Contracting Institutions

Abstract

To provide a fastening mechanism capable of improving rigidity of a case of a change gear while suppressing oil leakage from a gap between an oil discharge port of a valve body and an oil introduction port of the case.SOLUTION: The present invention relates to a fastening mechanism for fastening a valve body to a case of a change gear in such a manner that an oil discharge port of the valve body overlaps an oil introduction port of the case in a predetermined direction. The fastening mechanism comprises a fastening member fixed to the case and a fixing member fixing the fastening member to the valve body. In the fastening mechanism, the fixing member includes a head part, and a shaft part which extends from the head part and has an outer diameter smaller than that of the head part. The fastening member includes a penetration hole. The shaft part extends in a direction across the predetermined direction, penetrates the penetration hole while being separated from an inner peripheral surface of the penetration hole and is fitted to a fitting hole formed in the valve body. The head part holds the fastening member with the valve body.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a fastening system. [Background technology]

[0002] In order to increase the rigidity of a transmission case, a fastening mechanism for fastening a valve body to the case is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-054723 A Summary of the Invention [Problem to be solved by the invention]

[0004] The valve body is fastened to the case so that the oil outlet of the valve body overlaps with the oil inlet of the case of the transmission. In this case, depending on how the fastening mechanism is used, the reaction force of the fastening mechanism may act to pull the oil outlet of the valve body away from the oil inlet of the case, causing oil to leak from this gap.

[0005] Therefore, an object of the present invention is to provide a fastening mechanism that can increase the rigidity of the case while suppressing oil leakage from the gap between the oil outlet of the valve body and the oil inlet of the transmission case. [Means for solving the problem]

[0006] The above object can be achieved by a fastening mechanism that fastens the valve body to a transmission case so that an oil outlet of the valve body overlaps with an oil inlet of the case in a predetermined direction, the fastening mechanism comprising: a fastening member fixed to the case; and a fixing member that fixes the fastening member to the valve body, the fixing member including a head and a shank extending from the head and having an outer diameter smaller than that of the head, the fastening member having a through hole, the shank extending in a direction intersecting the predetermined direction, passing through the through hole at a distance from an inner circumferential surface of the through hole, and fitting into a fitting hole formed in the valve body, the head clamping the fastening member between the head and the valve body. Effect of the Invention

[0007] According to the present invention, it is possible to provide a fastening mechanism that can increase the rigidity of the case while suppressing oil leakage from the gap between the oil outlet of the valve body and the oil inlet of the transmission case. [Brief description of the drawings]

[0008] [Figure 1] 1A and 1B are schematic diagrams showing a valve body fixed to a transmission case. [Diagram 2] 2A and 2B are explanatory diagrams of a fastening mechanism in a comparative example. [Diagram 3] 3A and 3B are explanatory views of the fastening mechanism in this embodiment. [Figure 4] 4A and 4B are explanatory views of the bolt and its surroundings. [Diagram 5] 5A and 5B are explanatory diagrams of a first modified example. [Figure 6] 6A and 6B are explanatory diagrams of a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Outline of the configuration of the transmission case 10 and the valve body 50] 1A and 1B are schematic diagrams showing a valve body 50 fixed to a case 10 of a transmission. In Fig. 1A and Fig. 1B, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are shown. Fig. 1A is a side view of the case 10 when viewed in the X-axis + direction. Fig. 1B is a bottom view of the case 10 when viewed in the Z-axis + direction.

[0010] The case 10 includes a central wall portion 11, a front wall portion 12, and a rear wall portion 13. The central wall portion 11 is a generally rectangular cylinder extending along the Y axis, covers a transmission body (not shown), and has an oil pan 30 and a valve body 50 fastened thereto. The front wall portion 12 is provided forward of the central wall portion 11 in the Y axis + direction, is a generally cylindrical shape with a diameter enlarged in the Y axis + direction, and covers a torque converter (not shown). The rear wall portion 13 protrudes from the central wall portion 11 in the Y axis - direction, and supports an output shaft of the transmission body (not shown).

