Transmission

Abstract

Regarding the transmission, the engagement clutch can be forcibly set to neutral. [Solution] The disclosed transmission 1 comprises a meshing clutch 10 having a low-side dog gear 11, a high-side dog gear 13, and a sleeve 16. The transmission 1 comprises an axial shaft 4, a casing 5, an end hole 7, a closing member 8, and a spacer 9. A shift fork 17 that fits onto the outer circumference of the sleeve 16 is fixed to the shaft 4. The casing 5 has a shaft hole 6 that supports the shaft 4 so as to be axially slidable. The end hole 7 is formed in the casing 5 near the end of the shaft 4 and connects the outer surface of the casing 5 to the inside of the shaft hole 6. The closing member 8 closes the end hole 7. The spacer 9 is interposed between the outer surface of the casing 5 and the closing member 8 and maintains the separation state between the closing member 8 and the shaft 4.

Description

Technical Field

[0001] The present invention relates to a transmission device provided with an engagement clutch.

Background Art

[0002] In a four-wheel drive vehicle, a transfer for distributing the driving force to the front and rear wheels may be provided. Inside the transfer, for example, a switching device for switching between a state where the driving force is transmitted to all the front and rear wheels and a state where the driving force is transmitted to either the front or rear wheels is incorporated. Further, an electric engagement clutch is interposed in the driving force transmission path so that one of a plurality of gears (low-speed gear, high-speed gear) having different reduction ratios can be selected (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the power supply of the engagement clutch is stopped, the engagement state of the clutch cannot be controlled, and in many cases, either the front or rear wheels and the drive source are connected. However, assuming a failure in which the vehicle cannot move forward, it is desirable to prepare a mechanism that can forcibly fix the engagement clutch in the neutral state so that the vehicle can be towed smoothly by another vehicle without hesitation. Existing transmission devices provided with an engagement clutch have room for improvement in this regard. In particular, in a transfer, a structure that avoids a neutral state in which the driving force is not transmitted to the front and rear wheels is generally adopted, and it is often impossible to forcibly set the engagement clutch in the neutral state.

[0005] One of the objectives of this invention is to provide a transmission that can forcibly put the engagement clutch into a neutral position, as devised in light of the above-mentioned problems. However, other objectives of this invention include achieving effects and benefits that cannot be obtained with conventional technology, derived from the various configurations shown in the "Modes for Carrying Out the Invention" section below. [Means for solving the problem]

[0006] The disclosed transmission can be implemented in the following embodiments (examples of application) and solves at least some of the above-mentioned problems. Each of the embodiments from Embodiment 2 onward is an additional embodiment that can be appropriately selected and each of the embodiments is optional. None of the embodiments from Embodiment 2 onward disclose any embodiments or configurations that are essential to this case.

[0007] Embodiment 1. The transmission disclosed is a transmission comprising a meshing clutch having a low-side dog gear, a high-side dog gear, and a sleeve. The transmission comprises a shaft formed in an axial shape to which a shift fork fitted to the outer circumference of the sleeve is fixed; a casing having a shaft hole that supports the shaft so as to be slidable in the axial direction; an end hole formed in the casing near the end of the shaft and connecting the outer surface of the casing to the inside of the shaft hole; a closing member that closes the end hole; and a spacer interposed between the outer surface and the closing member to maintain a separation state between the closing member and the shaft.

[0008] Embodiment 2. With respect to embodiments including Embodiment 1 described above, it is preferable that the shaft is provided so as to be movable between a low position in which the sleeve engages with the low-side dog gear, a high position in which the sleeve engages with the high-side dog gear, and a neutral position in which the sleeve does not engage with either the low-side dog gear or the high-side dog gear. Furthermore, it is preferable that the length of the spacer is defined as the first dimension, the distance from the tip of the closing member attached to the end hole via the spacer to the end face of the shaft in the neutral position is defined as the second dimension, and the first dimension is greater than or equal to the second dimension.

[0009] Embodiment 3. With respect to embodiments including Embodiment 2 described above, it is preferable that the closing member attached to the end hole via the spacer is not in contact with any of the shafts, whether in the low position, the high position or the neutral position. Embodiment 4. With respect to embodiments including Embodiment 1 described above, it is preferable that the end hole is a hollow cylindrical hole arranged coaxially with the shaft.

