Power case shaft extraction structure

Abstract

To provide a shaft extraction part structure of a power case that prevents foreign matter, such as slurry, falling along a case external surface from reaching a sliding portion, that is, a shaft extraction part so as to reduce the risk that an oil seal and a bearing are prone to wear, by further devising its structure.SOLUTION: In a shaft extraction structure of a power case, an insertion hole part 14 through which a rotational shaft 3 is passed is formed in a case outer wall 1A of a power case 1, and the case outer wall 1A is provided with a guide part G capable of diverting foreign matter i falling along a case outer surface 1C of the power case 1 from the insertion hole part 14. The guide part G has a rib-like wall 17 formed on the case outer wall 1A so as to protrude from the case outer surface 1C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a shaft extraction structure of a power case such as an engine cylinder block, a transmission case, or a transmission case, in which an insertion hole for passing a rotating shaft is formed in the outer wall of the power case. [Background technology]

[0002] For example, as disclosed in Patent Document 1, a crankshaft (5) is taken out from a timing transmission case (2: power case) in an engine. Specifically, the crankshaft (5) is taken out from a crankshaft through hole (4: shaft outlet portion) of the timing transmission case (2) via a sleeve (21) and an oil seal (6), and a crank pulley (22) is attached to the crankshaft (5).

[0003] The engines described above are often mounted on self-propelled vehicles such as agricultural tractors, combine harvesters, lawnmowers, and other industrial vehicles that are primarily used outdoors. In most cases, the engine is housed in the bonnet or the like in such self-propelled vehicles, but when driving in the rain or on rough roads such as wasteland, fields, or rice paddies, foreign objects such as rainwater or muddy water may reach the engine.

[0004] Foreign objects that reach the engine tend to fall along the outer walls of the engine, i.e., the outer surfaces of the cylinder block and transmission case, and foreign objects such as muddy water may reach the crankshaft outlet. Therefore, if the engine is designed in such a way that muddy water or rainwater that falls along the outer surface of the case can easily reach the oil seal at the outlet, there is an increased risk that the sealing function will be prematurely impaired or the bearings will be easily worn out.

[0005] The above-mentioned risk exists not only in Patent Document 1 (see FIG. 1), but also in the PTO shaft (47) taken out from the rear end of the transmission case (1) in Patent Document 2 (see FIG. 2 and FIG. 4 in Patent Document 2). Therefore, there is still room for improvement in the risk of foreign matter, such as muddy water, dropping down from the outer surface of the case reaching the shaft take-out portion of the power case. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-51949 A [Patent Document 2] JP 2007-321823 A Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide an improved shaft outlet structure for a power case that reduces the risk of wear of oil seals and bearings through further structural innovation and makes it less likely that foreign matter, such as muddy water, that runs down the outer surface of the case will reach the sliding part of the shaft, i.e., the shaft outlet. [Means for solving the problem]

[0008] The main configuration of the present invention is as follows. The present invention provides a shaft take-out structure for a power case, the power case having an outer wall formed with an insertion hole for passing a rotating shaft therethrough, the outer wall being provided with a guide portion for diverting foreign matter that falls along the outer surface of the power case away from the insertion hole, The guide portion is configured to have a rib-shaped wall formed on the outer wall of the case so as to protrude from the outer surface of the case, The rib-like wall is formed in a mountain shape when viewed in the axial direction of the rotating shaft, one end and the other end in the radial direction of the rotating shaft, which are both lower ends of the rib-shaped wall, protrude radially outward beyond a diameter of the insertion hole portion, When viewed in the axial direction of the rotating shaft, a horizontal line passing through the axis of the rotating shaft is assumed, and the two lower ends of the rib-like walls are positioned at a position coinciding with the horizontal line or at a position below the horizontal line.

[0009] For other inventions, see the claims. Effect of the Invention

[0010] According to the present invention, a guide portion is provided on the outer wall of the case, so that even if foreign matter such as rainwater or muddy water falls down the outer wall of the power case, the guide portion guides the foreign matter such as rainwater or muddy water away from the insertion hole portion, preventing it from reaching the insertion hole portion. Therefore, even if an oil seal is placed in the insertion hole, muddy water or rainwater dripping down the outer surface of the case is unlikely to reach the insertion hole or oil seal, thereby reducing or eliminating the risks of the sealing function being easily impaired or the bearings being easily worn.

