Drive Unit

Abstract

To provide a drive unit capable of improving theft prevention of a vehicle by making it difficult to access a parking actuator from the outside using existing members without increasing the number of parts or manufacturing costs. [Solution] A drive unit 10 is provided with a drive unit that drives the drive wheels (front wheels) 2 of a vehicle 1 to rotate, and is configured by attaching a parking actuator 7, the drive of which is controlled by a control unit (ECU) 6 that receives a shift operation signal, to the outer surface of a housing 11 that houses a parking lock mechanism 20 that locks the rotation of the drive wheels 2. At least a portion of the parking actuator 7 is covered by a member 12 arranged on the outer side of the parking actuator 7 in the vehicle width direction. Here, the member 12 that covers at least a portion of the parking actuator 7 is one of a pair of left and right mounting brackets that are support members that support the housing 11 of the drive unit 10 on the vehicle body 1A.

Description

[Technical Field]

[0001] The present invention relates to a drive unit having a parking actuator mounted thereon, the drive of which is controlled by a control unit that receives a shift operation signal. [Background technology]

[0002] In recent years, particularly in electric vehicles (EVs), a drive unit called an eAxle has been adopted, which packages together the main components such as the electric motor, reducer, and inverter into a single unit, in order to save space, improve power efficiency, and reduce costs.

[0003] Vehicles also employ a shift-by-wire (SBW) system, which electrically detects shift operations using a shift lever or shift switch and switches the shift range using an electrically controllable actuator. This shift-by-wire system offers the advantage of allowing greater freedom in the operation method and placement of the shift operation unit. Vehicles employing this shift-by-wire system are equipped with a parking lock mechanism that mechanically locks the rotation of any rotating member in the power transmission path from the drive source to the drive wheels when the shift lever is switched to parking range ("P" range), thereby preventing the vehicle from moving.

[0004] The parking lock mechanism is provided with a parking actuator whose drive is controlled by a control unit that receives a shift operation signal. When the control unit receives a signal that the shift lever has been switched to parking range ("P" range), the control unit controls the drive of the parking actuator to lock the parking lock mechanism.

[0005] However, since the parking actuator is usually attached to the outer surface of the housing of the drive unit, it is possible that the parking actuator could be operated from the outside, releasing the locked state of the parking lock mechanism and making it possible to steal the vehicle.

[0006] Therefore, for example, Patent Document 1 proposes an anti-theft structure in which a cover member covering a parking actuator is composed of a metal cover portion and a resin cover portion, and an extension portion of the metal cover portion is directed toward the parking actuator.

[0007] Furthermore, Patent Document 2 proposes an anti-theft structure that enhances the vehicle's anti-theft capabilities by fixing a heat insulator with separate fastening bolts so as to cover a parking actuator fixed with multiple fastening bolts. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-092134 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-169208 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the anti-theft structures proposed in Patent Documents 1 and 2 require new parts, which increases the number of parts and increases the manufacturing costs of the new parts.

[0010] The present invention has been made in consideration of the above problems, and its purpose is to provide a drive unit that can improve the vehicle's anti-theft capabilities by making it difficult to access the parking actuator from outside using existing components without increasing the number of parts or manufacturing costs. [Means for solving the problem]

[0011] To solve the above-mentioned problems, the present invention provides a drive unit (10) comprising a housing (11) that houses a parking lock mechanism (20) that locks the rotation of the drive wheels (2) of a vehicle and a parking actuator (7) whose drive is controlled by a control unit (6) that receives a shift operation signal, the drive unit (10) being equipped with a drive unit that rotates the drive wheels (2) of the vehicle, and characterized in that at least a portion of the parking actuator (7) is covered by a member (12) that is arranged on the outer side of the parking actuator (7) in the vehicle width direction.

[0012] With this configuration, since at least a portion of the parking actuator is covered by a member disposed on the outer side of the parking actuator in the vehicle width direction, it becomes difficult to access the parking actuator from the outside, making it difficult to remove the parking actuator and release the parking lock state set by the parking lock mechanism. Therefore, it is possible to improve the theft prevention of the vehicle by using existing parts.

[0013] The member (12) may also be a support member that supports the housing (11) on the vehicle body (1A).

[0014] In addition, the parking actuator (7) may be attached to one of the left and right sides of the housing (11), and the support member (12) may be one of a pair of left and right mounting brackets that support both sides of the housing (11) relative to the vehicle body (1A).