[0010] Embodiment 5. With respect to embodiments including Embodiment 1 described above, it is preferable that the closing member is a bolt and the end hole is a bolt hole. Embodiment 6. With respect to embodiments including Embodiment 1 described above, it is preferable that the end holes are provided near both ends of the shaft, and that a pair of the closing member and the spacer are provided. [Effects of the Invention]

[0011] According to the disclosed transmission, the spacer maintains the separation between the closing member and the shaft, allowing the engagement clutch to operate correctly. Furthermore, by removing the spacer and pushing the closing member into the end hole, the shaft can be physically fixed in the neutral position, forcing the engagement clutch into the neutral state. Therefore, convenience can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] This is a block diagram of a transmission according to an embodiment. [Figure 2] This is a cross-sectional view of the transmission to illustrate the position of the shaft, with (A) showing the low position, (B) the neutral position, and (C) the high position. [Figure 3] This is a magnified cross-sectional view of the main part of the transmission. [Figure 4] This is a cross-sectional view of a transmission that has been forcibly put into neutral. [Modes for carrying out the invention]

[0013] [1. Structure] Figure 1 is a block diagram illustrating the configuration of a transmission 1 according to an embodiment. The transmission 1 is a device for transmitting driving force to the drive wheels 3, and is, for example, a transfer case for distributing driving force to the front and rear wheels. The transmission 1 is installed in a vehicle that can switch between two-wheel drive (2WD) and four-wheel drive (4WD).

[0014] The transmission 1 incorporates a clutch 10 (HL clutch, high-low clutch) for changing the gear ratio (reduction ratio) of the driving force transmitted from the drive source 2 to the drive wheels 3, and a switching device (not shown) for changing the target of the driving force transmission to four wheels or two wheels. The drive source 2 is, for example, an internal combustion engine (gasoline engine, diesel engine) or an electric motor (motor, generator). The drive wheels 3 are the front and rear wheels in four-wheel drive mode, and either the front or rear wheels in two-wheel drive mode.

[0015] The clutch 10 is a meshing clutch having a low-side dog gear 11, a high-side dog gear 13, and a sleeve 16. The clutch 10 shown in Figure 1 is provided with a low gear 12 that is loosely mounted relative to the output shaft of the drive source 2, and a high gear 14 that is provided separately from the low gear 12 and is loosely mounted relative to the output shaft. The low-side dog gear 11 is loosely mounted relative to the output shaft of the drive source 2 in a state in which it can rotate together with the low gear 12. The high-side dog gear 13 is loosely mounted relative to the output shaft of the drive source 2 in a state in which it can rotate together with the high gear 14.

[0016] A hub 15 is fixed to the output shaft of the drive source 2. A sleeve 16, which has a cylindrical shape and splines on its inner surface, is attached to the outer surface of the hub 15. The sleeve 16 is slidable relative to the hub 15 in the direction of the output shaft of the drive source 2, and is provided to mesh with the low-side dog gear 11 and the high-side dog gear 13, respectively. By meshing the sleeve 16 with the low-side dog gear 11, the low gear 12 rotates integrally with the output shaft of the drive source 2. On the other hand, by meshing the sleeve 16 with the high-side dog gear 13, the high gear 14 rotates integrally with the output shaft of the drive source 2.

[0017] Inside the transmission 1, a shaft 4 is provided to control the meshing between the sleeve 16 and the low-side dog gear 11 and the high-side dog gear 13. The shaft 4 is formed, for example, in the shape of a cylinder or column and is arranged parallel to the output shaft of the drive source 2. A shift fork 17 that fits onto the outer circumference of the sleeve 16 is fixed to the shaft 4. As the shaft 4 moves in its axial direction C, the shift fork 17 drives the sleeve 16 in the output axial direction, changing the meshing between the sleeve 16 and the low-side dog gear 11 and the high-side dog gear 13.

[0018] The shaft 4 is built in and supported by the casing 5 of the transmission 1. The casing 5 has a shaft hole 6 that supports the shaft 4 slidably in its axial direction C. The shaft holes 6 are provided at positions corresponding to one end portion of the shaft 4 and positions corresponding to the other end portion of the shaft 4. The shaft hole 6 is formed in a hollow cylindrical shape so as to correspond to the outer peripheral cylindrical surface of the shaft 4. Each of one end portion and the other end portion of the shaft 4 is slidably supported by the shaft hole 6. The position of the shaft 4 in the axial direction C is controlled by an actuator (for example, an electric motor) not shown in the figure.

[0019] An end hole 7 is provided in the casing 5 near the end portion of the shaft 4. The end hole 7 is a through hole that communicates the outer surface of the casing 5 and the inside of the shaft hole 6. The end hole 7 of the present embodiment is a bolt hole (hollow cylindrical hole). The inner surface of the end hole 7 is cylindrical, and a thread groove is formed on the surface at a predetermined pitch. The end hole 7 is provided, for example, one by one near each of both end portions of the shaft 4 and is arranged coaxially with the shaft 4.

