JP2012041996A - Case of transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a case of a transmission for a vehicle, which is improved in oiltight performance easily at low cost without changing the shape of the joint flange part of a unit case or adding fastening bolts.SOLUTION: For the case of a transmission for a vehicle, the plurality of unit cases including the joint flange part 21 which is extended outward from the end part of a cylindrical circumferential sidewall and has a plurality of fastening holes 22 separately disposed in a circumferential direction are disposed along the longitudinal direction of a horizontally extended gear shaft, a fastening member (fastening bolt) 5 is inserted to the respective fastening holes 22 and 32 corresponding to the joint flange parts 21 and 31 facing each other of the adjacent unit cases and fastened, and lubricating oil is enclosed in the inside. In the case of the transmission for the vehicle, at least at one part between the fastening holes 22 adjacent in the circumferential direction of the joint flange part 21 of the unit case, a reinforcing plate 6 having prescribed mechanical strength is trained about and joined by the fastening member 5. Further, it is preferable that the reinforcing plate 6 has a press contact part 64 and a reinforcing rib 65 in the intermediate part 63.

Description

  The present invention relates to a transmission case used in a vehicle, and more particularly to an oil-tight structure at a joint surface of a plurality of unit cases.

  A vehicle transmission is structurally formed by a case that holds a transmission gear and a transmission shaft and encloses and holds lubricating oil. The case is generally configured by arranging and joining a plurality of unit cases along the longitudinal direction of the transmission shaft in order to facilitate assembly of various members such as the transmission shaft. In order to join and connect adjacent unit cases, each unit case is provided with a joining flange portion having a plurality of fastening holes spaced in the circumferential direction, and a fastening bolt is inserted into the corresponding fastening hole of the facing joining flange portion. And concluded. Here, the joining force between the joining flange portions is small between the bolts, and a gap may be generated by an external force, and the lubricating oil may leak. For this reason, the liquid solidified sealing material is applied and filled between the joint surfaces of the joint flange portions facing each other to form an oil-tight structure to prevent oil leakage.

  An example of the technology of this type of vehicle transmission case is disclosed in Patent Document 1. The tractor of Patent Literature 1 forms a transmission case by connecting and connecting a plurality of cylindrical cases in the front-rear direction, and a shaft support wall forming body can be detachably attached to the inner peripheral edge of the end of one of the cylindrical cases. It is attached. Thereby, it is said that oil leakage can be prevented only by ensuring the sealing performance between the end faces of the cylindrical case without involving the shaft support portion in the sealing function.

JP 2005-282612 A

  By the way, in cases where a plurality of unit cases are joined, such as Patent Document 1, when a large external force is applied, the entire case may be deformed and a gap may be formed in a part of the joining surface to cause oil leakage. As countermeasures, usually, the flange width in the radial direction and the flange thickness in the axial direction of the joining flange portion are increased, or fastening bolts are added by closing the circumferential intervals of the fastening holes. However, due to problems in production equipment, changing the shape of the joining flange portion may increase the cost significantly. In addition, it may be difficult to add a fastening bolt due to the problem of ease of assembly when mounted on a vehicle.

  The present invention has been made in view of the problems of the background art described above, and is a vehicle that has improved oil tightness easily and at low cost without changing the shape of the joining flange portion of the unit case and adding a fastening bolt. It is an object of the present invention to provide a transmission case.

  The case of the vehicle transmission according to the present invention includes a unit case having a joint flange portion extending outward from an end portion of the cylindrical peripheral side wall and having a plurality of fastening holes spaced apart in the circumferential direction. A plurality of horizontally extending transmission shafts along the longitudinal direction, and a fastening member is inserted into each of the corresponding fastening holes of the joining flange portions facing each other of the adjacent unit cases and fastened, and lubricating oil is contained therein. In the enclosed case of the vehicle transmission, the fastening member is formed by spanning a reinforcing plate having a predetermined mechanical strength at least at one place between the fastening holes adjacent in the circumferential direction of the joining flange portion of the unit case. It is characterized by being fastened together.