[0015] According to these configurations, since the parking actuator is disposed on the outer side in the vehicle width direction and at least a portion of the parking actuator is covered by an existing support member, specifically, one of a pair of left and right mount brackets that support both sides of the housing on the vehicle body, it becomes difficult to access the parking actuator from the outside, making it difficult to remove the parking actuator and release the parking lock state set by the parking lock mechanism. Therefore, it is possible to improve the theft prevention of the vehicle by using existing parts.

[0016] In addition, the gap (δ3) in the vehicle width direction between the parking actuator (7) and the support member (12) may be set to be smaller than the engagement length (L) between the parking actuator (7) and the detent shaft (21) of the parking lock mechanism (20).

[0017] With this configuration, even if fasteners such as bolts that secure the parking actuator are removed from the outside, the gap between the parking actuator and the support member (mount bracket) is set smaller than the engagement length between the parking actuator and the detent shaft of the parking lock mechanism, making it impossible to completely remove the parking actuator. As a result, the detent shaft of the parking lock mechanism cannot be forcibly turned from the outside to release the locked state of the parking lock mechanism, improving the vehicle's theft prevention capabilities. [Effects of the Invention]

[0018] According to the drive unit of the present invention, it is possible to utilize existing components to make it difficult to access the parking actuator from outside, thereby improving the vehicle's anti-theft capabilities, without increasing the number of parts or manufacturing costs. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic plan view of an electric vehicle (EV) equipped with a drive unit according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. 2 is a partial perspective view of the drive unit as seen from diagonally front left. [Figure 4] FIG. 10 is a left side view of the mounting portion of the parking actuator of the drive unit. [Figure 5] FIG. 2 is a partial cutaway rear view showing the engagement length of the detent shaft of the parking lock device with the parking actuator. [Figure 6] FIG. 10 is a partial bottom view showing the gap between the mounting bracket and the ECH (electric water heater) in the drive unit. [Figure 7] FIG. 2 is a perspective view of a parking lock mechanism. [Figure 8] 1 is a partial cross-sectional side view showing the parking lock mechanism in an unlocked state. [Figure 9] FIG. 4 is a partial cross-sectional side view showing the locked state of the parking lock mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0021] [Overall vehicle configuration] First, the overall configuration of a vehicle equipped with a drive device unit according to one embodiment of the present invention will be described with reference to Fig. 1. The vehicle 1 shown in Fig. 1 is an electric vehicle (EV) that runs using an electric motor (not shown) as a drive source, and employs a front-wheel drive (FF) drive system. Note that, hereinafter, the directions of the arrows shown in Fig. 1 represent the "front-rear" and "left-right" directions of the vehicle 1, respectively.

[0022] The vehicle 1 has a body 1A that is supported for running by a pair of left and right front wheels 2, which are both drive and steerable wheels, and a pair of left and right rear wheels 3. A drive unit 10 according to the present invention is disposed at the front of the body 1A, and the drive force output from the drive unit 10 drives the pair of left and right front wheels 2 to rotate, thereby causing the vehicle 1 to run on the road.

[0023] As shown in FIG. 2, the drive unit 10 includes a housing 11 arranged along the vehicle width direction. The housing 11 houses major components (none of which are shown) such as an electric motor serving as a drive source, an automatic transmission, and an inverter. The drive unit 10 is attached to the vehicle body 1A at its left and right lower portions by a pair of left and right mount brackets 12, which are support members arranged vertically on the outer width sides of the housing 11. More specifically, although not shown, both left and right ends of a motor frame arranged horizontally along the vehicle width direction above the drive unit 10 are attached to the vehicle body 1A, and the upper ends of the pair of left and right mount brackets 12 are attached to the vehicle body 1A via mounts (not shown). Therefore, the drive unit 10 is attached to the vehicle body 1A at its left and right portions by the pair of left and right mount brackets 12, the motor frame (not shown), and the mounts.

[0024] As shown in Figure 2, a pair of left and right output shafts (front axles) 13 extend left and right from the lower left and right sides of the housing 11 of the drive unit unit 10, and a pair of left and right front wheels 2 (drive wheels) shown in Figure 1 are attached to the vehicle width direction ends of each output shaft 13.