[0020] FIGS. 2(A) to (C) are cross-sectional views of the transmission 1 for explaining the position of the shaft 4. The shaft 4 is provided so as to be movable to a low position, a high position, and a neutral position. The low position is a position where the sleeve 16 meshes with the low-side dog gear 11 as shown in FIG. 2(A). The high position is a position where the sleeve 16 meshes with the high-side dog gear 13 as shown in FIG. 2(C). The neutral position is a position where the sleeve 16 does not mesh with either the low-side dog gear 11 or the high-side dog gear 13, and is, for example, an intermediate position between the low position and the high position, as shown in FIG. 2(B).

[0021] A closing member 8 for closing the end hole 7 is attached to the end hole 7. The closing member 8 of the present embodiment is a bolt or a flange bolt corresponding to the end hole 7 (bolt hole) and is fastened and fixed to the end hole 7. Further, a spacer 9 is interposed between the outer surface of the casing 5 and the closing member 8. The spacer 9 is fixed in a state of being sandwiched between the peripheral surface of the end hole 7 (bolt hole) and the head (bolt head) of the closing member 8.

[0022] As shown in FIGS. 2(A) to (C), the lengths of the blocking member 8 and the spacer 9 are set such that the tip of the blocking member 8 is always non-contact with the shaft 4 regardless of the position of the shaft 4. That is, in the mounted state of the spacer 9, the blocking member 8 does not interfere with the sliding operation of the shaft 4, and the lengths of the blocking member 8 and the spacer 9 are set so that the clutch 10 operates correctly.

[0023] As shown in FIG. 3, let the length of the spacer 9 (the length in the axial direction C) be the first dimension A. Also, let the dimension from the tip of the blocking member 8 (the end face on the shaft 4 side) attached to the end hole 7 through the spacer 9 to the end face of the shaft 4 in the neutral position be the second dimension B. In this embodiment, the first dimension A is set to be equal to or greater than the second dimension B. For example, when the spacer 9 is removed and the blocking member 8 is fastened to the end hole 7, the tip of the blocking member 8 abuts against the end face of the shaft 4 in the neutral position.

[0024] FIG. 4 is a cross-sectional view of the transmission 1 showing a state in which a pair of blocking members 8 abut against both end faces of the shaft 4 and the position of the shaft 4 is forcibly set to the neutral position. When the first dimension A and the second dimension B are the same, by removing the spacer 9 and fastening the blocking member 8 to the end hole 7, the tip of each blocking member 8 abuts against the end face of the shaft 4 in the neutral position. As a result, the position of the shaft 4 is physically fixed and the neutral position is reliably maintained.

[0025] Note that a washer may be interposed between the peripheral surface of the end hole 7 and the blocking member 8 to absorb some dimensional errors or to make the blocking member 8 less likely to loosen. Also, since there is a certain allowable width in the neutral position of the shaft 4, the first dimension A of the left and right spacers 9 and the second dimension B of the blocking member 8 may be set in consideration of that allowable width.

[0026] [2. Effect] (1) The transmission 1 of this embodiment comprises a clutch 10 having a low-side dog gear 11, a high-side dog gear 13, and a sleeve 16. The transmission 1 comprises a shaft 4 formed axially, a casing 5, an end hole 7, a closing member 8, and a spacer 9. A shift fork 17 that fits onto the outer circumference of the sleeve 16 is fixed to the shaft 4. The casing 5 has a shaft hole 6 that supports the shaft 4 so as to be slidable in the axial direction C. The end hole 7 is formed in the casing 5 near the end of the shaft 4 and connects the outer surface of the casing 5 to the inside of the shaft hole 6. The closing member 8 closes the end hole 7. The spacer 9 is interposed between the outer surface of the casing 5 and the closing member 8 and maintains the separation state between the closing member 8 and the shaft 4.

[0027] In this way, the spacer 9 maintains the separation between the blocking member 8 and the shaft 4, allowing the clutch 10 to operate correctly. Furthermore, by removing the spacer 9 and pushing the blocking member 8 into the end hole 7, the shaft 4 can be physically fixed in the neutral position. This allows the clutch 10 to be forcibly put into the neutral position, for example, in the event of a breakdown that prevents the vehicle from moving under its own power. Therefore, it becomes easier to have the vehicle towed by another vehicle, improving convenience.

[0028] (2) The shaft 4 in this embodiment is provided to be movable between a low position, a high position and a neutral position. The low position is the position in which the sleeve 16 engages with the low-side dog gear 11. The high position is the position in which the sleeve 16 engages with the high-side dog gear 13. The neutral position is the position in which the sleeve 16 does not engage with either the low-side dog gear 11 or the high-side dog gear 13.

[0029] Here, the length of the spacer 9 is denoted as the first dimension A. The distance from the tip of the closing member 8, which is attached to the end hole 7 via the spacer 9, to the end face of the shaft 4 in the neutral position is denoted as the second dimension B. The first dimension A is set to be greater than or equal to the second dimension B. As a result, by removing the spacer 9, the tip of the closing member 8 can be brought into contact with the end face of the shaft 4, and the shaft 4 can be held more reliably in the neutral position. Therefore, the clutch 10 can be forced into the neutral position, improving convenience.

