Work vehicle

Abstract

To provide a working vehicle which drives rear wheels or the like with high energy efficiency, and suppresses breakage of a battery due to vibration occurring in a travel vehicle body in traveling.SOLUTION: In a working vehicle, a pair of left and right front wheels 2 are disposed in the front part of a travel vehicle body 1, a pair of left and right rear wheels 3 are disposed in the rear part of the travel vehicle body 1, and a bonnet part 5 formed with a predetermined space is disposed at the front side on the top face of the vehicle body 1. There are provided an electric motor 30 for driving the rear wheels 3, and a battery 50 in the bonnet part 5 for storing power to be supplied to the electric motor 30. A battery bracket 52 having a left longitudinal frame 52L and a right longitudinal frame 52R extending in a cross direction is fixed to the battery 50. A left support member 12L disposed in the left part of the travel vehicle body 1 and the left longitudinal frame 52L are connected via a left vibration-proofing member 53L, and a right support member 12R disposed in the right part of the travel vehicle body 1 and the right longitudinal frame 52R are connected via a right vibration-proofing member 53R.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a work vehicle that travels through parks and the like to cut grass and the like. [Background technology]

[0002] Conventionally, a known working vehicle has an engine mounted in the bonnet, and the output rotation of the engine is transmitted to rear wheels or a working machine such as a mower deck supported on the bottom of the working vehicle so as to be freely raised and lowered to drive the machine (Patent Document 1).

[0003] Also, a known working vehicle has a battery mounted at the rear of the vehicle, and the battery's power is supplied to an electric motor, and the output rotation of the electric motor is transmitted to the rear wheels or a working machine such as a mower deck supported at the front of the vehicle so that it can be raised and lowered to drive the vehicle (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-158907 A [Patent Document 2] JP 2020-156340 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the solution of Patent Document 1 has a risk of low energy efficiency because the transmission device that transmits the output rotation of the engine to the rear wheels and the working machine has a complex configuration and a large number of parts.

[0006] Furthermore, in the solution of Patent Document 2, there was a risk that the battery would be damaged by vibrations generated in the vehicle body while the vehicle was traveling.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a work vehicle that drives the rear wheels etc. with high energy efficiency and suppresses damage to the battery due to vibrations generated in the vehicle body while traveling. [Means for solving the problem]

[0008] The present invention which has solved the above problems is as follows. That is, the invention described in claim 1 provides a vehicle body (1) having a pair of left and right front wheels (2) at the front, a pair of left and right rear wheels (3) at the rear, a bonnet section (5) having a predetermined space formed in the front side of the upper surface of the vehicle body (1), and a control section (6) on which a driver sits at the rear of the bonnet section (5). 、 A working machine (4) for cutting grass such as grass is provided on the underside of the traveling vehicle body (1). In the work vehicle, an electric motor (30) for driving the rear wheel (3); a battery (50) for storing electricity to be supplied to the electric motor (30) is provided in the bonnet portion (5); A battery bracket (52) having a left front-rear frame (52L) and a right front-rear frame (52R) extending in the front-rear direction is fixed to the battery (50); a left support member (12L) provided on the left part of the traveling body (1) and the left front and rear frame (52L) are connected via a left vibration isolating member (53L); This is a work vehicle characterized in that a right support member (12R) provided on the right part of the traveling body (1) and the right front and rear frame (52R) are connected via a right vibration isolating member (53R).

[0009] The invention described in claim 2 is a work vehicle described in claim 1, in which, when viewed from the front, the connecting portion of the left support member (12L) and the connecting portion of the left front and rear frame (52L) are formed with an upward slope toward the left, and the connecting portion of the right support member (12R) and the connecting portion of the right front and rear frame (52R) are formed with an upward slope toward the right.

[0010] The invention described in claim 3 is a work vehicle described in claim 2, in which, when viewed from the front, the connecting portion of the left support member (12L) and the connecting portion of the left front and rear frame (52L) are formed perpendicular to a left imaginary line (55L) connecting the center of the left vibration-damping member (53L) and the center of the left front wheel (2L) of the front wheels (2), and the connecting portion of the right support member (12R) and the right front and rear frame (52R) are formed perpendicular to a right imaginary line (55R) passing through the center of the right vibration-damping member (53R) and the center of the right front wheel (2R) of the front wheels (2).