[0025] As shown in FIG. 1, the housing 11 of the drive unit 10 incorporates a parking lock mechanism 20 that prevents the vehicle 1 from moving when parked. The parking lock mechanism 20 uses a shift-by-wire (SBW) system to lock or unlock the rotation of a rotating member (in this embodiment, a lock gear 25 (see FIGS. 7 to 9)) provided in a power transmission path from the drive unit 10 to the left and right front wheels 2, thereby preventing or allowing the vehicle 1 to move. More specifically, when a range detection sensor 5 detects a shift operation by the driver using the shift lever 4 and sends a detection signal to an ECU (Electronic Control Unit) 6, which is a control unit, the ECU 6 drives and controls a parking actuator 7 attached to the outer surface of a side wall of the housing 11 of the drive unit 10. The parking actuator 7 operates the parking lock mechanism 20 to prevent or allow the rotation of the pair of left and right front wheels 2, which are drive wheels.

[0026] The ECU 6 includes a CPU (Central Processing Unit) that performs arithmetic processing according to a control program, memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), an input interface including an A / D converter, an output interface including a relay circuit, and a communication interface (none of which are shown) that communicates with the ECU 6. In this embodiment, shift operations, such as shifting to the parking range ("P" range), neutral range ("N" range), forward (drive) range ("D" range), and reverse range ("R" range), are performed using the shift lever 4, but they may also be performed using a shift switch (not shown) in addition to the shift lever 4.

[0027] 2 to 5, the parking actuator 7, which operates upon receiving a shift operation signal from the ECU 6, is attached to the outer surface of the left side wall of the housing 11 of the drive unit 10 with three bolts 8 (see FIG. 4). The parking actuator 7 attached to the outer surface of the left side wall of the housing 11 of the drive unit 10 is located inside the width direction of the left mounting bracket 12, that is, between the housing 11 and the left mounting bracket 12 in the vehicle width direction (left-right direction), and a portion of the parking actuator 7 is covered by the mounting bracket 12. As shown in FIG. 4, each of the pair of left and right mounting brackets 12 (only one is shown in FIG. 5) has a truss structure, and multiple locations (four locations in the illustrated example) of the mounting brackets 12 are attached to the outer surface of the left side wall of the housing 11 of the drive unit 10 with bolts 15.

[0028] 2 and 3, an electric water heater (hereinafter referred to as "ECH (Electric Coolant Heater)") 14 is attached to the left side wall of the housing 11 of the drive unit unit 10. Here, the ECH 14 is disposed on the outer side of the left mounting bracket 12 in the vehicle width direction, and as shown in FIG. 6, a gap of δ1 (δ1 = 5 mm in this embodiment) is formed between the ECH 14 and the left mounting bracket 12 in the vehicle width direction, and a gap of δ2 (δ2 = 20 mm in this embodiment) is formed between the mounting bracket 12 and the housing 11 in the vehicle width direction.

[0029] [Parking lock mechanism configuration and operation] Next, the configuration and operation of the parking lock mechanism 20 will be described with reference to FIGS.

[0030] The parking actuator 7 rotates a rotatable detent shaft 21, which is arranged horizontally along the vehicle width direction, forward and reverse by a predetermined angle, and is equipped with an electric motor such as a stepping motor or a servo motor and a reducer (neither of which are shown). A fan-shaped detent plate 22 is attached to the detent shaft 21, and two engagement grooves 22a are formed on the outer periphery of the detent plate 22.

[0031] Also, as shown in Figures 8 and 9, a leaf spring-shaped locking plate 23 is attached by two bolts 24 to a boss portion 11a protruding from the inner wall of a cover 11B that covers the upper part of the main body portion 11A of the housing 11 of the drive unit unit 10, and an engagement portion 23a is formed at the tip of this locking plate 23 extending toward the detent plate 22, which selectively engages with either of the two engagement grooves 22a of the detent plate 22 to restrict the rotation of the detent plate 22.

[0032] An output shaft 13 that rotates the front wheels 2 (see FIG. 1) is disposed parallel to the detent shaft 21 and along the vehicle width direction below the detent shaft 21, and a lock gear 25 is attached to the output shaft 13. Four engagement grooves 25a are formed on the outer periphery of the lock gear 25 at equal angular intervals (90° intervals) in the circumferential direction.