  Further, the reinforcing plate has an arc shape along the joining flange portion, and has insertion holes through which the fastening member is inserted at both ends, and on the side facing the joining flange portion at an intermediate portion between the both ends. A pressure contact portion projecting by a predetermined dimension from the both end portions; and when the both end portions of the reinforcing plate are fastened together by the fastening member, the reinforcing plate is deformed and the both end portions are in contact with the joining flange portion, The pressure contact portion may be in pressure contact with the joint flange portion.

  Further, the reinforcing plate has an arc shape along the joining flange portion, and has insertion holes through which the fastening members are inserted at both ends, and on the side not facing the joining flange portion at an intermediate portion between the both ends. You may make it have the reinforcement rib formed thicker than the said both ends.

  In the case of the vehicle transmission according to the present invention, a reinforcing plate having a predetermined mechanical strength is stretched over at least one place between the fastening holes adjacent in the circumferential direction of the joint flange portion of the unit case. Tighten. This reinforcing plate can be selectively used for a portion to be reinforced where there is a great need to prevent oil leakage. For example, it can be selectively used in a place having a long interval when the fastening holes are not arranged at equal intervals, or a location where stress is concentrated even if the fastening holes are arranged at equal intervals. Thereby, the rigidity in the said reinforcement | strengthening object location of a joining flange part is improved, the deformation amount with respect to an external force reduces, oil-tight performance improves, and the oil-tight performance as the whole case improves.

  Further, it is only necessary to add a reinforcing plate to the conventional configuration, and no major change such as a change in the shape of the joining flange portion of the unit case or the addition of a fastening bolt does not occur, which is simple and inexpensive.

  Further, in the aspect in which the reinforcing plate has an arc shape and has a front insertion hole at both ends and a pressure contact portion at the middle portion, the reinforcement plate is deformed by co-fastening, and both ends are in contact with the joint flange portion, and the pressure contact portion is joined. Press contact with the flange. Thereby, in the said reinforcement object location of a joining flange part, a load generate | occur | produces in the direction which closes the joining surface of the intermediate part between adjacent fastening holes, and oil-tight performance improves further.

  Furthermore, in the aspect in which the reinforcing plate has an arc shape and has front insertion holes at both ends and reinforcing ribs in the middle, the rigidity of the joint flange portion at the portion to be reinforced is further enhanced by the reinforcing ribs, and the oil tight performance Is further improved.

It is a figure which shows the example of the case of the transmission for vehicles which can implement this invention. It is the expanded sectional view which showed typically a part of junction connection part of a front side case and a rear side case. It is a perspective view which shows the shape of a reinforcement plate. (1) is a plan view of the reinforcing plate, and (2) is a side view of the reinforcing plate. It is sectional drawing explaining the state which spanned the reinforcement plate between the fastening holes which a joint flange part adjoins, and was fastened together with the fastening bolt. It is the figure which exaggerated and showed the state when external force acted on the location which does not have a reinforcement plate of a joining flange part. It is the figure which exaggerated and showed the state when external force acted on the location which has a reinforcement plate of a joining flange part.

  An embodiment for carrying out the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an example of a case 1 of a vehicle transmission that can implement the present invention. As shown in FIG. 1, a case 1 of a vehicle transmission is configured by arranging and connecting a front case 2 and a rear case 3 forward and backward along a rotation axis AX that extends horizontally. The front case 2 and the rear case 3 correspond to the unit case of the present invention.

  The front case 2 is made of cast and has a joining flange portion 21 extending outward from the rear end portion of the cylindrical peripheral side wall. Ten fastening holes are arranged in the joining flange portion 21 at substantially equal intervals in the circumferential direction. Similarly, the rear case 3 is also made of a casting, and has a joining flange portion 31 extending outward in the circumferential direction in a three-layered manner at the front end portion of the cylindrical peripheral side wall. The joint flange portion 31 is provided with ten fastening holes corresponding to the fastening holes of the joint flange portion 21 of the front case 2. A fastening bolt 5 is inserted and fastened from a fastening hole of the front case 2 to a fastening hole of the rear case 3, and both the cases 2 and 3 are integrally connected. Since the present invention does not limit the thickness of the joining flange portions 21 and 31, the following description will be made schematically by taking as an example a case where the thicknesses of both the joining flange portions 21 and 31 are substantially the same.