[0011] In the invention described in claim 4, when viewed from the side, the traveling vehicle body (1) is formed of a traveling vehicle body main body (10) extending in the front-rear direction and a steering post (11) extending in the up-down direction and supporting a steering shaft (63) of the operation unit (6), A buffer member (15) is provided at a lower portion of the front surface of the steering post (11) at a predetermined interval in the left-right direction, The work vehicle according to any one of claims 1 to 3, wherein a tip end of the buffer member (15) is pressed against a rear surface of the battery (50). Effect of the Invention

[0012] According to the invention described in claim 1, the rear wheels (3) are driven with high energy efficiency, and damage to the battery (50) caused by vibrations generated in the vehicle body (1) during driving can be suppressed. In addition, the space formed in the bonnet part (5) can be effectively utilized to prevent rainwater from splashing on the battery (50).

[0013] According to the invention recited in claim 2, in addition to the effect of the invention recited in claim 1, it is possible to further prevent damage to the battery (50) due to large lateral vibrations generated in the traveling vehicle body (1) during traveling.

[0014] According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, large vibrations caused by unevenness of the driving surface can be suppressed via the left front wheel (2L) and the right front wheel (2R), thereby further suppressing damage to the battery 50.

[0015] According to the invention recited in claim 4, in addition to the effect of the invention recited in any one of claims 1 to 3, it is possible to prevent the battery (50) from moving backward when the work vehicle starts moving, thereby suppressing the battery (50) from colliding with surrounding members and being damaged. [Brief description of the drawings]

[0016] [Figure 1] FIG. [Diagram 2] FIG. 2 is a left side view of the work vehicle with the bonnet cover in an open position. [Diagram 3] 1 is a perspective view of a main portion of a work vehicle with a part cut away. [Figure 4] FIG. [Diagram 5] FIG. 2 is a plan view of the rear wheels and essential parts of the working machine. [Figure 6] FIG. 4 is a left side view of the rear wheel and essential parts of the work machine. [Figure 7] FIG. 2 is a left side view of the electric motor for the rear wheels and the electric motor for the work machine. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 2 is a perspective view of a battery and a battery bracket. [Figure 11] FIG. [Figure 12] FIG. 2 is a front view of the front wheel, the battery, and the battery bracket. [Figure 13] FIG. 2 is a plan view of a main portion of the work vehicle with a part cut away. [Figure 14] FIG. [Figure 15] FIG. 2 is a perspective view of a housing of the inverter device. [Figure 16] FIG. 2 is a perspective view of a housing of the battery monitoring device. [Figure 17] FIG. 2 is a left side view of the brake pedal, the electric cylinder, and the drum brake. [Figure 18]FIG. 2 is a plan view of the brake pedal, the electric cylinder, and the drum brake. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] As shown in Fig. 1, a work vehicle such as a riding lawnmower has a traveling body 1, a pair of left and right front wheels 2 provided at the front of the traveling body 1, a pair of left and right rear wheels 3 provided at the rear of the traveling body 1, and a working machine 4 for cutting grass or the like provided between the front wheels 2 and the rear wheels 3 on the underside of the traveling body 1. In addition, a bonnet section 5 is provided at the front of the upper side of the traveling body 1, a control unit 6 on which a driver sits is provided behind the bonnet section 5, and a grass collection container 7 for storing grass cut by the control unit 4 is provided behind the control unit 6.

[0018] 2 and 3, a battery 50 that stores electricity to be supplied to the electric motor 30 that drives the rear wheels 3 and the like are provided in the bonnet section 5, and the battery 50 is covered by a bonnet cover 51. The bonnet cover 51 is supported by a support shaft (not shown) that is provided at the front of the traveling body 1 and extends in the left-right direction. This makes it possible to effectively utilize the space formed in the bonnet section 5, and also makes it possible to suppress differences in the weight balance in the front-rear direction of the work vehicle.

[0019] Electrical components 61 are provided below the pilot's seat 60 of the control section 6. This allows the space formed below the pilot's seat 60 to be utilized effectively.