[0011] The valve body 50 is fastened to the central wall 11 by a fastening mechanism 70 or the like so as to contact the bottom wall surface 16 of the central wall 11, as will be described in detail later. This increases the rigidity of the case 10, and suppresses noise during vibration. The oil pan 30 is fixed to the central wall 11 so as to be located further downward in the Z-axis negative direction than the valve body 50. A hydraulic circuit including various valves for supplying oil to the transmission body and the torque converter is formed inside the valve body 50. The valve body 50 sucks oil stored in the oil pan 30 by an oil pump through a strainer, and supplies it to the transmission body and the torque converter as lubricating oil or hydraulic oil. The oil pan 30 collects oil discharged from the transmission body and the torque converter.

[0012] [Fastening mechanism in comparative example] Before describing the fastening mechanism 70 in the present embodiment, a comparative fastening mechanism 70x will be described. Figures 2A and 2B are explanatory diagrams of the fastening mechanism 70x in the comparative example. Figure 2A is a rear view of the valve body 50 as viewed in the Y-axis + direction. Note that the oil pan 30 is omitted from Figure 2A.

[0013] As shown in Fig. 2A, the valve body 50 is fastened to the case 10 such that the upper surface 51 of the valve body 50 contacts the bottom wall surface 16 of the case 10. The bottom wall surface 16 is recessed from the right side wall portion 14 and the left side wall portion 15 of the case 10. Although one bolt 61 is shown in Fig. 2A, in reality, the valve body 50 is fastened to the case 10 such that a plurality of bolts 61 penetrate from the lower surface 52 to the upper surface 51 of the valve body 50. In addition, a knock pin 62 is disposed between the bottom wall surface 16 of the case 10 and the upper surface 51 of the valve body 50, and the knock pin 62 restricts positional deviation of the valve body 50 relative to the case 10 in the XY plane direction.

[0014] An oil discharge port 57 is formed on the top surface 51 of the valve body 50. An oil inlet port 17 is formed on the bottom wall surface 16 of the case 10. The oil inlet port 17 is connected to oil passages formed in the transmission body and the torque converter. The valve body 50 is fastened to the case 10 so that the oil discharge port 57 overlaps with the oil inlet port 17 in the +Z axis direction. The +Z axis direction is an example of a predetermined direction. The oil discharge port 57 discharges oil introduced into the valve body 50 to the oil inlet port 17. The oil discharged from the oil discharge port 57 and introduced into the oil inlet port 17 is supplied to each part via oil passages formed in the transmission body and the torque converter.

[0015] 2B is a detailed view of the fastening mechanism 70x. The fastening mechanism 70x includes a stiffener 71x and bolts 81 and 82. The stiffener 71x is a thin metal plate with its longitudinal direction along the X-axis and its short side along the Y-axis, and is fixed to the case 10 and the valve body 50 in a position substantially parallel to the XY plane. One end of the stiffener 71x is fixed to the left side wall 15 of the case 10 by the bolt 81. The other end of the stiffener 71x is fixed to the lower surface 52 of the valve body 50 by the bolt 82. In detail, the bolt 81 passes through a through hole formed in one end of the stiffener 71x and is screwed into a screw hole formed in the left side wall 15, thereby fixing one end of the stiffener 71x to the left side wall 15. Similarly, the bolt 82 passes through a through hole formed in the other end of the stiffener 71x and screws into a screw hole formed in the valve body 50, thereby fixing the other end of the stiffener 71x to the valve body 50. In this manner, the fastening mechanism 70x fastens the case 10 and the valve body 50 together so as to support the valve body 50 from the lower surface 52.

[0016] The bolt 82 extends along the Z-axis. Therefore, depending on the amount of screwing of the bolt 82, a force may act so that the other end of the stiffener 71x on the bolt 82 side is curved toward the Z-axis + direction more than the one end on the bolt 81 side. In this state, a force may act on the valve body 50 in the Z-axis - direction due to the reaction force of the stiffener 71x in the Z-axis - direction. Here, the pressure of the oil flowing from the oil discharge port 57 to the oil inlet port 17 acts between the top surface 51 and the bottom wall surface 16. If this oil pressure is large, a force may act to pull the top surface 51 away from the bottom wall surface 16. In this way, a gap may be generated between the top surface 51 and the bottom wall surface 16 due to the action of the reaction force of the stiffener 71x and the pressure of the oil, and oil may leak from this gap. If oil leaks, the amount of oil supplied to the transmission may be insufficient.

