first drive pulley), 51B ... Reverse drive pulley (second drive pulley), 52 ... Forward belt (V belt), 53 ... Reverse belt (V belt), 55 ... Upper transmission, 56 ... Lower transmission, 61 ... Forward rotation shaft (first input shaft), 62 ... Reverse rotation shaft (second input) Axis), 64 ... Forward driven pulley (first pulley), 66 ... Reverse driven pulley (second pulley), 70 ... Neutral holding means (holding mechanism), 77 ... Upper transmission positioning pin, 81 ... Holding position pin, 82 , 83 ... Holding plate, 84 ... Tensile coil spring, 90 ... Belt switching means (rotating mechanism), 121 ... Drive shaft, 137 ... Forward rotation gear train (first gear train), 138 ... Reverse rotation gear train (second Gear train) .

Claims (1)

In the power transmission device capable of switching the rotation direction of the drive shaft between normal rotation and reverse rotation when transmitting power from the drive source to the drive shaft (121) via the power transmission device (25) ,
The power transmission device is connected to a forward drive pulley (51A) and a reverse drive pulley (51B) connected to the output shaft (27) of the drive source, and to the drive shaft via a forward gear train (137). Forward rotation shaft (61) , a forward rotation driven pulley (64) attached to the forward rotation shaft, and a forward rotation belt (52 ) stretched around each of the forward rotation drive pulley and the forward rotation driven pulley. ) , A reverse shaft (62) coupled to the drive shaft via a reverse gear train (138) , a reverse driven pulley (66) attached to the reverse shaft, and these reverse drive pulley and reverse driven transmission and the reverse rotation belt passed over the respective pulleys (53), the power among the forward rotation belt and the reverse rotation belt by tensioning the only one of these forward rotation belt and the reverse rotation belt That a belt switching means (90) for switching the belt, to hold the neutral state in which refused transmission of power in both the forward rotation belt and the reverse rotation belt by loosening both forward rotation belt and the reverse rotation belt neutral An upper transmission (55) having a holding means (70);
The upper transmission (55) is rotatably attached to the vertically extending drive shaft (121) provided in the lower transmission (56).
The neutral holding means includes an upper transmission positioning pin (77) provided to extend downward from the upper transmission and a holding position pin (81) provided to extend upward from the lower transmission (56). One end portion is rotatably attached to the upper transmission portion, and the other end portion is hung on the holding plate and a pair of left and right holding plates (82, 83) sandwiching the upper transmission portion positioning pin and the holding position pin. Consisting of a passed tension coil spring (84),
A power transmission device characterized by that.

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