[0020] As shown in Figures 4 to 7, an electric motor 30, such as a synchronous motor or induction motor operated with a three-phase AC voltage waveform for driving the rear wheels 3, is provided below the electrical components 61. An output shaft 30A formed to extend in the left-right direction of the electric motor 30 is connected to the upper part of a gear box 31 which reduces the speed of the output rotation transmitted from the output shaft 30A to increase the output torque or reverse the direction of rotation. The electric motor 30 is provided at a position offset to the left of the center in the left-right direction. Also, The output rotation accelerated or decelerated by the gear box 31 is transmitted to a drive shaft 33 extending in the left-right direction via a differential gear 32 formed by a differential gear or the like, which is provided at the bottom of the gear box 31. The output rotation transmitted to the drive shaft 33 is then transmitted to the rear wheels 3 supported at both ends of the drive shaft 33. As a result, An electric motor 40, such as a synchronous motor or an induction motor, is provided below the electric motor 30 and is operated by a three-phase AC voltage waveform to drive the working machine 4. An output shaft 40A extending in the front-rear direction of the electric motor 40 is connected to the rear of a universal joint 41 extending in the front-rear direction. The output shaft 40A is provided above the drive shaft 33 and perpendicular to the drive shaft 33. This allows the space formed below the electric motor 30 to be effectively utilized. In addition, the transmission path between the electric motor 40 and the working machine 4 can be shortened, so that the output rotation of the electric motor 40 can be efficiently transmitted to the working machine 4. The electric motor 40 is provided at a position offset to the left of the center in the left-right direction.

[0021] A front portion of the universal joint 41 is connected to a gear box 42 which reduces the speed of the output rotation transmitted from the universal joint 41 to increase the output torque. The output rotation transmitted to the gear box 42 is transmitted to a left cutting blade (not shown) provided in the left discharge passage 45L of the work machine 4 via an output shaft formed to extend in the vertical direction of the gear box 42.

[0022] A connecting member 43 extending in the left-right direction is connected to the left part of the gearbox 42, and a right part of the connecting member 43 is connected to the gearbox 44. The output rotation transmitted to the gearbox 44 is transmitted to a right cutting blade (not shown) provided in a right discharge passage 45R of the work machine 4 via an output shaft formed to extend in the up-down direction of the gearbox 44. The output rotation speeds of the output shafts of the gearbox 42 and gearbox 44 are the same but the rotation directions are opposite; that is, in a plan view, the output shaft of the gearbox 42 rotates clockwise and the output shaft of the gearbox 44 rotates counterclockwise.

[0023] The discharge outlets of the left discharge passage 45L and the right discharge passage 45R are connected to the inlet of a chute 46 that transports cut grass, etc. to the grass collection container 7. The discharge outlet of the chute 46 is connected to the inlet of the grass collection container 7.

[0024] In a plan view, the front part of the chute 46 is provided to the right of the universal joint 41, and the rear part of the chute 46 is provided to the right of the gear box 31, and in a rear view, the chute 46 and the grass collection container 7 are provided between the gear box 31 and the right rear wheel 3. This makes it possible to provide a large chute 46 in the space formed to the right of the universal joint 41 and the gear box 31, and allows grass and the like cut by the work machine 4 to be efficiently transported to the grass collection container 7.

[0025] In a side view, the upper wall of the chute 46 is formed with a rearward upward inclination, and the rear portion of the chute 46 is provided extending downward below the electrical components 61. This makes it possible to enlarge the rear portion of the chute 46 and prevent the inside of the chute 46 from becoming clogged with grass or the like.

[0026] As shown in FIGS. 8 and 9, the vehicle body 1 is formed of a vehicle body main body 10 that supports the front wheels 2 and the rear wheels 3, and a steering post 11 that supports the steering shaft 63.

[0027] The vehicle body 10 is formed with a left front-rear frame 10L and a right front-rear frame 10R extending in the front-rear direction, and the lower part of the steering post 11 is formed with a left connecting portion 11L and a right connecting portion 11R extending forward.

[0028] The left connecting portion 11L is fixed to the left front and rear frame 10L by fastening means such as bolts, and the right connecting portion 11R is fixed to the right front and rear frame 10R by fastening means such as bolts, thereby forming the traveling body 1 as one body.