[0011] As a result, it is possible to provide an improved shaft outlet structure for a power case that reduces the risks associated with the insertion hole portion, such as the tendency of oil seals and bearings to wear out, and prevents foreign matter, such as muddy water, that runs down the outer surface of the case from reaching the sliding portion of the shaft, i.e., the insertion hole portion. [Brief description of the drawings]

[0012] [Figure 1] A front view showing the lower end of the transmission case [Diagram 2] A partially cutaway side view showing the surrounding structure of the shaft outlet of the transmission case [Diagram 3] (A) A cross-sectional view of the ZZ line in FIG. 1, (B) a front view of the main part showing the muddy water guiding action of the guide part [Figure 4] Front view of transmission case [Diagram 5] Engine front view [Figure 6] Left side view of the engine DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of a shaft take-out portion structure for a power case according to the present invention will be described with reference to the drawings, with an example in which the structure is applied to a transmission case in an industrial engine mounted on an agricultural tractor or the like.

[0014] 5 and 6 show a vertical in-line multi-cylinder diesel engine E as an example of an industrial engine. This engine E includes a cylinder block 2, a cylinder head 18, a head cover 19, a transmission case (front case) 1, a flywheel housing 20, and an oil pan 21. The cylinder block 2 is composed of a lower crankcase 2a and an upper cylinder section 2b. A cylinder head 18 is attached to the top of the cylinder section 2b, and a head cover 19 is attached to the top of the cylinder head 18.

[0015] The direction of the axis Q of the crankshaft 3 is defined as the front-rear direction, with the side where the flywheel housing 20 is located being the rear, and the side where the transmission case 1 assembled to the cylinder block 2 is located being the front. The side where the exhaust manifold 23 and the EGR cooler 24 are located being the left, and the opposite side where the intake manifold (not shown) and the like are located being the right.

[0016] 5 and 6, reference numeral 25 denotes an alternator, 26 denotes a cooling fan, 27 denotes a water pump, 28 denotes a turbocharger, 29 denotes a transmission belt, 31 denotes an exhaust pipe, 32 denotes an exhaust treatment case, 33 denotes an oil cooler, and 34 denotes an oil filter. The transmission case 1 is a transmission mechanism d (see FIG. 2) for driving the engine accessories h (see FIG. 2) by the crankshaft 3 in the engine E and / or a housing (structural body) that covers the engine accessories h. The engine accessories h include the oil pump P, the water pump 27, the supply pump 42, a valve mechanism (not shown), a side PTO shaft (not shown), etc., and the transmission mechanism d includes the gear interlocking mechanism 22 (see FIG. 2), etc.

[0017] The engine E is equipped with an oil pan 21, an oil pump P provided in the transmission case 1, an oil filter 34 and an oil cooler 33 attached to the transmission case 1, and an oil gallery (not shown) provided in the cylinder block 2. The engine oil in the oil pan 21 is pumped by the oil pump P through the oil filter 34 and the oil cooler 33, and is then supplied from the oil gallery to various parts to be lubricated, such as a valve train (not shown) and a bearing j of the crankshaft 3 (see FIG. 2).

[0018] Next, the shaft outlet portion 1B will be described. As shown in Figures 1 and 2, one end of the crankshaft 3 is pivotally supported by a bearing portion j on the side wall 2A of the cylinder block 2, and the shaft tip portion 3A of the crankshaft 3 extends to the outside by penetrating the front wall (one example of the case outer wall) 1A of the transmission case 1. A crank pulley 4 is fitted to the shaft end portion 3a projecting to the outside of the transmission case 1 at the shaft tip portion 3A in a state of integral rotation by engagement means 5 such as spline engagement, and an oil pump (trochoid pump) P is configured on the inside portion of the front wall 1A.

[0019] The shaft tip 3A has a first drive shaft portion 3k at the root side (the side of the bearing shaft portion 3h pivotally supported on the side wall 2A), a shaft end portion 3a at the tip side formed on a spline shaft, and a second drive shaft portion 3c located between the first drive shaft portion 3k and the shaft end portion 3a in the direction of the axis Q. The diameter of the first drive shaft portion 3k is clearly smaller than the bearing shaft portion 3h and slightly larger than the second drive shaft portion 3c, and the diameter of the shaft end portion 3a (the outer diameter of the spline shaft) and the diameter of the second drive shaft portion 3c are the same. The first and second drive shaft portions 3k, 3c are located outside the cylinder block 2 and are covered by the transmission case 1.

[0020] The transmission case 1 is fixed mainly by bolts to the front surface of the cylinder block 2, and as shown in Fig. 4, has a mounting portion 30 for an oil cooler 33, an accommodation portion 35 for the water pump 27, a suction water passage 36 to the water pump 27, and a number of holes 37 for bolting. A shaft outlet portion 1B, i.e., a bulging case portion 1B, is formed at the bottom of the transmission case 1 to allow the crankshaft 3 to pass through and to accommodate the oil pump P.