[0033] Furthermore, a support shaft 26 is disposed horizontally in the vehicle width direction, parallel to the output shaft 13, at an obliquely forward upper portion of the output shaft 13. The base end of an arm-shaped parking pole 27 is rotatably inserted and supported by the support shaft 26. An engagement protrusion 27a protrudes downward integrally from a longitudinal intermediate portion of the parking pole 27. The engagement protrusion 27a selectively engages with one of four engagement grooves 25a formed in the lock gear 25. A coil-shaped return spring 28 is wound around the support shaft 26. One end of the return spring 28 is engaged with the base end of the parking pole 27, and the other end is engaged with the inner wall of the housing 11, as shown in FIGS. 8 and 9. Therefore, the parking pole 27 is biased in a direction (the direction of arrow a in FIG. 7) in which the engagement protrusion 27a formed on the parking pole 27 engages with the engagement groove 25a formed in the lock gear 25.

[0034] The tip of the parking pole 27 and the detent plate 22 are connected to each other by a parking rod 29. That is, the upper end of the parking rod 29 is connected to the tip of an arm portion 22A formed integrally with the detent plate 22 by a pin 30, and the lower end of the parking rod 29 is connected to the tip of the parking pole 27 by a pin 31 inserted into an arc-shaped elongated hole 27b formed in the tip of the parking pole 27.

[0035] Next, the operation of the parking lock mechanism 20 configured as above will be described.

[0036] When the shift lever 4 shown in FIG. 1 is in a range ("N," "D," or "R") other than the parking range ("P" range), ECU 6 receives a shift operation signal detected by range detection sensor 5. This ECU 6 controls and drives the parking actuator 7 to rotate the detent shaft 21 shown in FIGS. 7 to 9 in the direction of arrow a by a predetermined angle. This causes the detent plate 22 connected to the detent shaft 21 to rotate in the same direction, pushing the parking rod 29 upward in the direction of arrow a. This causes the parking pole 27 to rotate around the support shaft 26 in the direction of arrow a. As a result, as shown in FIG. 8, the engaging projection 27a formed on the parking pole 27 disengages from the engaging groove 25a of the lock gear 25, resulting in a disengaged state. This allows the lock gear 25, the output shaft 13 connecting the lock gear 25, and the front wheels 2 (see FIG. 1) attached to the output shaft 13 to rotate freely. This allows the vehicle 1 shown in FIG. 1 to be driven in a parking unlocked state.

[0037] On the other hand, when the driver switches the shift lever 4 shown in FIG. 1 to the parking range ("P" range) from the parking lock release (unlocked) state and the ECU 6 receives a shift operation signal detected by the range detection sensor 5, the ECU 6 controls the parking actuator 7 to rotate the detent shaft 21 in the direction of arrow b by a predetermined angle, as shown in FIGS. 7 and 9. This causes the detent plate 22 connected to the detent shaft 21 to rotate in the same direction, pushing the parking rod 29 downward in the direction of arrow b, causing the parking pole 27 to rotate around the support shaft 26 in the direction of arrow b. As a result, as shown in FIGS. 7 and 9, the engaging protrusion 27a formed on the parking pole 27 engages with one of the engaging grooves 25a of the lock gear 25, thereby locking the rotation of the lock gear 25, the output shaft 13 connecting the lock gear 25, and the front wheels 2 (see FIG. 1) attached to the output shaft 13. This places the vehicle 1 shown in FIG. 1 in a parking state and prevents it from moving.

[0038] [Vehicle theft prevention structure] Next, the vehicle theft prevention structure provided in the drive unit 10 of this embodiment and its effects will be described.

[0039] In the drive unit 10 of this embodiment, in order to improve vehicle theft prevention, as described above, a portion of the parking actuator 7 attached to the outer surface of the left wall of the housing 11 of the drive unit 10 by three bolts 8 is covered by one (left side) existing mounting bracket 12 arranged outside the parking actuator 7 in the vehicle width direction, making it difficult to access the parking actuator 7 from outside.

[0040] In this embodiment, as described above (see FIG. 6 ), the ECH 14 is positioned on the outside of the left-side mounting bracket 12 in the vehicle width direction, and a gap of δ1 in the vehicle width direction is formed between the ECH 14 and the mounting bracket 12 (δ1=5 mm in this embodiment), and a gap of δ2 in the vehicle width direction is formed between the mounting bracket 12 and the housing 11 (δ2=20 mm in this embodiment). However, it is difficult to insert one's hand through these gaps δ1 and δ2 to access the parking actuator 7, and it is extremely difficult to loosen the bolts 8 that attach the parking actuator 7 and remove the parking actuator 7 from the housing 11 of the drive unit unit 10.