[0029] A left support member 12L is provided at the front of the left front-rear frame 10L, and the connecting portion of the left support member 12L is formed with an upward incline to the left. A right support member 12R is provided at the front of the right front-rear frame 10R, and the connecting portion of the right support member 12R is formed with an upward incline to the right. The left support member 12L and the right support member 12R are made of channel steel.

[0030] A left support member 13L is provided in front of the left connecting portion 11L, and the connecting portion of the left support member 13L is formed with an upward incline to the left. A right support member 13R is provided in front of the right connecting portion 11R, and the connecting portion of the right support member 12R is formed with an upward incline to the right. The left support member 13L and the right support member 13R are made of channel steel.

[0031] A protrusion 14 is formed at the bottom of the steering post 11 so as to protrude forward at a predetermined interval in the left-right direction, and a buffer member 15 made of a rubber material or the like is provided at the tip of the protrusion 14.

[0032] As shown in Fig. 10, the lower part of the battery 50 provided inside the bonnet section 5 is fitted inside the inner periphery of the battery bracket 52. The battery 50 is formed by connecting multiple lithium ion batteries with high energy density in series and in parallel. This makes it possible to effectively utilize the space formed in the bonnet section 5. In addition, because the lithium ion battery has a high energy density, the work vehicle can travel long distances on a single full charge.

[0033] 11, the battery bracket 52 is formed of a left front-rear frame 52L and a right front-rear frame 52R extending in the front-rear direction, a front left-right frame 52A connecting the front portions of the left front-rear frame 52L and the right front-rear frame 52R, and a rear left-right frame 52B connecting the rear portions of the left front-rear frame 52L and the right front-rear frame 52R. The left front-rear frame 52L and the right front-rear frame 52R are formed of angle steel, and the front left-right frame 52A and the rear left-right frame 52B are formed of channel steel.

[0034] The connecting portion of the left front and rear frame 52L is inclined upward to the left, and the connecting portion of the right front and rear frame 52R is inclined upward to the left. In rear view, the connecting portion of the left support member 13L, the connecting portion of the left support member 12L, and the connecting portion of the left front and rear frame 52L are inclined upward to the left at the same inclination angle, and the connecting portion of the right support member 12R, the connecting portion of the right support member 12R, and the connecting portion of the right front and rear frame 52R are inclined upward to the right at the same inclination angle.

[0035] A circular left vibration-isolating member 53L is provided on the underside of the connecting portion of the left front-rear frame 52L at a predetermined interval in the front-rear direction, and a circular right vibration-isolating member 53R is provided on the underside of the connecting portion of the right front-rear frame 52R at a predetermined interval in the front-rear direction.

[0036] The left front and rear frame 52L is connected to the left support member 12L of the left front and rear frame 10L and the left support member 13L of the left connecting portion 11L via the left vibration isolating member 53L, and the right front and rear frame 52R is connected to the right support member 12R of the right front and rear frame 10R and the right support member 13R of the right connecting portion 11R via the right vibration isolating member 53R. This makes it possible to suppress the vibration of the traveling vehicle body 10 that occurs when the work vehicle is traveling from being transmitted to the battery 50, thereby preventing damage to the battery 50, etc.

[0037] As shown in FIG. 12, the connecting portion of the left front and rear frame 52L is provided perpendicular to a left imaginary line 55L connecting the center of the left vibration isolator 53L and the center of the left front wheel 2L on the left side. Also, the connecting portion of the right front and rear frame 52R is provided perpendicular to a right imaginary line 55R connecting the center of the right vibration isolator 53R and the center of the right front wheel 2R on the right side. This makes it possible to suppress large vibrations caused by unevenness of the running surface via the front wheels 2 and the rear wheels 3, and to prevent damage to the battery 50. Reference numeral 57 denotes a front wheel support frame that supports the left and right front wheels 2, and reference numeral 56 denotes a connecting portion between the front wheel support frame and the running vehicle body 10, and denotes a swing axis of the front wheel support frame.

[0038] Additionally, the tip of the buffer member 15 of the steering post 11 is pressed against the rear surfaces of the left and right rear frames 52B of the battery bracket 52. This makes it possible to restrict rearward movement of the battery 50 when the work vehicle starts moving, thereby preventing damage to the battery 50, etc.