  FIG. 2 is an enlarged cross-sectional view schematically showing a part of the joint connecting portion of the front case 2 and the rear case 3. The inner diameter of the fastening hole 22 of the joining flange portion 21 of the front case 2 is larger than the outer diameter of the male screw portion 51 of the fastening bolt 5 that is a fastening member, and the fastening bolt 5 is freely inserted. On the other hand, on the inner peripheral surface of the fastening hole 32 of the joining flange portion 31 of the rear case 3, a female screw to which the male screw portion 51 of the fastening bolt 5 is screwed is formed. The fastening bolts 5 are inserted into the fastening holes 22 of the front case 2 and screwed into the fastening holes 32 of the rear case 3 so that the front case 2 and the rear case 3 are joined and connected. It is like that. Further, as shown in FIG. 2, both the joint flange portions 21 and 31 are in surface contact with each other at the joint surfaces 25 and 35 facing each other so as not to leak the lubricating oil.

  In the present embodiment, there are 10 positions (adjacent positions shown in FIG. 2) between adjacent fastening holes 22, and the reinforcing plate 6 is spanned at least at one position. 3 is a perspective view showing the shape of the reinforcing plate 6. FIG. 4A is a plan view of the reinforcing plate 6, and FIG. 3B is a side view of the reinforcing plate 6. FIG. As shown in the drawing, the reinforcing plate 6 is formed in an arc shape along the joining flange portion 21. Further, the reinforcing plate 6 has insertion holes 62 and 62 through which the fastening bolts 5 are freely inserted at both end portions 61 and 61.

  Further, a pressure contact portion 64 protruding from the both end portions 61 by a predetermined dimension D is formed on the surface of the intermediate portion 63 between the both end portions 61 of the reinforcing plate 6 on the side facing the joining flange portion 21. Further, on the side of the intermediate portion 63 that does not face the joint flange portion 21, there is a reinforcing rib 65 that is formed with a thickness slightly less than twice that of the both end portions 61 and extends along the joint flange portion 21. By having the reinforcing rib 65, the rigidity of the reinforcing plate 6 is enhanced. The length of the reinforcing plate 6 in the arc direction is determined from the interval between the adjacent fastening holes 22, and the width dimension, thickness, and material can be appropriately designed according to the desired rigidity. Further, the size and shape of the reinforcing rib 65 can be designed as appropriate.

  The reinforcing plate 6 is spanned between the adjacent fastening holes 22. Specifically, the reinforcing plate 6 is disposed at a long interval when the fastening holes 22 are not arranged at equal intervals, or at equal intervals. Also, it is preferable to selectively use a reinforcing target portion such as a portion where stress is concentrated. FIG. 5 is a cross-sectional view illustrating a state in which the reinforcing plate 6 is spanned between the adjacent fastening holes 22 of the joint flange portion 21 and fastened together with the fastening bolts 5. As shown in the figure, the reinforcing plate 6 is used by sandwiching both end portions 61 between the head 52 of the fastening bolt 5 and the joining flange portion 21 and fastening them together. In addition, you may make the length of the fastening bolt 5 of the location which fastens the reinforcement plate 6 together longer than the other location which is not fastened together.

  When the fastening bolt 5 inserted through the insertion hole 62 of the reinforcing plate 6 is tightened into the fastening hole 32 of the joint flange portion 31, both end portions 61 of the reinforcing plate 6 are pressed and the predetermined dimensions shown in FIG. The deformation is equivalent to D, and both end portions 61 are in contact with the joining flange portion 21. Further, the press contact portion 64 that protrudes from both end portions 61 is pressed strongly against the joint flange portion 21. Due to this pressure contact, a load F is generated in a direction in which the joint surfaces 25 and 35 of the two joint flange portions 21 and 31 are closed. Further, since the reinforcing plate 6 is deformed together with the joining flange portion 21, the rigidity of the joining flange portion 21 with respect to an external force is increased.