[0021] 2, a drive gear 6 is fitted to the first drive shaft portion 3k in a state of integral rotation by key connection or the like, and an inner rotor 8 is fitted to the second drive shaft portion 3c in a state of integral rotation via a cylindrical pump sleeve 7. An outer rotor 9 that meshes with the inner rotor 8 is fitted inside the bulging case portion 1B of the transmission case 1 so as to be relatively rotatable. Reference numeral 10 denotes a pump cover that serves as an inner lid for the bulging case portion 1B, and a pressing flange 11 is fitted to the second drive shaft portion 3c between the pump sleeve 7 and the drive gear 6 in the direction of the axis Q.

[0022] A seal sleeve 12 fitted onto the shaft end 3a is provided between the boss portion 4A of the crank pulley 4 and the pump sleeve 7 in the direction of the axis Q, and an oil seal (one example of a sealing mechanism) 13 is fitted onto the seal sleeve 12 in a relatively rotatable state. A cylindrical boss wall 14a is formed on the radially inner side of the vertical side wall 1b of the bulging case portion 1B, and a stop wall 14b expanding radially from the axis Q is formed on the inner side of the boss wall 14a in the direction of the axis Q.

[0023] The oil seal 13 is fitted into the boss wall 14a by, for example, press fitting while abutting against the stop wall 14b. In other words, a trochoid type oil pump P is provided which is made up of the inner and outer rotors 8, 9, the bulging case portion 1B which houses these rotors, the pump cover 10, etc. 1 and 4, reference numeral 38 denotes an attachment portion for the rotation sensor, 39 denotes an intake portion (an intake oil path of the oil pump P), 40 denotes a pressure relief portion (a leak pressure relief path of the oil pump P), and 41 denotes a discharge portion (a pressurized oil path of the oil pump P). The attachment portion 38, the intake portion 39, the pressure relief portion 40, and the discharge portion 41 are all provided on or near the outer periphery of the bulging case portion 1B.

[0024] As shown in Fig. 2, a driven gear 15 meshing with the drive gear 6 is pivotally supported on a support shaft 16 fixedly attached to the outside of the side wall 2A of the cylinder block 2. A gear interlocking mechanism 22 (transmission mechanism d) having the drive gear 6 and the driven gear 15 is configured inside the transmission case 1. The gear interlocking mechanism 22 drives an engine accessory h that directly or indirectly meshes with the driven gear 15. Examples of the engine accessory h driven by the gear interlocking mechanism 22 include a valve mechanism (not shown) such as an intake and exhaust cam, a supply pump 42, or a side PTO shaft (side PTO device: not shown).

[0025] 1 and 2, an insertion hole 14 consisting of a boss wall 14a and a stop wall 14b is formed in the bulging case portion 1B. That is, the insertion hole 14 through which the crankshaft (an example of a rotating shaft) 3 passes is formed in the front wall (an example of a case outer wall) 1A of the transmission case (an example of a power case) 1. More specifically, the shaft tip 3A of the crankshaft 3 passes through an insertion hole 14c, which is the inner peripheral surface of the stop wall 14b, in a loosely fitted state.

[0026] Next, the guide portion G will be described. As shown in Fig. 1 and Fig. 2, the vertical side wall 1b of the bulging case portion 1B is provided with a guide portion G capable of diverting foreign matter i such as rainwater, muddy water, straw, dust, etc., that runs down the case outer surface 1C (of the front wall 1A) of the transmission case 1 from the insertion hole portion 14, preferably from the oil seal 13. The guide portion G is configured with a rib-like wall 17 formed on the vertical side wall 1b of the bulging case portion 1B so as to protrude forward (sideways) from the case outer surface 1C, and the rib-like wall 17 is formed in a mountain shape (see Fig. 1) when viewed from the direction of the axis Q.

[0027] As shown in Fig. 1, the rib-like wall 17 is a narrow rib portion that protrudes forward (laterally) from the case outer surface 1C, which is the outer surface (notation omitted) of the vertical side wall 1b, and has a shape (triangular roof shape: pent roof) that is symmetrical (or asymmetrical) when viewed in the direction of the axis Q. The left rib portion 17L and the right rib portion 17R slope downward to the left and right from an apex located above the axis Q on the vertical line X passing through the axis Q, specifically, at a point that is the same as or slightly lower than the apex of the outer peripheral surface 1g of the bulging case portion 1B. The lower ends of the ribs 17L and 17R are aligned with the horizontal line Y, Below that 2, the outer surface of the vertical side wall 1b, the outer peripheral surface 1g of the bulging case portion 1B, and the ring-shaped front peripheral surface (notation omitted) of the boss wall 14a are also the case outer surface 1C.