[0039] As shown in FIGS. 2 and 3, a steering wheel 62 is provided in front of a pilot's seat 60 of the pilot's section 6, and the steering wheel 62 is supported on an upper portion of a steering shaft 63 that extends in the vertical direction.

[0040] A cleaner lever 65 for controlling the transport of grass clippings remaining inside the chute 46 to the grass collection container 7 at the rear is provided on the left fender 64L on the left side of the operator's seat 60, and an operation lever 66 for controlling the raising and lowering of the work implement 4 is provided on the right fender 64R of the operator's seat 60. A brake pedal 68 is provided on the left front part of the floor 67 on which the operator places his / her feet when operating the vehicle, and a forward accelerator pedal 75 and a reverse accelerator pedal 76 are provided side by side on the right front part.

[0041] As shown in Figures 13 and 14, the electrical components 61 provided under the cockpit 60 are composed of an inverter device 80 that converts the DC voltage supplied from the battery 50 into AC voltage and generates a three-phase AC voltage waveform for operating the electric motor 30, etc., a battery monitoring device 81 that monitors the temperature, charging state, voltage protection, and short-circuit state of each cell of the battery 50, an auxiliary battery 82 such as a lead-acid battery that stores electricity to be supplied to a meter panel (not shown) provided in front of the cockpit 60 that displays the driving speed, etc., and a converter device 83 that converts the DC voltage supplied from the battery 50 into a DC voltage to be supplied to a sensor that detects the operating position of the cleaner lever 65, etc.

[0042] The inverter device 80 is formed of an inverter device 84 that operates the electric motor 30 and an inverter device 85 that operates the electric motor 40. The inverter device 84 also functions as a charging device that charges the battery 50 with the power supplied from the electric motor 30 to the inverter device 80 when regenerative braking is activated, that is, when the forward accelerator pedal 75 or the reverse accelerator pedal 76 is released and the output shaft 30A rotates due to the inertial force of the traveling vehicle body 1, causing the electric motor 30 to operate as a generator.

[0043] In a plan view, an inverter device 80 is provided in the front below the driver's seat 60, and a battery monitoring device 81 is provided behind the inverter device 80. An auxiliary battery 82 is provided to the left of the inverter device 80, and a converter device 83 is provided to the left of the battery monitoring device 81 and behind the auxiliary battery 82. This makes it possible to effectively utilize the space formed below the driver's seat 60. Also, by providing the heavy battery monitoring device 81 at the rear, the difference in weight applied to the front and rear of the traveling vehicle body 10 can be suppressed, thereby improving traveling stability.

[0044] As shown in Fig. 15, circular grommets 86 are provided on the inner surfaces of the left and right walls of the housing 80A of the inverter device 80 at a predetermined interval in the front-rear direction. The housing 80A is connected to the left and right frames 16 extending in the left-right direction provided at the rear of the traveling vehicle body 10 via the grommets 86. This makes it possible to suppress the transmission of vibrations of the traveling vehicle body 10 generated when the work vehicle is traveling to the inverter device 80, thereby preventing damage to the inverter device 80. Furthermore, electric wires connecting the inverter device 80 and the electric motor 30 can be inserted into the hollow portion formed in the grommet 86 to facilitate the wiring of the electric wires.

[0045] As shown in Fig. 16, round grommets 87 are provided at a predetermined interval in the front-rear and left-right directions on the bottom wall of the housing 81A of the battery monitoring device 81. The housing 81A is connected to the support frame 18 connected to the left and right frames 17 provided on the rear side of the left and right frames 16 via the grommets 87. This makes it possible to suppress the vibration of the traveling vehicle body 10 generated when the work vehicle is traveling from being transmitted to the battery monitoring device 81, thereby preventing damage to the battery monitoring device 81. Furthermore, electric wires connecting the battery monitoring device 81 and the battery 50 can be inserted into the hollow portion formed in the grommet 87 to easily arrange the electric wires.

[0046] 17 and 18, the electric cylinder 70 and the brake 71 provided on the rear wheel 3 are connected by a rod 72 extending in the front-rear direction. The rod tip of the electric cylinder 70 and the rod 72 are connected by a connecting member 73.