[0017] [Fastening mechanism in this embodiment] 3A and 3B are explanatory diagrams of the fastening mechanism 70 in this embodiment. Note that, in this embodiment, the same components as those in the comparative example are denoted by the same reference numerals, and redundant explanations are omitted. FIGS. 3A and 3B correspond to FIGS. 2A and 2B, respectively. The fastening mechanism 70 includes a stiffener 71, bolts 81 and 82. The stiffener 71 is a thin metal plate whose longitudinal direction is along the X-axis, like the stiffener 71x, but includes a horizontal portion 72 and a vertical portion 73. The horizontal portion 72 is fixed to the left side wall portion 15 by the bolt 81 and is approximately parallel to the XY plane. In contrast, the vertical portion 73 is fixed to the valve body 50 by the bolt 82 and is approximately parallel to the XZ plane. That is, the stiffener 71 has a shape twisted by approximately 90° around the X-axis midway from one end to the other end. Therefore, the bolt 81 extends along the Z-axis, while the bolt 82 extends along the Y-axis + direction. The stiffener 71 is an example of a fastening member. The bolt 82 is an example of a fixing member. The Y-axis + direction is an example of a direction intersecting with the predetermined direction.

[0018] 4A and 4B are explanatory diagrams of the bolt 82 and its periphery. FIG. 4A is a cross-sectional view parallel to the YZ plane showing the bolt 82 and its periphery. FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A. The valve body 50 has a rib portion 53 protruding from the lower surface 52. The rib portion 53 has a predetermined thickness along the Y axis and protrudes in the negative direction of the Z axis from the lower surface 52. The rib portion 53 is formed with a fitting hole 54 penetrating along the Y axis. A female screw groove is formed on the inner periphery of the fitting hole 54. FIGS. 4A and 4B show a central axis 54C of the fitting hole 54 along the Y axis.

[0019] A through hole 74 is formed in the vertical portion 73 of the stiffener 71. The bolt 82 has a head 821 and a shaft portion 822 that has an outer diameter smaller than that of the head 821 and is longer than the head 821. A male screw groove is formed on the outer periphery of the shaft portion 822. The outer diameter of the head 821 is larger than the inner diameter of the through hole 74. FIGS. 4A and 4B show a center axis 74C of the through hole 74 along the Y axis. The shaft portion 822 of the bolt 82 passes through the through hole 74 and screws into the fitting hole 54, and the vertical portion 73 of the stiffener 71 is sandwiched between the head 821 of the bolt 82 and the rib portion 53 of the valve body 50.

[0020] Here, the inner diameter of the through hole 74 is formed to be larger than the outer diameter of the shaft portion 822 so that the shaft portion 822 passes through the through hole 74 with some play. Therefore, as shown in Figures 4A and 4B, the shaft portion 822 is separated from the inner peripheral surface of the through hole 74 without contacting it, and the central axis 54C of the fitting hole 54 and the central axis 74C of the through hole 74 are shifted from each other in the XZ plane direction.

[0021] Because the bolt 82 extends along the Y-axis in this manner, no force in the Z-axis direction acts on the stiffener 71, regardless of the amount of engagement between the shaft portion 822 of the bolt 82 and the fitting hole 54. This makes it possible to avoid the generation of a reaction force in the negative Z-axis direction as in the stiffener 71x of the comparative example, and suppress oil leakage.

[0022] Also, for example, assume that the inner diameter of the through hole 74 and the outer diameter of the shaft portion 822 are the same, the shaft portion 822 is in contact with the inner peripheral surface of the through hole 74, and the other end side of the stiffener 71 is bent in the Z-axis + direction and fixed to the rib portion 53 by the bolt 82. In this case, as in the comparative example, a reaction force acts on the stiffener 71 in the Z-axis - direction, which may cause oil leakage. In this embodiment, the inner diameter of the through hole 74 is larger than the outer diameter of the shaft portion 822, and the shaft portion 822 is separated from the inner peripheral surface of the through hole 74. For this reason, it is possible to avoid the above-mentioned reaction force being generated on the stiffener 71, and to suppress oil leakage.

[0023] Furthermore, since the valve body 50 is fixed to the case 10 by such stiffeners 71, the rigidity of the case 10 is increased while oil leakage is suppressed.