[0028] As shown in FIG. 1, the left and right rib portions 17L, 17R are formed as linear ribs 17t on the upper side (vertical line X side) from an intermediate angle (e.g., 20 to 50 degrees) between a horizontal line Y and a vertical line X passing through the axis Q, and are formed as arc-shaped ribs 17r with respect to the axis Q on the lower side (horizontal line Y side) from the intermediate angle. As shown in FIG. 3(B), the downward angle θ of the linear rib 17t with respect to the horizontal line (horizontal line Y) is preferably 30 to 40 degrees. As shown in FIG. 3(A), an L-shaped recessed corner portion s is formed by the upper surface 17a of the rib-like wall 17 and the case outer surface 1C of the vertical side wall 1b. The vertical side wall 1b and the outer peripheral surface 1g are defined as parts of the front wall 1A.

[0029] 1 to 3, the front wall 1A of the transmission case 1, more specifically, the bulging case portion 1B that protrudes slightly forward from the front wall 1A, is formed with an insertion hole 14 through which the crankshaft 3 passes, and the case outer surface 1C of the bulging case portion 1B having the insertion hole 14 is provided with a guide portion G that can deflect foreign object i that falls along the case outer surface 1C from the insertion hole 14. The action and effect of the guide portion are as follows.

[0030] In other words, in the case of a conventional structure that does not have the ribbed wall 17 (guide portion G), rainwater or muddy water i that drips down can easily run down the vertical side wall 1b of the bulging case portion 1B and reach the boss wall 14a (insertion hole portion 14), i.e., the oil seal 13. In contrast, in the shaft removal portion 1B of this embodiment, due to the presence of the bulging case portion 1B that protrudes slightly forward, foreign matter i, such as rainwater or muddy water i, that runs down the case outer surface 1C of the front wall 1A is first guided to the left and right by the outer peripheral surface 1g of the bulging case portion 1B, making it difficult for it to reach the case outer surface 1C of the vertical side wall 1b.

[0031] Even so, some rainwater or muddy water i will flow downward over the outer peripheral surface 1g and fall. However, since there is guide portion G, even if rainwater or muddy water i falls from the case outer surface 1C of the front wall 1A to the case outer surface 1C of the bulging case portion 1B, as shown in FIG. 3(B), the rainwater or muddy water i will be guided to the left and right along the mountain-shaped ribbed wall 17 (guide portion G) (mainly along the corner portion s), and will almost never climb over the ribbed wall 17 and reach the insertion hole portion 14.

[0032] In other words, if the structure is such that muddy water or rainwater that runs down the outer surface of the case can easily reach the insertion hole or oil seal, there is an increased risk that the sealing function will be easily impaired or the bearing will be easily worn. However, the shaft extraction part structure of this embodiment reduces or eliminates this risk, and the function of the oil seal is maintained and durability is improved. The addition of the guide part G also provides the following operational effects (1) to (4).

[0033] (1) Rainwater and muddy water i can be actively guided to the side surface (upper surface 17a) and base of the ribbed wall 17 by surface tension, thereby preventing the rainwater and muddy water i from entering the boss wall 14a, i.e., the oil seal 13. (2) Since the ribbed wall 17 has a pent roof shape when viewed from the direction of the axis Q, a drip-proof structure is provided in which rainwater or muddy water i does not reach the insertion hole portion 14 even if the attitude of the engine E changes. (3) The forward protrusion (protruding height) of the ribbed wall 17 from the vertical side wall 1b is low (e.g., 1 to 3 mm), so that the shape of the mating part (such as the crank pulley 4) arranged opposite the bulging case portion 1B is not changed.

[0034] (4) One end of the rib-shaped wall 17 in the radial direction (of the axis Q) of the rotating shaft 3 and The other ends (the lower ends of the ribs 17L, 17R in this embodiment) protrude radially outward (outward in the left-right direction) from the diameter of the insertion hole 14, more specifically, the inner diameter of the boss wall 14a. Therefore, even if the foreign matter i that has traveled down the rib-like walls 17 to the left and right lower ends travels from there vertically or slightly toward the axis Q along the case outer surface 1C of the vertical side wall 1b, it is advantageously prevented from reaching the insertion hole 14 (the inner peripheral surface of the boss wall 14a).