[0030] (3) In this embodiment, the closing member 8, which is attached to the end hole 7 via the spacer 9, does not come into contact with the shaft 4 in the low position, the shaft 4 in the high position, or the shaft 4 in the neutral position. As a result, the closing member 8 does not obstruct the sliding motion of the shaft 4 when the spacer 9 is installed, and the clutch 10 can be operated correctly. On the other hand, when it is necessary to forcibly move the shaft 4 to the neutral position, it is only necessary to remove the spacer 9, thus improving convenience.

[0031] (4) The end hole 7 in this embodiment is a hollow cylindrical hole arranged coaxially with the shaft 4. As a result, the mounting direction of the closing member 8 attached to the end hole 7 is the same as the axial direction C of the shaft 4. Therefore, the movement of the shaft 4 in the axial direction C can be reliably restrained by the closing member 8, and the clutch 10 can be forced into a neutral state.

[0032] (5) In this embodiment, the closing member 8 is a bolt, and the end hole 7 is a bolt hole. This allows for a simple configuration and stable mounting of the closing member 8. It also has the advantage of being easy to attach, detach, and replace the closing member 8. Alternatively, a rivet may be used as the closing member 8 instead of a bolt, and a rivet hole may be used as the end hole 7 instead of a bolt hole.

[0033] (6) In this embodiment, the end holes 7 are provided near both ends of the shaft 4. In addition, one closing member 8 and one spacer 9 are provided at each end of the shaft 4, as a pair. This allows the shaft 4 to be clamped and fixed in the axial direction C by the closing member 8, and the shaft 4 can be held more reliably in the neutral position. Therefore, the clutch 10 can be forced into the neutral state, improving convenience.

[0034] [3. Others] In the above embodiment, one end hole 7, one closing member 8, and one spacer 9 are provided near each end of the shaft 4, but one end hole 7, one closing member 8, and one spacer 9 may be provided at one end of the shaft 4. Also, in the above embodiment, the end hole 7 is arranged coaxially with the shaft 4, but such arrangement is not a necessary element. At the very least, by interposing the spacer 9, which maintains the separation state between the closing member 8 and the shaft 4, between the outer surface of the casing 5 and the closing member 8, the movement of the shaft 4 can be physically fixed when the spacer 9 is removed, forcing it into a neutral position. [Industrial applicability]

[0035] This technology is applicable to the manufacturing industry of transmissions installed in vehicles, and to the manufacturing industry of vehicles to which transmissions are applied. [Explanation of symbols]

[0036] 1. Transmission 2. Power source 3 drive wheels 4 shafts 5. Casing 6 shaft holes 7 End hole 8. Closure member 9 Spacers 10 Clutch 11 Low-side dog gear 12 Low gear 13 High-side dog gear 14 High Gear 15 Hubs 16 sleeves 17 Shift fork A First dimension B Second dimension C-axis direction

Claims

1. A transmission comprising a clutch having a low-side dog gear, a high-side dog gear, and a sleeve, A shaft formed in an axial shape, to which a shift fork fitted to the outer circumference of the sleeve is fixed, A casing having a shaft hole that supports the shaft so as to be slidable in the axial direction, The casing has an end hole formed near the end of the shaft, which connects the outer surface of the casing with the inside of the shaft hole, A closing member that closes the end hole, A spacer is interposed between the outer surface and the closing member to maintain the separation state between the closing member and the shaft. A transmission characterized by being equipped with the following features.

2. The shaft is provided so as to be movable between a low position in which the sleeve engages with the low-side dog gear, a high position in which the sleeve engages with the high-side dog gear, and a neutral position in which the sleeve does not engage with either the low-side dog gear or the high-side dog gear. Let the length of the spacer be the first dimension, and let the distance from the tip of the closing member attached to the end hole via the spacer to the end face of the shaft in the neutral position be the second dimension, wherein the first dimension is greater than or equal to the second dimension. The transmission according to claim 1, characterized in that

3. The closing member, which is attached to the end hole via the spacer, is not in contact with the shaft in the low position, the shaft in the high position, or the shaft in the neutral position. The transmission according to claim 2, characterized in that

4. The end hole is a hollow cylindrical hole arranged coaxially with the shaft. The transmission according to claim 1, characterized in that

5. The aforementioned closing member is a bolt, The end hole is a bolt hole. The transmission according to claim 1, characterized in that

6. The end holes are provided near both ends of the shaft. A pair of the aforementioned closing member and the aforementioned spacer is provided. The transmission according to claim 1, characterized in that

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