[0024] In this embodiment, the through hole 74 is circular, but the shape is not limited as long as it is large enough so that the shaft portion 822 of the bolt 82 does not come into contact with it.

[0025] [Modified fastening mechanism] Next, several modified examples will be described. In addition, the same reference numerals are given to the same configurations as those of the present embodiment described above, and the duplicated description will be omitted. Figures 5A and 5B are explanatory diagrams of a first modified example. Figures 5A and 5B correspond to Figures 3A and 3B, respectively. The stiffener 71a of the fastening mechanism 70a is not twisted in the middle, unlike the stiffener 71 of this embodiment, and is fixed to the case 10a and the valve body 50 in a posture approximately parallel to the XZ plane, unlike the comparative example. Furthermore, both of the bolts 81 and 82 extend along the Y axis. A fitting hole into which the bolt 81 is screwed is formed along the Y axis in the left wall portion 15a of the case 10a. Also, similar to the stiffener 71 of the present embodiment described above, the stiffener 71a has a through hole 74 through which the shaft portion 822 of the bolt 82 passes with play. The stiffener 71a is an example of a fastening member.

[0026] In this way, even if the bolt 81 extends along the Y-axis, the generation of a reaction force in the negative Z-axis direction in the fastening mechanism 70a can be avoided, as in this embodiment, to suppress oil leakage. Note that the direction in which the bolt 81 and the fitting hole in the case 10a into which the bolt 81 is screwed extend is not limited to the Y-axis direction and is arbitrary. Therefore, the direction in which the bolt 81 and the fitting hole extend may be set in consideration of the ease of mounting the fastening mechanism 70a to the case 10a.

[0027] 6A and 6B are explanatory diagrams of the second modified example. FIG. 6A and FIG. 6B correspond to FIG. 3A and FIG. 3B, respectively. In the fastening mechanism 70b of the second modified example, rivets 81b and 82b are used instead of the bolts 81 and 82. Like the bolt 82, the rivet 82b also includes a head and a shaft portion extending from the head and having an outer diameter smaller than that of the head. No male thread groove is formed on the outer periphery of the shaft portion of the rivets 81b and 82b. Similarly, no female thread groove is formed on the inner periphery of the fitting hole of the left side wall portion 15b of the case 10b and the fitting hole of the valve body 50b into which these rivets are respectively fitted. Therefore, the shaft portions of the rivets 81b and 82b are press-fitted into the respective fitting holes. The rivet 82b is an example of a fixing member. In the fastening mechanism 70 of the present embodiment described above, the rivet 81b may be used instead of the bolt 81. That is, the method for fixing the stiffeners 71 and 71a to the case 10 or the like is not limited.

[0028] In the above embodiment and modified examples, the fastening mechanisms 70, 70a, and 70b are located on the negative Z-axis side relative to the oil inlet 17 and the oil outlet 57, but this is not limited thereto. Also, the stiffeners 71 and 71a are arranged such that their longitudinal direction is along the X-axis, but this is not limited thereto. Also, in the above embodiment and modified examples, the bolts 82 and rivets 82b are shown as examples of the fixing members, but this is not limited thereto, and screws, bolts, and rivets may also be used.

[0029] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0030] 10 Cases 17 Oil inlet 50 Valve body 54 Fitting hole 57 Oil outlet 70 Fastening mechanism 71, 71a Stiffener (fastening member) 74 Through Hole 82 Bolt (fixing member) 821 Head 822 Shaft 82b Rivet (fixing member)

Claims

[Claim 1] A fastening mechanism for fastening a valve body to a transmission case such that an oil outlet of the valve body overlaps with an oil inlet of the transmission case in a predetermined direction, A fastening member fixed to the case; a fixing member that fixes the fastening member to the valve body, The fixing member includes a head portion and a shaft portion extending from the head portion and having an outer diameter smaller than that of the head portion, The fastening member has a through hole, the shaft portion extends in a direction intersecting the predetermined direction, passes through the through hole while being spaced apart from an inner circumferential surface of the through hole, and is fitted into a fitting hole formed in the valve body, The fastening mechanism includes a head portion that sandwiches the fastening member between the head portion and the valve body.

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