  Next, the operation of the case 1 of the vehicle transmission according to the embodiment will be described while comparing the presence or absence of the reinforcing plate 6. FIG. 6 is a diagram schematically exaggerating a state when the external force FX is applied to a portion of the joining flange portion 21 that does not have the reinforcing plate 6. Both joint flange portions 21 and 22 are deformed by the external force FX, and a gap G <b> 1 is generated between the joint surfaces 25 and 35 in an intermediate portion between the fastening bolts 5. Moreover, FIG. 7 is the figure which exaggerated and showed the state when the external force FX acted on the location which has the reinforcement plate 6 of the joining flange part 21. As shown in FIG. In the portion having the reinforcing plate 6, the deformation amount of the joint flange portions 21 and 22 with respect to the same external force FX decreases due to the overall effect of the increased rigidity and the load F generated at the press contact portion 64. As a result, the gap G2 generated in the intermediate portion between the fastening bolts 5 is significantly smaller than the gap G1 where the reinforcing plate 6 is not provided, and the oil-tight performance is significantly improved. Therefore, the oil-tight performance of the case 1 as a whole can be improved by appropriately selecting the location to be reinforced and using the reinforcing plate 6.

  Further, it is only necessary to add the reinforcing plate 6 to the conventional configuration, and no major changes such as the shape change of the joining flange portions 21 and 31 and the addition of the fastening bolts 5 occur, so that it is simple and low cost.

  In the embodiment, the fastening bolt 5 is inserted through the fastening hole 22 of one joining flange portion 21 and screwed and fastened to the fastening hole 32 of the other joining flange portion 31, but is not limited thereto. For example, the fastening bolt 5 may pass through the fastening holes of both joining flange portions and be screwed and fastened separately using a nut. According to this, a reinforcement plate can be used for both sides of a joint flange part, respectively.

1: Vehicle transmission case 2: Front case (unit case)
21: Joining flange portion 22: Fastening hole 25: Joining surface 3: Rear case (unit case)
31: Joining flange part 32: Fastening hole 35: Joining surface 5: Fastening bolt (fastening member) 51: Male screw part 52: Head 6: Reinforcing plate
61: Both ends 62: Insertion hole 63: Intermediate part
64: Pressure contact portion 65: Reinforcement rib

Claims (3)

A longitudinal direction of a transmission shaft that extends horizontally from a unit case having a joint flange portion that extends outward from an end portion of a cylindrical peripheral side wall and has a plurality of fastening holes spaced apart in the circumferential direction In the case of a transmission for a vehicle, a plurality of arrangements are arranged along, and a fastening member is inserted and fastened into each corresponding fastening hole of the joining flange portion facing each other in adjacent unit cases, and lubricating oil is sealed inside.
A vehicle characterized in that a reinforcing plate having a predetermined mechanical strength is stretched over at least one place between fastening holes adjacent to each other in the circumferential direction of the joint flange portion of the unit case and fastened together by the fastening member. Transmission case. The reinforcing plate has an arc shape along the joining flange portion, and has insertion holes through which the fastening member is inserted at both ends, and the both ends on the side facing the joining flange portion at an intermediate portion between the both ends. Having a press-contact portion protruding by a predetermined dimension from the
The both ends of the reinforcing plate are fastened together by the fastening member, and the reinforcing plate is deformed so that the both ends are in contact with the joint flange, and the pressure contact is in pressure contact with the joint flange. Vehicle transmission case.   The reinforcing plate has an arc shape along the joining flange portion, and has insertion holes through which the fastening member is inserted at both ends, and the both ends on the side of the intermediate portion between the both ends not facing the joining flange portion. The vehicle transmission case according to claim 1, further comprising a reinforcing rib formed thicker than the portion.

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