[0041] Moreover, in this embodiment, as shown in FIG. 5, the gap δ3 (δ3 = 8.4 mm in this embodiment) in the vehicle width direction between the parking actuator 7 and the mount bracket 12 is set smaller than the fitting length L (L = 12.7 mm in this embodiment) between the parking actuator 7 and the detent shaft 21 of the parking lock mechanism 20 (δ3 < L). Therefore, even if the three bolts 8 are removed and an attempt is made to remove the parking actuator 7 from the housing 11, as shown by the dashed line in FIG. 5, the parking actuator 7 can only move in the vehicle width direction by the gap δ3. For this reason, even in this state, the parking actuator 7 continues to fit to the detent shaft 21 of the parking lock mechanism 20 by the length ΔL shown by the following formula.

[0042] ΔL = L - δ3 = 12.7 mm - 8.4 mm = 4.3 mm

[0043] Therefore, even if access is made to the parking actuator 7 from the outside and the three bolts 8 are removed, the parking actuator 7 cannot be completely removed from the housing 11, and the detent shaft 21 of the parking lock mechanism 20 is not exposed to the outside. For this reason, it is impossible to forcibly rotate the detent shaft 21 in the direction of arrow a in FIG. 7 to release (unlock) the locked state of the parking lock mechanism 20, and it is impossible to move the vehicle 1 shown in FIG. 1. Therefore, the anti-theft performance of the vehicle 1 is enhanced.

[0044] And in this embodiment, since the above effect is obtained by using the existing mount bracket 12 without adding new parts, an increase in the number of parts and the manufacturing cost is not caused.

[0045] As is clear from the above explanation, the drive unit 10 of this embodiment has the effect of making it difficult to access the parking actuator 7 from the outside by utilizing the mount bracket 12, which is an existing part, without increasing the number of parts or manufacturing costs, thereby improving the theft prevention properties of the vehicle 1.

[0046] The present invention is not limited to the application of the above-described embodiment, and various modifications are possible within the scope of the claims and the technical ideas described in the specification and drawings.

[0047] For example, in the above embodiment, the present invention has been described as being applied to a drive unit mounted on a front-wheel drive (FF) electric vehicle (EV), but the present invention can also be applied to a rear-wheel drive (FR) electric vehicle, or a hybrid vehicle (EHV) that runs using an electric motor and engine as a drive source regardless of the drive system, or a drive unit mounted on a vehicle that uses only an engine as a drive source, and in such cases, the same effects as those described above can be obtained. [Explanation of symbols]

[0048] 1 vehicle 1A Body 2 Front wheels (drive wheels) 3 rear wheels 4 Shift lever 5 Range detection sensor 6 Control unit (ECU) 7 Parking Actuator 8 volts 10 Drive unit 11. Housing 12 Mounting bracket (supporting member) 14 Electric water heater (ECH) 20 Parking lock mechanism 21 Detent shaft L Engagement length between parking actuator and detent shaft δ1 Gap between ECH and mounting bracket in the vehicle width direction δ2 Gap between the mount bracket and the housing in the vehicle width direction δ3 Gap between the parking actuator and the mounting bracket in the vehicle width direction

Claims

1. A drive unit unit is provided with a drive unit that rotates drive wheels of a vehicle, and is configured by attaching a parking actuator whose drive is controlled by a control unit that receives a shift operation signal to an outer surface of a housing that accommodates a parking lock mechanism that locks the rotation of the drive wheels, A drive unit characterized in that at least a portion of the parking actuator is covered by a mount bracket arranged on the vehicle width outer side of the parking actuator and serving as a support member for supporting the housing relative to the vehicle body.

2. The parking actuator is attached to one of the left and right sides of the housing, 2. The drive unit according to claim 1, wherein the support member is one of a pair of left and right mount brackets that support both sides of the housing on the vehicle body.

3. The drive unit according to claim 1 or 2, characterized in that the vehicle width direction gap between the parking actuator and the support member is set to be smaller than the engagement length between the parking actuator and the detent shaft of the parking lock mechanism.

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