[0035] [Another embodiment] The rib-like wall 17 may be configured as a guide portion G having arc-shaped ribs 17r all in a semicircular mountain shape (lid-like) when viewed in the direction of the axis Q. The present invention is also applicable to a transmission case 1 having no bulging case portion 1B and a structure in which the insertion hole portion 14 is formed in the front wall 1A itself (no outer peripheral surface 1g). The rib-like wall 17 can be set in various shapes, such as a downward U-shape, a sloped roof shape, or an elliptical arc shape when viewed in the direction of the axis Q.

[0036] The rib-like wall 17 may have an acute corner portion s at the front end side of its outer circumferential surface 1g that is closer to the outside in the radial direction of the axis Q, which has the advantage of strengthening the effect of preventing foreign matter i from entering the insertion hole portion 14. Also, the rib-like wall 17 may be a separate part from the transmission case 1, and may be attached liquid-tightly to the case outer surface 1C.

[0037] As the power case 1, various types of cases can be used, such as a transmission case, a cylinder block 2, a transmission case, etc. As foreign matter i that runs down the case outer surface 1C, various types of matter can be considered, such as rainwater, muddy water, grass clippings, straw, dirt and dust, water from a car wash, etc. As the sealing mechanism 13, various types of seals can be used, such as an oil seal, a dust seal, a mechanical seal, etc. (summary) In this embodiment, the insertion hole portion 14 has a cylindrical boss wall 14a and a stop wall 14b inside the boss wall 14a, with the direction of the axis Q of the rotating shaft 3 being the front-to-rear direction, the protruding side of the guide portion G being the front side, and the side opposite the front side being the rear side, the oil seal 13 is fitted inside the boss wall 14a with the stop wall 14b abutting on the rear side, and is fitted outside the seal sleeve 12 fitted on the rotating shaft 3 in a state of rotating relative to it, the gap between the stop wall 14b and the seal sleeve 12 being covered from the rear side by an inner rotor 8 of a trochoidal oil pump P, and the inner rotor 8 and outer rotor 9 of the oil pump P are covered from the rear side by a pump cover 10. [Explanation of symbols]

[0038] 1 Power case, transmission case 1A Case outer wall 1B Bulging case part 1C Case exterior 3 Rotating shaft, crankshaft 13 Sealing mechanism, oil seal 14 Insertion hole 17 Ribbed Wall 22 Transmission Mechanism E-Engine G Guide part Q axis center i Foreign matter

Claims

1. an insertion hole for passing a rotating shaft through the case outer wall of the power case; and a guide portion for directing foreign matter falling along the case outer surface of the power case away from the insertion hole, the guide portion being provided on the case outer wall; The guide portion is configured to have a rib-shaped wall formed on the outer wall of the case so as to protrude from the outer surface of the case, The rib-like wall is formed in a mountain shape when viewed in the axial direction of the rotating shaft, one end and the other end in the radial direction of the rotating shaft, which are both lower ends of the rib-shaped wall, protrude radially outward beyond a diameter of the insertion hole portion, A shaft outlet structure of a power case, in which, when viewed in the axial direction of the rotating shaft, a horizontal line is assumed to pass through the axis of the rotating shaft, and the both lower ends of the rib-like walls are positioned at a position that coincides with the horizontal line or at a position below the horizontal line.

2. 2. The shaft outlet structure of a power case as described in claim 1, wherein the insertion hole portion is formed in a bulging case portion that protrudes outward from the power case, and the rib-shaped wall is formed to protrude from the outer case surface of the bulging case portion.

3. A shaft extraction portion structure of a power case as described in claim 1 or 2, wherein a sealing mechanism acting on the rotating shaft is embedded in the insertion hole portion.

4. A shaft extraction portion structure of a power case as described in Claim 3, wherein the sealing mechanism is an oil seal.

5. The shaft outlet structure of a power case as described in claim 4, wherein the insertion hole portion has a cylindrical boss wall and a stop wall inside the boss wall, the direction of the axis of the rotating shaft is the front-to-rear direction, the protruding side of the guide portion is the front side, and the side opposite the front side is the rear side, the oil seal is fitted inside the boss wall with the stop wall abutting the rear side and is fitted outside in a state of rotating relative to a seal sleeve fitted on the rotating shaft, the gap between the stop wall and the seal sleeve is covered from the rear side by the inner rotor of a trochoidal oil pump, and the inner rotor and outer rotor of the oil pump are covered from the rear side by a pump cover.

6. The shaft outlet structure of a power case according to any one of claims 1 to 5, wherein the power case is a transmission mechanism for driving engine accessories by a crankshaft in an engine and / or a transmission case covering the engine accessories.

Images