[0047] When a brake switch (not shown) provided on the steering unit 6 is turned ON, the rod of the electric cylinder 70 contracts, moving the rod 72 forward to activate the brake 71 and stop the drive of the rear wheels 3. As a result, in the event of an emergency, the brake switch can be turned ON to drive the electric cylinder 70 and bring the work vehicle to an emergency stop.

[0048] When the brake switch is turned OFF, the rod of the electric cylinder 70 extends to move the rod 72 rearward, thereby stopping the operation of the brake 71 and allowing the rear wheels 3 to be driven.

[0049] The front part of the rod 72 is connected to the rear part of the brake pedal 68. When the brake pedal 68 is depressed, the brake pedal 68 rotates counterclockwise around a support shaft 68A extending in the left-right direction, and the rod 72 can be moved forward. This makes it possible to operate the brake 71 by depressing the brake pedal 68 even if the electric cylinder 70 malfunctions, thereby improving safety.

[0050] In addition, when the brake pedal 68 is released, a traction means 69 such as a spring provided at the bottom of the brake pedal 68 rotates the brake pedal 68 clockwise about the support shaft 68A, moving the rod 72 rearward to stop the operation of the brake 71 and drive the rear wheel 3. [Explanation of symbols]

[0051] 1 Running vehicle 2 Front wheels 2L left front wheel 2R Right front wheel 3 Rear wheel 4 Work equipment 5 Bonnet 6. Control Unit 10 Running vehicle body 11 Steering post 12L Left support member 12R Right support member 13L Left support member 13R Right support member 15 Cushioning material 30 Electric motor (1st electric motor) 40 Electric motor (second electric motor) 50 Battery 52 Battery bracket (bracket) 53L Left vibration isolation member 53R Right vibration isolation member 55L Left virtual line 55R Right virtual line

Claims

1. A pair of left and right front wheels (2) are provided at the front of a traveling vehicle body (1), and a pair of left and right rear wheels (3) are provided at the rear of the traveling vehicle body (1). A bonnet portion (5) with a predetermined space formed on the front side of the upper surface of the traveling vehicle body (1) is provided, and a control portion (6) for an operator to board is provided on the rear side of the bonnet portion (5). In a work vehicle provided with a working machine (4) for mowing grass such as turf on the lower surface of the traveling vehicle body (1), An electric motor (30) for driving the rear wheels (3) is provided. A battery (50) for storing electric power supplied to the electric motor (30) is provided in the bonnet portion (5). A battery bracket (52) having a left front and rear frame (52L) and a right front and rear frame (52R) extending in the front-rear direction is fixed to the battery (50). The left support member (12L) provided on the left portion of the traveling vehicle body (1) and the left front and rear frame (52L) are connected via a left vibration-proof member (53L). A work vehicle characterized in that the right support member (12R) provided on the right portion of the traveling vehicle body (1) and the right front and rear frame (52R) are connected via a right vibration-proof member (53R).

2. The work vehicle according to claim 1, wherein in a front view, a connecting portion of the left support member (12L) and a connecting portion of the left front and rear frame (52L) are formed to incline upward to the left, and a connecting portion of the right support member (12R) and a connecting portion of the right front and rear frame (52R) are formed to incline upward to the right.

3. The work vehicle according to claim 2, wherein in a front view, a connecting portion of the left support member (12L) and a connecting portion of the left front and rear frame (52L) are formed to be orthogonal to a left virtual line (55L) connecting the center of the left vibration-proof member (53L) and the center of the left front wheel (2L) of the front wheels (2), and a connecting portion of the right support member (12R) and a connecting portion of the right front and rear frame (52R) are formed to be orthogonal to a right virtual line (55R) passing through the center of the right vibration-proof member (53R) and the center of the right front wheel (2R) of the front wheels (2).

4. In a side view, the traveling vehicle body (1) is formed by a traveling vehicle body main body (10) extending in the front-rear direction and a steering post (11) extending in the vertical direction for supporting a steering shaft (63) of the control portion (6). Buffer members (15) are provided at a lower portion of the front surface of the steering post (11) at a predetermined interval in the left-right direction. The work vehicle according to any one of claims 1 to 3, wherein a tip end portion of the buffer member (15) is pressed against the rear surface of the battery (50).

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